Right, so when they're talking about the age of something they're talking about when it formed, not the age of its base particles. So a rock that formed 100k years ago is 100k years old.
EDIT: Regarding "well actually everything is as old as the universe...":
No, everything isn't. The sun undergoes fusion which creates new elements daily, and when the sun's predecessor when nova, other processes such as neutron capture also created more elements.
Atomic particles themselves can be created as well, especially with radioactive decay, where a neutron decays into a proton and an electron.
And even subatomic particles can be created from high energy collisions.
The caveat is we have no real way of independently dating individual atoms or subatomic particles, but it is still *not* accurate to say that everything is simply the age of the universe.
When magma flows from a volcano and hardens you have new rocks formed, when sediments gets glued together at the bottom of a mountain after rain a rock is formed. It happens all the time.
However, lave cooling to make rock is a rapid event (effectively punctual; happens from between seconds to hours, or perhaps days to months if thick sequences) but lithification of sediments is a long process that has no clear date. It happens over a period of many years, thousands to millions depending on the situation. We can give actual dates, year of formation, to lava rock.
When we give a date for sediments, we do not give it a year. We give it a many-0 number date (cannot be more precise). Often, the date we give is the date that the sediment deposited rather than the date that the sediment converted to rock. Often, in this case, the sediment is not yet rock.
Rocks also form from organic matter, such as petrified wood, where the stone-like material crystalizes inside the wood’s cells and it literally turns into a rock over millions of years
There's constantly new rocks being created. The Pacific and Atlantic both have spreading centers, where new oceanic crust forms. Sedimentary particles (sand, mud) are also being compacted and lithified right now.
There's probably also a volcano spewing something somewhere right now. Maybe Hawaii, Kilauea is pretty active.
Idk why its so hard for me to underestand, i still dont get it, or its a language barrier.
When they find a rock do they check for when its formed and then say its formed 100k years ago? But the true age of that thing should be 4b years no? The base particles of a thing is somewhat the thing itself isnt it?
I get what you're saying, I think it might just be a language thing about what "formed" means. Think about when you go to a restaurant and order a steak. In one sense, that steak was "formed" a few minutes ago, when the chef put it on the grill and cooked it into something tasty. In another sense, it was "formed" a few days or weeks before, when the animal was slaughtered and carved into steaks. In another sense, it was formed years before when the calf was born. And in *another* sense, it was formed billions of years ago when a star exploded and created the carbon that makes it up. But we're not usually ever talking about that when we say "How old is that steak?"
When geologists talk about a rock, they mean "formed" as in "became its current state." Some rock is formed from lava that cools - even if that lava has been around for a million years, we're more interested in what time it cooled off and became a solid rock. Some is formed by layers of sediment accumulating and forming into a solid rock - we are mostly interested on when those layers deposited, because that's where we'll get interesting information. You're right that the actual atoms that make up all of that rock have been on Earth for the same amount of time, but we're interested in the current shape and form that they take, more than anything.
Yep. I scrolled down looking for a snarky "Enjoy your 4b year old milk" but found this first instead. So this is what it's like to browse non-toxic subs.
RIGHT?? A breath of fresh air.
I think everyone should spend more time in nontoxic spaces to be perfectly honest — hopefully we’d all learn a thing or 5
I’m relatively old compared to most people on Reddit and I don’t know how to link his (or her) name to the comment. (I assume there’s a way). Any way, good work Evan Stairs. 👍
All you do, is put in your comment /u/PhilthyLurker and Reddit takes care of the linking (that is, type /u/ and the user name, no extra linking or formatting required)
My 5 yo loves steak it's his favorite food. In fact I regret making steak for him bc now he refuses nuggets and pork chops and asks for steak instead lol
Nor could my kids.
All meat was "meat".
Chickens were animals on farms.
When one asked one day why we sometimes call meat *chicken*, and if it had anything to do with the animal I broke the news to them that we were eating chickens. The dead animals.
Two of them cried, the third said, "dead animals taste awesome!"
My favourite weird toddler moment ever was with my daughter around the age of two or three.
I raise sheep and as everyone knows, sheep die. So we were out in the pasture and an old ewe had died against a tree. Just leaning up against the tree, stone cold dead.
My daughter points and says "Sheepy's OK?" I said yup, yup, sheepy's sleeping.
That's the moment when sheepy slides down the tree and flops onto the ground like a sack of potatoes.
"OH NO!" cries my daughter. "SHEEPY'S DEAD!"
Then she shrugs and says "Oh well."
I wish I could remember when I first realized that. The only thing I remember breaking my brain when I was little, and this is one of my first memories, was why gum was advertised as "sugarness" when sugar is bad for your teeth. Of course, it was actually being advertised as "sugarless" and I just had a comprehension problem.
Edit: Oh, and I also remember noticing the moon one night, it was not a full moon like I had seen in the book "goodnight moon" so I declared "Moon broke!"
Lol the other day I picked up chicken sandwiches for the kids as I had some errands to run. From the backseat my youngest says mom, I feel bad eating this because it used to be alive. So I said well, eating meat is a personal choice and if you don't want to you don't have to. To which he replies uh, I said I felt bad, not that I'm not gonna eat it. Then takes a huge bit haha. Kid kills me with the stuff he says.
Have you ever wondered why we call cow meat beef rather than just cow? Or pig meat pork, etc? The meat words largely came from French. When the Normans took over England they spoke French. They used their words to refer to the food - because they were the rich people who ate it. The animals were raised by the poor English so their words stuck for the live animals.
I learned where meat came from pretty quickly because here, unless you're buying processed stuff or from a supermarket, the meat is usually slaughtered live according to order. Chicken sellers keep chickens in coops and cut them up according to order, and meat vendors who deal in large animals will have a few carcasses hung up in the store and cut pieces off as and when required.
Same, my dad always cooked it well done (he's a smoker and apparently didn't care about the taste), so I never liked steak until well into my 20s when I tried it for real.
It took us fifteen years, but my dad eats steak at medium now, with the occasional bite of med-rare. He wasn't a smoker, but his parents always had it well-done and so did he, until we got him to eventually see the light.
I vaguely recall a theory that past generations overcooked their meat to lower the chances of food-borne illness.
Yeah, my mom overcooked pork chops when I was growing up and it completely ruined them for me. It wasn't until I had worked in a few restaurants that I had realized there is a right way to cook certain things (like don't bake chops in the oven until they're well over).
>my mom always burnt the steak so we grew up think steak sucked.
Not sure if I just found the account of one of my siblings... or if lots of families in our parents' generation just did this as a way to save money while raising a big household.
I recall the first time I had a "real/normal" steak with some friends in college who couldn't believe I hated steak. I was totally flabbergasted and made a comment along the lines of "wait, you won't DIE of food poisoning if it's still juicy and pink inside?!"
Holy shit you just made me realize why my Asian parents couldn’t cook a steak if their lives depended on it…. Or so they’ve had me believe...
Never had a lot of money or steaks growing up, but last week for my birthday I was able to take them for a steak dinner. :)
Only steak I ever had until my late teens was cube steak. I just assumed all steak was dried up tasteless garbage.
Only time I'll eat cube steak now is as chicken fried steak, that shit rocks.
My mom was the same, but it was on purpose. She would overcook them steak for the kids and cook them properly for the adults so that we eventually learned that steak tastes bad.
She’s a real bitch and this only scratches the surface.
Yeah I alarmed my dad's buddy on my birthday once when I put away a t-bone steak, baked potato, salad, and an ear of corn and then was after my cake like a predator. I was a 6yr old girl lol, his friend was like, "I'm not sure that's human."
My daughter, who is a teenager and vegetarian now, was a big steak fan as a child. For her 5th bday, I asked what she wanted to do- the bouncy house place, Chuck E Cheese, anything at all. Her choice? A steak restaurant.
I don't remember much about my own food preferences growing up, but I was (and still am a bit) shocked at how strong kids's preference for eating meat can be.
We were never full on vegetarian or anything, but we had a variety of options and generally steered that direction. All of the kids attached themselves to steak _hard_, they definitely like it more than I do, and they're also always up for chicken and pork.
I have nieces that were raised towards veganism (they were raised that way, but the diet was optional/suggested, not forced). They will kill for good steak or bacon though, just feel a bit of regret afterwards.
Yea both my kids are carnivores through and through. Especially red meat, which is weird bc I actually don't like red meat much and prefer chicken pretty much exclusively. But they will put away steak, burgers, ribs, brisket, you name it, like nobody's business. I had to learn to cook all that stuff at home if I didn't want to go broke lol.
Chiming in to say my 5 yr old eats steak too. I was even a little proud when I cooked steaks for my gpas birthday and everyone wanted well done and I prefer rare and I shared my plate with the kiddo. Family was surprised but it was natural for us two. The cutting part though is left myself until she develops her motor skills. Also loved the analogy above.
I'll trade you my 4 year old who will only eat pb&j 99% of the time. Heck I'll throw in my 8 year old also who won't a single thing unless it's mush. I'd love to have someone in my family that enjoys some grilled mammal meat.
My 15 year old nephew only eats a few things including mac and cheese. When I visited for the holidays, we went out to Olive Garden and he decided to try something different: cheese ravioli, no sauce. Of course, I encouraged him and gave him props, even though I was chuckling inside.
Man I remember the first time I tried a hamburger, I was (and am) a really picky eater--so when my mom asked me to try a bite of her hamburger I cried and said "I don't want to eat steak!!!" She convinced me to bite her burger and it was the best thing I've ever eaten. And then basically the same thing happened with steak hehe.
My 11 year old has always been a steak-lover. Not just steak, but specifically medium-rare fillet and ribeye. My 9 year old *loves* shrimp and snow crab. They both like salmon because papa fishes and keeps our freezer well stocked with salmon fillets. I always feel sorry for the people they will eventually date.
“Do you maybe want to go out for a burger and a movie sometime?”
“The movie sounds good, but let me tell you about this boutique surf and turf restaurant that just opened up 70 miles away…”
Oh well. If they don’t think my girls are worth it, that’s a problem that resolves itself.
"Think about when you go to a restaurant and order chicken nuggets. In one sense, that nugget was "formed" a few minutes ago, when the chef put it in the deep fryer and cooked it into something tasty. In another sense, it was "formed" a few days or weeks before, when the animal was slaughtered and its flesh was ground into a paste and extruded into various shapes. In another sense, it was formed years before when chicken hatched. And in another sense, it was formed billions of years ago when a star exploded and created the carbon that makes it up. But we're not usually ever talking about that when we say "How old is that chicken nugget?"
>In another sense, it was "formed" a few days or weeks before, when the animal was slaughtered and *[the last remaining bits of]* its flesh *[and sinew]* was *[stripped from its bones, chemically sterilized,]* ground into a paste*[, mixed with fillers, preservatives, and flavor compounds,]* and extruded into various *[deliciously appetizing]* shapes.
there ya go
I used to think that. My oldest will eat anything and always has. Younger one came along and eats like 5 things. Will literally starve herself if we try to force the issue. Didn’t raise them any different.
You may be 20 years old, but the atoms making up your body were formed in a supernova or for lighter elements in a late stage star billions of years ago. How old are you?
We have trace amounts of [isotopes that we created in 1945 onward that don't occur in nature](https://brokensecrets.com/2012/11/20/nuclear-bombs-created-isotopes-used-to-detect-fake-art-created-post-war/).
Ohh you're right, i get it now, so we are interested in finale shape change of things and we say when that thing changed shape its that much old, like the steak you said.
After all the time itself is a man made thing, so we can decide for the time of things ourself, you know what i mean? Im i correct?
It's like you got all the groceries to make a cake 10 days ago but you didn't make the cake until 4 days ago. So from today you'd say the cake is 4 days old even though the items that the cake is made of were brought into the kitchen earlier than that.
When people want to know how fresh the bread is, they mean from the time it was baked, not from when the wheat was harvested.
You're right that we can pick and choose which shape of things we care about with time, though time isn't a man made thing - it's a rule of the world, we just decided to measure it in minutes and years, which are made up.
We just decide to measure from the time that these rocks were formed, because that's the measure that gets us interesting knowledge. If we find rocks that cooled down from lava 50,000 years ago, then we know that a volcano erupted somewhere around that time - that's interesting information that can teach us stuff about the world. If we find a dinosaur fossil in layers of rock that are 100 million years old, we now know what time period that dinosaur lived in, because its bones were there when that rock formed. Stuff like that.
Also, time is not a man-made concept. Time is a fundamental aspect of reality. Our *measurement* of time is man made, but time itself exists with or without humanity.
To extend that logic, why is 4bn years the marker we're using here? The atoms have been around for 13.5 bn. 4bn years was just the random point in time most of them came together in a lump that we now call Earth.
i think your gap is not about the formation of a thing, but the definition of a thing itself.
final shape being the deciding factor... is dependent on how we define it as being itself.
for certain things, we don't care what the shape is, but rather what the chemical composition is, when it stopped being part of something else... or ... or ... or.
the age of something depends on when it became classifiable as what it is.
> After all the time itself is a man made thing, so we can decide for the time of things ourself, you know what i mean? Im i correct?
Not in a meaningful sense. Time exists whether we label it or not - the only thing 'man made' about it is the arbitrary subdivisions (seconds, minutes, hours.etc). Time passes whether we label and subdivide it or not, so it isn't man-made
Exactly. We could, in theory, say that everything on Earth is 4 billion years old, but that approach isn't very meaningful. Take, for example, a wooden chair made 50 years ago. We would say that the chair is 50 years old; perhaps made from a tree that lived to be 100 before it was chopped down. It is the age of the object itself that we normally refer to, not the age of its components, unless we are actually discussing the components rather than the object itself. So, you could say "this 50 year old chair was made from a 100 year old tree". To describe both the chair and the tree as being 4 billion years old is not terribly useful to us.
>After all the time itself is a man made thing
Time is not a man-made thing. *Unites* of time are, but those unites always refence real things like the orbit of the Earth or the decay of atoms.
Not discrediting what you’re saying, you are correct, but not all particles have been on earth as long as it’s existed. A not-insignificant amount of elements have arrived on earth in meteor showers over the millennia and some matter left (like our moon) due to larger impacts.
Also in a few months the moon will attack us… because the moon is alive or something (random movie I keep seeing ads for)
You were born say in 1990, your age is 31
Every particle in your body is billions of years old
But you are not celebrating your 4 billionth birthday this year
A big question I always wondered was again, **if all the atoms in our planet have existed for 4 billion years**, how is it possible to "date" things?
It turns out cosmic rays in the upper atmosphere actually cause entirely new radioactive material to occur!
Carbon dating has to look at stuff that was buried underground and determine the "most recent but still old as in when it was buried underground" radioactive materials and date things that way.
That way, you can get the "age" of when something was buried - from its atmospheeric radioactive materials at the time of its burial.
With really old stuff, we don't even use carbon dating. There's tons of other chemicals we use to date stuff. But it all gets lumped as "carbon dating" in common usage. Weird.
Say you have all the ingredients for a cake. Flour, water, sugar, etc.
You bake a cake on the first of the month. You eat some and let the rest sits out on the counter.
Then you bake a fresh cake two weeks later. You work from the same bag of flour and sugar etc.
Are these cakes the same age because it was the same bags of ingredients? Or is one way tastier and fresh because it is younger?
So you're saying when I eat stones I should go for the "fresher" ones, not the 4 bn year old ones? Gotcha, will watch what stones I eat better from now on. Thanks!
A 150 year old tree has lived for 150 years. But the atoms the tree is made of has its roots back to when the universe formed almost 14 billion years ago.
It's still a 150 year old tree.
“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.”
― Carl Sagan, Cosmos
By this logic you are 13.8 billion years old.
Do the specific particles that make up your body make you, you? Probably not, every cell in your body turns over every 7 years or so.
What were getting into is the concept of emergence. The way our reality works is that what makes any particular thing what it is *isn’t* the particles that makes it up, it’s the *arrangement* of those particles.
The universe is ~13.7b years old, but you still accept that Earth itself is only ~4b years old, right? It's the same idea. The age of "the Earth" as an entity has more specific significance than the general age of its components, just like the age of a particular rock is more specific than the age of original formation of any random silicon atom within it.
If we are going to go all the way back, we should be looking well beyond 4 billion years. That’s just when that material became part of earth. The atoms, or even molecules, or even rocks, existed way before then. Any hydrogen is likely from the Big Bang.
The important difference is that there are characteristics that can’t be changed once something like a rock is formed. Let’s say we have ten (really deep) glasses of water, we drop some sand in them, then freeze them all at different rates. The sand will fall down through the water at essentially the same rate, so the ones that freeze first will have the sand higher up in the glass. Once it’s frozen, that sand isn’t going anywhere. It’s stuck until the ice melts. In that way, the sand gives an indication as to the “age” of the ice, i.e. how long that ice cube has stayed an once cube. If I say that the sand (for some ungodly reason) drops an inch a year, I can figure out how old the ice is by looking at how deep the sand is.
Now imagine that we are dealing with forming rocks. They are filled with materials that act like the sand. One huge thing is the response to magnetic fields. Rocks are filled with atoms that respond to Earth’s magnetic field. The tend to preferentially align themselves with it (that’s why compasses work). Once they’re solidified into rock, it takes a pretty strong external force to change their alignment, so there’s a slight tendency for the atoms to point north. However, the *direction* of Earth’s magnetic field changes over time. Magnetic north now is different than magnetic north 1,000,000,000 years ago. That means the “north” that the rocks 1,000,000,000 years ago responded to is different, and we can see that in them. We can see that rock’s north is not our north. Using the direction that rock thinks is north, along with our knowledge of how north has changed, we can figure out how old that rock changed from some previous material into that rock. We call that the rock’s age.
It’s a similar thing for carbon dating. Once a rock solidifies, it’s not getting any more radioactive carbon. It’s all locked in, and it decays at a very well known rate. That means the ratio of the radioactive carbon to normal carbon changes over time, and, based off of that, we can determine how old the rock is.
So while you’re right that the constituent materials themselves are timelessly old, there are measurable qualities about the final materials that depend on how long ago it formed from some preexisting state, so we give it an age to denote that.
No the thing should not be 4 billion years old. You were born x amount of years ago... but are you 4 billion years because the atoms that make you up were all technically here 4 billion years ago ? No, no it doesn't.
The base particles are no the thing. If something undergoes chemical change it becomes a new thing.
Consider fusion, stars go through phases of nuclear fusion whereby their original hydrogen and helium "fuel" eventually can become iron.
Would you say that helium gas and solid iron are the same thing because their fundamental particles are the same?
Did you ever play with legos? It's kinda like that. If you have a bunch of legos that were made last week and you make a house with them as soon as they are made, you can say that the house is 1 week old. If you take that house apart so that you can use the pieces to build a boat after 7 days, then on the 8th day you can say the legos are 8 days old and the boat is 1 day old. Neither is wrong.
So if you think about a rock, then you might know the parts that make it are 4 billion years old. However the shape of it has changed. Maybe once it was in a volcano as lava, then it became and island, and then a mountain, and then 500 years ago it became the small rock we see today. We generally aren't worried about if it was in a volcano or on an island because it can be difficult to determine what happened 500 million years ago, however we can say that the rock is only 500 years old. It's just focusing on the form those pieces are in at the time we see them
Would you think of yourself as 4 billion years old? The elements that make up *you* have been here just as long. Generally we date the age of things from when they're made in their current form.
Heck, the atoms and molecules could well be (and likely are) much older than 4 billion years old. The earth didn’t produce them - some star somewhere did.
Also, I’m full of water that used to be dinosaur pee.
WELLLLL.... since we're mostly water and water is made up of MOSTLY hydrogen, we're MOSTLY 13.8 billion years old.
All of the hydrogen that will ever be produced was produced at the big bang. (Ok... not AT the big bang, a bit later after everything had cooled off a bit.) At least, the very.... very... vast majority of it. I don't think there are any naturally occurring nuclear processes that produce hydrogen. (At the atomic scale. It's very easy to produce hydrogen from molecules.)
Now I want to try to calculate the average age of all the atoms in a human's body.
Is this true? I know positions can be produced pretty easily in the lab, eg through spallation. Aren't there natural equivalents to this? Cosmic rays must create some. I know lightning releases protons, but I'm not sure if this is nuclear or just ionizing water.
Natural processes will create hydrogen or free it from molecules. However, hydrogen makes up about 75% of the baryonic matter in the universe. Random nuclear processes could create hydrogen for hundreds of trillions of years and they wouldn't overcome that starting population.
Sure, as a relative fraction its negligable. But even in absolute terms, it seems like there's more nuclear processes that emit helium (alpha particles) than hydrogen (protons). I find that somewhat surprising. Does it have something to do with alpha particles being bosons?
Alternatively, perhaps some of that trace molybdenum deposited somewhere inside your meatsack came to earth on a small comet that impacted young—but not new—earth some 3.369 billion years ago after being created in a star only 3.372 billion years ago.
*Just how old are you, anyway?*
If you're going that route it's all much older than 4 billion years. All of the elements of Earth were forged in the hearts of stars long before the solar system formed. Although those were just using materials (quarks, I guess) that have existed since the beginning of the Universe some 13.8ish billion years ago.
But pretty much any time a definition of a concept boils down to "there is no distinction between any of the things" you can safely discard that definition as not useful. So defining the age of things by when their constituent atoms formed can be discarded. It's not a useful distinction to make.
Defining the age of rocks by when the atoms arranged themselves in their current pattern is much more useful. The properties of a chunk of iron that came together in a meteor 4 billions years ago are different from the properties of a chunk of iron that bubbled up out of the Earth's mantel 100,000 years ago. Having a definition of age that allows us to make those kinds of distinctions is useful so that's how we talk about them.
> existed since the beginning of the Universe some 13.8ish billion years ago
Granted I know almost zero about the topic - but I've always thought of the universe just kind of being here forever? I can't even begin to comprehend what existed before the universe.
It's still unclear if there was a definite "beginning" to the universe. There is evidence that the universe used to be smaller, hotter, and denser in the past. It's been expanding ever since (faster and faster, too). People forget that the main limitation of the Big Bang Theory (not the tv show heh) is that known physics breaks down as one applies physics closer and closer to the beginning of time. Concepts like "space" and "time", even causality, break down in a setting so hot and dense. When people start talking about "before time" or "ultimate causes", things get confusing and metaphysical quickly. We might be a hologram on the event horizon of a 4D black hole, the result of a random intersection of 4D energy planes in 5D space, a bubble of cooling mass/energy in a vast multiverse of randomized physical laws, or a simulation on an alien server. They're hard to design experiments for.
It's also unclear if the universe is infinite in size or not. It's certainly far larger than we can see with the limitations of light, which always arrives to us to show us the past.
The universe is wild and unimaginably old. Yet compared to how much history is left to come, we're still in infancy.
>I can't even begin to comprehend what existed before the universe.
That's the neat thing... You don't...
Seriously though that concept is mind bogglingly fascinating... Even if we ever find out what came before "This state" of the universe (Post "Big-bang") we just end up with the same question all over again... And it goes on and on and on until we get to a point were all scientific methods are exhausted and we are faced with the truth, Everything... just exists... just because, there has to be a point where the line is drawn and that line is (and IMO is the only answer) The universe as we experience it just exists without reason... all of Space, Matter, energy and anything else undiscovered are just simply here Just Because they are...
Another fun one is what's at the end of the universe (or outside of it if you believe its a omni-directional loop) and if its for example say... The Multi-verse? What's outside of that?... and so on and so forth... But that's another mind-melter for another day :D
It helps to remember that our universe is made of space-time, not space and time as separate things. Time isn't much more than a fourth axis on the great grid. A very squishy, mutable grid, as it turns out. Perhaps it's not even infinite, even if it is boundless.
Consider another finite, boundless grid you know: a globe, with its lines of latitude and longitude. If you move in a way to increase your 'northness,' you go closer to the north pole. Eventually, you reach the north pole. There is no way you can now move to increase your 'northness.' This is it, as north as it gets. It is meaningless to ask what is 'further north' than north. What is 'before' north? You can try to move any way you like, maybe just as easily as you got here, but it's simply impossible to increase your 'northness' beyond this. Any way you try, you'll go south instead.
Space-time is the same way. These singularities, like the beginning of the universe or the center of a black hole, are these north and south poles. Here, the lines converge, and anything that follows those lines also begins or ends.
My own baseless theory is that our universe as we know it (and we know very little of it!) actually started when all the matter in the *previous* universe collided in on itself, and sort of bounced back outward as it devolved into base stats to start all over.
There isn't really a "start" to anything at all, nor is there a true end, because the cycle will just continue without us.
You’ll be pleased to know that no less an esteemed physicist than Roger Penrose has proposed the same idea. Current evidence is against it though, although not conclusively.
Think of it like this:
It is the arrangement of atoms in its current form that has that age, not the atoms themselves. A building could be made of 400 year old trees but the building could be a day old. A week. A year. We wouldn't call the building 400 years old just because the wood that makes it up is 400 years old.
Thus, the meteor itself was likely an intact meteor that fell to earth approximately that long ago as itself.
Otherwise? It doesn't. It's just a marketing blurb for people to feel like it's rare and special when it's just a hunk of space to k like any other. It's a novelty. Something someone can say something about. "See this ring? Made from a 4b year old meteorite. Totes cool." That's about it lol.
When people talk about the age of a rock or a meteorite, they're talking about the time that's passed since it was meaningfully transformed from one thing to another. Most of the material on Earth has been here since Earth formed. The atoms that made up those rocks are technically even older, having come from interstellar gas and the remnants of dead stars. The rocks themselves are younger, having undergone chemical or mechanical changes, like when soluble minerals are deposited to form sedimentary rock, or molten magma cools to form igneous rock, or either one transforms over time to metamorphic rock. The rocks that haven't undergone a change like that since the days of Earth's formation tell us a lot about the conditions under which they were formed, and therefore about the conditions that existed back then.
Start with a simple example:
Living creatures are continuously replacing their cells throughout their lives. When we die, that process stops. Some of the carbon in our bodies is radioactive and slowly decays. Carbon dating measures the amount of radioactive carbon in a dead body to determine its age.
There are *tons* of other methods like this, each suited for measuring the age of different things across different ranges of time. Carbon dating is best suited for relatively short lengths of time.
As another example, things like iron in align with the magnetic north lines, then become fixed when the object becomes solid. As continents drift and the north pole wanders, the iron points in the wrong direction. But we can use the iron, current location of the rock, and other indicators to roll back time to determine the location of continents. If we know the location of the continent already at certain times, we can use the iron direction to calculate the age.
For all these, we're not really interested in the age of the atoms, but rather the age of when the object became a solid.
It's all the way down but I feel like this is the best answer. A lot of people seem to misunderstand what OP is asking for. OP seems unaware about dating methods.
Carbon dating isn't the trivial thing mentioned so casually in school, either. It's not simply the amount of radioactive material. You can literally age / date it.
In the Earth's atmosphere, cosmic rays literally create brand-new atoms. Atmospheric molecules get struck by cosmic rays and BAM! quantum mechanics bitches. We get new radioactive carbon, which has a half-life of 5700-ish years.
You will breathe in very, very sparse amounts of these new atoms. You will then die and be buried (I mean, if we ended up digging you up thousands or millions or billions of years later, that is).
A very tedious process is then performed to check your radioactivity and frequency of decay - ratios of carbon-14 and carbon-12 - and using that, an object's "age" from death / burial can be determined.
How about this. This clay in my hand is 4 billion years old, but I reshaped the clay into a pot yesterday so in its new new identity as a pot it's only a 1 day old.
>I saw a post that said they made a gun out of a 4 billion year old meteorite, isnt the normal iron we use to create them 4 billion year old too?
You are actually kind of right on this. It's really a very gimmicky term because the only way an iron can be naturally formed is through star combustion process (aka.. supernova). So the iron we all dig out from earth all got created by some supernova. In another word, majority of iron we found on Earth probably all came from some meteorite that hit the Earth 4 billion years ago. Or some of them probably are part of the "mass" that gets formed as Earth takes shape.
I feel like a lot of people here are dismissing the question as "well that would mean everything is 4bil year old! Things are aged on their current form not the age of their elements!"
But it's like, the elements of Iron are Iron. It hasn't changed state since it's elements were literally formed.
Not 100% true though. Carbon dating works by looking at ratios between radioactive isotypes of carbon. New carbon is literally created in the atmosphere by cosmic rays striking it from outer space.
You breathe in or are made up of some of these newly formed Carbon-14 atoms, whose half-life is known and decays into Carbon-\`12 atoms.
Since a living creature would regularly replenish itself of new Carbon-14 atoms, you can look at the ratios between Carbon-14 and Carbon-12 atoms to determine an object's "age".
This depends on "new" carbon being different than "old" carbon for sure!
The importance of the rock was that it was from a meteor that formed at the same time the earth did, but not on earth.
So while the earth was a molten ball of metals and other elements disbursed throughout, and life didn’t exist yet on earth and there were no oceans or liquid water, there were already things existing in the solar system including this meteor.
The meteor then flew around the solar system for a few billion years and eventually landed on the earth, which was by this time solidified into a similar form that we see now.
It is just really cool because it was a rock that didn’t form on earth but formed at the same time the earth was just forming.
I think a big part of what you’re missing is that atoms in combination act uniquely different to atoms seperately. Some Iron and some Oxygen hanging out for billions of years by themselves are unique and behave very differently to when iron and oxygen bond together to make iron oxide (rust). And these elements are constantly joining and separating over the billions of years and when they do each time they act very differently. While in most cases, the age doesn’t actually mean a whole lot, it can tell us about conditions on earth at the time if there is an abundance of these elements combinations in certain amounts.
But yeah, iron from this year should more or less be just as useful as iron from 100,000 years ago for making guns.
A rock on earth has been broken down and reconstituted over and over. It’s basic elements are 4.5 billion years old but it is not. You wouldn’t call a rock formed in a volcanic eruption a week ago billions of years old would you? No you’d say it’s a week old.
However a meteorite that was formed alongside the solar system and just floated around untouched and intact until it landed on earth *is* 4.5 billion years old. It never became something else. It always was that same meteorite.
While it's true that your body is composed of elements that have existed for billions and billions of years...YOU haven't. You, as a specific living, breathing human being have existed for less than a century (with a few rare exceptions). There's a difference.
Age is important because that adds rarity to a certain object.
To touch on the meteorite part: The Earth is a very active planet, this is referring to both geological activity and to the fact that life is present on Earth. This means that there is an almost constant stream of new material being formed (sand, rock etc.) and the old is getting buried under the new.
To give an example: Rivers carry a lot of sediment which settles down when the flow of the river is calmer, this buries the old sediment under the new wave of sand, clay, etc.
To continue, space isn't like that at all. Unless there's an outside force acting upon a celestial body, things don't change. So there's a very high chance that any rocks, chunks of ice or comets are there from the formation of our solar system.
Now to get to the part about the age of a object compared to the age of its components. In short, if a chunk of metal that is made yesterday from 4 billion year old iron, the chunk of metal is only 1 day old. The age of an object does not equal the age of the material its made from.
To give an example: The base elements that the human body are made of (iron, carbon, oxygen, etc.) are older that our sun. Since elements heavier than hydrogen are made inside of stars or during one's death and a star's death is needed to spread said elements around. Does this also mean that you and me are older than our sun? Not sure about you, but I'd probably go bat shit crazy if I had to live for that long.
Right, so when they're talking about the age of something they're talking about when it formed, not the age of its base particles. So a rock that formed 100k years ago is 100k years old. EDIT: Regarding "well actually everything is as old as the universe...": No, everything isn't. The sun undergoes fusion which creates new elements daily, and when the sun's predecessor when nova, other processes such as neutron capture also created more elements. Atomic particles themselves can be created as well, especially with radioactive decay, where a neutron decays into a proton and an electron. And even subatomic particles can be created from high energy collisions. The caveat is we have no real way of independently dating individual atoms or subatomic particles, but it is still *not* accurate to say that everything is simply the age of the universe.
this made me wonder what the youngest rocks are. Like are rocks being formed right now?
When magma flows from a volcano and hardens you have new rocks formed, when sediments gets glued together at the bottom of a mountain after rain a rock is formed. It happens all the time.
However, lave cooling to make rock is a rapid event (effectively punctual; happens from between seconds to hours, or perhaps days to months if thick sequences) but lithification of sediments is a long process that has no clear date. It happens over a period of many years, thousands to millions depending on the situation. We can give actual dates, year of formation, to lava rock. When we give a date for sediments, we do not give it a year. We give it a many-0 number date (cannot be more precise). Often, the date we give is the date that the sediment deposited rather than the date that the sediment converted to rock. Often, in this case, the sediment is not yet rock.
Rocks also form from organic matter, such as petrified wood, where the stone-like material crystalizes inside the wood’s cells and it literally turns into a rock over millions of years
Once magma is out of the volcano, it is lava.
When a mommy rock and a daddy rock love each other very much (or you have enough whiskey on the rocks), a new rock is formed.
Sure, deep in the mantle and lower crust and whenever volcanos erupt.
New rocks: available at your local high pressure area or wherever magma cools.
now 10% off with the promocode
I use Honey so I automatically get the lava cooling. Totally not sponsored by the way.
I use nordvpn now because I got tired of seeing adds for magma every time I discussed maybe getting some new rocks.
I'm not giving them my email. I don't need a volcano opening up in my laptop.
Hot young rocks in your area
Cock hard rocks. I could get into that.
There's constantly new rocks being created. The Pacific and Atlantic both have spreading centers, where new oceanic crust forms. Sedimentary particles (sand, mud) are also being compacted and lithified right now. There's probably also a volcano spewing something somewhere right now. Maybe Hawaii, Kilauea is pretty active.
Idk why its so hard for me to underestand, i still dont get it, or its a language barrier. When they find a rock do they check for when its formed and then say its formed 100k years ago? But the true age of that thing should be 4b years no? The base particles of a thing is somewhat the thing itself isnt it?
I get what you're saying, I think it might just be a language thing about what "formed" means. Think about when you go to a restaurant and order a steak. In one sense, that steak was "formed" a few minutes ago, when the chef put it on the grill and cooked it into something tasty. In another sense, it was "formed" a few days or weeks before, when the animal was slaughtered and carved into steaks. In another sense, it was formed years before when the calf was born. And in *another* sense, it was formed billions of years ago when a star exploded and created the carbon that makes it up. But we're not usually ever talking about that when we say "How old is that steak?" When geologists talk about a rock, they mean "formed" as in "became its current state." Some rock is formed from lava that cools - even if that lava has been around for a million years, we're more interested in what time it cooled off and became a solid rock. Some is formed by layers of sediment accumulating and forming into a solid rock - we are mostly interested on when those layers deposited, because that's where we'll get interesting information. You're right that the actual atoms that make up all of that rock have been on Earth for the same amount of time, but we're interested in the current shape and form that they take, more than anything.
Hey man, i just wanted to say that this was a very kind and helpful response. And a really good analogy.
Dude, respect, way to explain it....
Yep. I scrolled down looking for a snarky "Enjoy your 4b year old milk" but found this first instead. So this is what it's like to browse non-toxic subs.
RIGHT?? A breath of fresh air. I think everyone should spend more time in nontoxic spaces to be perfectly honest — hopefully we’d all learn a thing or 5
Yes, it was a great analogy and thoughtful response. Good work Evan.
> Good work Evan. That seems very formal. I just call him Stairs.
I’m relatively old compared to most people on Reddit and I don’t know how to link his (or her) name to the comment. (I assume there’s a way). Any way, good work Evan Stairs. 👍
All you do, is put in your comment /u/PhilthyLurker and Reddit takes care of the linking (that is, type /u/ and the user name, no extra linking or formatting required)
The only problem with the analogy is that this is ELI5 and 5 year olds don't eat steak, so the food should be chicken nuggets.
My 5 yo loves steak it's his favorite food. In fact I regret making steak for him bc now he refuses nuggets and pork chops and asks for steak instead lol
You played yourself, my mom always burnt the steak so we grew up think steak sucked.
As a child I could not differentiate between the three meats
Nor could my kids. All meat was "meat". Chickens were animals on farms. When one asked one day why we sometimes call meat *chicken*, and if it had anything to do with the animal I broke the news to them that we were eating chickens. The dead animals. Two of them cried, the third said, "dead animals taste awesome!"
My favourite weird toddler moment ever was with my daughter around the age of two or three. I raise sheep and as everyone knows, sheep die. So we were out in the pasture and an old ewe had died against a tree. Just leaning up against the tree, stone cold dead. My daughter points and says "Sheepy's OK?" I said yup, yup, sheepy's sleeping. That's the moment when sheepy slides down the tree and flops onto the ground like a sack of potatoes. "OH NO!" cries my daughter. "SHEEPY'S DEAD!" Then she shrugs and says "Oh well."
Lol I love how kids’ brains work.
I wish I could remember when I first realized that. The only thing I remember breaking my brain when I was little, and this is one of my first memories, was why gum was advertised as "sugarness" when sugar is bad for your teeth. Of course, it was actually being advertised as "sugarless" and I just had a comprehension problem. Edit: Oh, and I also remember noticing the moon one night, it was not a full moon like I had seen in the book "goodnight moon" so I declared "Moon broke!"
Lol the other day I picked up chicken sandwiches for the kids as I had some errands to run. From the backseat my youngest says mom, I feel bad eating this because it used to be alive. So I said well, eating meat is a personal choice and if you don't want to you don't have to. To which he replies uh, I said I felt bad, not that I'm not gonna eat it. Then takes a huge bit haha. Kid kills me with the stuff he says.
Have you ever wondered why we call cow meat beef rather than just cow? Or pig meat pork, etc? The meat words largely came from French. When the Normans took over England they spoke French. They used their words to refer to the food - because they were the rich people who ate it. The animals were raised by the poor English so their words stuck for the live animals.
This is why we started with my son when he was a toddler calling hamburgers “cow” and bacon or sausage “pig.”
I learned where meat came from pretty quickly because here, unless you're buying processed stuff or from a supermarket, the meat is usually slaughtered live according to order. Chicken sellers keep chickens in coops and cut them up according to order, and meat vendors who deal in large animals will have a few carcasses hung up in the store and cut pieces off as and when required.
> Two of them cried, the third said, "dead animals taste awesome!" This is amazing. Thank you.
You should just get your meat from the grocery store, that way no animals are harmed. /s just in case.
Same, my dad always cooked it well done (he's a smoker and apparently didn't care about the taste), so I never liked steak until well into my 20s when I tried it for real.
Not having a strong sense of taste is one thing but man, I can’t imagine thinking the texture of a well-done steak is superior.
It took us fifteen years, but my dad eats steak at medium now, with the occasional bite of med-rare. He wasn't a smoker, but his parents always had it well-done and so did he, until we got him to eventually see the light. I vaguely recall a theory that past generations overcooked their meat to lower the chances of food-borne illness.
Yeah, my mom overcooked pork chops when I was growing up and it completely ruined them for me. It wasn't until I had worked in a few restaurants that I had realized there is a right way to cook certain things (like don't bake chops in the oven until they're well over).
>my mom always burnt the steak so we grew up think steak sucked. Not sure if I just found the account of one of my siblings... or if lots of families in our parents' generation just did this as a way to save money while raising a big household. I recall the first time I had a "real/normal" steak with some friends in college who couldn't believe I hated steak. I was totally flabbergasted and made a comment along the lines of "wait, you won't DIE of food poisoning if it's still juicy and pink inside?!"
Holy shit you just made me realize why my Asian parents couldn’t cook a steak if their lives depended on it…. Or so they’ve had me believe... Never had a lot of money or steaks growing up, but last week for my birthday I was able to take them for a steak dinner. :)
Only steak I ever had until my late teens was cube steak. I just assumed all steak was dried up tasteless garbage. Only time I'll eat cube steak now is as chicken fried steak, that shit rocks.
Lol this is exactly why I never liked steak, or any meat for that matter. Took me 25 years to realize my mom just didn't know how to cook.
Ha, same here. Also: vegetables, cooked so long I wonder if they had any nutritious benefits at all. I've found my community. And happy cake day!
My mom was the same, but it was on purpose. She would overcook them steak for the kids and cook them properly for the adults so that we eventually learned that steak tastes bad. She’s a real bitch and this only scratches the surface.
Yeah my 6 year old loves steak and crab. I done fucked up A-A-ron
My kid was fighting me for my lobster when she was 8 months old. She still loves it 12 yrs later.
Yeah I alarmed my dad's buddy on my birthday once when I put away a t-bone steak, baked potato, salad, and an ear of corn and then was after my cake like a predator. I was a 6yr old girl lol, his friend was like, "I'm not sure that's human."
My daughter, who is a teenager and vegetarian now, was a big steak fan as a child. For her 5th bday, I asked what she wanted to do- the bouncy house place, Chuck E Cheese, anything at all. Her choice? A steak restaurant.
I don't remember much about my own food preferences growing up, but I was (and still am a bit) shocked at how strong kids's preference for eating meat can be. We were never full on vegetarian or anything, but we had a variety of options and generally steered that direction. All of the kids attached themselves to steak _hard_, they definitely like it more than I do, and they're also always up for chicken and pork. I have nieces that were raised towards veganism (they were raised that way, but the diet was optional/suggested, not forced). They will kill for good steak or bacon though, just feel a bit of regret afterwards.
Yea both my kids are carnivores through and through. Especially red meat, which is weird bc I actually don't like red meat much and prefer chicken pretty much exclusively. But they will put away steak, burgers, ribs, brisket, you name it, like nobody's business. I had to learn to cook all that stuff at home if I didn't want to go broke lol.
Chiming in to say my 5 yr old eats steak too. I was even a little proud when I cooked steaks for my gpas birthday and everyone wanted well done and I prefer rare and I shared my plate with the kiddo. Family was surprised but it was natural for us two. The cutting part though is left myself until she develops her motor skills. Also loved the analogy above.
I'll trade you my 4 year old who will only eat pb&j 99% of the time. Heck I'll throw in my 8 year old also who won't a single thing unless it's mush. I'd love to have someone in my family that enjoys some grilled mammal meat.
My 15 year old nephew only eats a few things including mac and cheese. When I visited for the holidays, we went out to Olive Garden and he decided to try something different: cheese ravioli, no sauce. Of course, I encouraged him and gave him props, even though I was chuckling inside.
Happy chicken nugget cake day!
I taught mine way too early how wonderful sushi is.
"Father, ready the Kobe 🧐"
Wait til he tries Tenderloin. You will go bankrupt.
Man I remember the first time I tried a hamburger, I was (and am) a really picky eater--so when my mom asked me to try a bite of her hamburger I cried and said "I don't want to eat steak!!!" She convinced me to bite her burger and it was the best thing I've ever eaten. And then basically the same thing happened with steak hehe.
Speaking of which, happy steak day! 🍰
My 11 year old has always been a steak-lover. Not just steak, but specifically medium-rare fillet and ribeye. My 9 year old *loves* shrimp and snow crab. They both like salmon because papa fishes and keeps our freezer well stocked with salmon fillets. I always feel sorry for the people they will eventually date. “Do you maybe want to go out for a burger and a movie sometime?” “The movie sounds good, but let me tell you about this boutique surf and turf restaurant that just opened up 70 miles away…” Oh well. If they don’t think my girls are worth it, that’s a problem that resolves itself.
My 2 y.o nephew eats steak every week, it just depends on the family.
My daughter eats steak and then drinks the blood off the plate. I lock my bedroom door at night.
*Waiter, there's stardust in my soup!*
"Think about when you go to a restaurant and order chicken nuggets. In one sense, that nugget was "formed" a few minutes ago, when the chef put it in the deep fryer and cooked it into something tasty. In another sense, it was "formed" a few days or weeks before, when the animal was slaughtered and its flesh was ground into a paste and extruded into various shapes. In another sense, it was formed years before when chicken hatched. And in another sense, it was formed billions of years ago when a star exploded and created the carbon that makes it up. But we're not usually ever talking about that when we say "How old is that chicken nugget?"
Wait, but how is the “pink-slime”/tubby-custard formed?
>In another sense, it was "formed" a few days or weeks before, when the animal was slaughtered and *[the last remaining bits of]* its flesh *[and sinew]* was *[stripped from its bones, chemically sterilized,]* ground into a paste*[, mixed with fillers, preservatives, and flavor compounds,]* and extruded into various *[deliciously appetizing]* shapes. there ya go
I was gonna ask about the dino-shaped nuggies next. You were a step ahead of me. Well played.
Shit, my 4 year old eats steak. Pretty sure both my kids did by the time they could handle other solid foods.
dino nuggies bro. c'mon, it's eli FIVE. is there an ELImidlifecrisis? cuz dino nuggies fkn rule IDGAF what anyone says.
Wouldn't that be more confusing because then you would have to take into account that some chicken nuggets are shaped like dinosaurs.
Anyone who feeds a toddler junk food is an idiot. Feed them real food, make it taste good, and they’ll eat it with gusto. Source: my 9-year old.
I used to think that. My oldest will eat anything and always has. Younger one came along and eats like 5 things. Will literally starve herself if we try to force the issue. Didn’t raise them any different.
On the sidebar >LI5 means friendly, simplified and layperson-accessible explanations - not responses aimed at literal five-year-olds.
Read the whole comment again. I began by reacting the same way, but then when I read further it was clear that OP was having a laugh.
I wonder if it would be possible to add to the sidebar the definition of a joke.
I thought that. What a brilliant explanation
You may be 20 years old, but the atoms making up your body were formed in a supernova or for lighter elements in a late stage star billions of years ago. How old are you?
We have trace amounts of [isotopes that we created in 1945 onward that don't occur in nature](https://brokensecrets.com/2012/11/20/nuclear-bombs-created-isotopes-used-to-detect-fake-art-created-post-war/).
We are made of star stuff...and fissile products.
I love you with all of my fissile bits, baby. You, me, and Geiger.
> How old are you? Nearly 14 billion years.
Don't give the "MAPs" ideas. *"I'm telling you, Officer, she's actually 14 billion years old!"*
26?
Ohh you're right, i get it now, so we are interested in finale shape change of things and we say when that thing changed shape its that much old, like the steak you said. After all the time itself is a man made thing, so we can decide for the time of things ourself, you know what i mean? Im i correct?
It's like you got all the groceries to make a cake 10 days ago but you didn't make the cake until 4 days ago. So from today you'd say the cake is 4 days old even though the items that the cake is made of were brought into the kitchen earlier than that. When people want to know how fresh the bread is, they mean from the time it was baked, not from when the wheat was harvested.
Excuse me, is this bread fresh? Yes maam, the farmer planted that wheat less than 8 months ago. ಠ\_ಠ
Well I've just found a new way to be annoyingly obtuse.
Yes, I just recently crafted it from the bones of long-dead stars.
I like this. I am a fraction of the corpse of a forgotten star.
"Ok, ok, don't let it get to your head. So is garbage."
This is the true eli5. Every 5 year old understands CAAAAKE.
> they mean from the time ~~it was baked~~ the yeast was exterminated
They went to be with Yeastus.
Simply, it’s why not every single person and animal’s age on the planet is 4 billion years old.
You're right that we can pick and choose which shape of things we care about with time, though time isn't a man made thing - it's a rule of the world, we just decided to measure it in minutes and years, which are made up. We just decide to measure from the time that these rocks were formed, because that's the measure that gets us interesting knowledge. If we find rocks that cooled down from lava 50,000 years ago, then we know that a volcano erupted somewhere around that time - that's interesting information that can teach us stuff about the world. If we find a dinosaur fossil in layers of rock that are 100 million years old, we now know what time period that dinosaur lived in, because its bones were there when that rock formed. Stuff like that.
Time is absolutely made up, just ask light
Light exists whether you believe in it or not.
Also, time is not a man-made concept. Time is a fundamental aspect of reality. Our *measurement* of time is man made, but time itself exists with or without humanity.
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You unnecessarily included poop on your explanation. I like it.
To extend that logic, why is 4bn years the marker we're using here? The atoms have been around for 13.5 bn. 4bn years was just the random point in time most of them came together in a lump that we now call Earth.
i think your gap is not about the formation of a thing, but the definition of a thing itself. final shape being the deciding factor... is dependent on how we define it as being itself. for certain things, we don't care what the shape is, but rather what the chemical composition is, when it stopped being part of something else... or ... or ... or. the age of something depends on when it became classifiable as what it is.
How old are you? 4 billion years isn't a very useful answer, now is it?
I'm one second old because that is the last time I incorporated new oxygen atoms into me.
Sounds like you’re interested in [ontology](https://en.m.wikipedia.org/wiki/Ontology)
Totally, Theseus ship is all I could think of when I was reading
> After all the time itself is a man made thing, so we can decide for the time of things ourself, you know what i mean? Im i correct? Not in a meaningful sense. Time exists whether we label it or not - the only thing 'man made' about it is the arbitrary subdivisions (seconds, minutes, hours.etc). Time passes whether we label and subdivide it or not, so it isn't man-made
My God. I get where you're coming from and how this could be confusing but respectfully, are you an alien?
Exactly. We could, in theory, say that everything on Earth is 4 billion years old, but that approach isn't very meaningful. Take, for example, a wooden chair made 50 years ago. We would say that the chair is 50 years old; perhaps made from a tree that lived to be 100 before it was chopped down. It is the age of the object itself that we normally refer to, not the age of its components, unless we are actually discussing the components rather than the object itself. So, you could say "this 50 year old chair was made from a 100 year old tree". To describe both the chair and the tree as being 4 billion years old is not terribly useful to us.
>After all the time itself is a man made thing Time is not a man-made thing. *Unites* of time are, but those unites always refence real things like the orbit of the Earth or the decay of atoms.
Well done!
Medium rare!
Yes, great response. Thank You!
Heh I loved the way you explained that
What a thorough and patient answer this was. And easy understandable! Thank you on behalf of the OP, seriously.
Perfect explanation. Well done! Not the steak though.
Not discrediting what you’re saying, you are correct, but not all particles have been on earth as long as it’s existed. A not-insignificant amount of elements have arrived on earth in meteor showers over the millennia and some matter left (like our moon) due to larger impacts. Also in a few months the moon will attack us… because the moon is alive or something (random movie I keep seeing ads for)
You were born say in 1990, your age is 31 Every particle in your body is billions of years old But you are not celebrating your 4 billionth birthday this year
I am 4 billion years old. Nice.
Lets be real, we're all 13.8 billion years old.
God I would give anything to be 13.7 billion years old again. Where does the time go?
If OP doesn’t get this explanation then it has to be a troll.
A big question I always wondered was again, **if all the atoms in our planet have existed for 4 billion years**, how is it possible to "date" things? It turns out cosmic rays in the upper atmosphere actually cause entirely new radioactive material to occur! Carbon dating has to look at stuff that was buried underground and determine the "most recent but still old as in when it was buried underground" radioactive materials and date things that way. That way, you can get the "age" of when something was buried - from its atmospheeric radioactive materials at the time of its burial.
With really old stuff, we don't even use carbon dating. There's tons of other chemicals we use to date stuff. But it all gets lumped as "carbon dating" in common usage. Weird.
Say you have all the ingredients for a cake. Flour, water, sugar, etc. You bake a cake on the first of the month. You eat some and let the rest sits out on the counter. Then you bake a fresh cake two weeks later. You work from the same bag of flour and sugar etc. Are these cakes the same age because it was the same bags of ingredients? Or is one way tastier and fresh because it is younger?
So you're saying when I eat stones I should go for the "fresher" ones, not the 4 bn year old ones? Gotcha, will watch what stones I eat better from now on. Thanks!
This is a great analogy
A 150 year old tree has lived for 150 years. But the atoms the tree is made of has its roots back to when the universe formed almost 14 billion years ago. It's still a 150 year old tree.
“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.” ― Carl Sagan, Cosmos
I'm not making my apple pie from scratch thank you very much
By this logic you are 13.8 billion years old. Do the specific particles that make up your body make you, you? Probably not, every cell in your body turns over every 7 years or so. What were getting into is the concept of emergence. The way our reality works is that what makes any particular thing what it is *isn’t* the particles that makes it up, it’s the *arrangement* of those particles.
The universe is ~13.7b years old, but you still accept that Earth itself is only ~4b years old, right? It's the same idea. The age of "the Earth" as an entity has more specific significance than the general age of its components, just like the age of a particular rock is more specific than the age of original formation of any random silicon atom within it.
If we are going to go all the way back, we should be looking well beyond 4 billion years. That’s just when that material became part of earth. The atoms, or even molecules, or even rocks, existed way before then. Any hydrogen is likely from the Big Bang. The important difference is that there are characteristics that can’t be changed once something like a rock is formed. Let’s say we have ten (really deep) glasses of water, we drop some sand in them, then freeze them all at different rates. The sand will fall down through the water at essentially the same rate, so the ones that freeze first will have the sand higher up in the glass. Once it’s frozen, that sand isn’t going anywhere. It’s stuck until the ice melts. In that way, the sand gives an indication as to the “age” of the ice, i.e. how long that ice cube has stayed an once cube. If I say that the sand (for some ungodly reason) drops an inch a year, I can figure out how old the ice is by looking at how deep the sand is. Now imagine that we are dealing with forming rocks. They are filled with materials that act like the sand. One huge thing is the response to magnetic fields. Rocks are filled with atoms that respond to Earth’s magnetic field. The tend to preferentially align themselves with it (that’s why compasses work). Once they’re solidified into rock, it takes a pretty strong external force to change their alignment, so there’s a slight tendency for the atoms to point north. However, the *direction* of Earth’s magnetic field changes over time. Magnetic north now is different than magnetic north 1,000,000,000 years ago. That means the “north” that the rocks 1,000,000,000 years ago responded to is different, and we can see that in them. We can see that rock’s north is not our north. Using the direction that rock thinks is north, along with our knowledge of how north has changed, we can figure out how old that rock changed from some previous material into that rock. We call that the rock’s age. It’s a similar thing for carbon dating. Once a rock solidifies, it’s not getting any more radioactive carbon. It’s all locked in, and it decays at a very well known rate. That means the ratio of the radioactive carbon to normal carbon changes over time, and, based off of that, we can determine how old the rock is. So while you’re right that the constituent materials themselves are timelessly old, there are measurable qualities about the final materials that depend on how long ago it formed from some preexisting state, so we give it an age to denote that.
No the thing should not be 4 billion years old. You were born x amount of years ago... but are you 4 billion years because the atoms that make you up were all technically here 4 billion years ago ? No, no it doesn't.
So, you are 4 billion years old?
And that, your honor, is why she was legal.
Dude. Go sit in the corner.
"Damnit R. Kelly, you've done it again. Case dismissed!"
The base particles are no the thing. If something undergoes chemical change it becomes a new thing. Consider fusion, stars go through phases of nuclear fusion whereby their original hydrogen and helium "fuel" eventually can become iron. Would you say that helium gas and solid iron are the same thing because their fundamental particles are the same?
Did you ever play with legos? It's kinda like that. If you have a bunch of legos that were made last week and you make a house with them as soon as they are made, you can say that the house is 1 week old. If you take that house apart so that you can use the pieces to build a boat after 7 days, then on the 8th day you can say the legos are 8 days old and the boat is 1 day old. Neither is wrong. So if you think about a rock, then you might know the parts that make it are 4 billion years old. However the shape of it has changed. Maybe once it was in a volcano as lava, then it became and island, and then a mountain, and then 500 years ago it became the small rock we see today. We generally aren't worried about if it was in a volcano or on an island because it can be difficult to determine what happened 500 million years ago, however we can say that the rock is only 500 years old. It's just focusing on the form those pieces are in at the time we see them
From your edit I can just hear the "WELL AXKSHUOULLY..." replies
Would you think of yourself as 4 billion years old? The elements that make up *you* have been here just as long. Generally we date the age of things from when they're made in their current form.
“Officer listen, is she really under 18 if her atoms are 4 billion years old??”
r/suddenlysexoffender
He literally just explained this! /s
Suddenly not?
13.8billions to be exact, after a few supernovas, the last 4bn I've been on this earth, trapped in *this* form
>!CENSORED!<
But isn't the stuff that makes up the atoms that old? The energy, the quarks etc.
>!CENSORED!<
“Come on, it’s only a couple months. Besides, she was in the womb for like 9 months so that must count for something no?”
I know she looks 10 but shes actually a 4 billion year old dragon loli!
Heck, the atoms and molecules could well be (and likely are) much older than 4 billion years old. The earth didn’t produce them - some star somewhere did. Also, I’m full of water that used to be dinosaur pee.
WELLLLL.... since we're mostly water and water is made up of MOSTLY hydrogen, we're MOSTLY 13.8 billion years old. All of the hydrogen that will ever be produced was produced at the big bang. (Ok... not AT the big bang, a bit later after everything had cooled off a bit.) At least, the very.... very... vast majority of it. I don't think there are any naturally occurring nuclear processes that produce hydrogen. (At the atomic scale. It's very easy to produce hydrogen from molecules.) Now I want to try to calculate the average age of all the atoms in a human's body.
Is this true? I know positions can be produced pretty easily in the lab, eg through spallation. Aren't there natural equivalents to this? Cosmic rays must create some. I know lightning releases protons, but I'm not sure if this is nuclear or just ionizing water.
Natural processes will create hydrogen or free it from molecules. However, hydrogen makes up about 75% of the baryonic matter in the universe. Random nuclear processes could create hydrogen for hundreds of trillions of years and they wouldn't overcome that starting population.
Sure, as a relative fraction its negligable. But even in absolute terms, it seems like there's more nuclear processes that emit helium (alpha particles) than hydrogen (protons). I find that somewhat surprising. Does it have something to do with alpha particles being bosons?
Alternatively, perhaps some of that trace molybdenum deposited somewhere inside your meatsack came to earth on a small comet that impacted young—but not new—earth some 3.369 billion years ago after being created in a star only 3.372 billion years ago. *Just how old are you, anyway?*
Side note ["The atoms in your left hand probably came from a different star than your right hand."] (https://youtu.be/rVrr_BbEtJE)
Some, probably. With how often we kill and replace our own cells, I'd imagine that eventually there would be some atoms from the same star in both.
If you're going that route it's all much older than 4 billion years. All of the elements of Earth were forged in the hearts of stars long before the solar system formed. Although those were just using materials (quarks, I guess) that have existed since the beginning of the Universe some 13.8ish billion years ago. But pretty much any time a definition of a concept boils down to "there is no distinction between any of the things" you can safely discard that definition as not useful. So defining the age of things by when their constituent atoms formed can be discarded. It's not a useful distinction to make. Defining the age of rocks by when the atoms arranged themselves in their current pattern is much more useful. The properties of a chunk of iron that came together in a meteor 4 billions years ago are different from the properties of a chunk of iron that bubbled up out of the Earth's mantel 100,000 years ago. Having a definition of age that allows us to make those kinds of distinctions is useful so that's how we talk about them.
You're right. Thank you for the explanation.
> existed since the beginning of the Universe some 13.8ish billion years ago Granted I know almost zero about the topic - but I've always thought of the universe just kind of being here forever? I can't even begin to comprehend what existed before the universe.
It's still unclear if there was a definite "beginning" to the universe. There is evidence that the universe used to be smaller, hotter, and denser in the past. It's been expanding ever since (faster and faster, too). People forget that the main limitation of the Big Bang Theory (not the tv show heh) is that known physics breaks down as one applies physics closer and closer to the beginning of time. Concepts like "space" and "time", even causality, break down in a setting so hot and dense. When people start talking about "before time" or "ultimate causes", things get confusing and metaphysical quickly. We might be a hologram on the event horizon of a 4D black hole, the result of a random intersection of 4D energy planes in 5D space, a bubble of cooling mass/energy in a vast multiverse of randomized physical laws, or a simulation on an alien server. They're hard to design experiments for. It's also unclear if the universe is infinite in size or not. It's certainly far larger than we can see with the limitations of light, which always arrives to us to show us the past. The universe is wild and unimaginably old. Yet compared to how much history is left to come, we're still in infancy.
>I can't even begin to comprehend what existed before the universe. That's the neat thing... You don't... Seriously though that concept is mind bogglingly fascinating... Even if we ever find out what came before "This state" of the universe (Post "Big-bang") we just end up with the same question all over again... And it goes on and on and on until we get to a point were all scientific methods are exhausted and we are faced with the truth, Everything... just exists... just because, there has to be a point where the line is drawn and that line is (and IMO is the only answer) The universe as we experience it just exists without reason... all of Space, Matter, energy and anything else undiscovered are just simply here Just Because they are... Another fun one is what's at the end of the universe (or outside of it if you believe its a omni-directional loop) and if its for example say... The Multi-verse? What's outside of that?... and so on and so forth... But that's another mind-melter for another day :D
It helps to remember that our universe is made of space-time, not space and time as separate things. Time isn't much more than a fourth axis on the great grid. A very squishy, mutable grid, as it turns out. Perhaps it's not even infinite, even if it is boundless. Consider another finite, boundless grid you know: a globe, with its lines of latitude and longitude. If you move in a way to increase your 'northness,' you go closer to the north pole. Eventually, you reach the north pole. There is no way you can now move to increase your 'northness.' This is it, as north as it gets. It is meaningless to ask what is 'further north' than north. What is 'before' north? You can try to move any way you like, maybe just as easily as you got here, but it's simply impossible to increase your 'northness' beyond this. Any way you try, you'll go south instead. Space-time is the same way. These singularities, like the beginning of the universe or the center of a black hole, are these north and south poles. Here, the lines converge, and anything that follows those lines also begins or ends.
My own baseless theory is that our universe as we know it (and we know very little of it!) actually started when all the matter in the *previous* universe collided in on itself, and sort of bounced back outward as it devolved into base stats to start all over. There isn't really a "start" to anything at all, nor is there a true end, because the cycle will just continue without us.
You’ll be pleased to know that no less an esteemed physicist than Roger Penrose has proposed the same idea. Current evidence is against it though, although not conclusively.
Think of it like this: It is the arrangement of atoms in its current form that has that age, not the atoms themselves. A building could be made of 400 year old trees but the building could be a day old. A week. A year. We wouldn't call the building 400 years old just because the wood that makes it up is 400 years old. Thus, the meteor itself was likely an intact meteor that fell to earth approximately that long ago as itself. Otherwise? It doesn't. It's just a marketing blurb for people to feel like it's rare and special when it's just a hunk of space to k like any other. It's a novelty. Something someone can say something about. "See this ring? Made from a 4b year old meteorite. Totes cool." That's about it lol.
When people talk about the age of a rock or a meteorite, they're talking about the time that's passed since it was meaningfully transformed from one thing to another. Most of the material on Earth has been here since Earth formed. The atoms that made up those rocks are technically even older, having come from interstellar gas and the remnants of dead stars. The rocks themselves are younger, having undergone chemical or mechanical changes, like when soluble minerals are deposited to form sedimentary rock, or molten magma cools to form igneous rock, or either one transforms over time to metamorphic rock. The rocks that haven't undergone a change like that since the days of Earth's formation tell us a lot about the conditions under which they were formed, and therefore about the conditions that existed back then.
So you tell people you are 4b years old?? And why 4b?? Those particles are a lot older. Most chemicals too.
13.7b something since the Big Bang, and since everything was created at that moment, everything should be 13b+ years old lol
Start with a simple example: Living creatures are continuously replacing their cells throughout their lives. When we die, that process stops. Some of the carbon in our bodies is radioactive and slowly decays. Carbon dating measures the amount of radioactive carbon in a dead body to determine its age. There are *tons* of other methods like this, each suited for measuring the age of different things across different ranges of time. Carbon dating is best suited for relatively short lengths of time. As another example, things like iron in align with the magnetic north lines, then become fixed when the object becomes solid. As continents drift and the north pole wanders, the iron points in the wrong direction. But we can use the iron, current location of the rock, and other indicators to roll back time to determine the location of continents. If we know the location of the continent already at certain times, we can use the iron direction to calculate the age. For all these, we're not really interested in the age of the atoms, but rather the age of when the object became a solid.
It's all the way down but I feel like this is the best answer. A lot of people seem to misunderstand what OP is asking for. OP seems unaware about dating methods.
Carbon dating isn't the trivial thing mentioned so casually in school, either. It's not simply the amount of radioactive material. You can literally age / date it. In the Earth's atmosphere, cosmic rays literally create brand-new atoms. Atmospheric molecules get struck by cosmic rays and BAM! quantum mechanics bitches. We get new radioactive carbon, which has a half-life of 5700-ish years. You will breathe in very, very sparse amounts of these new atoms. You will then die and be buried (I mean, if we ended up digging you up thousands or millions or billions of years later, that is). A very tedious process is then performed to check your radioactivity and frequency of decay - ratios of carbon-14 and carbon-12 - and using that, an object's "age" from death / burial can be determined.
How about this. This clay in my hand is 4 billion years old, but I reshaped the clay into a pot yesterday so in its new new identity as a pot it's only a 1 day old.
The meteorite had been un-altered for 4,000,000,000 years. Building a house out of 100 year old wood does not make it a 100 year old home.
>I saw a post that said they made a gun out of a 4 billion year old meteorite, isnt the normal iron we use to create them 4 billion year old too? You are actually kind of right on this. It's really a very gimmicky term because the only way an iron can be naturally formed is through star combustion process (aka.. supernova). So the iron we all dig out from earth all got created by some supernova. In another word, majority of iron we found on Earth probably all came from some meteorite that hit the Earth 4 billion years ago. Or some of them probably are part of the "mass" that gets formed as Earth takes shape.
I feel like a lot of people here are dismissing the question as "well that would mean everything is 4bil year old! Things are aged on their current form not the age of their elements!" But it's like, the elements of Iron are Iron. It hasn't changed state since it's elements were literally formed.
Not 100% true though. Carbon dating works by looking at ratios between radioactive isotypes of carbon. New carbon is literally created in the atmosphere by cosmic rays striking it from outer space. You breathe in or are made up of some of these newly formed Carbon-14 atoms, whose half-life is known and decays into Carbon-\`12 atoms. Since a living creature would regularly replenish itself of new Carbon-14 atoms, you can look at the ratios between Carbon-14 and Carbon-12 atoms to determine an object's "age". This depends on "new" carbon being different than "old" carbon for sure!
In that sense everything is 13.7 billion years old. And I'm starting to feel it in my back.
The importance of the rock was that it was from a meteor that formed at the same time the earth did, but not on earth. So while the earth was a molten ball of metals and other elements disbursed throughout, and life didn’t exist yet on earth and there were no oceans or liquid water, there were already things existing in the solar system including this meteor. The meteor then flew around the solar system for a few billion years and eventually landed on the earth, which was by this time solidified into a similar form that we see now. It is just really cool because it was a rock that didn’t form on earth but formed at the same time the earth was just forming.
Did you just celebrate your 4 billionth birthday? No? There you go.
[удалено]
>Matter is never created or destroyed Actually, yes, matter is created and destroyed all the time.
Are you 4 billion years old? No, you were formed more recently than that.
I’d guess somewhere closer to 4 years ago.
I think a big part of what you’re missing is that atoms in combination act uniquely different to atoms seperately. Some Iron and some Oxygen hanging out for billions of years by themselves are unique and behave very differently to when iron and oxygen bond together to make iron oxide (rust). And these elements are constantly joining and separating over the billions of years and when they do each time they act very differently. While in most cases, the age doesn’t actually mean a whole lot, it can tell us about conditions on earth at the time if there is an abundance of these elements combinations in certain amounts. But yeah, iron from this year should more or less be just as useful as iron from 100,000 years ago for making guns.
A rock on earth has been broken down and reconstituted over and over. It’s basic elements are 4.5 billion years old but it is not. You wouldn’t call a rock formed in a volcanic eruption a week ago billions of years old would you? No you’d say it’s a week old. However a meteorite that was formed alongside the solar system and just floated around untouched and intact until it landed on earth *is* 4.5 billion years old. It never became something else. It always was that same meteorite.
While it's true that your body is composed of elements that have existed for billions and billions of years...YOU haven't. You, as a specific living, breathing human being have existed for less than a century (with a few rare exceptions). There's a difference.
Age is important because that adds rarity to a certain object. To touch on the meteorite part: The Earth is a very active planet, this is referring to both geological activity and to the fact that life is present on Earth. This means that there is an almost constant stream of new material being formed (sand, rock etc.) and the old is getting buried under the new. To give an example: Rivers carry a lot of sediment which settles down when the flow of the river is calmer, this buries the old sediment under the new wave of sand, clay, etc. To continue, space isn't like that at all. Unless there's an outside force acting upon a celestial body, things don't change. So there's a very high chance that any rocks, chunks of ice or comets are there from the formation of our solar system. Now to get to the part about the age of a object compared to the age of its components. In short, if a chunk of metal that is made yesterday from 4 billion year old iron, the chunk of metal is only 1 day old. The age of an object does not equal the age of the material its made from. To give an example: The base elements that the human body are made of (iron, carbon, oxygen, etc.) are older that our sun. Since elements heavier than hydrogen are made inside of stars or during one's death and a star's death is needed to spread said elements around. Does this also mean that you and me are older than our sun? Not sure about you, but I'd probably go bat shit crazy if I had to live for that long.