Sean Carroll

In this scenario I was just talking about, the one from the Arrow of Time paper with Jennifer Chen, we had the idea of baby universes, where you have a pre-existing universe that can undergo a fluctuation inside itself that would cause a little tiny bit of universe to pinch off and go its own way. There we have a picture of what it would look like.

In this scenario I was just talking about, the one from the Arrow of Time paper with Jennifer Chen, we had the idea of baby universes, where you have a pre-existing universe that can undergo a fluctuation inside itself that would cause a little tiny bit of universe to pinch off and go its own way. There we have a picture of what it would look like.

It would look like, well, let me emphasize the important point here. The amount of baby universe you need to pinch off is very, very tiny. It's just a little Planck scale-sized thing. You don't need to undergo the entire history of the universe backwards. It's not anything like that at all. What it would look like is a number of particles, photons or whatever.

It would look like, well, let me emphasize the important point here. The amount of baby universe you need to pinch off is very, very tiny. It's just a little Planck scale-sized thing. You don't need to undergo the entire history of the universe backwards. It's not anything like that at all. What it would look like is a number of particles, photons or whatever.

I'm not sure what the most likely thing would be. would actually be, but a bunch of particles come in by random fluctuation and collide with each other in a small region of space, enough to make what looks to the outside like a black hole, but actually inside is a baby universe pinching off.

I'm not sure what the most likely thing would be. would actually be, but a bunch of particles come in by random fluctuation and collide with each other in a small region of space, enough to make what looks to the outside like a black hole, but actually inside is a baby universe pinching off.

And then that thing that looks like a black hole then radiates away, and that whole process looks more or less symmetric, right? Bunch of particles come together, make a black hole, black hole evaporates into a bunch of particles. But the set of particles there is enormously smaller than what you would need to make a big universe-sized thing like us.

And then that thing that looks like a black hole then radiates away, and that whole process looks more or less symmetric, right? Bunch of particles come together, make a black hole, black hole evaporates into a bunch of particles. But the set of particles there is enormously smaller than what you would need to make a big universe-sized thing like us.

The reason why that's viable is because of inflation. Because inside the baby universe, you can use the laws of physics, take advantage of the property that a closed universe has zero total energy.

The reason why that's viable is because of inflation. Because inside the baby universe, you can use the laws of physics, take advantage of the property that a closed universe has zero total energy.

So if that closed universe is full of an inflaton field, it can expand to an arbitrary size, and that inflaton field can turn into ordinary matter and radiation and create many, many, many, many more particles than you actually needed to make the baby universe in the first place.

So if that closed universe is full of an inflaton field, it can expand to an arbitrary size, and that inflaton field can turn into ordinary matter and radiation and create many, many, many, many more particles than you actually needed to make the baby universe in the first place.

If what you're referring to is some self-contained universe, then I would not use the vocabulary of fluctuating into existence. For a baby universe that comes from a pre-existing space-time, I think that language is appropriate. For the universe as a whole, if you mean a universe that just has a beginning, then I would just say it's a universe that has a beginning.

If what you're referring to is some self-contained universe, then I would not use the vocabulary of fluctuating into existence. For a baby universe that comes from a pre-existing space-time, I think that language is appropriate. For the universe as a whole, if you mean a universe that just has a beginning, then I would just say it's a universe that has a beginning.

I would not say that it's fluctuating into existence out of nothingness or anything like that. Johann Yartelius says, can a molecule be earmarked? There's this factoid, or perhaps trueoid, that with every breath we breathe, we get an oxygen atom once breathed by Julius Caesar. Now, from a probability point of view, I'm sure this makes mathematical sense.

I would not say that it's fluctuating into existence out of nothingness or anything like that. Johann Yartelius says, can a molecule be earmarked? There's this factoid, or perhaps trueoid, that with every breath we breathe, we get an oxygen atom once breathed by Julius Caesar. Now, from a probability point of view, I'm sure this makes mathematical sense.

But if one would want to test it, how would one do so? Is the likelihood larger that a water molecule, for instance, stays closer to where it met me, or is the dispersion equal? If I wanted to register individual molecules to see if that particular molecule returns to some given point, i.e. a water molecule passing through my faucet again, could I do so, and if so, how?

But if one would want to test it, how would one do so? Is the likelihood larger that a water molecule, for instance, stays closer to where it met me, or is the dispersion equal? If I wanted to register individual molecules to see if that particular molecule returns to some given point, i.e. a water molecule passing through my faucet again, could I do so, and if so, how?

So to the actual question, can you earmark the molecule, Not really, is the answer. It depends on what you mean. I mean, you can always take that molecule and attach it to another molecule. But if you're talking about an oxygen atom or a water molecule, they're sufficiently small that if you attach them to large other molecules, you're going to completely change their dynamics, right?

So to the actual question, can you earmark the molecule, Not really, is the answer. It depends on what you mean. I mean, you can always take that molecule and attach it to another molecule. But if you're talking about an oxygen atom or a water molecule, they're sufficiently small that if you attach them to large other molecules, you're going to completely change their dynamics, right?