Sean Carroll

But there's a probability that a tiny little black hole pops into existence and then radiates away again. Okay. Okay. Now for Claudio's question, it's a little bit different. Claudio is asking whether or not you could do science in this region. Could you study the cosmological constant in questions such as the heat-death of the universe in the sealed-off sphere? Well, in principle, yes.

But there's a probability that a tiny little black hole pops into existence and then radiates away again. Okay. Okay. Now for Claudio's question, it's a little bit different. Claudio is asking whether or not you could do science in this region. Could you study the cosmological constant in questions such as the heat-death of the universe in the sealed-off sphere? Well, in principle, yes.

In practice, no. In principle, the cosmological constant, which is equivalent to the energy density of empty space, has an effect on the geometry of spacetime here in our solar system? If that's what you're getting at, then the answer is yes, it absolutely does.

In practice, no. In principle, the cosmological constant, which is equivalent to the energy density of empty space, has an effect on the geometry of spacetime here in our solar system? If that's what you're getting at, then the answer is yes, it absolutely does.

So for example, the orbit of Mercury, which famously was a test of general relativity, because general relativity predicts that Mercury's elliptical orbit precesses a little bit more than Newtonian gravity predicts. the cosmological constant adds a contribution to the predicted precession of the orbit of Mercury.

So for example, the orbit of Mercury, which famously was a test of general relativity, because general relativity predicts that Mercury's elliptical orbit precesses a little bit more than Newtonian gravity predicts. the cosmological constant adds a contribution to the predicted precession of the orbit of Mercury.

But when you plug in the numbers, that extra addition is so incredibly tiny that breathing on Mercury is probably at least as effective, okay? The numbers actually matter here, and with things like the cosmological constant or the heat depth of the universe, size matters. The cosmological constant has effects that build up over space and time.

But when you plug in the numbers, that extra addition is so incredibly tiny that breathing on Mercury is probably at least as effective, okay? The numbers actually matter here, and with things like the cosmological constant or the heat depth of the universe, size matters. The cosmological constant has effects that build up over space and time.

So if you have a small region of space, in principle there's an effect of the cosmological constant, but that's exactly the wrong place to look for a noticeable effect. That's why in practice when we try to constrain the cosmological constant we are generally doing cosmology experiments.

So if you have a small region of space, in principle there's an effect of the cosmological constant, but that's exactly the wrong place to look for a noticeable effect. That's why in practice when we try to constrain the cosmological constant we are generally doing cosmology experiments.

Okay, Pete Faulkner says, in your December 2024 AMA, in response to a question about black holes, you mentioned that details like a black hole's size, composition, and the observer's velocity significantly impact the experience of someone falling into a black hole.

Okay, Pete Faulkner says, in your December 2024 AMA, in response to a question about black holes, you mentioned that details like a black hole's size, composition, and the observer's velocity significantly impact the experience of someone falling into a black hole.

This seems to contrast with my understanding of the no-hair theorem, which suggests that black holes are fundamentally characterized by just mass, angular momentum, and electric charge. Could you explain how these seemingly conflicting perspectives are reconciled? Sure, it's the difference between falling in and staying outside. It's as simple as that.

This seems to contrast with my understanding of the no-hair theorem, which suggests that black holes are fundamentally characterized by just mass, angular momentum, and electric charge. Could you explain how these seemingly conflicting perspectives are reconciled? Sure, it's the difference between falling in and staying outside. It's as simple as that.

If I throw a bunch of things into a black hole, then from the perspective of someone outside, the details of what I've thrown in completely disappear. I mean, things that are just visible, like I throw in a red ball or a blue ball, that literally disappears. It's now behind the black hole. I just don't know.

If I throw a bunch of things into a black hole, then from the perspective of someone outside, the details of what I've thrown in completely disappear. I mean, things that are just visible, like I throw in a red ball or a blue ball, that literally disappears. It's now behind the black hole. I just don't know.

Things like the lumpiness, the spatial configuration, would initially distort the shape of the black hole, but the black hole would quickly radiate away any such distortions in the form of gravitational radiation. So the black holes settle down from the perspective of an outside observer. But if you're falling into the black hole, you could still see what I threw in.

Things like the lumpiness, the spatial configuration, would initially distort the shape of the black hole, but the black hole would quickly radiate away any such distortions in the form of gravitational radiation. So the black holes settle down from the perspective of an outside observer. But if you're falling into the black hole, you could still see what I threw in.

You know, if I threw in a ball and you don't know whether it's red or blue, But if you fall in fast enough after the ball, you can just catch up to it and look at it. So it's completely consistent. It's just you're asking two different questions from two different points of view. Robo says, I liked your solo episode 295 on emergence.

You know, if I threw in a ball and you don't know whether it's red or blue, But if you fall in fast enough after the ball, you can just catch up to it and look at it. So it's completely consistent. It's just you're asking two different questions from two different points of view. Robo says, I liked your solo episode 295 on emergence.