# Time Dilation and Neutron Stars **URL:** \ **Category:** Factual Questions\ **Created:** [April 25, 2021, 7:42pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748 "2021-04-25T19:42:39Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [April 27, 2021, 12:42pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/21 "2021-04-27T12:42:17Z")
Life also tends (extrapolating from the one example we have, anyway) to form in places where there is an energy gradient to take advantage of. The extreme environment of a neutron star would have some pretty strong energy gradients. Certainly no life as we know it could exist in such a place, but that doesn’t mean that no life _could_. I kinda have my doubts about it, but we don’t know nearly enough to rule it out with anything like a certainty. Space travel off of such a surface would definitely pose some challenges, though. ---
**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\ **Post date:** [April 27, 2021, 12:55pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/22 "2021-04-27T12:55:01Z")
I honestly don’t have a good answer for that. I can say that the rotation affects the structure of spacetime in the vicinity, “dragging” nearby objects in the direction of the rotation like a whirlpool. There’s a certain region near the black hole where it’s actually impossible to remain “at rest” relative to the black hole, but you can enter and leave this region at will so long as you are moving in the same direction as the rotation of the black hole. So the rotation has a profound effect on how nearby objects behave. But beyond that, I don’t have a good answer; it just seems to be how the math comes out. I’ll have to think on it further. ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [April 27, 2021, 12:57pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/23 "2021-04-27T12:57:37Z")
> [@CookingWithGas](#): > > I’m afraid to ask, because I may not understand the answer–but why does spinning matter for how close you can orbit it? The simple answer that is “close enough” is frame dragging. As it rotates, it drags space around it, and if you are in that space, you are dragged along with it. This gives extra velocity if you are orbiting along with the spin. Of course, if you try to orbit in the opposite direction than the spin, then your innermost stable circular orbit is going to be further from the black hole. > [@MikeS](#): > > This in turn allows you to get arbitrarily large time dilation, though you have to get the black hole spinning stupidly fast to get the magnitude of the time dilation as large was shown in _Interstellar_ . I only say the movie once, and didn’t pay too close attention to it, as I figured it would annoy me, but they must have had some sort of magictech propulsion to have matched orbits with that planet, much less leaving it and climbing back up out of the BH’s gravity well. With whatever type of propulsion that they had to reach, land on, and leave the planet, they could have gotten the same sort of time dilation simply by flying out one way, then coming back. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 27, 2021, 2:00pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/24 "2021-04-27T14:00:25Z")
> [@k9bfriender](#): > > Space travel off of such a surface would definitely pose some challenges, though. The Cheela used a [space fountain](https://en.wikipedia.org/wiki/Space_fountain). ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [April 27, 2021, 2:04pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/25 "2021-04-27T14:04:17Z")
A system seemingly designed to have highly dramatic failure modes… ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [April 27, 2021, 2:15pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/26 "2021-04-27T14:15:16Z")
I assume that it is intentional that a Cheela is also a type of pancake. > [@Darren\_Garrison](#): > > The Cheela used a [space fountain](https://en.wikipedia.org/wiki/Space_fountain). Still a pretty impressive engineering feat. Then of course, they wouldn’t be stable outside their home, and have to bring along black holes, tricky proposition that. Drop a micro black hole into Earth, and chances are it evaporates faster than it grows. Drop a micro black hole into a neutron star, and now it’s a black hole. Not sure how landing on a new neutron star works out for them. Or what range of gravities they can handle. Sure, it doesn’t seem like the difference between 67 billion G’s and say 90 G’s is that much, until you realize that it’s a difference of 23 billion G’s. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [April 27, 2021, 2:31pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/27 "2021-04-27T14:31:43Z")
The “life” couldn’t be corporeal because it would be crushed out of existence. It would have to be some kind of pure energy “feeding” on the enormous magnetic field generated by the neutron star. I mean, what else is there that it could possibly be “eating”? ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [April 27, 2021, 2:39pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/28 "2021-04-27T14:39:13Z")
> [@Jasmine](#): > > The “life” couldn’t be corporeal because it would be crushed out of existence. If it were relying on chemical bonds and other electromagnetic interactions, certainly. But in this case, it was not, it was based on much stronger nuclear forces. > [@Jasmine](#): > > I mean, what else is there that it could possibly be “eating”? The difference in temperature of a millimeter on a neutron star would be, let me do the math real quick, a whole lot. Keep in mind that this is a work of fiction that employs forces that we do not yet understand all that well. They _probably_ don’t work that way, but I’m not sure we know that they don’t, and given the time of the writing of the novel, they would have known even less. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 27, 2021, 2:44pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/29 "2021-04-27T14:44:40Z")
> [@k9bfriender](#): > > Then of course, they wouldn’t be stable outside their home, and have to bring along black holes Which is exactly what they did. > **[Cheela](https://aliens.fandom.com/wiki/Cheela)** > > The Cheela are a sapient species of lifeforms which inhabit the surface of a rogue pulsar (neutron star) named Dragon's Egg, which was passing close to the Sol System in the mid 21st century. Flattened by the extreme gravity of their world, they are... ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [April 27, 2021, 2:51pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/30 "2021-04-27T14:51:55Z")
Yeah, like I said, tricky proposition, that. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 27, 2021, 9:00pm UTC](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748/31 "2021-04-27T21:00:46Z")
As an aside, the wormhole special effects in Interstellar were literally the first accurate visualization ever made of a wormhole. They got Kip Thorne, the world’s top expert on wormholes and probably the greatest physicist of our time, as a science advisor, and it turns out that Hollywood special effects guys have some really good computer programs for raytracing through a given set of equations. They ran Thorne’s equations through their programs and asked him “did we get it right?”, and his answer was “Wow, let me take a look at that code”. [Previous page](https://boards.straightdope.com/t/time-dilation-and-neutron-stars/940748.md?page=1)