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Kip Thorne: The science of Interstellar

blogs.scientificamerican.com

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Re: Kip Thorne: The science of Interstellar

#21

Post by martinko »

ThePhysicist wrote: post #17

Accuracy aside, from a scientific point of view Interstellar was one of the most interesting movies in a long time, and it really made me think about Physics a lot again. It's really cool to see how much you can actually learn about the universe of Interstellar by making use of some Physics knowledge and the information given to you in the movie. An example: The first planet they visit orbits Gargantua (the supermass…

> here we have to assume that the black hole is not rotating very fast

From the article: "The black hole needs to be spinning very fast"

Re: Kip Thorne: The science of Interstellar

#22

Post by chton »

gglon wrote: post #15
chton wrote: post #13

Earlier quoted context omitted.

Yes, they knew about the relativistic effects. And they could obviously send some data. But somehow they can't figure out that they've been getting a repeat of the same ping for the last 10 years? And even if they couldn't figure that out, how could the person on the planet possibly send a ping every year, if she only spent an hour and half on it according to her frame of reference?

I don't remember how many pings they received in the movie. I've understood that they had received just one ping from that planet.

They expected a ping every year, if it ever stopped pinging they would write off that planet. It was up to the scientists to keep the ping going, if they considered the planet still a suitable candidate for humanity. The signal they received from the time dilation planet was supposedly "looped around the black hole" and repeated yearly.

Re: Kip Thorne: The science of Interstellar

#23

Post by Osmium »

ThePhysicist wrote: post #17

Accuracy aside, from a scientific point of view Interstellar was one of the most interesting movies in a long time, and it really made me think about Physics a lot again. It's really cool to see how much you can actually learn about the universe of Interstellar by making use of some Physics knowledge and the information given to you in the movie. An example: The first planet they visit orbits Gargantua (the supermass…

> here we have to assume that the black hole is not rotating very fast

I read that, for Interstellar, it's actually very important to include rotation of the black hole: http://www.slate.com/blogs/bad_astronomy/2014/11/09/interste...

> which offer great 'Fermi problems'

An aside, but I'm curious. I see this mentioned a lot more often lately, and I know Randall Monroe talks about them a lot in his 'What if?' series, so I'm not sure if it's because of that popularising the term, or if it's just the Baader-Meinhof phenomenon on my part. A Google Trends search suggests increased interest, but it could just be coincidental.

Re: Kip Thorne: The science of Interstellar

#24

Post by chton »

martinko wrote: post #21
ThePhysicist wrote: post #17

Accuracy aside, from a scientific point of view Interstellar was one of the most interesting movies in a long time, and it really made me think about Physics a lot again. It's really cool to see how much you can actually learn about the universe of Interstellar by making use of some Physics knowledge and the information given to you in the movie. An example: The first planet they visit orbits Gargantua (the supermass…

> here we have to assume that the black hole is not rotating very fast From the article: "The black hole needs to be spinning very fast"

Calculations about time dilation become enormously more complicated in a system where the black hole is spinning, because you get effects like frame dragging that influence the orbits and time. For the purposes of the parent poster, a ball-park number of distance is enough, they don't need the whole shebang.

Re: Kip Thorne: The science of Interstellar

#25

Post by NetMonkey »

ThePhysicist wrote: post #17

Accuracy aside, from a scientific point of view Interstellar was one of the most interesting movies in a long time, and it really made me think about Physics a lot again. It's really cool to see how much you can actually learn about the universe of Interstellar by making use of some Physics knowledge and the information given to you in the movie. An example: The first planet they visit orbits Gargantua (the supermass…

The time dilation was really quite fascinating. However, I assume that the entire planet would not behave as if it had the same time dilation all the time?

Considering the massive dilation (1 hour -> 7 years, a factor of 1 : 61320), wouldn't even relatively small distances on the planet surface create different dilation effects depending on an objects/individuals distance to the black hole?

I'm just wondering if there would not only be noticable effects from a distance (orbit -> planet), but also within visible distance on the surface itself.

If the dilation could act on scales such as the 200 meter wave, I'm having trouble imagining how it would look / behave, if for example the top of the wave was moving "slower" compared to the bottom of the wave.

Re: Kip Thorne: The science of Interstellar

#26

Post by chton »

dijxtra wrote: post #9
chton wrote: post #5

Earlier quoted context omitted.

That's a possibility, but the special fuel they have would have to have been extremely expensive then. That would have been a fine explanation, and if they had mentioned it in the movie that would be one less point I could make. But here's another one: They set up this nice system with pings to know what planets might be suitable, but they can't detect when a ping is being repeated instead of actually sent by a perso…

The biggest issue I see is the fact that gravitational time dilation is considerable on the surface of the Miller's planet, but not so much in the relatively close proximity of the planet, where the mothership is. I just don't get that part.

I figured the mothership was still orbiting the black hole, in a much wider orbit. They could rendezvous by matching orbits using pretty standard manoeuvres, it would just take more time than if it was moving in a similar orbit as the planet itself.

Re: Kip Thorne: The science of Interstellar

#27

Post by TorKlingberg »

ThePhysicist wrote: post #17

Accuracy aside, from a scientific point of view Interstellar was one of the most interesting movies in a long time, and it really made me think about Physics a lot again. It's really cool to see how much you can actually learn about the universe of Interstellar by making use of some Physics knowledge and the information given to you in the movie. An example: The first planet they visit orbits Gargantua (the supermass…

I also love the movie, but there one thing with the time dilation I suspect does not add up. If the first planet is so deep into Gargantua's gravity well that it has such time dilation, would the energy required to get a spaceship out of the gravity well not be ridiculously huge? Given that they had limited energy, did it make sense to visit that planet first?

Re: Kip Thorne: The science of Interstellar

#29

Post by harshreality »

ThePhysicist wrote: post #17

Accuracy aside, from a scientific point of view Interstellar was one of the most interesting movies in a long time, and it really made me think about Physics a lot again. It's really cool to see how much you can actually learn about the universe of Interstellar by making use of some Physics knowledge and the information given to you in the movie. An example: The first planet they visit orbits Gargantua (the supermass…

It's a supermassive black hole, spinning at close to the maximum permitted (apparently there's a maximum, beyond which photons at either the photon sphere or an event horizon get dragged faster than the speed of light, and Gargantua's spin is ridiculously close to the maximum for the math on the orbit and time dilation to work out, but it does)

If you can find a copy of Thorne's book (it's already leaked to the web) and skim the appropriate sections, it'll clear up some things.

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