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How did gravity worked on the Death Star? (feddit.org)

submitted 3 months ago by genfood@feddit.org to c/science_memes@mander.xyz

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cross-posted from: https://feddit.org/post/1104168

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[-] lolcatnip@reddthat.com 69 points 3 months ago

It's the size of a very, very small moon, and mostly hollow.

[-] Kusimulkku@lemm.ee 47 points 3 months ago

I should call her

[-] Khrux@ttrpg.network 33 points 3 months ago

Yeah the fact it's called a small moon is slightly deceptive to us because our moon is absolutely huge as far as moons go. The natives of the SW universe would be used to much much smaller moons.

For reference, our moon is 3475km across and the death star is 150km across, so it's diameter is 23 smaller. It's also weighed at about 900million tonnes or 9*10^14kg.

If I'm right (which I'm likely not). g=(GM)/r² or g=(6.66710^-119*10^13)/75².

That's a gravity of 1.086x10^-5m/s² or if I round with pure disrespect for physics, 100,000 times weaker than earth's gravity. Essentially it's totally negligible compared to their artificial gravity. Hell, I don't even think a marble on the floor would overcome it's own grip and roll towards the center of the space station.

My maths is almost certainly wrong somewhere here, I failed it badly.

[-] lolcatnip@reddthat.com 9 points 3 months ago

Our moon is huge for a planet of Earth's size, but not compared to the big moons of Jupiter and Saturn.

Last time I looked it up, I used Pluto's moons as a reference because some of them are smaller than DS1, but Charon is quite a bit bigger. Based on the shapes of Pluto's moons, I think even if DS1 were solid it would still be too small to compact itself into a sphere with its own gravity.

Fun fact: Charon is even more huge relative to Pluto (just over 50% of Pluto's diameter) than Luna is compared to Earth (about 25% of Earth's diameter).

[-] ASeriesOfPoorChoices@lemmy.world 5 points 3 months ago

fun fact, pluto and charon are technically a binary planet(oid), because the point they orbit is in-between them. (Charon doesn't orbit Pluto, they both circle empty space)

[-] FinalRemix@lemmy.world 4 points 3 months ago* (last edited 3 months ago)

For kids who like a movie reference to rely upon: https://media1.tenor.com/m/jl-z-8otCc0AAAAC/titanic-weee.gif

[-] Klear@sh.itjust.works 2 points 3 months ago

Pluto has more than one satellite?

[-] lolcatnip@reddthat.com 3 points 3 months ago

It has five that we know of.

[-] Klear@sh.itjust.works 2 points 3 months ago

Must have missed that. Cool!

[-] MotoAsh@lemmy.world 6 points 3 months ago

I mean, we mostly only have info on our solar system for moon sizes. We could easily be an oddball, although it's not good science to assume we're special in any way.

[-] frezik@midwest.social 2 points 3 months ago* (last edited 3 months ago)

So small that a natural body of that size probably wouldn't be massive enough to hold a spherical shape. DS1 was a little smaller than the real asteroid 128 Nemesis, which isn't spherical. Maybe if it were made of something extremely dense, it would be, but you're not likely to find a natural spherical object that size.

Now that I think of it, this puts the "that's no moon" scene in perspective. Luke is a country bumpkin who just calls it a moon, but Obi-wan has an idea of its size (perhaps from glancing at the Falcon's scans, since size and distance is hard to judge by eye; or he's just a space wizard), and knows a natural object couldn't be that spherical.