Serious Scientific Answers to Absurd Hypothetical questions

[Green Baron]

6 hours ago, Gargamel said:

That's not a g load, that's a traumatic crush injury. 

It is a defined mass, nothing more. And i don't always mean things totally serious. It totally depends on the application of that mass, which one can use to trivially calculate the acceleration a dead carcass can endure before is breaks. I mean, if one doesn't have centrifuge with a means to calculate the rpm at hand, which in my case isn't the case, at least not all the time.

:-)

Edited August 21, 2018 by Green Baron

[KG3]

10 hours ago, TeslaPenguin1 said:

How many saturn V's, placed at the equator, would it take to stop the earth's spin?

How many would it take to crash the moon into earth?

 

Scott Manley did a video on this subject a few years ago.  In the description he says "Warning: Big Numbers Ahead"

https://www.youtube.com/watch?v=G01NoaTM46o&pbjreload=10

 

[Xd the great]

52 minutes ago, KG3 said:

 

Scott Manley did a video on this subject a few years ago.  In the description he says "Warning: Big Numbers Ahead"

https://www.youtube.com/watch?v=G01NoaTM46o&pbjreload=10

 

Actually, you cant stop earths rotation, unless you hold the rockets at the edge of earths SOI

Rotation speed: 460m/s.

Momentum= 2.568E27 m kg /s?

Im dead.

 

[MaverickSawyer]

13 hours ago, Gargamel said:

That's not a g load, that's a traumatic crush injury. 

WAIT!!    What?   When did we send turtles to the moon?

Buy a second one, give to a friend, and joust.   Loads of fun. 

Agreed.

On at least one of the Zond missions.

No thanks. I have a healthy respect for the amount of energy those deliver. I've been zapped by broken ones... Not always accidentally, I might add. >.>

[Gargamel]

21 hours ago, kerbiloid said:

Not turtles but tortoises! _{Just a lol, as in my language this is the same word.}

In 1968, Zond-5.
Two Soviet tortoises (and various invertebrates) were the first Earth beings ever sent to another celestial body (and successfully returned back).
Of course, it was a fly-by, not landing.
3 months later Apollo-8 repeated this with three mammals. 

Wonder if your average tortoise would be aerodynamically stable enough to have it's shell act as a heat shield if it was coated properly.

 

And now I'm wondering if I should talk to somebody about my apparent penchant for decelerating animals at high g loads.....

13 hours ago, Xd the great said:

Actually, you cant stop earths rotation, unless you hold the rockets at the edge of earths SOI

Earth doesn't have a SOI. 

[kerbiloid]

1 hour ago, Gargamel said:

Wonder if your average tortoise would be aerodynamically stable enough to have it's shell act as a heat shield if it was coated properly.

Greece has tested something similar in the past.

Spoiler

 

https://en.wikipedia.org/wiki/Aeschylus#Death

.
 

1 hour ago, Gargamel said:

Earth doesn't have a SOI. 

It has.

(Other planets' gravity is negligible compared to Sun.
And any n-body system consists of 2-body pairs, so you can take the least between the values, )

Edited August 22, 2018 by kerbiloid

[magnemoe]

3 hours ago, kerbiloid said:

Greece has tested something similar in the past.

  Hide contents

 

https://en.wikipedia.org/wiki/Aeschylus#Death

.

Not Greece, they just observed. 
Eagles on the other hand crash test tortoises, if they break the eagle get an meal, if not it has to try again. 
Pretty smart. 

[Xd the great]

4 hours ago, Gargamel said:

Wonder if your average tortoise would be aerodynamically stable enough to have it's shell act as a heat shield if it was coated properly.

I think, no. Assuming the coating layer is very thin, using marios tortoise shell, there are concave curves in the shell that traps air. Aka shockwaves and pressure waves.

[kerbiloid]

Some problem could be with aerodynamic stability.
The T-capsule should have raised something above-behind to keep proper AoA.

Spoiler

Spoiler

Why at all distinct turtles and tortoises? 

 

Edited August 22, 2018 by kerbiloid

[Green Baron]

5 hours ago, Gargamel said:

Wonder if your average tortoise would be aerodynamically stable enough to have it's shell act as a heat shield if it was coated properly.

The shell is made from ribs, pelvis- and shoulder bone. It is not a "heat shield" and judging from its history of development i tend to negate its aerodramatic usefulness :-)

Quote

Earth doesn't have a SOI. 

Nope, but the RL expression would probably be hill sphere.

Edited August 22, 2018 by Green Baron

[kerbiloid]

16 minutes ago, Green Baron said:

Quote

Earth doesn't have a SOI. 

Nope, but the RL expression would probably be hill sphere.

Hill sphere and SOI are different concepts.

Hill sphere is a region where a body can stay a satellite of the reference body.
Sphere of Influence is a region where gravity of the reference body is greater than other bodies gravity.

No problem with having both in a zillion-body system.

Edited August 22, 2018 by kerbiloid

[peadar1987]

Quote

Why at all distinct turtles and tortoises? 

It's a British English thing. Turtles live in the sea, tortoises live on the land. In American English they're all just called turtles.

[KG3]

2 hours ago, peadar1987 said:

It's a British English thing. Turtles live in the sea, tortoises live on the land. In American English they're all just called turtles.

Unless you are reading Lewis Carol's Alice's Adventures Wonderland.  The Mock Turtle went to school in the sea.  His teacher was an old sea turtle named Tortoise "We called him Tortoise because he taught us" 

[Mad Rocket Scientist]

10 hours ago, magnemoe said:

Not Greece, they just observed. 
Eagles on the other hand crash test tortoises, if they break the eagle get an meal, if not it has to try again. 
Pretty smart. 

Crows will drop walnuts on roads so the cars crack them open when they drive over: http://www.pbs.org/lifeofbirds/brain/

[MaverickSawyer]

Re: turtle vs. tortoise: Turtles live near or in water. Tortoises live exclusively on land.

[Green Baron]

And, before someone asks (which probably nobody will but i annoy you nevertheless), both turtles and tortoises are amniotes and reptiles who do not principally need water. Their eggs have a membrane/shell to keep the inside from drying out.

:-)

Edited August 22, 2018 by Green Baron

[magnemoe]

5 hours ago, Mad Rocket Scientist said:

Crows will drop walnuts on roads so the cars crack them open when they drive over: http://www.pbs.org/lifeofbirds/brain/

And its an magnitude smarter. 
Just hope wolfs don't get that tricks with moose as it would give a lot more accidents. its an well know that moose, caribou and dear don't understand cars, this is why its so many accidents and why its illegal to hunt from cars in most cases. 

[mikegarrison]

15 hours ago, kerbiloid said:

Hill sphere is a region where a body can stay a satellite of the reference body. Sphere of Influence is a region where gravity of the reference body is greater than other bodies gravity.

These are, of course, very similar things.

And I must say, it's rather annoying how people in this forum love to pedantically jump on anyone who uses SOI as shorthand for "region of space near an object where the gravitation affects of other bodies are fairly negligible compared to the close body".

[kerbiloid]

4 hours ago, mikegarrison said:

And I must say, it's rather annoying how people in this forum love to pedantically jump on anyone who uses SOI as shorthand for "region of space near an object where the gravitation affects of other bodies are fairly negligible compared to the close body"

If this is about me, I just don't understand why people in this forum sometimes doubt in existence of both spheres for any celestial body in the (milions-body) Solar System.

Solar System is enough roomy to let almost every flying piece have its satellites (i.e. to have a Hill sphere).
As well as any flying object except smallest ones has its own several meters of SoI around it.

So, there's just no need to invent a replacement, especially when both spheres have more or less similar size and in most cases are interchangeable.

Edited August 23, 2018 by kerbiloid

[Gargamel]

Fair enough, point taken guys.   I should have expounded on that so the poster understands the difference between realworld SOI's and KSP SOI's. 

[Spaceception]

How big can a rotating ringworld be, using the most advanced, and known, materials? I understand that a space elevator using carbon nanotubes would be at least ~35,700k km long (I think it can be longer). And those would be used to keep it stable.
But since the stress of the material on the ring itself would limit that to be smaller, how much smaller would it be? At least, if you want to spin it for gravity.

[StrandedonEarth]

2 hours ago, Spaceception said:

How big can a rotating ringworld be, using the most advanced, and known, materials? I understand that a space elevator using carbon nanotubes would be at least ~35,700k km long (I think it can be longer). And those would be used to keep it stable.
But since the stress of the material on the ring itself would limit that to be smaller, how much smaller would it be? At least, if you want to spin it for gravity.

Depends how much simulated gravity you want. A full gee? I suggest scrith It's a known material. You didn't specify a real existing material...

[Spaceception]

38 minutes ago, StrandedonEarth said:

Depends how much simulated gravity you want. A full gee? I suggest scrith It's a known material. You didn't specify a real existing material...

Well, aside from possible impracticality, I'd like it to be technically possible to construct in our universe. No magical materials. Preferably a gee, but down to 0.35 gees is ok.

Carbon nanotubes, Titanium, Steel, Graphene, etc. Probably supported in a fashion more similar to a suspension bridge.

[magnemoe]

2 hours ago, Spaceception said:

Well, aside from possible impracticality, I'd like it to be technically possible to construct in our universe. No magical materials. Preferably a gee, but down to 0.35 gees is ok.

Carbon nanotubes, Titanium, Steel, Graphene, etc. Probably supported in a fashion more similar to a suspension bridge.

You can not make an ringworld, something like the one in Halo or Banks orbitals are more realistic, think the point is that it rotates once every 24 hours so you get natural day and light. Use spokes like in an bicycle wheel, you want them for an spaceport and 0g facilities anyway and this helps a lot. No idea how large it would be but the 24 hour and 1g set an fixed size. 

Note that you can theoretically build an ringworld with known materials. put a lot of mass on the outside who will push inward because of gravity. rotate the ring to counter this. You would need a lots of mass way more than the Niven design, you also have the problem that this require an complex system of magnetic bearings to work all the time, its no way to turn it off 

[Spaceception]

5 hours ago, magnemoe said:

You can not make an ringworld, something like the one in Halo or Banks orbitals are more realistic, think the point is that it rotates once every 24 hours so you get natural day and light. Use spokes like in an bicycle wheel, you want them for an spaceport and 0g facilities anyway and this helps a lot. No idea how large it would be but the 24 hour and 1g set an fixed size. 

Note that you can theoretically build an ringworld with known materials. put a lot of mass on the outside who will push inward because of gravity. rotate the ring to counter this. You would need a lots of mass way more than the Niven design, you also have the problem that this require an complex system of magnetic bearings to work all the time, its no way to turn it off 

Would a Ringworld with a diameter of 26,000 km be able to hold, or need that extra mass on the outside?

Yeah, that's what I was planning on. (To the first part)