Because 2020 was not eventful enough... UFOs

[Vertigo 7]

https://www.artificial-gravity.com/sw/SpinCalc/

Found this calculator that can show the differences in relative comfort of occupants based on size and angular velocity of a spinning station/ship. Granted the "comfort" level is conjecture from several different authors but they do all tend to agree that the bigger the spinning thing is, the less discomfort the occupants will feel.

Anywho, based on this calculator, the best experience for the occupants isn't achievable until the object has a radius of about 250 meters.

[CBJ]

Well there you go; I learned something. Apologies are in order to brucewarren then!

[pjknibbs]

Granted the "comfort" level is conjecture from several different authors but they do all tend to agree that the bigger the spinning thing is, the less discomfort the occupants will feel.

Well, yes, that's pretty obvious--the larger the object the slower it needs to spin to provide an effective 1g at the edge. Question is, though, when you're talking about a long duration space mission, at what point does the discomfort of spinning the ship work out better than the discomfort of living in zero gee? I think we're comparing how comfortable it is to living on Earth, here, and it's never going to get close to that until you get to full-on spinning space station.

By the way, I'm not sure why you think the B5 "have part of the ship spinning, but not all" approach wouldn't work. They also used that concept in 2001: A Space Odyssey, only in that the spinning part was essentially a drum inside the ship that was used for exercise due to the long duration of the mission; in the sequel (2010) the Discovery is tumbling when they find it, because friction between the drum and the ship has caused it to transfer the spin to the ship. In a ship that's not derelict you just need a bit of extra manoeuvring fuel to stop the spin, or else have a counter-rotating mass designed to compensate for the spin.

[Mightysword]

Question is, though, when you're talking about a long duration space mission, at what point does the discomfort of spinning the ship work out better than the discomfort of living in zero gee?

I think it's more than just a matter of comfort but long term health issue as well. Astronauts who spent months in zero G suffer muscles decay and need to go through rehab so they can move around normally again. Having gravity, even if it's not a full G like Earth would do wonder to long term sustainability of space travel.

By the way, I'm not sure why you think the B5 "have part of the ship spinning, but not all" approach wouldn't work. They also used that concept in 2001: A Space Odyssey, only in that the spinning part was essentially a drum inside the ship that was used for exercise due to the long duration of the mission;

I think it would actually easier to do 'work' in zero G anyway, especially heavy labor work (i.e mechanical maintenance). Seeing a good chunk of effort in those kind of works down on earth is about lifting and scaffolding, which is rendered moot in zero G.

Not sure if anyone here played the latest mechcommander game released a few years back called Battletech. The player's flagship is called the Argo and I love how the designer put some thought in on the design. The working area of the ship is still zero G, but the 3 living quarter "pods" are designed to have gravity most of the time. During travels, they fold alone the body of the ship, and use the linear acceleration from the engine to generate gravity. When the ship is stationary or orbiting a planet, they open up and rotate around the ship axis and use centrifuge force to generate gravity. It's probably one of the best design I've seen about space travelling aside from the magic gravity device (ala starwar/startrek ship). Here are 2 pics of the 2 mods:

travel mode

stationary mode

[BrasatoAlBarolo]

For very long trips (years and up), you need some sort of cryo-pods to store people and avoid them age on their way to destination.
If aliens come to Earth, their trip from home may be very short (Dune style), quite short (Star Trek style, so perhaps in the magnitude of weeks / months), or very long (decades / centuries), depending on how fast they can move and the means of transport (warp, wormhole, fart-drive and so on). Even if they were immortal beings, centuries on the void waiting to come here and be bombed / eaten / sexually harassed (depending on my first contact scenarios) would be pretty boring, so I'd expect them to have some sort of "sleep mode".

[Vertigo 7]

Granted the "comfort" level is conjecture from several different authors but they do all tend to agree that the bigger the spinning thing is, the less discomfort the occupants will feel.

Well, yes, that's pretty obvious--the larger the object the slower it needs to spin to provide an effective 1g at the edge. Question is, though, when you're talking about a long duration space mission, at what point does the discomfort of spinning the ship work out better than the discomfort of living in zero gee? I think we're comparing how comfortable it is to living on Earth, here, and it's never going to get close to that until you get to full-on spinning space station.

For health things, this article pretty well summarizes it. I haven't read all of the publications that are referenced but I do believe the term "comfort" is applied liberally to include avoidance of adverse health impacts that can occur due to long term exposure to low/zero gravity.

By the way, I'm not sure why you think the B5 "have part of the ship spinning, but not all" approach wouldn't work. They also used that concept in 2001: A Space Odyssey, only in that the spinning part was essentially a drum inside the ship that was used for exercise due to the long duration of the mission; in the sequel (2010) the Discovery is tumbling when they find it, because friction between the drum and the ship has caused it to transfer the spin to the ship. In a ship that's not derelict you just need a bit of extra manoeuvring fuel to stop the spin, or else have a counter-rotating mass designed to compensate for the spin.

Well, those are science fiction movies/tv shows. They don't accurately represent physics. There is no substance in existence that can reduce a frictional coefficient to 0, even in 0 gravity. Any amount of friction experienced between disparate parts of a ship will cause a transfer of energy.

[red assassin]

By the way, I'm not sure why you think the B5 "have part of the ship spinning, but not all" approach wouldn't work. They also used that concept in 2001: A Space Odyssey, only in that the spinning part was essentially a drum inside the ship that was used for exercise due to the long duration of the mission; in the sequel (2010) the Discovery is tumbling when they find it, because friction between the drum and the ship has caused it to transfer the spin to the ship. In a ship that's not derelict you just need a bit of extra manoeuvring fuel to stop the spin, or else have a counter-rotating mass designed to compensate for the spin.

Well, those are science fiction movies/tv shows. They don't accurately represent physics. There is no substance in existence that can reduce a frictional coefficient to 0, even in 0 gravity. Any amount of friction experienced between disparate parts of a ship will cause a transfer of energy.

You don't need to reduce friction to zero, just counteract it with something. A counterweight spinning the opposite way with an adjustable brake or extra usage of thrusters (though this is wasteful of fuel) would both solve that problem as pjk suggests.

I am largely unconvinced that you need to have a spun and unspun section though; thruster control software can easily compensate for the spin when working out what to fire when (it'll need to compensate for the gyroscope effect anyway if any part of your ship spins), or just stop the rotation for the rare moments the ship is actually manoeuvring and spin it back up when you're only firing the primary engine or coasting.

[pjknibbs]

I am largely unconvinced that you need to have a spun and unspun section though; thruster control software can easily compensate for the spin when working out what to fire when (it'll need to compensate for the gyroscope effect anyway if any part of your ship spins), or just stop the rotation for the rare moments the ship is actually manoeuvring and spin it back up when you're only firing the primary engine or coasting.

That's pretty much what they did in "Interstellar" (which, while it's SF, did have an awful lot of hard science in it)--the ship would manoeuvre in zero-gee, then spin up to provide gravity while it was coasting, which is most of a spacecraft's life especially on a long-duration mission. Yes, you have to burn a bit of extra fuel to spin up and stop the ship as required, but it's not a huge amount.

[euclid]

This may be a tad out-of-date but the question of a spinning part to generate artificial gravity came up during a conference in Orlando in the early 2000. There was a chap from NASA and I kept asking him as to why they don't do it rather than risking the crew to weaken their bones. The answer was somewhat vague but he claimed that they conduct experiments which are sensitive to gravity even if it's generated artificially via a spin. But as I said, it may be out dated.

Cheers Euclid

Edit: Did some digging and this is what seems to be the state-of-art. E.

[Tycow]

Dragging this back to the OP, this video shows attempts to debunk the released footage showing their (likely) terrestrial origins!

https://youtu.be/Le7Fqbsrrm8

Worth a watch.

[fiksal]

Dragging this back to the OP, this video shows attempts to debunk the released footage showing their (likely) terrestrial origins!

https://youtu.be/Le7Fqbsrrm8

Worth a watch.

Very cool, thanks for the link

[Tycow]

Dragging this back to the OP, this video shows attempts to debunk the released footage showing their (likely) terrestrial origins!

https://youtu.be/Le7Fqbsrrm8

Worth a watch.

Very cool, thanks for the link

No problem. The guy is a bit dry but I thought it was informative.

[euclid]

Something worth watching on the question whether we are alone in the universe or not: click

Cheers Euclid

[Observe]

Something worth watching on the question whether we are alone in the universe or not: click

From the video: "Could the probability of life beginning be a number so small that we are alone?"

On the other hand, perhaps all those trillions of stars and planets are alive themselves. Perhaps we need to expand our definition of what life is?

Just another possibility.

[Vertigo 7]

On the other hand, perhaps all those trillions of stars and planets are alive themselves. Perhaps we need to expand our definition of what life is?

If you're saying balls of gas are alive, then every time i rip one im spawning new life.

[brucewarren]

@Observe

This would not help. The moment a star tries to cross the Wall and leave Stormhold she turns to black dust.