Have we found an ancient space habitat?

[Al_]

TL;DR

Fast rotating asteroids could be rotating habitats

Fast rotating asteroids

The rotation is so fast that if there were internal spaces it would have an actual simulated gravitational force inside. This force would be much greater than the small, in fact tiny, gravity from the mass itself.

If there were space stations built and then abandoned thousands or even millions of years ago, they might still be rotating now.

How can we tell if they are artificial? Can we see the surface? Perhaps the surface is covered with shielding made of asteroid material.

Sure, I am using a big helping of imagination here, but I am interested to know which observations could rule out this theory.

 

[DaveC426913]

The article talks a lot, but gets into some numbers down near the end.

It's a pity that after all that business about "could it be artificial gravity?" they leave the magnitude calcs entirely as an exercise for the reader*. (I suspect that the whole "could it be gravity" thing is a figment of the journalist writing the article, not the observatory's study.)


* @Al_ , you're up!


Some exerpts:

"The study presents 76 asteroids with reliable rotation periods. This includes 16 super-fast rotators with rotation periods between roughly 13 minutes and 2.2 hours, and three ultra-fast rotators that complete a full spin in less than five minutes.

All 19 newly identified fast-rotators are longer than the length of an American football field (100 yards or about 90 meters). The fastest-spinning main-belt asteroid identified, named 2025 MN45, is 710 meters (0.4 miles) in diameter and it completes a full rotation every 1.88 minutes. This combination makes it the fastest-spinning asteroid with a diameter over 500 meters that astronomers have found.

"Clearly, this asteroid must be made of material that has very high strength in order to keep it in one piece as it spins so rapidly," says Greenstreet.

"We calculate that it would need a cohesive strength similar to that of solid rock. This is somewhat surprising since most asteroids are believed to be what we call 'rubble pile' asteroids, which means they are made of many, many small pieces of rock and debris that coalesced under gravity during solar system formation or subsequent collisions."

...

In addition to 2025 MN45, other notable asteroid discoveries made by the team include 2025 MJ71 (1.9-minute rotation period), 2025 MK41 (3.8-minute rotation period), 2025 MV71 (13-minute rotation period), and 2025 MG56 (16-minute rotation period). These five super- to ultra-fast rotators are all several hundred meters in diameter and join a couple of NEOs as the fastest spinning sub-kilometer asteroids known."

 

[Ken Fabian]

No reason to think they are artificial and extraordinary claims require extraordinary evidence - but making them increases the views and clicks without any such requirement. Stone and nickel-iron in very large pieces seem possible and mixed rubble bound together with ice is too. Not sure how much spin carbonaceous chondrite type material can take, but a solid piece could probably survive a lot.

Lots of asteroids out there, all spinning. Some will be spinning near to their limit.

They are all presumably in similar unexceptional orbits as other asteroids and unless they are inner solar system or Earth orbit crossing they are 'parked' where there is nothing much happening, for no reason. The reasonable conclusion is they are natural objects.

 

[Baluncore]

Why do aliens need to simulate gravity by spinning a rock ?
Residents, with a vestibular system, could not just look the other way.

 

[DaveC426913]

The fastest-spinning main-belt asteroid identified, named 2025 MN45, is 710 meters (0.4 miles) in diameter and it completes a full rotation every 1.88 minutes.

My calcs show this to have .112g on the inside surface.

I'd weigh 20lbs.

Less than the Moon, where I'd weigh 29lbs.

 

[DaveC426913]

Why do aliens need to simulate gravity by spinning a rock ?

? What would they not need to simulate gravity? Did they not grow up on a planet?

 

[Al_]

No reason to think they are artificial and extraordinary claims require extraordinary evidence - but making them increases the views and clicks without any such requirement. Stone and nickel-iron in very large pieces seem possible and mixed rubble bound together with ice is too. Not sure how much spin carbonaceous chondrite type material can take, but a solid piece could probably survive a lot.

Lots of asteroids out there, all spinning. Some will be spinning near to their limit.

They are all presumably in similar unexceptional orbits as other asteroids and unless they are inner solar system or Earth orbit crossing they are 'parked' where there is nothing much happening, for no reason. The reasonable conclusion is they are natural objects.

One of them is a near-Earth object. The rest are in the asteroid belt.
The asteroid belt could be a source of zero-g materials to an advanced civilization.

But I take your point - extraordinary claims.

If the differentiated core of a minor planet was shattered in a collision, the fragments might well be fast spinning and solid. A suitable place for our advanced civilization to make a habitat perhaps!

Unless someone had beaten us to it.

 

[DaveC426913]

If the differentiated core of a minor planet was shattered in a collision, the fragments might well be fast spinning and solid.

Which is exactly why it is a plausible phenom without speculating about aliens. No evidence points in that direction.

If you wanted to discuss the speculative aspects of it, can I suggest you mosey on over to the sci-fi sub-forum?

 

[Cerenkov]

Then there's the logic behind constructing such a habitat.

Assuming that only a technology many hundreds of years more advanced than us could fabricate such a thing - why would they even want to?

Why bother hollowing out and setting a rocky or metallic asteroid rotating rapidly enough to generate artificial gravity when there four terrestrial planets with a variety of gravities to choose from in this solar system. Or, if you want to push the envelope further, our Moon or Titan too.

If you've already travelled interstellar distances to get here, why make work for yourself when there are a choice of gravity wells to suit whatever your needs are?

I'm sorry, but I just don't see why any self respecting aliens journeying here would even bother.

Thank you,

Cerenkov.

 

[Baluncore]

? What would they not need to simulate gravity? Did they not grow up on a planet?

Then why park in orbit with other asteroids when they could be going somewhere.
Thrust could give them artificial gravity, while accelerating, then decelerating, towards a more viable destination.

 

[DaveC426913]

Then there's the logic behind constructing such a habitat.

Assuming that only a technology many hundreds of years more advanced than us could fabricate such a thing - why would they even want to?

Why bother hollowing out and setting a rocky or metallic asteroid rotating rapidly enough to generate artificial gravity when there four terrestrial planets with a variety of gravities to choose from in this solar system. Or, if you want to push the envelope further, our Moon or Titan too.

etc.

Maybe they like living inside things. The reasons are myriad.

Then why park in orbit with other asteroids when they could be going somewhere.
Thrust could give them artificial gravity, while accelerating, then decelerating, towards a more viable destination.

Maybe they aren't planning a trip.


Both of the above require insight into the hypothetical alien mind, its motives, mission goals and capabilities. Those can't logically be used to argue against a given project.

IMO, the question of what they would do is much wilder speculation than what they could do (given physics), no?

 

[Al_]

Which is exactly why it is a plausible phenom without speculating about aliens. No evidence points in that direction.

If you wanted to discuss the speculative aspects of it, can I suggest you mosey on over to the sci-fi sub-forum?

Yeah, but they just talk about unicorns. Oops, I didn't mean to end the thread.
I like to talk about things that actually could be true. And if anyone knows of any hard evidence - either way.

 

[Al_]

My calcs show this to have .112g on the inside surface.

I'd weigh 20lbs.

Less than the Moon, where I'd weigh 29lbs.

That sounds comfortable. If I were living that far from home, I'd want comfort. And at least 6 meters of radiation shielding.

 

[Baluncore]

Caves and rock shelters on Earth are warmer than being exposed to radiative heat loss to the night sky. The internal thermal gradient of the Earth keeps the rocks warm. The surface rock also averages the night-day temperature distribution on Earth.

A hollow asteroid rock shelter could not benefit from internal heat, like the Earth, as the asteroid would cool rapidly by radiation directly to space, making it the ultimate deep freeze at about -100°C.
A hollow asteroid rock wall, would shelter the occupants from some cosmic rays, and most of the smaller physical impacts, that are to be expected, without an atmosphere, in the asteroid belt.

 

[Ken Fabian]

Why bother hollowing out and setting a rocky or metallic asteroid rotating rapidly enough to generate artificial gravity when there four terrestrial planets with a variety of gravities to choose from in this solar system.

Artificial habitats make conditions just right. Gravity is just one of the potential constraints, but with rotation is readily solvable in space. I suspect planets - where artificial habitats of some sort would very likely be needed anyway - would be more difficult to exploit, not less. A species able to travel interstellar distances seems unlikely to need planets.

One of them is a near-Earth object.

Seems a bit imaginatively paranoid to me to think it is fast spinning because aliens are using it as an artificial habitat, from which to observe Earth. Or as a staging base for invasion/colonization or... whatever. Human capability to dream and imagine is unbounded by physics. And can be unbounded by ethics as well.

Doing major constructions in asteroids of a star far, far away seems so unlikely as to overlap with 'impossibly impractical and unrealistic'.

(Is this thread likely to go the way of the Alien life, probabilities one into moderation and possible closure? - sci-fi speculations, admittedly prompted by the linked article, are taking it beyond the scope of 'astronomy and astrophysics'. I don't object to such speculating or to threads wandering off topic, but it isn't my site and I am not a moderator)

 

[Ken Fabian]

'We would weigh around 20lbs'

That sounds comfortable.

But would it be? As a novelty, for a short time maybe. Longer term probably increasingly uncomfortable - stomach in mouth, burp and fart only with care, helmets or padded ceilings recommended indoors, muscle and bone deterioration.

 

[DaveC426913]

(Is this thread likely to go the way of the Alien life, probabilities one into moderation and possible closure? - sci-fi speculations, admittedly prompted by the linked article, are taking it beyond the scope of 'astronomy and astrophysics'. I don't object to such speculating or to threads wandering off topic, but it isn't my site and I am not a moderator)

I think I'd get murderized if I try to get it moved to sci-fi...

 

[Al_]

Then there's the logic behind constructing such a habitat.

Assuming that only a technology many hundreds of years more advanced than us could fabricate such a thing - why would they even want to?

Why bother hollowing out and setting a rocky or metallic asteroid rotating rapidly enough to generate artificial gravity when there four terrestrial planets with a variety of gravities to choose from in this solar system. Or, if you want to push the envelope further, our Moon or Titan too.

If you've already travelled interstellar distances to get here, why make work for yourself when there are a choice of gravity wells to suit whatever your needs are?

I'm sorry, but I just don't see why any self respecting aliens journeying here would even bother.

Thank you,

Cerenkov.

Why hollow out - the reason is delta-V. Why not find mass that is already moving where you want it to. And why rotate them? - find ones that are already rotating - momentum again.

Who says they travelled interstellar distances - at least in recent times - its all just guessing. Maybe they weren't much more advanced. Maybe they had reason to save on fuel or energy, or whatever.

I admit its an unlikely theory. But - evidence. Bigger telescopes please!

Artificial habitats make conditions just right. Gravity is just one of the potential constraints, but with rotation is readily solvable in space. I suspect planets - where artificial habitats of some sort would very likely be needed anyway - would be more difficult to exploit, not less. A species able to travel interstellar distances seems unlikely to need planets.


Seems a bit imaginatively paranoid to me to think it is fast spinning because aliens are using it as an artificial habitat, from which to observe Earth. Or as a staging base for invasion/colonization or... whatever. Human capability to dream and imagine is unbounded by physics. And can be unbounded by ethics as well.

Doing major constructions in asteroids of a star far, far away seems so unlikely as to overlap with 'impossibly impractical and unrealistic'.

(Is this thread likely to go the way of the Alien life, probabilities one into moderation and possible closure? - sci-fi speculations, admittedly prompted by the linked article, are taking it beyond the scope of 'astronomy and astrophysics'. I don't object to such speculating or to threads wandering off topic, but it isn't my site and I am not a moderator)

Paranoid? Imaginative I will grant.
Not so much "fast spinning because aliens are using it" - more like - aliens are using it because its fast spinning.
Or some life is using it. Or we will.

 

[Al_]

Caves and rock shelters on Earth are warmer than being exposed to radiative heat loss to the night sky. The internal thermal gradient of the Earth keeps the rocks warm. The surface rock also averages the night-day temperature distribution on Earth.

A hollow asteroid rock shelter could not benefit from internal heat, like the Earth, as the asteroid would cool rapidly by radiation directly to space, making it the ultimate deep freeze at about -100°C.
A hollow asteroid rock wall, would shelter the occupants from some cosmic rays, and most of the smaller physical impacts, that are to be expected, without an atmosphere, in the asteroid belt.

"ultimate deep freeze at about -100°C." yes but insulation is much easier in vacuum, and so is arranging to expose it to sunlight.

 

[Al_]

Why do aliens need to simulate gravity by spinning a rock ?
Residents, with a vestibular system, could not just look the other way.

I think you may be referring to the nausea that is caused by turning your head in a small radius rotating environment. But these asteroids are too slowly rotating to cause this as far as we know, although experimental evidence is a bit scarce to say the least. We could ask Elon or Jeff if they would like to firm up the science.

 

[russ_watters]

But they're asteroids? Where would the implication that they could be hollow space stations even come from? It makes no sense and there's no evidence to suggest it could be true.

Thread closed pending moderation but this looks like a (particularly silly) personal theory to me.