# Can I have a very dense asteroid belt ring around a star?

I'd like to have an advanced civilization that lives in a ring around their sun, but a ring planet just can't work. In this case, they are among densely agglomerated asteroids (with life support, there's no atmosphere or anything) about as far out as our first asteroid belt, and have built bridges, etc. between the asteroids, many of which have been hollowed out for habitats.

Could there be a 'thick,' densely packed ring of asteroids that form a belt around the sun, or how long could that last. Could they be orbiting in a manner that keeps them from clumping together at least for a while? I'm imagining the distance to be like something out of Star Wars, whereby they have managed to stabilize and bridge those rocks.

EDIT: (Additional, maybe superfluous information), as requested.

The intent is to have a continuous civilization (could be far-future human) in a ring around a star. A ring-planet that is not the inevitably impossible ring-planet. The geography is flexible, but to keep it scientifically possible (it might not be), I'll venture a ring of large rocks the majority of which range between 10-20km of size, and several times that distance between each other.

The very basic question (hence the science-based tag), is if this is remotely possible. It sounds like it won't be, at least around a star.

EDIT2: I wonder, if I reduce the size of the rocks to mere meters (e.g. - 20m diameter) orbiting, if it allows for bouncing off each other, but remaining dispersed such as this, for at least human scales of time, say 30,000 years. If this introduces a new question, please let me know, and I'll remove this edit and add a new question.

• If you can define dense scientifically (i.e. open space vs asteroid space) that may help, thick, densely is sorta vague. – James Aug 26 '15 at 18:19
• @James - asteroids of varying size, but of the 'useful' ones, an average diameter of 10-20km (?) and varying distance, with the average spacing being about 5 or 6 asteroids, such as the precedent image I provided. – Mikey Aug 26 '15 at 18:23
• Could these asteroids be placed close together artificially? So most of the belt would be like a regular asteroid belt, but some places are clumped together due to human intervention? – DaaaahWhoosh Aug 26 '15 at 18:26
• I can't quite tell from the picture what the number density is, because the 3D perspective is nil and there are size variations. Can you give me a hard number for that? – HDE 226868 Aug 26 '15 at 21:58
• I'll make an edit, but it sounds like no matter what, it won't be possible. Please see edit. – Mikey Aug 27 '15 at 4:52

This won't work.

The reason that asteroid belts can persist is that they don't have enough mass to accrete into a planet. If an asteroid belt had the density depicted in typical science fiction (meters or kilometers apart) there would be far more than enough mass to collapse into a planet. Which they would promptly (on an astronomical scale) do.

In our asteroid belt the distance between asteroids is, on average, about 2 million miles and its entire mass is about 4% that of our moon.

The solution is to have these aliens inhabiting a ring system of a planet. Saturn's rings, for instance, are made up of rocks that are on the order of meters apart.

• Do you have an explanation for why Saturn's rings are so much more densely packed? One that might account for why it couldn't just be scaled up? – DaaaahWhoosh Aug 26 '15 at 19:34
• @DaaaahWhoosh It's the same issue, mass. – Samuel Aug 26 '15 at 19:42
• Mass of the individual rocks, or the entire ring? Could you have a ring of large, close asteroids around a planet, or a ring of small, close rocks around a star? Or does the size and distance between orbiting bodies scale up or down based on the mass of the object they're orbiting? – DaaaahWhoosh Aug 26 '15 at 19:55
• @DaaaahWhoosh The entire thing. The entire mass needs to be low or it needs be inside the roche limit of the body its orbiting. – Samuel Aug 26 '15 at 19:58
• All right, so last question: might such a ring as the OP desires be plausible within the Sun's Roche limit? As far as I can tell, as long as the mass of the ring isn't greater than the mass of the sun, it doesn't matter how much there is, nothing big can form without being destroyed by tidal forces. – DaaaahWhoosh Aug 26 '15 at 20:14

No. Not like in the picture. Even Saturn's rings are usually enhanced for dramatic effect when shown up close in movies. The real universe is really sparse and boring.

The asteroid belt in our solar system is a good example of an actual astroid belt around a star. Some people say that it was created by two planets with intercepting orbits smashing together. The asteroids are so far apart that you cannot see two of them at the same time with the naked eye. The real universe is not going to deviate far from here.

If you want a dense ring like that to live on you'll need to go within the Roche limit of a degenerate body.

• Why a degenerate body? – HDE 226868 Aug 26 '15 at 23:10
• @HDE226868 Nothing else will allow you enough mass without frying the asteroids in it's glow. – Loren Pechtel Aug 27 '15 at 3:13