Is it just dumb luck that our probes (e.g. Juno, Voyager I, Voyager 2) never collide with even the smallest rocks in space? Is space in our solar system so void that the odds of a collision are so low? Does NASA (and other global space programs) have details about natural debris throughout our solar system that they can avoid collisions through navigation?
In: Physics
The average distance between asteroids in the asteroid belt is around 2.5 times the distance between the earth and out the moon.
So the asteroid belt do not look like movies at all.
The average size of the asteroids is relatively small if you were on one it is very unlikely that you would be able to see the light for any other.
If you were close to one of the large one you could likely see it but in most cases, you would not. The larges is Ceres with a 27% the diameter of the moon
[Ceres and Vesta, Moon size comparison](https://en.wikipedia.org/wiki/Asteroid#/media/File:Ceres_and_Vesta,_Moon_size_comparison.jpg)
For a sense of scale here, you can put every planet in the solar system between the Earth and the Moon (sorry Pluto, you don’t count)
Space is extremely large and the objects within it are extremely small by comparison. The asteroid belt isn’t what you see in Star Wars with dense asteroids bouncing off each other, its a couple big hunks of rock that are separated by millions of miles from the next sizable chunk of rock. 30% of the total mass in the asteroid belt is in Ceres, if you steer around the 4 big ones then the odds of hitting anything are super low.
There’s always a chance that a random rock could take out a billion dollar probe just like there’s always a chance you could find a winning powerball ticket on the sidewalk. Its not a very big chance, but it could technically happen.
“Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.” – Douglas Adams
Okay that’s kind of a joke quote but space IS vastly, hugely, mind-bogglingly big. Think… motes of dust in an auditorium for solar systems (how likely is that dust to smack into each other in the next hour, really)… and then, think of how far apart auditoriums are from each other and pretend there is NOTHING between them.
There is a LOT of nothing out there.
Space is really big. Like, OMG big. Think if you put all space probes ever made in one place. They would probably fit in your house. Now think of the distances in space. You could fit 13 trillion Earths in the area formed by a sphere the size of Earth’s orbit around the sun.
That’s a lot of space for a few Earth probes and a smattering of asteroids.
>Is space in our solar system so void that the odds of a collision are so low?
yes. And most objects of significant size are captured in the asteroid belt, they’re not just wandering free in the middle of space
it’s like putting a couple of friend at random spots on a football field and having them all throw tennis balls in the air. The odds of any two colliding are just astronomically (heh) small
We do have a lot of information about where most of the major asteroids are in the solar system (although at the time a lot of these deep space probes were launched, we knew significantly less). However, we also knew at the time that planets and other massive celestial bodies (like moons) tend to clear their orbits of debris (either by slinging it away or absorbing it). This means that, aside from the astroid belts and the legrange points (which are spots on/around an objects orbit around a larger object that smaller objects can also orbit safely), most of the solar system has been emptied of space debris.
Outside of that, the only major concern is debris in the Kuiper belt (like a second astroid belt out past neptune) and dust from the Oort cloud (a sphere of dust on the edge of the solar winds, the theoretical limit of our solar system’s influence). But the Kuiper belt is flat (so you could jut go over/under it and the Oort cloud is super far away.
many of the large asteroids that pose a risk to earth are cataloged and you can check them out as well as all things space weather [here.](https://spaceweather.com/) But, most of it really occurs because the asteroids are following large gravitational pulls and usually circle around a large body of mass before they either crash into it or burn up in the atmosphere of the celestial body there are orbiting on their entry. so most of it is dumb luck that they don’t intersect any asteroids path, but also because the probes and satellites don’t have enough mass to change the gravitational orbit of the asteroids and cause them to hit the satellites.
Well they have but it was done on purpose.
why not accidentally? well space is big and asteroids are small and far between.
asteroid belts for example do not look like what they look like on tv/ the movies they’re very far apart.
Interestingly Probes are pelted with small bits of stuff, plasma, gasses, radiation etc a lot of these things are too small to do any damage real or in the case of radiation the electronics are hardened against it.
To collect material for future examination they used areogel for sample capture via the Stardust probe. This probe collected both cosmic dust and particles from the tail of the comet Wild 2 and returned it to earth for analysis.
NASA knows where most of the asteroids are and thus knows where the asteroids aren’t. They know that there are so few asteroids that they only check to see if there is a chance of collision because it would be negligent otherwise. Despite checking, they’ve never had to adjust the course of a probe and most probes don’t even spot a single asteroid.
Its hard to appreciate just how much space there is in Space.
The odds of hitting anything while passing through the asteroid belt are so small that NASA doesn’t bother to calculate them for missions crossing through that region. Every asteroid is at least tens of millions of miles away from its nearest neighbor. That’s dozens of times the distance to the moon. If you were standing on one asteroid, you wouldn’t be able to see any others.
Space is empty.
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