Just to add, if you read the early science fiction stories, there was a lot of discussion of asteroid belts. Even in hard science, Asimov's "Marooned off Vesta", hardest of hard science fiction, starts with a collision in the asteroid belt. That's written way back in 1938 though - long before we had a thorough understanding of these things.
And many movies that have this vision of dense clusters of space boulders. Right to today. But that's an example of a movie trope, that is perpetuated because it gives enthralling images on the big screen, not likely in reality.
Perhaps they get their ideas mainly from previous science fiction movies - or they do this as artistic license to make the movie more dramatic.
Here is a nice youtube talk about the asteroid belt and its depiction in movies and the actuality in real life, by Fraser Cain, publisher of Universe Today.
And here is his article about it in Universe Today: How Dense is the Asteroid Belt?
And see also this Scientific American article: In science fiction movies, the "asteroid belt" is always pictured as a very crowded place. How dense is it really: impossible to navigate, risky or just interesting?
It makes great movies. But - in reality it is the other way around. When traveling through the asteroid belt, you can expect to have to change course by thousands of kilometers just to pass close to a single asteroid close enough to see it.
Now, when it comes to rings, that's different. Cassini when it orbits Saturn has to be careful to avoid dense parts of the rings. It passes through gaps, or through the fainter rings.
When it did its orbital insertion maneuver when it first arrived at Saturn, they targeted a gap in its rings, and they flew it with its high gain antenna n the forward direction as a shield. See NASA Cassini: Ring Plane Crossing of Saturn Up Ahead
In the case of Cassini - a ring particle only 1 mm in diameter could destroy it.
In this video you can actually hear the impacts of tiny dust grains as they hit Cassini as it passes through a less dense part of the ring plane - the visuals of course simulate the crossing as there was no other spacecraft there to observe Cassini:
The "solid" parts of Saturn's rings are far more like the movie pictures of an asteroid belt. This is a modern artist's impression of what they might look like close up.
NASA - Saturn's Recycling Rings
A spacecraft would definitely want to avoid those altogether. It may be some time before we get a photo like this from space.
In the case of New Horizons also as it approached Pluto, they searched for other moons and rings. If they'd spotted a ring, they'd have switched to an alternative path to avoid it, and used a similar strategy to the one used by Cassini for Saturn ring crossing - high gain antenna in the forward direction as a shield.
Also - if you were to pass through the disk of a solar system in the early stages while the planets are still forming, that would also be hazardous, surely. The reason it isn't hazardous today is because most of the matter in the sun's disk has been gathered up in the planets - or else spiraled into the sun, or been ejected from the solar system by the solar winds and by gravitational encounters with the planets.
But no special precautions are ever taken for passing through the asteroid belt - the chance of a collision with anything is thought to be too tiny to be worth taking any precautions against it at all, even flying with high gain antenna as a shield (which would be easy to do if anyone thought there was any point in doing it).
Simulated fly over of Vesta using Dawn data - Vesta is the second largest asteroid in the belt after Ceres.
Full rotation of Vesta as viewed by Dawn. Asimov's first published story in 1938 was "Marooned off Vesta" where the crew are marooned in a damaged ship due to the captain's decision to fly through the asteroid belt rather than fly over it. NASA Cassini: Ring Plane Crossing of Saturn Up Ahead
And many movies that have this vision of dense clusters of space boulders. Right to today. But that's an example of a movie trope, that is perpetuated because it gives enthralling images on the big screen, not likely in reality.
Perhaps they get their ideas mainly from previous science fiction movies - or they do this as artistic license to make the movie more dramatic.
Here is a nice youtube talk about the asteroid belt and its depiction in movies and the actuality in real life, by Fraser Cain, publisher of Universe Today.
And here is his article about it in Universe Today: How Dense is the Asteroid Belt?
And see also this Scientific American article: In science fiction movies, the "asteroid belt" is always pictured as a very crowded place. How dense is it really: impossible to navigate, risky or just interesting?
It makes great movies. But - in reality it is the other way around. When traveling through the asteroid belt, you can expect to have to change course by thousands of kilometers just to pass close to a single asteroid close enough to see it.
Now, when it comes to rings, that's different. Cassini when it orbits Saturn has to be careful to avoid dense parts of the rings. It passes through gaps, or through the fainter rings.
When it did its orbital insertion maneuver when it first arrived at Saturn, they targeted a gap in its rings, and they flew it with its high gain antenna n the forward direction as a shield. See NASA Cassini: Ring Plane Crossing of Saturn Up Ahead
In the case of Cassini - a ring particle only 1 mm in diameter could destroy it.
In this video you can actually hear the impacts of tiny dust grains as they hit Cassini as it passes through a less dense part of the ring plane - the visuals of course simulate the crossing as there was no other spacecraft there to observe Cassini:
Video description:
"The Radio and Plasma Wave Science (RPWS) instrument on Cassini-Huygens measured little puffs of plasma produced by dust impacts. While crossing the plane of Saturn's rings, the instrument detected up to 680 dust hits per second, or roughly 100 000 hits in less than five minutes.
"Scientists at University of Iowa, where the RPWS was designed, converted these impacts into audible sounds that resemble hail hitting a tin roof. "
The "solid" parts of Saturn's rings are far more like the movie pictures of an asteroid belt. This is a modern artist's impression of what they might look like close up.
A spacecraft would definitely want to avoid those altogether. It may be some time before we get a photo like this from space.
In the case of New Horizons also as it approached Pluto, they searched for other moons and rings. If they'd spotted a ring, they'd have switched to an alternative path to avoid it, and used a similar strategy to the one used by Cassini for Saturn ring crossing - high gain antenna in the forward direction as a shield.
Also - if you were to pass through the disk of a solar system in the early stages while the planets are still forming, that would also be hazardous, surely. The reason it isn't hazardous today is because most of the matter in the sun's disk has been gathered up in the planets - or else spiraled into the sun, or been ejected from the solar system by the solar winds and by gravitational encounters with the planets.
But no special precautions are ever taken for passing through the asteroid belt - the chance of a collision with anything is thought to be too tiny to be worth taking any precautions against it at all, even flying with high gain antenna as a shield (which would be easy to do if anyone thought there was any point in doing it).
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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