I'm working on a novel where the characters inhabit a rogue planet. Would that planet get hit by more asteroids due to the fact that it isn't orbiting a star? I have a feeling that the distance is negligible, but I can't really find an answer to this question.

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    $\begingroup$ Where is the planet, intergalactic space, interstellar space or wandering through a solar system (with an asteroid-belt/Oort-type cloud)? $\endgroup$ Mar 9, 2023 at 23:03
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    $\begingroup$ Intergalactic space. Probably not populated by a lot of asteroids. $\endgroup$
    – jtb
    Mar 9, 2023 at 23:57
  • $\begingroup$ Well there's your answer : "Probably not." ... "the distance is negligible" ? I have a feeling that you haven't read HHGttG. ... Intergalactic space isn't populated by anything (between galaxies). You want interstellar space (between stars). $\endgroup$
    – Mazura
    Mar 11, 2023 at 0:15

2 Answers 2


Fewer. There is very little in interstellar space. The gravitational attraction of stars pulls most of the material into stellar systems. Furthermore, it keeps it there. To be sure, the orbits and other planets may cause an asteroid to miss a planet, but it will get many chances unless its orbit takes it out of the system. Any given rogue asteroid will get one chance at any rogue planet.

It is conceivable that there might be systems where orbital dynamics protect a planet from asteroids (some scientists believe Jupiter limits the asteroids striking Earth), and some interstellar space where supernovae explosions have driven a lot of asteroids from orbits, where one given rogue planet is more likely to be hit than one given system planet, but by and large, rogue planets will get fewer.

  • $\begingroup$ There are some scientists who believe that the combination of Jupiter and the Moon have protected the Earth from a large majority of the potential impacts, possibly being a great filter solution for Fermi's Paradox. $\endgroup$ Mar 10, 2023 at 14:18
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    $\begingroup$ Yes. If you're truly rogue, then you'd experience a FANTASTIC number of collisions if you plowed through another solar system, but in extrasolar space? No. $\endgroup$ Mar 10, 2023 at 19:41

I upvoted @Mary's answer and you should too, but I'd like to build on it.

It depends...

Mary is absolutely correct that statistically a rogue planet is unlikely to be struck by an asteroid or meteor. But you've not told us where that rogue is. Is it passing through a nebula? How dense is the nebula? I can easily imagine a supernova resulting in an expanding field of gravel that was once a planet moving away from the center of the exploded star. Is it passing through that?

In other words, this is one of those rare questions that can be answered as-is without voting to close it as story-based because, as Mary says, the statistical likelihood of impact in interstellar space is, on average, whomping low.

But this question also has a story-based element in that if you want the rogue to have plentiful asteroid/meteor strikes, there are plenty of natural phenomena that rationalize that result.

It all depends on where the rogue's travels took it.

  • $\begingroup$ Not to mention anything that's tagged along for the ride in it's gravity-well getting just slightly perturbed..... $\endgroup$ Mar 10, 2023 at 5:11
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    $\begingroup$ @AngryMuppet there's nothing like a rogue planet, minding its own business, and then getting kicked in the butt by something it's dragging. $\endgroup$
    – JBH
    Mar 10, 2023 at 5:30
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    $\begingroup$ I thought this as well: Yes, averaged over millennia it'd have hardly any impacts, but there could be times where asteroids pelting the surface are a daily occurrence. Aka any frequency desired for story purposes is perfectly legitimate. You could also have permanent bright streaks across the sky being a myth from a thousand years ago and then finally one single asteroid again (resolving some religious quarrel or whatever). Basically: Do what you want and you'd still be within the hard-science tag that you didn't even ask for :) $\endgroup$
    – Hobbamok
    Mar 10, 2023 at 9:16

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