Q: What would happen if a black hole passed through our solar system?

Astronomer: Most black holes form when a star which is ten times more massive than our Sun runs out of fuel for fusion. This causes the star to collapse, explode as a supernova, and, if enough material is left over after the explosion, becomes what is called a stellar black hole. A black hole is an object with such a high density that even light doesn’t travel fast enough to escape its gravity. Something that falls into a black hole can never escape, because nothing can travel faster than the speed of light.

What would happen if one of these stellar black holes wandered into our solar system? Very Bad Things. The first indication we might get that something unusual was happening would be subtle changes in the orbits of the outer planets. These changes would be detectable at least by the time the black hole was a few hundred thousand times the distance between the Earth and the Sun.

By then the black hole would be near the outer reaches of the solar system, in an area filled with icy comet-like objects called the Oort cloud. It’s possible that the gravitational disruption caused by the black hole traveling through the Oort cloud could gravitationally catapult a large number of additional comets into the inner solar system, some of which might strike Earth or other planets. If the black hole passed through only this outer part of the solar system, for example if it were moving too fast to be strongly affected by the Sun’s gravitational influence, an increase in comets in the inner solar system might be the only effect we would observe.

At this point we likely wouldn’t see anything at the black hole’s position, even if we looked with the best available telescopes. The black hole itself doesn’t doesn’t give off light, and the only way we might detect it is through the energy released when it consumes some gas. Even the black hole’s affect on the light from stars behind it – which causes the light to be bent into an apparent ring around the black hole – would be too small for us to see. Only until the black hole reaches the inner edge of the asteroid belt would we be able to directly observe the light-bending effects of the black hole. By this point, the effects on the Earth’s orbit would be extreme and it’s likely the black hole would have become visible through its interaction with one of the outer planets.

If the black hole continued to move toward the inner solar system, the orbits of the planets would continue to be disrupted in dramatic ways. Jupiter, the most massive planet, might be snared by the black hole due to their strong mutual gravitational attraction. The black hole would pull gas from Jupiter, forming a bright disk of swirling, hot gas. The hot gas disk gives off x-ray radiation. Despite the fact that Jupiter is thousands of times larger than the black hole, the black hole is thousands of times more massive than Jupiter and easily wins. Jupiter is entirely consumed onto the relatively tiny black hole.

A black hole eating the sun. Om nom nom.

By this time, the Earth is already in grave trouble. The gravitational effects of the black hole have caused earthquakes and volcanic eruptions more extreme than those ever seen before by humans. The Earth would be pulled out of its usual orbit, possibly experiencing abrupt changes in direction or being pulled away or towards the Sun. By the time the black hole crosses Earth’s orbit the geologic effects from tidal forces will have effectively repaved the Earth’s surface with magma and wiped out all life. Since the Sun contains 99.9% of the mass of the solar system, the Sun and the black hole experience a strong gravitational pull towards each other. The black hole would approach the Sun, whose gas is stripped and pulled into the black hole. The Earth, whose inhabitants have already died, would approach the sun/black hole pair, heat up, be torn apart by gravitational forces, and then be pulled into the black hole itself.

Now that we’ve set this morbid scene, you might wonder how likely is it that a black hole will wander into our solar system, causing widespread death and destruction. Here, at least, we have some good news. With what we know today, it seems exceedingly unlikely to happen anywhere in the galaxy (except at the very center), much less our own solar system. Distances between black holes are huge, and the density of black holes is less because we are in the outer third of our galaxy. In addition, most black holes aren’t zipping around the galaxy at high speed, which makes them far less likely to encounter a solar system.

(picture credit: University of Warwick/ Mark A. Garlick)

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70 Responses to Q: What would happen if a black hole passed through our solar system?

  1. Rex Z-06 says:

    How common are other stars consumed by black holes.

  2. coolish says:

    will our sun become a blackhole and will it hit other galaxies

  3. Abbey Pharr says:

    Highly unlikely that the sun would do that but if so it wouldn’t matter if we were sucked in because we can’t live without it.

  4. Wasabi says:

    “Most black holes form when a star which is ten times more massive than our Sun runs out of fuel for fusion.”

    Our sun will definitely not become a black hole. Even if it somehow did, it would be billions of years in the future and we would be long gone or an interstellar race. Also, it is unlikely it would reach other galaxies; it would probably stay inside the Milky Way, possibly eventually being sucked into our central black hole. Or it would become attached to another galaxy as it collides with our galaxy if the two galaxies do not fuse.

  5. Hypatia says:

    There is some great simulation software available to show such an event.


  6. Brian says:

    This may be a silly question, but is gravity “faster” than light? If black holes, supposing they exist, are defined as objects so dense that not even light can escape it then does that mean that gravitational forces exceed the speed of light?

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  8. HY says:


  9. Landen says:

    How does earth orbit the sun?

  10. Stefenie Dowel says:

    i study stars,and i am a scientist, so i have concluded that black holes can be really dangerous, but they will probably be not dangerous to us, so you see that they are formed thousands of light years away and will probably never get to our solar system.

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  12. Chris Rasko says:

    If our sun became a black hole on it’s own, it’s mass would be unchanged, and therefore there would be no gravitational affects on the rest of the solar system. But we would all freeze to depth!

  13. tempestteacup says:

    What happens on the far side of a black hole?

    Does it have anything to do with dark matter?

  14. deshapriyabarik says:

    I know the black hole gravity same as sun gravity.it Will not harmful to us. and I know also that black hole is like a black body, it will absorb energy.so, I’m confused …..

  15. M.VEERA BHADRU says:

    when was Sun turn into black hole?

  16. how did you shouts the black hole images?

  17. how was our space born?

  18. i want to study outer space. i am just 11 years old and i’m very interested in our Our Solar System. now, if the sun becomes a black hole, we won’t frezze to death but we will all die.look, how do you know that the sun will not become a black hole? see, all stars will become a black hole, the sun or OUR sun will become a black hole for sure. but, do you think the sun will die? well, not really because the sun will die when ten centuries has passed.your questions and ideas are very good but, you need to make sure that they are real facts about outer space.

    P.S: like i said, i’m just 11 years old, so i am not too young to know all this scientific facts, you know.

  19. Miles Christopher says:

    Sorry about this, but a large amount of the things you just said are wrong. First, if the sun somehow became a black hole we would freeze most definitely freeze to death, second, in order for a star to become a black hole it needs to be much much bigger than our sun. The reason for this is that, when a star runs out of it’s fuel, the reactions within it stop, and the pressure that was stopping all of the gasses inside of it from being compacted together due to gravity cease to exist. After a long while of compressing in on itself, the repulsive forces of electrons are enough to stop the compression, causing what is commonly known as a white dwarf. When a star much larger than ours runs out of that material, the gravitation force is strong enough to overpower the electrons, and collapses to a super-dense object with almost no volume, a black hole or singularity. On a final note, the sun will last much longer than ten centuries, which is equivalent to 1,000 years, according to most calculations the sun will expand into a red giant in 5 billion years, before collapsing to a white dwarf.

  20. Matthew Adeeko says:

    If light has no mass, then why is it affected by gravity?

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