EarthSky // FAQs // Space By EarthSky Jan 25, 2010

Could Earth’s gravity capture an asteroid?

The Earth could capture an asteroid if all the conditions – speed, size and angle – were just right.

Earth could capture an asteroid, but only under certain conditions. The asteroid would have to be a certain size, traveling at just the right speed, and grazing by Earth at just the right angle. For example, a bus-sized asteroid grazing Earth’s atmosphere might be captured by our planet’s gravity. Afterward, moon’s gravity might pull it into a stable orbit above Earth – to give Earth a second moon.

Planetary scientists believe that asteroid capture was common billions of years ago. The planets are thought to have formed by a process of “accretion” – where small chunks of debris came together to form larger chunks. So there were lots more chunks – what we now call “asteroids” – moving through the solar system back then.

Also, dense gas and dust surrounded the forming planets. When an asteroid passed through this material, drag slowed it down – making capture by a planet easier. Mars’ two small moons were probably captured in this way, as were various satellites of Jupiter, Saturn, Uranus, and Neptune. Now asteroid capture is less common – but it is possible if the right asteroid comes along.

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6 Responses to Could Earth’s gravity capture an asteroid?

  1. patrick stotts says:

    Vary cool i didnt no that thank you for telling me i love space so

  2. [...] Earth’s gravity: Earth could capture an asteroid, but only under certain conditions. The asteroid would have to be a certain size, traveling at just the right speed, and grazing by Earth at just the right angle. For example, a bus-sized asteroid grazing Earth’s atmosphere might be captured by our planet’s gravity. Afterward, moon’s gravity might pull it into a stable orbit above Earth – to give Earth a second moon. Planetary scientists believe that asteroid capture was common billions of years ago. The planets are thought to have formed by a process of “accretion” – where small chunks of debris came together to form larger chunks. So there were lots more chunks – what we now call “asteroids” – moving through the solar system back then. –Earth-Sky [...]

  3. [...] Earth’s gravity: Earth could capture an asteroid, but only under certain conditions. The asteroid would have to be a certain size, traveling at just the right speed, and grazing by Earth at just the right angle. For example, a bus-sized asteroid grazing Earth’s atmosphere might be captured by our planet’s gravity. Afterward, moon’s gravity might pull it into a stable orbit above Earth – to give Earth a second moon. Planetary scientists believe that asteroid capture was common billions of years ago. The planets are thought to have formed by a process of “accretion” – where small chunks of debris came together to form larger chunks. So there were lots more chunks – what we now call “asteroids” – moving through the solar system back then. –Earth-Sky [...]

  4. [...] more chunks – what we now call “asteroids” – moving through the solar system back then. –Earth-Sky Share this:TwitterFacebookLike this:LikeBe the first to like this [...]

  5. [...] more chunks – what we now call “asteroids” – moving through the solar system back then. –Earth-Sky Search For Related Stories or [...]

  6. [...] Earth’s gravity: Earth could capture an asteroid, but only under certain conditions. The asteroid would have to be a certain size, traveling at just the right speed, and grazing by Earth at just the right angle. For example, a bus-sized asteroid grazing Earth’s atmosphere might be captured by our planet’s gravity. Afterward, moon’s gravity might pull it into a stable orbit above Earth – to give Earth a second moon. Planetary scientists believe that asteroid capture was common billions of years ago. The planets are thought to have formed by a process of “accretion” – where small chunks of debris came together to form larger chunks. So there were lots more chunks – what we now call “asteroids” – moving through the solar system back then. –Earth-Sky [...]

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