Astronomers Want To Hunt Down Earth's Mini-Moons 44
astroengine writes "The Earth has one permanent moon — you know, 'The Moon' — but at any given time there are thought to be two temporary interlopers that were once asteroids, but get captured by our planet's gravity to become mini-moons for a few months or even years. They eventually get flung back out into interplanetary space. This ultimate 'catch and release' provides an interesting opportunity for any future asteroid mission. So now astronomers want to find them, possibly using the newly-minted Hubble-class spy telescopes donated to NASA by the National Reconnaissance Office."
What a letdown (Score:5, Funny)
I was six when I learned that the Man on the Moon wasn't real. And now I'm hearing that he doesn't even do his own stunts.
Re: (Score:1)
Re: (Score:3)
Yes Sheldon.
Wacky physics, or... (Score:3, Informative)
They left out the part that it's not the Earth alone somehow capturing and releasing these objects, it's the interaction between Earth's gravity and the moon's gravity that can result in a temporary capture.
Re:Wacky physics, or... (Score:4, Insightful)
They left out the part that it's not the Earth alone somehow capturing and releasing these objects, it's the interaction between Earth's gravity and the moon's gravity that can result in a temporary capture.
And the gravity of the Sun, Jupiter, Mars, and your neighbor's Honda Civic... and that's just the tip of the iceburg. Pick a flower, and you move the furthest star. However, listing everything that plays a role in this (which is, literally, everything) is rather cumbersome, so it's fair to simply list the one object that has the greatest influence and leave out the 10^80 other objects involved.
Re: (Score:3)
it's fair to simply list the one object that has the greatest influence
I'd go one step further and include the Sun. Solar gravity gradients are within the same order of magnitude as those of the Moon.
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Way to make an argument. Don't bore people with the details.
Do you work for Fox News ?
Re: (Score:2)
Way to make an argument. Don't bore people with the details.
Do you work for Fox News ?
No, I just can't be bothered arguing.
Re: (Score:3)
If the Earth, the Moon, and the asteroids were the only objects in the universe, the capture would still happen the way it does. If Earth, the asteroids, and the rest of the universe were still present but the Moon wasn't there, it wouldn't. (The asteroids might still be captured by Earth's gravity, of course, but not in the way they are now.) So I think you don't really understand OP's point.
Re: (Score:2)
And the gravity of the Sun, Jupiter, Mars, and your neighbor's Honda Civic... and that's just the tip of the iceburg
I knew Dirk Gently was right about "the fundamental interconnectedness of all things"!
Mini moons? (Score:3)
Re: (Score:3)
so the NRO actually found them (Score:1)
Cruithne (Score:2)
Re: (Score:1)
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Cruithne [wikipedia.org] has been referred to as Earth's Second Moon, but it is really in orbit around the Sun in 1:1 orbital resonance with the Earth, whatever that means.
Co-orbital asteroid. They count as moons if you stretch the definition of 'moon' a bit, as they do trace a complete orbit of the Earth itself (except those that don't obviously).
Re: (Score:1)
where did we get the quantity 2? (Score:2)
Having read the article, the Earth may have any number of temporarily captured asteroids.
Where did the idea come that we have two of them?
Not moons. (Score:2)
If the objects only temporarily orbit the Earth, they're not moons.
If the objects orbit the Earth-Moon system, they're not moons.
I know it's pedantic, but accuracy is important, even on /..