# Asteroid DD45 40,000 mile near miss of Earth



## Happy Joe (Mar 4, 2009)

There was a close near impact of a small (200ft) asteroid today;

Earth in near miss asteroid encounter - Science

Could have been a very not good thing...

Enjoy!


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## Saeltari (Mar 4, 2009)

Wow. The comments are quite entertaining. . (not quite in a good way, but entertaining nontheless)


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## Grimward (Mar 4, 2009)

Don't let TEiN see this....


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## Drachir (Mar 4, 2009)

If you like that story then you will really like this.  
2029 A Near Miss Odyssey :: Astrobiology Magazine - earth science - evolution distribution Origin of life universe - life beyond :: Astrobiology is study of earth science evolution distribution Origin of life in universe terrestrial

Three Earth diameters - that is really scary - only 20,000 km.


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## The Procrastinator (Mar 4, 2009)

My brush with fame! I know the bloke who spotted this asteroid (and many many others). Its his job to look for bodies on a possible collision course with Earth. Works at a nearby observatory. So the first person to spot Rama will be him.


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## Cayal (Mar 4, 2009)

Sorry...but why is 40,000 miles a 'near miss'?

That's like being in Russia and saying you were almost hit by the Hiroshima A-Bomb.

I understand on the whole scale of things it is close, but really...40,000 miles is a long long way away.


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## Keldaris (Mar 4, 2009)

Cayal said:


> Sorry...but why is 40,000 miles a 'near miss'?
> 
> That's like being in Russia and saying you were almost hit by the Hiroshima A-Bomb.
> 
> I understand on the whole scale of things it is close, but really...40,000 miles is a long long way away.



you have to remember that it has to pass far enough away to be out of the earths gravitational pull. the moon is ~200,000 miles from earth(might be a little more), and the moon is a hell of a lot bigger than the asteroid...


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## Dave (Mar 4, 2009)

Cayal said:


> ...really...40,000 miles is a long long way away.


Geostationary Satellites are only 23,900 miles, so it is less than twice as far.

And all the comments flaming disgusted on that website were correct, it is old news. I heard about it last week, along with there being nothing to worry about.


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## Saeltari (Mar 4, 2009)

Dave said:


> Geostationary Satellites are only 23,900 miles, so it is less than twice as far.
> 
> And all the comments flaming disgusted on that website were correct, it is old news. I heard about it last week, along with there being nothing to worry about.


 

They may have been correct but a lot of the comments had me questioning the commentors intelligence, in one way or another


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## Dave (Mar 4, 2009)

Saeltari said:


> ...a lot of the comments had me questioning the commentors intelligence, in one way or another



I didn't read into the second page earlier - "I wonder where it would have hit" & "Make your peace with God as our days are numbered" - I see what you mean.


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## Cayal (Mar 4, 2009)

Keldaris said:


> you have to remember that it has to pass far enough away to be out of the earths gravitational pull. the moon is ~200,000 miles from earth(might be a little more), and the moon is a hell of a lot bigger than the asteroid...



You or someone else might be able to answer this. It is probably simple physics.

How strong is the gravitational pull? It can hold the moon in sway, it can pull in an asteroid travelling at ridiculous speeds...but a spaceship/satellite can fly out of it? 

I just imagine it as a spider web of sorts, once you are caught in it, how do you get out?


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## Ursa major (Mar 5, 2009)

Grimward said:


> Don't let TEiN see this....


 

He may already have seen it; from page 2 of the comments:


> *Jim B* Mar 3rd, 2009 - 23:17:29
> Make your peace with God as our days are numbered.


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## chrispenycate (Mar 5, 2009)

Cayal said:


> You or someone else might be able to answer this. It is probably simple physics.
> 
> How strong is the gravitational pull? It can hold the moon in sway, it can pull in an asteroid travelling at ridiculous speeds...but a spaceship/satellite can fly out of it?
> 
> I just imagine it as a spider web of sorts, once you are caught in it, how do you get out?



It's not quite like that. The Earth's gravitational field extends to the edge of the universe (if the universe had an edge, which of course it doesn't, but as it's dropping off as the square of the distance, it is fairly quickly overwhelmed by other sources, like the sun or the galaxy. But at a few tens of thousands of kilometres it's applying quite a large force - megatonnes, at least - to the asteroid, and modifying it's path.

But if its kinetic energy (the rate it's travelling) is greater than its potential it would have to be a very accurate bullseye to hit the planet. Otherwise it just accelerates in, flies past and slows down on the way out. If there wasn't too much atmospheric friction, it should finish up with the same speed, though a different heading.


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