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Online Comics => Escape From Terra => Topic started by: paddyfool on August 29, 2010, 12:49:30 pm

Title: Half a million asteroids
Post by: paddyfool on August 29, 2010, 12:49:30 pm
Look at them, up there, dancing around and taunting us beyond our steep little gravity well...

Video link, (http://www.youtube.com/watch?v=S_d-gs0WoUw) courtesy of Bad Astronomy (http://blogs.discovermagazine.com/badastronomy/2010/08/27/30-years-a-half-million-asteroids/).

Title: Re: Half a million asteroids
Post by: Scott on August 29, 2010, 11:50:43 pm
Yeah, I saw that video, linked from Freedom's Phoenix a couple of days ago. Pretty spiffy.

What's wild is, despite there being so many rocks out there, when you're in the Belt, you hardly see any of them. It's not the crowded field of hurtling boulders they show in the movies.

Because Space is big. Really, really big.
Title: Re: Half a million asteroids
Post by: wdg3rd on August 30, 2010, 04:20:03 am
Yah.  It's maybe a tenth of Earth's mass, spread in a really wide orbital torus.  But it's almost all accessible, unlike well over 99% of Earth's mass.  (Ask them guys down in Chile how accessible resources are on Earth).
Title: Re: Half a million asteroids
Post by: paddyfool on August 30, 2010, 11:43:00 am
Much less than a tenth - more like 1/2000 (total mass of the main belt is about 3 x1021 kg, of which nearly 1/3 is Ceres, whereas the Earth masses 6 x 1024 kg). 

However you're right about the accessibility, particularly of metals; most of the metal in the Earth has long ago sunk to the core, and we only have access to the upper bits of the crust.  And most of the deposits of many metals there came from asteroids (http://www.sciencedaily.com/releases/2009/10/091018141608.htm), according to some geologists.
Title: Re: Half a million asteroids
Post by: NotDebonair on September 03, 2010, 02:31:58 am
If you have not done so, I strongly recommend that this be viewed in full-screen.