5 ms·

Now I'm interested in knowing the value of Earth crust (up to a depth of, say, 1km) according to those measures.

• jessriedel 12y ago
  I dunno about compositions, but: > The combined mass of all of the asteroids is about 25 times less than the Moon's mass (with Ceres making up over a third of the total) http://www.astronomynotes.com/solfluf/s2.htm http://www.astronomynotes.com/solfluf/s2.htm Moon mass: 7x10^22 kg Total asteroid mass: 3x10^21 kg Earth mass: 6x10^24 kg Density Earth's crust: 2.7 g/cm^3 Earth area: 5.1x10^8 km^2 Mass Earth's crust to 1km depth: 1.4x10^21 So all asteroids combined and the Earth's crust down to 2km are very close to the same mass. But like I said, I have no idea about the composition.
  • maaku 12y ago
    Composition would be strikingly different. Elements which are rare in the Earth's crust (and therefore, expensive) are rare because during the formation of the Earth they sank under gravity and now reside near the core of the planet. Chondritic asteroids, on the other hand, are left over from the primordial solar system and have the original relative abundances of rare earth materials. Hence the interest as a source of industrial resources.
  • deleted 12y ago
    [deleted]