bob haller wrote:

On Wednesday, May 31, 2017 at 5:15:43 PM UTC-4, Fred J. McCall wrote:
wrote:

"Space will be unusable within 20 years unless something is done to clean up the
170 million pieces of debris orbiting the Earth and constantly growing in number.

That's the opinion of Dr Ben Greene, CEO of Space Environment Research Centre
(SERC), who today (31 May) hosted an event in Canberra, Australia, to figure out
how to clean up Earth's orbital space."

See:

http://www.ibtimes.co.uk/space-will-...expert-1624141


Space is big. Really, really big.


big certinally. however the debris tend to expand and collide and create even more junk


And much of it tends to reenter over time all by itself. Think about
it, Bob. Total energy has to be conserved. So in a collision, part
of the energy of the system goes to breaking things up. A big chunk
of the debris have a lower orbital velocity than the original pieces.
That chunk of stuff will dip lower into the atmosphere and lose more
velocity to air drag. It eventually reenters and burns up. Much of
what's left will be disturbed to orbits we don't care much about.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn