If you're the kind of person who follows me, you may know about the Kessler Syndrome.
That's when collisions between satellites and space junk create enough debris to cause *more* collisions, leading to a runaway chain reaction. This could render certain regions of near-Earth space unusable!
It's one of nature's ways of containing stupid civilizations, sort of like how inflammation contains infections. So don't be surprised:
A new study by Lewis and Kessler argues that we've hit the "runaway threshold" - the point where a chain reaction is expected - at nearly all altitudes between 520 and 1000 kilometers.
Below that, or above that, space could remain usable. So we could still get out and ruin other layers of space - or go to other planets and mess up those. Luckily, planned deployments of large satellite constellations like Starlink, Amazon's Project Kuiper, etc. will reduce the risk of such a breakout.
Yes, I'm joking - we can differ on whether the expansion of stupidity into the cosmos would be a good or bad thing compared to a mostly dead cosmos, and I don't really have an opinion on that. But the study is for real, and worth checking out:
• Hugh G. Lewis and Donald J. Kessler, Critical number of spacecraft in low Earth orbit: a new assessment of the stability of the orbital debris environment, conference.sdo.esoc.esa.int/pr…
Thanks to @michael_w_busch for pointing this out.
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John Carlos Baez
in reply to John Carlos Baez • • •In case you're curious: Lewis and Kessler say that if the population of objects in some zone exceeds the "unstable threshold", collisions will drive it up to some higher value, but that higher value could be stable. If it exceeds the "runaway threshold", it will keep growing indefinitely.
This is obviously based on some sort of simplification, since the paper says "if the number of intact objects exceeds the runaway threshold, the fragment population will run away over an infinite amount of time to an infinite number of fragments."
You can have larger and larger numbers of smaller and smaller fragments, but the model must not bother figuring out what happens when the fragments become molecule-sized. That's okay.
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zl2tod
in reply to John Carlos Baez • • •Face Thumb
in reply to John Carlos Baez • • •Tor Iver Wilhelmsen
in reply to John Carlos Baez • • •BashStKid
in reply to John Carlos Baez • • •- an order of magnitude increases in sat numbers is going to go wrong
- Starlink already have to actively trim orbits several times a day to avoid collisions
- there’s no way to fix this, nor is there any control on sat design
- that’s far, far too much aluminium in the upper atmosphere.
Marc
in reply to John Carlos Baez • • •Marc (@corpsmoderne@mamot.fr)
Mamot - Le Mastodon de La Quadrature du NetGreengordon
in reply to John Carlos Baez • • •Uh oh:
"A new study by Lewis and Kessler argues that we've hit the "runaway threshold" - the point where a chain reaction is expected - at nearly all altitudes between 520 and 1000 kilometers."