Recent comments in /f/space

Spiritual_Navigator OP t1_j9257o3 wrote

Reply to New auroras detected on Jupiter's four largest moons by Spiritual_Navigator

"Astronomers have discovered new auroras over Jupiter's four largest moons: Io, Europa, Ganymede, and Callisto, observable at visible wavelengths. The new auroras reveal in greater detail the composition of the thin atmospheres of these Jovian moons, including traces of oxygen and sodium, but only minimal water vapor. "

Never expected that moons could have auroras

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spork3 t1_j91w2zp wrote

Reply to comment by Flamingotough in Where does space really begin? Chinese spy balloon highlights legal fuzziness of ‘near space’ by HarpuasGhost

What I like about 100 km is that it’s place where two different fields independently agree that space begins. The Karman line is an aeronautic definition, but space physicists also define the space boundary at about 100 km based on composition. It’s about where the ionosphere begins and the mesosphere ends. As a physicist, I had never heard of the Karman line until somewhat recently, so it was interesting to learn that the what many people use to define the boundary for space is the same as what I knew it to be.

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Alexthelightnerd t1_j91ltq4 wrote

Reply to comment by abstractengineer2000 in Where does space really begin? Chinese spy balloon highlights legal fuzziness of ‘near space’ by HarpuasGhost

The problem is not everyone agrees that it's the correct line, there are several options. Even when there isn't much consequence to the distinction, people can't agree on it - see Blue Origin and New Shepherd.

When talking about international law, there's even less agreement. The mechanism for creating an international standard isn't particularly clear, nor are enough nations probably willing to agree for it to be feasible at all.

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