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Long lines. Narrow seats. Baggage fees. You recognize this list. It's the downside of flying on modern commercial airlines. And now we have a new item to add: neutrons.
Spaceweather.com and Earth to Sky Calculus have just completed a 5-continent survey of cosmic ray neutrons at aviation altitudes. From Dec. 2018 through Feb. 2019, Hervey Allen of the University of Oregon's Network Startup Resource Center carried Earth to Sky radiation sensors including neutron bubble chambers onboard commercial flights from North America to Europe, Africa, South America and Asia. Neutrons from deep space were detected on every flight.
Hervey logged 83 hours in the air as he traveled 41,500 miles above 30,000 feet. For reference, that's almost twice the circumference of the Earth. The entire time, he gathered data on X-rays, gamma-rays and neutrons in an energy range (10 keV to 20 MeV) similar to that of medical radiology devices and "killer electrons" from the Van Allen Radiation Belts.
The results were eye-opening. During the trip, Hervey recorded 230 uGy (microGrays) of cosmic radiation. That's about the same as 23 panoramic dental x-rays or two and a half chest X-rays. Moreover, 41% of the dose came in the form of neutrons. This confirms that cosmic-ray neutrons are abundant at aviation altitudes and must be considered in any discussion of "Rads on a Plane."
https://spaceweatherarchive.com/2019/03/12/neutrons-detected-on-commercial-airplane-flights/
(Score: 2) by Immerman on Friday March 15 2019, @03:52PM (6 children)
Evaporation doesn't rely on boiling, and happens at pretty much any temperature. It accelerates as you approach boiling, and slowing it will reduce the equilibrium humidity somewhat, but it's not going to fundamentally alter the process.
Especially if we're only talking 2atm instead of Venus's 90atm. Assuming vaporization was the primary cause of atmospheric pressure increase, we'd be talking about ~103% of the current atmospheric mass being water, instead of 3%. So about 33x the amount of greenhouse gasses. That might not be truly Venus-like, but it'd be close enough that we couldn't survive.
(Score: 0) by Anonymous Coward on Friday March 15 2019, @04:07PM (5 children)
If you want Temperatures like Venus you need pressures like Venus (even higher since Earth is farther from the sun). You can find ~1.5 atm down some mineshafts and see the temperature already rises 42 K:
http://nopr.niscair.res.in/bitstream/123456789/2506/1/IJRSP%2037%281%29%2064-67.pdf [niscair.res.in]
(Score: 2) by Immerman on Friday March 15 2019, @04:24PM (2 children)
I don't want temperatures like Venus - temperatures too high to support complex life are quite sufficient for us to be "Venus-like" enough for me.
(Score: 0) by Anonymous Coward on Friday March 15 2019, @04:33PM (1 child)
Which is what temperature? The moon goes up to nearly 400 K, so if you aren't worried about the pressure aspect then I would say you are thinking more of a "moon-like" than "venus-like" situation.
https://www.sciencedirect.com/science/article/pii/S0019103516304869 [sciencedirect.com]
(Score: 2) by Immerman on Friday March 15 2019, @04:47PM
Peak temperatures are rather irrelevant, you can always find somewhere to hide. And the Moon's average temperature varies between 215K at the equator, to 104K above 85* latitude.
Meanwhile the Earth's average is currently 287K, and only has to increase by 86C to make it awful difficult to find liquid water on the surface (well, a bit more to compensate for increased pressure, but even increasing it to 10atm only increases the boiling point by about 70C, we don't have to get anywhere near Venus's average of 735K to make life as we know it impossible.
(Score: 1) by khallow on Friday March 15 2019, @05:55PM (1 child)
Because the Earth is warm. From your article:
(Score: 1) by khallow on Friday March 15 2019, @05:56PM