If the sun went out and our atmosphere froze solid, what color would it be?
I read that without the Sun's heat, the Earth's atmosphere would precipitate out into oxygen and nitrogen snow. What colour would this be?
The short answer: Solid oxygen is clear with a very pale sky-blue color, and solid nitrogen is clear and colorless. If our atmosphere froze solid and turned into snow, it would probably look much like normal snow, since water ice is clear and colorless or light blue.
The long answer: Now we know what color the atmosphere would be, but let's find out more. How much snow would there be? The earth's atmosphere has a mass of about 5000 trillion metric tons (this can be estimated using atmospheric pressure, newton's law Force = Pressure / Area = Mass x Acceleration, and the earth's gravitational acceleration and the surface area). If we assume that the "snow" formed when the atmosphere freezes has a density comparable to freshly fallen water snow (about 100 kg/m^3), then we can find the depth of the frozen atmosphere.
Depth of "Snow" = Atmosphere's Mass / Density of Snow /Surface Area
Using numbers that I looked up online, and making sure all the units work out, I calculate about 100 meters of frozen atmosphere will snow out onto the surface.
Thankfully, the sun will keep shining for another 5 billion years or so. Some places in the solar system still have to worry about their atmospheres freezing solid, though. Triton, a moon of Neptune may have wispy clouds of frozen Nitrogen in its tenuous atmosphere, and Pluto and the other objects far out in the Kuiper belt show evidence of frozen nitrogen and methane on their surfaces. These frigid worlds are so distant that the sun looks like just a bright star in their skies.
Get More 'Curious?' with Our New PODCAST:
- Podcast? Subscribe? Tell me about the Ask an Astronomer Podcast
- Subscribe to our Podcast | Listen to our current Episode
- Cool! But I can't now. Send me a quick reminder now for later.
How to ask a question:
If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist
This page has been accessed 15919 times since September 12, 2006.
Last modified: September 12, 2006 12:38:55 AM
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.
Warning: Your browser is misbehaving! This page might look ugly. (Details)