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14 votes

Why is Ganymede's aurora only visible in ultraviolet while Earth's is bright green and red?

Quoting from Nat.Geo. article (which has that same UV image), Then, in 2010 and 2011, Hubble took a close look at the moon. More specifically, it looked at the auroral bands ringing Ganymede’s ...
Carl Witthoft's user avatar
7 votes

Why do Auroras only occur in polar regions?

The reason is because of Earth's global magnetic field. Take a look at the image below which shows a representation of what the magnetic field lines around Earth look like. What you see above is what'...
zephyr's user avatar
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6 votes
Accepted

Could Ganymede's aurora be seen with the naked eye?

The aurora depicted in the artist's conception is of ultraviolet light. It would not be seen with the naked eye. "NASA's Hubble Space Telescope observed a pair of auroral belts encircling the Jovian ...
Bob516's user avatar
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6 votes
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How come the northern and southern lights are the same?

As most people are aware when they play with bar magnets, magnetic poles repel magnets of the same polarity and attract opposites. Magnets have two polarities: north and south. Electric charges are ...
FJC's user avatar
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3 votes

I spotted a very small, quite foggy but uniform aurora-type looking green light in the sky, but I live near the equator

I can't be sure but what you saw could have been a small iridescent cloud in the dark of nightfall. To see if it could have been the case, try read https://earthsky.org/earth/iridescent-clouds-have-...
Alchimista's user avatar
2 votes
Accepted

What is the difference between aurorae and electroglow?

Aurorae are caused by charged particles (usually electrons) being drawn into the polar atmosphere by the planet's magnetic field. Airglow is caused by just photons interacting with the atmosphere. ...
IronEagle's user avatar
  • 641
1 vote
Accepted

Can cosmic rays alone produce noticeable aurorae in bodies far away from the Sun?

You may be interested to learn that Jupiter experiences aurora on its poles nearly (if not totally) non-stop. These aurora never cease, because they do not rely entirely on the sun as their source of ...
Sigismund's user avatar
  • 168
1 vote

Auroras: is there any bump in frequency at certain times of night, or times of year?

Magnetic midnight occurs when the sun, the observer and the magnetic poles are in the same plane. This occurs around local midnight: In the USA it is about 1 hour before local midnight, in the UK it ...
James K's user avatar
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