Sun Rays

30 May 2014 ~Question of the Day~ Sun Rays

What kind of sun rays hit the north and south pole?

There are two major sources of light at the poles, and both come from the sun (other than starlight that is).

Ordinary sunlight is filtered a bit differently at the poles, because it comes in at such a low angle through the atmosphere. At the poles, even at high summer, the sun doesn’t get very high in the sky, like it does over most of the planet. This fact means that the light has to travel through more atmosphere, like it does in the morning and evenings at higher latitudes. So polar light tends to have more of that morning or evening (or winter) quality to it (a little redder and a little colder).
And of course there is no light for months on end at the poles, over the dead of winter.

The other source of light at the poles comes from the Aurora – the northern and southern lights.
This light is formed when charged particles thrown out from the sun during solar magnetic storms hit the Earth’s magnetic field, and get directed by the Earth’s magnetic lines of force into the polar regions. When these high energy charged particles hit the atmosphere they can cause the molecules in the atmosphere to glow if they are of the right energy. The most common auroral color, a pale yellowish-green, is produced by oxygen molecules located about 60 miles above the earth. Rare, all-red auroras are produced by high-altitude oxygen, at heights of up to 200 miles. Nitrogen produces blue or purplish-red aurora.

The solar storms are commonly called sunspots, and their frequency tends to vary on two levels of cycles. One is an 11 year cycle, and one is a roughly 180 year cycle. And there is a lot of variability. The sun has a lot of magnetic fields in its atmosphere, and when one of these magnetic lines gets stretched and breaks, and is pointing in the general direction of earth, we get auroral displays 2 to 4 days later (depending on how violent the break was and how fast the material is flung in our direction). Very large magnetic storms like this are able to take out our satellites and power grids.

And I hope that covers what Shar intended – it’s my best guess at an answer anyhow.

About Ted Howard NZ

Seems like I might be a cancer survivor. Thinking about the systemic incentives within the world we find ourselves in, and how we might adjust them to provide an environment that supports everyone (no exceptions) - see
This entry was posted in Question of the Day and tagged . Bookmark the permalink.

Comment and critique welcome

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s