[rileyj]

I was wondering if the ozone layer or magnetic field or a combination of both, prevents solar radiation from cooking our planet? and how?

[Noah]

The Ozone protects living beings on Earth from receiving the otherwise lethal doses of radiation that is emitted by the sun by reacting with the particles, and absording certain wavelengthes from the sun (such as UV radiation). The magnetic field catches some of the particles ejected from the sun, but they for the most part colide with the north and south poles. But during a period of high solar activity, the radiation from the sun can cause problems with electronics.
The atmosphere also acts as an insulator, to prevent the surface temperature from getting too hot or too cold.

This site may help explain it a bit better, although it is a lot to read
http://books.nap.edu/books/0309051487/html/50.html

[Freethinker]

Nova, a Science series on US Public TV, did an incredible show not long ago on the earth's magnetic field. It dicusses how it shields us from the solar storms and radiation from them. More so, it documents polarity reversals in the earth's field. Seems we are probably in the early stages of another reversal.

While there had been some talk about the earth's poles reversing occasionally, it seems it happens much more often that we had ever expected. In fact the earth is WAY past due for a reversal.

You can see the show and many extensive details at:

http://www.pbs.org/wgbh/nova/magnetic/

[rileyj]

yeah that was a good show. i thought that the ozone and magnetic field blocked solar radiation not absorded. i know the ozone allows some waves through, but isn't the reason there are nothern and southern lights is because thats the only place radiation can get through and funnel down. but which does the most to prevent it?

[Tormod]

Northern and southern lights are caused by plasma from the sun hitting the atmosphere when following the magnetic fields around the poles, yes. That is one of the ways we are protected.

Here is a site about Northern Lights:
http://www.northern-lights.no/


Radiation from the Sun cannot be completely blocked, only minimized (that's why you get a sunburn if you sit in the sun too long without suncream). The ozone layer helps minimize this radiation.

After all - if all the particles from the sun where blocked, we wouldn't see it. Protons and neutrons are what constitue the solar wind, which is deflected by the magnetic field. The photons hitting the upper surface is what we see as sunlight.

Tormod

[Tormod]

An interesting point is that Mars has only a marginal magnetic field, mostly in the southern hemisphere. It is speculated that any previous atmosphere on Mars may just have been blown away by the solar wind as the planet's interior cooled. The atmosphere on Mars today is extremely thin, and more of it is constantly being ripped away.

Mars did have a more substantial magnetic field billions of years ago. This is shown by the polarity of iron in very old rocks. Thus, Mars may once have had a much denser atmosphere, too.

What creates a magnetic field in the first place? It is believed that Mars has no molten interior. On Earth, the molten interior and a solid iron core makes the planet somewhat like a spinning dynamo, which in theory creates the magnetic fields.

Here is a page from NASA about the magnetic fields on Mars:
http://science.nasa.gov/headlines/y2001/ast31jan_1.htm


Tormod