[cal823]

I was talking to my dad, and he said that at any moment, we could look into the sky, and see funny lights like the aurora boreallis, and be like "oooh, thats pretty" and then die a few seconds or days later.
Apparently that would be a solar flare from the sun hitting the earrth. I've been told that solar flares can and have shot out that far enough from the sun to hit earth in the past, we've just been lucky enough not to be in the way.
What exactly would a solar flare impacting the earth do? How long would it take, and what would the series of events be?
How probable is this?

[Capuchin]

Solar flares eject huge amounts of charged matter towards the Earth. However the Earth's magnetic field protects us completely from them.

In 2005 the biggest ejection of protons from a flare ever recorded was observed, the protons took 15 minutes to reach the earth indicating a speed of 1/3 the speed of light.

These flares are of great concern to manned space missions and high-orbit satellites with sensitive electronics, but they don't pose any threat to us on the surface of Earth.

[Capuchin]

Here's a picture :)

[cal823]

Thank god! The idea of a flare of solar energy shooting out from the sun scared me!

[Capuchin]

See how the particles are channeled toward the north and south poles? That's why we see aurora there when the particles interact with the atmosphere. Most of the particles are deflected into free space though. It's very common and there's no need to worry unless the magnetic field weakens.

[cal823]

Thanks for the answers! They've been really helpful, id rep you, but apparently I need to spread rep around.

[Fr_Chuck]

well first of course you can't see a solar flare with your eyes, and they run in cycles,
and they are not going to destroy the earth, sounds like someone watching too much sci-fi channel movies



As the magnetic energy is being released, particles, including electrons, protons, and heavy nuclei, are heated and accelerated in the solar atmosphere. The energy released during a flare is typically on the order of ergs per second. Large flares can emit up to ergs of energy. This energy is ten million times greater than the energy released from a volcanic explosion. On the other hand, it is less than one-tenth of the total energy emitted by the Sun every second.

There are typically three stages to a solar flare. First is the precursor stage, where the release of magnetic energy is triggered. Soft x-ray emission is detected in this stage. In the second or impulsive stage, protons and electrons are accelerated to energies exceeding 1 MeV. During the impulsive stage, radio waves, hard x-rays, and gamma rays are emitted. The gradual build up and decay of soft x-rays can be detected in the third, decay stage. The duration of these stages can be as short as a few seconds or as long as an hour.

Solar flares extend out to the layer of the Sun called the corona. The corona is the outermost atmosphere of the Sun, consisting of highly rarefied gas. This gas normally has a temperature of a few million degrees Kelvin. Inside a flare, the temperature typically reaches 10 or 20 million degrees Kelvin, and can be as high as 100 million degrees Kelvin. The corona is visible in soft x-rays, as in the above image. Notice that the corona is not uniformly bright, but is concentrated around the solar equator in loop-shaped features. These bright loops are located within and connect areas of strong magnetic field called active regions. Sunspots are located within these active regions. Solar flares occur in active regions.

The frequency of flares coincides with the Sun's eleven year cycle. When the solar cycle is at a minimum, active regions are small and rare and few solar flares are detected. These increase in number as the Sun approaches the maximum part of its cycle. The Sun will reach its next maximum in the year 2011, give or take one year.

A person cannot view a solar flare by simply staring at the Sun. (NEVER LOOK DIRECTLY AT THE SUN! EYE DAMAGE CAN RESULT.) Flares are in fact difficult to see against the bright emission from the photosphere. Instead, specialized scientific instruments are used to detect the radiation signatures emitted during a flare. The radio and optical emissions from flares can be observed with telescopes on the Earth. Energetic emissions such as x-rays and gamma rays require telescopes located in space, since these emissions do not penetrate the Earth's atmosphere.

There effects can effect radio signals and communications on earth

Source: Solar Flares

[cal823]

Cool! Thanks for the explanations, I sort of understand them a lot better now.
Just one question.
What's Kelvin?

[Capuchin]

Kelvin is a temperature scale. It's the same as Celsius but it has 273 added on to the temperature so 0 Celsius is 273 kelvin.

[Fr_Chuck]

Kelvin
Abbreviated K. A unit of absolute temperature. Zero degrees Celsius is equal to 273.16 Kelvin.
It is a unit of mearsure of temperature used in a lot of science.

Source: Solar Physics Glossary

[cal823]

Thanks everyone for your help :)

[Capuchin]

If we didn't have the magnetic field, we would die in a matter of seconds, not from solar flares in particular, the solar wind would be plenty to kill us. The Earth wouldn't really be destroyed. Other planets survive just fine without a magnetic field.

[asterisk_man]

Take that picture yourself did you Capuchin? ;)

[Capuchin]

Yes, with a magnetic field camera.