The Sun -An Invisible Killer?

An often unacknowledged fact of life on Earth is the fact that species death is a way of life. It's estimated that between thirty billion and 4,0000 billion species of organisms have existed since life began. A number that is certain, however, is the fact that 99.99 percent of all species that ever lived, are no longer walking, crawling, burrowing, or breathing on Earth.

In short, most species have an average lifespan of about four million years -just about were the species homo sapiens is right now. The five major extinction events that have ravaged the planet have been blamed on oxygens depletion of the seas, giant asteroid and comet impacts, massive volcanic upwelling, epidemics, leaks of methane gas from the sea floor, global warming, global cooling leading to Snowball Earth, and, perhaps most lethal of all, catastrophic solar flares.

Since we've only been tracking solar flares since the beginning of the Space Age, we have no real idea of how massive solar flares can become. A solar flare occurs when magnetic energy that has built up in the solar atmosphere is suddenly released. Radiation is emitted across virtually the entire electromagnetic spectrum, from radio waves at the long wavelength end, through optical emission to x-rays and gamma rays at the short wavelength end. The amount of energy released from a single flare is the equivalent of millions of 100-megaton hydrogen bombs exploding simultaneously!

But we do know that a rogue flare, a solar tsunami of 100 times a normal flare would release the energy equivalent of billions of hydrogen bombs and spew into space hundred of billions of tons of murderous gamma rays that could overwhelm the natural defenses of the Earth's magnetosphere and atmosphere and zap all living creatures in its path. And mostly the most fascinating fact about this gruesome scenario is that it would left no, zero trace in history.

With a natural cycle averaging out at approximately 11 years, the sun is typically a storm of flares and sun-spots the size of planets, causing electromagnetic havoc and radiation problems within its sphere of influence. That influence can reach all the way to earth, and will often trouble astronauts who have to deal with the heightened levels of radiation as they patrol the skies.

It looks as if that this won’t be a problem for the next little while, with the sun being observed to have fallen in to a solar-minimum; essentially, a time of very little activity.

According to a report by NASA the sun is almost spotless. This lack of sun spots can often last for up to several days, and marks the epoch of the solar-cycle.

Over time, the sunspots will restart marking the beginning of the next cycle, and they will build to what is obviously known as the solar-maximum, a time denoted retroactively as being the time of greatest activity on the suns surface.

This activity consists of the creation of sunspots – a region of the photosphere of the sun that is marked by a drop in temperature compared to that around it – and solar flares – a violent explosion in the atmosphere of the sun that heats plasma up to millions of kelvins.

Posted by Josh Hill and Casey Kazan.

Related Galaxy Posts:

"Sunshine": The Voyage to Save to Sun --A New SF Film Classic?

 

Link 1: NASA

Link 2: Solar Flare

Link 3: Sunspot

Link 4: Sun

Comments

[JerryB]

"In short, most species have an average lifespan of about four million years -just about were the species homo sapiens is right now."

"Four million years"? Could you cite a source for that?

Yes, we can, Leakey & Lewin, "The Sixth Extinction," page 38. My best, Casey.

[newqed@shaw]

It seems to me solae cycles vary between 9 or 10 years and 11 or 12 years Comment ?

[newqed@shaw]

It seems to me solae cycles vary between 9 or 10 years and 11 or 12 years Comment ?

[Gary]

Is it possible that we have no idea what we are doing out there in space? After reading the article about the suns abilities, I tend to think there may be far more going on than we have ever thought! Maybe more correctly, what is it we don't know and we send human astronauts out there truly not knowing what dangers we are subjecting them too! It seems to me that we are so preoccupied about accumulating space data, we have given little attention to the safety factors of our astronauts!?

[John T]

And how does the Earths magnetic field protect us from X- and gamma photons?

[ganeshbrhills]

Gary:

The solar wind is a high-velocity plasma, streaming off the Sun in all directions at an average speed of 400 kilometers per second. In a few major bursts, the sun produces gamma rays with energies up to one million electron volts.

The magnetic field - or the magnetosphere - acts as a shield, forcing the particles to travel around the planet rather than bombarding the atmosphere or surface. The magnetosphere is roughly shaped like a hemisphere on the side facing the Sun, drawn out in a long wake on the opposite side.

Such battering of the magnetosphere is more intense during space storms, when solar flares give the solar wind an unusually high velocity/density, and a more powerful magnetic field configuration - typically a coronal mass ejection caused by release of magnetic energy by the sun.

(Incidentally, such impacts temporarily deform the Earth's magnetic field, inducing large electrical ground currents on our planet; turning into a geomagnetic storm. Such impacts move protons and electrons down toward Earth's atmosphere, where they form the aurorae.)