We all know the Sun produces U.V. rays and that if you spend too much time sunbathing, you’ll probably get skin cancer. Well, the Sun spews a lot of other stuff into space too. Ultraviolet radiation may be the least of your worries if you happen to live in space.

In addition to U.V. rays, the Sun also produces:

• X-rays: sort of like U.V. rays, only with more energy and, therefore, more harmful.
• Gamma rays: even more energetic and harmful than X-rays.
• Solar ejecta: solar flares and other nasty explosions on the Sun can accelerate protons, electrons, and other little bits and pieces of atoms to ludicrous speeds. Do not stand in their way!

Fortunately, Earth’s atmosphere and magnetic field protect us from most of the Sun’s deadly radiation. Even the crew of the International Space Station are in a low enough orbit that Earth still keeps them safe. Well, safe-ish.

But all this radiation makes human space exploration beyond low Earth orbit extremely hazardous. Before sending astronauts to the Moon, NASA had to wrestle with their collective conscience over how much radiation exposure should be considered acceptable. Now, NASA is wrestling with its conscience again as it plans to send astronauts to Mars.

Current technology cannot protect humans from solar radiation. The problem gets worse with increased solar flare activity. One of the things science fiction writers (like myself) have to figure out is how to keep our characters from dying of radiation sickness within the first few chapters of our books.

P.S.: Starlight can kill you too. In addition to solar radiation, astronauts have to worry about cosmic radiation: radiation from other stars, quasars, and God knows what else.

The Sun as pictured above isn’t exactly lying, but what he’s saying is misleading. The nine eight planets of the Solar System do orbit the Sun, which may give you the impression that the Sun is stationary with respect to the planets. It is not. The Sun wobbles.

This is due to the combined gravitational forces of all the planets, comets, asteroids (and even Pluto) tugging the Sun in multiple directions at once. The effect is small but not insignificant. Over the course of just a few years, the Sun can completely change its position relative to the rest of the Solar System.

The true center of the Solar System is a point in space called the barycenter. The barycenter happens to be located near (and sometimes inside) the Sun. You could say the Sun, planets, and everything else in the Solar System orbit the barycenter, but keep in mind that the barycenter is not stationary either.

If you want to get a better feel for how planets and stars tug on each other through gravity, I suggest checking out the game Super Planet Crash. It’s free. Just click here to start playing.

Sources

One Way to Find a Planet from NASA’s “The Space Place.”

Barycentric Coordinates (Astronomy) from Wikipedia.

The Wobbling Sun from Innumerable Worlds.