Friday, August 10, 2007

The Solar System

Okay, so the three celestial bodies I mention below are not planets, but I'm posting on them because: 1. they're cool, and 2. no tour of the Solar System would be complete without them. There are posts on the rest of the Solar System here, if you're interested. If you're really interested, there's an outstanding book on the subject called Astronomy: A Visual Guide, by Mark A. Garlick. Check it out.

The Sun:
Diameter: 865,000 miles (10,913% Earth)
Mass: 332,946 Earth
Surface Temperature: 9900 F (5500 C)
A giant ball of hydrogen and helium, the Sun makes up 99.99% of the Solar System's mass. Fueled by nuclear reactions in its core, the process releases an enormous amount of energy that slowly travels through the Sun's layers to the surface. Here, it escapes into space as heat and light, which allow life to exist on Earth. The surface is covered with dark spots called sunspots, which are considerably cooler than the rest of the sun.
In about six billion years, the hydrogen fuel will run out, causing the Sun to explode into a red giant, more than 160 times its current size. After this it will become an ember-like white dwarf, destined to fade forever.

The Moon:
Diameter: 2160 miles (27.2% Earth)
Mass: 0.012 Earth
Surface Temperature (daylight): 225 F (107 C)
Surface Temperature (night): -244 F (-153 C)
The Moon is the fifth-largest satellite in the Solar System. It is a lifeless, airless, barren rock. Liquid water has never existed there, and the only force known to have influenced its geography is the fall of meteorites, billions of years ago when the Solar System was young.
Even though the Moon is so far away, it is still able to exert a considerable gravitational pull on Earth. Together with the sun it forms the tides, by raising and lowering the temperature of our oceans.

Comets are the most primitive bodies in the Solar System. They are loose bundles of ice and rock a few miles across, often referred to as "dirty snowballs".
Comets spend most of their time in the frozen darkness at the edge of our Solar System. Occasionally their elliptical orbits bring them them past Earth as they travel around the Sun. Passing into warmer space melts some of the ice, leaving a trail of water which creates the "tails" for which comets are known. These tails can stretch for more than 100 million miles.

1 comment:

Detox said...

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