Make your own free website on

The Solar System

Image courtesy of MSU Ceres Project.

It is very hard for people to conceptualize the distances of the solar system and the universe. Astronomers use Astronomical Unites to measure the solar system. One Astronomical Unit (AU) is the average distance of the Earth and Sun, which is 93 million miles. To measure distances out side of the solar system, light years are used. One light year is equal to how far light travels in one year, about six trillion miles, the speed of light is 186,000 miles per second. In the descriptions below, there will also be distances in light minutes. If the sun were to burn out like a light bulb, the distance in light minutes would be how long it would take a person on one of the planets to see the light fade to black. The above image is not to scale as to the distances between the planets, it is to give you an idea of how they compare in size to each other. The descriptions below will give you an idea of just how big the solar system really is, there will also be descriptions of the Asteroid belt, which lies outside of Mars orbit, and the Kuiper belt and Oort cloud, which lie in the far far reaches of the solar system. The age of the solar system is estimated to be 4.5 billion years.

Greek Name: Helios -- Roman Name: Sol

The Sun is 860,000 miles in diameter, it is by far the largest object in the solar system. It contains 99.8% of the mass of the solar system. The suns energy output is around 386 billion billion megawatts, it is produced by nuclear fusion reaction. Every second about 700 million tons of hydrogen are converted into about 695 million tons of helium, producing about 5 million tons of energy in the form of gamma rays.

In 4 to 5 billion years the sun will become a Red Giant, at this point in its life it will swell in size (10's to 100"s of times its current size) enough to encompass the orbits of Mercury and Venus, of course life on Earth will cease to exist, as the atmosphere will be burnt away, the oceans will boil off and the land will be burnt worse than any desert. After a few million years of this, the sun will blow off its outer layers to create a Planetary Nebula, it will then become a White Dwarf star, and cool over time until it is no longer visible. A typical white dwarf is smaller than Earth, about the size of the United States. It is also very dense and hot. A spoonful of white dwarf material on Earth would weigh as much as a car.


The Roman god of commerce, travel and thievery.

Diameter: 3,032 miles. Average distance from sun: 36 million miles.

Distance in light minutes:3.2

Rotation period: 59 earth days

Revolution period: 88 earth days.

Number of moons:0.


The Roman goddess of love and beauty.

Diameter: 7,521 miles. Average distance from the sun: 67 million miles.

Distance in light minutes: 6.01

Rotation period: 243 earth days.

Revolution period: 225 earth days.

Number of moons:0.


The Earth is the only planet without a Greek/Roman mythology name,the name is derived from Old English and Germanic

Diameter: 7,926 miles. Average distance from the sun 93 million miles.

Distance in light minutes: 8.32

Rotation: 24 Earth hours.

Revolution: 365 Earth days.

Number of moons:1.


The Roman god of war.

Diameter: 4,222 miles. Average distance from the sun 142 million miles.

Distance in light minutes: 12.67

Rotation: 1 Earth hours.

Revolution: 687 Earth days.

Number of moons:2.

The Asteroid Belt:

Asteroids are rocky metallic objects, left over from the formation of the solar system. Some Astronomers believe that asteroids are the remains of a Protoplanetary that was destroyed in a massive collision long ago, the popular view is that asteroids are leftover rocky matter that never successfully coalesced into a planet. Most asteroids orbit the sun between Mars and Jupiter, and some past Saturn. Some are known to orbit inside of Earths orbit, these are known as Near Earth Objects or NEO's.


The king of the gods in Roman mythology.

Diameter: 88,846 miles Average distance from the sun 483 million miles.

Distance in light minutes: 43.27

Rotation: 10 Earth hours.

Revolution: 12 Earth years.

Number of moons:48.

If Jupiter would have been 50 to 100 times more massive, it would have been a star. As it is, it does not contain enough mass to ignite nuclear fusion.


The Roman god of agriculture.

Diameter: 74,898 miles Average distance from the sun 888 million miles.

Distance in light minutes: 1.3 hours

Rotation: 11 Earth hours.

Revolution: 29 Earth years.

Number of moons:30.


The ancient Greek deity of the Heavens, the earliest supreme god.

Diameter: 31,763 miles Average distance from the sun 1,784 million miles.

Distance in light minutes: 2.7 hours.

Rotation: 17 Earth hours.

Revolution: 84 Earth years.

Number of moons:2.


The Roman god of the sea.

Diameter: 30,775 miles Average distance from the sun 2,794 million miles.

Distance in light minutes: 4.2 hours

Rotation: 16 Earth hours.

Revolution: 165 Earth years.

Number of moons:8.


The Roman god of the underworld.

Diameter: 1,485 miles Average distance from the sun 3,647 million miles.

Distance in light minutes: 5.5 hours

Rotation: 6 Earth days.

Revolution: 248 Earth years.

Number of moons:1.

The Kuiper Belt And Oort Cloud:

The Kuiper belt was just a theory until 1992 when astronomers became aware of a vast number of small bodies orbiting the sun beyond Neptune at 30 to 50 AU's. Also know as the Oort cloud, it is thought that long period comets come from this cloud when they are perturbed by the gas giants like Jupiter or Saturn, they can also be perturbed by a passing star. Although the closet star is 4.5 light years away, its gravity reaches billions of miles.

Here are some links to other websites that will give you a wealth of information on the planets and there moons.

The Nine Planets

Astronomy 161 The Solar System