Astronomy Resource Guide

The galaxy of which the sun and solar system are a part, seen as a broad band of light arching across the night sky from horizon to horizon; if...

Star at the centre of our Solar System. It is about 5 billion years old, with a predicted lifetime of 10 billion years; its...

Dwarf planet. Until its reclassification in 2006 it was considered to be the smallest and, usually, outermost planet of the Solar...

The third planet from the Sun, having the following characteristics: mass 5·97 × 10 24 kg; orbital period 365·26 days...

The second planet from the Sun, attaining the greatest brilliancy in the night sky, outshining all the stars, hence its poetic names...

Fourth planet from the Sun. It is much smaller than Venus or Earth, with a mass 0.11 that of Earth. Mars is slightly pear-shaped...

The fifth planet from the Sun, and the innermost of the giant outer planets. It contains two-thirds of the matter in the Solar System, apart..

Sixth planet from the Sun, and the second-largest in the Solar System, encircled by bright and easily visible equatorial rings....

Seventh planet from the Sun, discovered by German-born British astronomer William Herschel in 1781. It is twice as far out as the...

The eighth planet from the Sun, the outermost of the four ‘gas giant’ planets; discovered in 1846 as a result of a prediction by...