Neptune is the eighth and farthest known planet from the Sun in the Solar System. In our Solar System it is the fourth largest planet by diameter, the third most massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth, slightly more massive than its near twin Uranus. Neptune is denser and physically smaller than Uranus because its…
Pluto, which now has a “minor planet designation” is a dwarf planet in the Kuiper belt which is a ring of bodies beyond Neptune. It was the first Kuiper belt object to be discovered and is the largest known plutoid or ice dwarf. Pluto is the largest and second most massive (after Eris) known dwarf planet in our…
A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems. A galaxy is held together by gravity. Our galaxy, the Milky Way, also has a supermassive Black Hole in the middle. Some galaxies are spiral-shaped like ours. They have curved arms that make it look like a pinwheel. Other galaxies are…
A nebula is a giant cloud of dust and gas in space. Some nebulae (more than one nebula) come from the gas and dust thrown out by the explosion of a dying star, such as a supernova. Other nebulae are regions where new stars are beginning to form. For this reason, some nebulae are called “star nurseries.” Most nebulae…
Star clusters are groups of stars. There are two types of star clusters. Globular clusters are tight groups of hundreds or thousands of very old stars which are gravitationally bound and Open clusters which are more loosely clustered groups of stars, generally they contain fewer than a few hundred members, and are often very young. Open…