Neptune

Neptune is the farthest planet from the Sun (excluding the dwarf planets Eris and Pluto) in our solar system. It is named for the Roman god of the sea and is 17 times more massive than Earth. Neptune orbits the Sun at 30 times the distance of the Earth. Neptune has 13 total moons (its largest being Triton) and has been visited by one spacecraft, the Voyager 2, in 1989. While considered a gas giant, Neptune (and Uranus) has an "icier" composition of water and methane, naming it an "ice giant" as well as a gas giant. The reason the planet appears blue is because there are traces of methane in the planets atmosphere.

Jupiter

Jupiter is the fifth planet away from the sun and the largest planet in our solar system. Jupiter is one of the gas giants, as are Saturn, Uranus, and Neptune. This group of planets is also referred to as Jovian (outer planets) group. Jupiter is mostly made of hydrogen and helium, but its core may have some heavier elements inside it. Jupiter's most noticeable feature is the Giant Red Spot, a storm that has been going on for at least 200 years. Jupiter also has at least sixty six moons, the largest being Ganymede, whose diameter is greater than that of Mercury. Jupiter has been visited by both the Pioneer and the Voyager.

Venus

Venus is the second planet from the sun, and its "year" is about 225 Earth days. Besides the moon, Venus is the brightest object in our night sky, and is named for the Roman goddess of love and beauty. Being a terrestrial planet and having very similar size and gravity to Earth, Venus is considered Earth's "sister" planet. Venus has the densest atmosphere of the four terrestrial planets, consisting of carbon dioxide, but its surface is not visible because of a layer of sulfuric clouds. Though Venus once had oceans, because of its "greenhouse" atmosphere, the temperature rose too high to sustain them.

Mercury

Mercury is the smallest (not including pluto, which is a dwarf planet) and innermost of the planets in our solar system. It's year, or orbit, around the sun is about 88 Earth days. Mercury is terrestrial, meaning that it is a "rocky" planet similar to Earth, Venus, and Mars.

Did you know?: Mercury is actually the second densest planet in the solar system. Just because Jupiter is big doesn't mean it's dense. Earth, surprisingly, is the most dense, but this is only attributed to its gravitational compression (gravity crushing down a planet into being smaller and therefore denser).

Mercury in color

Neutron Stars

Neutron stars are, as the name describes, stars that consist almost entirely of neutrons. Because neutrons have more mass than protons, these stars are extremely dense. These stars can result from a super-massive star collapsing during a supernova. This event is described in the video below (this depiction is actually that of a pulsar, a type of neutron star that emits a beam of extremely bright electromagnetic radiation).

When a star's core compresses into a neutron star, as shown above, its rotation increases incredibly rapidly. However, this effect wears down with time. Neutron stars can suffer gravitational collapse and become a black hole as well. Neil Degrasse Tyson describes neutron stars as so dense that "if you cram 50 million elephants into a thimble, you get the density [of a neutron star]." 

Solar Eclipse of May 20, 2012

A solar eclipse occurs when the moon passes between the Earth and the Sun, partially or completely obscuring the Sun's image. When the moon completely covers the Sun, a ring of light is all that is visible; this is called the Ring of Fire. The May 20 eclipse was visible from the Chinese coast to the Western United States, and it was the first solar eclipse in the United States in the 21st century. The eclipse was also annular, hence the ring that formed when the moon's path crossed completely over the sun. 

Animation of the 2012 eclipse

Ringed shadows formed by the eclipsed Sun's light passing through trees.