On Earth, gravity is fairly consistent, but our perception of it is not. People are better at judging how objects fall when they are sitting upright rather than lying on their sides, according to research published in the journal PLoS ONE in April 2011. The discovery implies that our perception of gravity may be based less on visual cues of gravity's true direction and more on body orientation. The findings could pave the way for new strategies to assist astronauts in dealing with microgravity in space.

Even on Earth, gravity isn't perfectly balanced. The globe's mass is distributed unevenly because it is not a perfect sphere. In addition, uneven mass results in slightly uneven gravity. One mysterious gravitational anomaly can be found in Canada's Hudson Bay (shown above). This region has lower gravity than other regions, according to a 2007 study, and now-melted glaciers are to blame.

The Sun is a very large sphere, with a diameter 109 times that of the Earth. Inside the Sun, you could fit 1.3 million Earths. Alternatively, you could flatten 11,990 Earths to cover the Sun's surface. That's significant, but there are much bigger stars out there. For example, if placed inside the Solar System, the largest star known to us would almost reach Saturn.

Astronomers believe the Sun (and the planets) formed around 4.59 billion years ago from the solar nebula. The Sun is currently in the main sequence, slowly depleting its hydrogen fuel supply. However, the Sun will eventually enter the red giant phase, where it will swell to consume the inner planets, including Earth, in about 5 billion years (probably). It will shed its outer layers before contracting to the size of a white dwarf.

Temperatures on the Sun's surface reach 6,000 Kelvin. However, this is far less than the atmosphere of the Sun. The chromosphere is a region of the atmosphere located above the Sun's surface, with temperatures reaching 100,000 K. That, however, is insignificant. The corona, which extends to a volume larger than the Sun itself, is an even more distant region. The corona can reach temperatures of one million degrees Celsius.

The $700 million New Horizons probe is just the size of a grand piano, weighing in about 1,000 pounds. On Tuesday morning, it completed the nine-year, 3-billion-mile trek to Pluto, passing within 6,000 feet of the dwarf planet at 31,000 mph and taking the closest images of Pluto ever taken.

Jupiter is the largest planet in the solar system, as everyone knows from school. However, this is a bit of an exaggeration. Jupiter is by far the most massive cosmic body in the solar system, with a mass 2.5 times that of all other planets combined. It is nearly 318 times more massive than Earth, and to match Jupiter's diameter, 11 Earths would have to be lined up next to each other.