The enormous visitor to our solar system may have been about 8 times the mass of Jupiter, and come nearly as close to the sun ...

However, it is now considered a dwarf planet instead. The universe has billions of galaxies, and our solar system is in the Milky Way Galaxy. The Milky Way contains at least 100 billion other ...

With a radius of 3,959 miles, Earth is the fifth largest planet in our solar system, and it's the only one known for sure to have liquid water on its surface. Earth is also unique in terms of ...

With a radius of 2,106 miles, Mars is the seventh largest planet in our solar system and about half the diameter of Earth. Its surface gravity is 37.5 percent of Earth’s. Mars rotates on its ...