Do All Planets Orbit a Star?

It had been believed that all planets orbit a star, but scientists found the first of dozens of free-floating, planet-like objects in 2002 in the constellation Orion. It is not known how these planets came to be. Scientists theorize that the objects might have once orbited stars but were kicked out of orbit for some reason. Another theory is that the planets might have been created through the collapse of dust and gas clouds. In 2012, a free-floating planet named CFBDSIR2149 was discovered less than 160 light years away from Earth, making it one the closest known planets of this type.

More about the planets:

• Jupiter is the largest planet in the Earth's solar system, with a mass that is about 300 times greater than the Earth's mass, but it takes Jupiter only 10 hours to rotate on its axis, the fastest rate of any planet in the solar system.
• Although Mercury is one of the hottest planets in Earth's solar system because it is the closest to the sun, scientists believe that some of its craters might actually contain ice.
• It takes Uranus 84 years to orbit the sun, which means that its seasonal cycles each last for 21 years.