Most solar companies set the price according to the solar system's wattage. A solar installation's “cost per watt” is a little like the “price per square foot” when you buy a house.

Light gases like helium hung around in the gas-and-dust nebula that formed the solar system for only a few million years. "It's very much debated how long it took the Earth to form," Olson said.

NEW YORK — Seven planets grace the sky at the end of February in what’s known as a planetary parade, though some will be difficult to spot with the naked eye. These planetary hangouts happen when ...

Now, using a powerful NASA supercomputer called "Pleiades," scientists have discovered yet another spiral structure on the edge of our solar system. The spiral is composed of billions of icy ...