Is a sun a star or a planet? While science now agrees the sun is a star, new telescopes may soon challenge how we define ...

How far it is from the sun: 886 million miles (1.4 billion kilometers), on average How big it is: 72,400 miles (116,500 km) across, or almost 10 times the size of Earth. How many moons it has: At ...

Earth is our home planet, and it's the only place in the universe where we know for certain that life exists. Earth formed over 4.5 billion years ago from a swirling cloud of gas and dust squished ...

Earth is home, but it’s also full of surprises. Some of these facts might make you stop and say, “Wait, is that true?” Let’s ...

FOR five months the little spacecraft sped through the interplanetary void. Last week, on the 157th day of an arcing, 242-million-mile journey across the solar system Mariner 6 reached its destination ...

Seven planets aligned in the night sky on Friday, Feb. 28, viewable from Earth. A similar planetary alignment with six planets will occur on Aug. 29. The planets appear to align from Earth's ...