The supermassive black hole at the heart of the neighboring galaxy M87 has the mass of 6.6 billion suns. It's the biggest black hole to be precisely measured, and it's us our best shot at really seeing these strange objects.

The internet is burning up with the news that the zodiac has been rearranged. There's a 13th sign, Ophiuchus, and people who think they're Virgos are actually Leos. What happened here? We talked to the astronomer who caused the fuss.

Saturn's moon Iapetus has a gigantic ridge running along its equator that's twice the height of Mount Everest and covers 75% of the moon's equator. And its existence points to something stranger still: Iapetus once had its very own moon.

Saturn's rings are among the most iconic sights in the solar system, but where did they come from? Long ago, an icy moon was ripped apart by Saturn's gravity, creating rings once a 100 times bigger than they are now.

The discovery of a fourth gas giant around the star HR 8799 doesn't seem like that big a deal, but it's become the latest flashpoint for a highly controversial and often intense debate about how gas planets are born.

Far away in the frozen outermost depths of our solar system, there might be a hidden planet four times the size of Jupiter. This secret companion to the Sun could be responsible for sending comets into the inner solar system.

We've discovered 500 exoplanets, most of them gas giants even bigger than Jupiter. But some, known as super-Earths, are rocky worlds only a bit larger than our planet, and now we've discovered the cloudy atmosphere of one of these worlds.

Check out that extra-bright galaxy towards the top of this image. That's an elliptical galaxy, which are among the largest galaxies in the universe. And now scientists believe these galaxies hold five to ten times more stars than previously thought.

Large groups of galaxies come together to form clusters, and those clusters are linked together by vast streams of hot gas known as filaments. These intergalactic links reach temperatures well over a million degrees and are almost completely invisible...until now.

At the furthest edges of our solar system lies the vast Oort Cloud, a hypothetical giant shell full of billions of frozen comets. Formed 4.5 billion years ago, the cloud is a frozen museum of the chemistries of neighboring stars.