Cosmic Journeys

Feel the pull of the largest object in our galaxy, a supermassive black hole. Astronomers are discovering its properties by probing the stars and small black holes that are buzzing around it.

Scientists have been reconstructing the history of the moon by scouring its surface, mapping its mountains and craters, and probing its interior. What are they learning about our own planet's beginnings?

Our Milky Way may harbor millions of black holes... the ultra dense remnants of dead stars. But now, in the universe far beyond our galaxy, there's evidence of something far more ominous. A breed of black holes that has reached incomprehensible size and destructive power. Just how large, and violent, and strange can they get?

The latest from the planet-hunting frontier. Find out what we are learning about our place in the cosmos from the search for earth-like planets. This journey started tens of thousands of years ago, when humans began to fan out across the planet, following unknown pathways, crossing unmeasured distances. We traced coastlines, and sailed uncertain seas.

Why did Earth thrive and our sister planet, Venus, died? From the fires of a sun's birth... twin planets emerged. Then their paths diverged. Nature draped one world in the greens and blues of life. While enveloping the other in acid clouds... high heat... and volcanic flows. Why did Venus take such a disastrous turn?

The answer to this question may depend on whether Stephen Hawking was right in his theory that describes how black holes shed mass and eventually decay. Time is flying by on this busy, crowded planet as life changes and evolves from second to second. At the same time, the arc of the human lifespan is getting longer: 67 years is the global average, up from just 20 years in the Stone Age.

It was one of the greatest mysteries in modern science: a series of brief but extremely bright flashes of ultra-high energy light coming from somewhere out in space. These gamma ray bursts were first spotted by spy satellites in the 1960s. It took three decades and a revolution in high-energy astronomy for scientists to figure out what they were.

Are the universe and its physical laws so fine-tuned that the rise of life is inevitable? Or is life a fluke, a lucky roll of cosmic dice? We look for the answer in the rise of two important components of life, dust and water.

Astronomers are probing the high-energy cosmic frontier with a series of key missions: Fermi, Swift, Chandra, NuSTAR, and Hubble. Their goal: to find out how the universe works on a fundamental level. This video was inspired by a NASA event at the Smithsonian National Air and Space Museum, where leading scientists delivered the latest news about black holes, supernovae, and gamma ray bursts.

Planet hunters have detected nearly 5000 confirmed and candidate planets beyond our solar system. Most sun-like stars, it seems, are ringed with giant planets that crowd their parent stars and leave no room for planets like ours. The old theories about planetary formation are giving way to a new one defined by fierce gravitational battles and titanic collisions. How did Earth manage to survive?