Supermassive black holes all over the universe are merging (合并), a fate that will eventually come for the black hole at the center of our galaxy (银河系). These magic universal structures at the heart of nearly every galaxy consume light and matter and are impossible to see with traditional telescopes. But now, for the first time, astrophysicists have gathered knowledge directly from these huge universal structures, in the form of gravitational waves that move around through space and time.

Essential to these findings is the detection of complicated gravitational waves, and understanding how they are produced. Any object with mass that is moving causes these waves—invisible bending in time and space that were first theorized by Albert Einstein in 1916 but not detected until roughly 100 years later. In 2015, scientists used the ground-based Laser Interferometer Gravitational Wave Observatory to detect how short, high-frequency gravitational waves from one merger between less massive black holes move around the Earth by less than the width of a single subatomic particle (亚原子微粒).

The findings help confirm what will one day happen to the supermassive black hole at our galaxy’s center known as Sagittarius A, as it crashes into the black hole at the heart of the Andromeda galaxy. “The Milky Way galaxy is on a crash course with the Andromeda galaxy, and in about 4.5 billion years, the two galaxies are set to merge, said Joseph Simon, a member of Nanograv. That merger, he said, will eventually result in the black hole at the center of Andromeda and Sagittarius A sinking into the center of the newly combined galaxy.

“Before now, we didn’t even know if supermassive black holes merged, and now we have evidence that hundreds of thousands of them are merging, said Chiara Mingarelli, another member of Nanograv.

If scientists understand more about the history of the merging supermassive black holes, it could help know how they form in the first place, said Masha Baryakhtar, a physicist who wasn’t involved in the research.

Researchers believe they have found evidence for a hidden ocean on Mimas, one of Saturn’s major moons. This makes Mimas a target for learning more about the origins of life in our solar system.

Saturn has 146 moons orbiting it. The biggest is larger than the planet Mercury; the smallest is roughly the size of a sports field on the Earth. Mimas, which was first discovered in 1789, is one of the major moons and is about 250 miles wide.

Experts used to think Mimas was mostly made out of solid ice and rock. In 2014, astronomers noticed its orbit around Saturn was moving unsteadily. A shaky orbit can be caused either by a core shaped like a rugby ball or a huge liquid ocean beneath the surface. At first, lots of astronomers argued against the suggestion that Mimas had an ocean because there is no sign of it on the surface.

To investigate more thoroughly, researchers looked at images taken by Cassini, a NASA spacecraft sent to study Satun. The images showed that the moon’s orbit around Saturn drifted by about six miles over 13 years. The team’s calculations found that the only way Mimas could move in this way is if it had a hidden ocean under the surface. They think the ocean formed when the moon’s core warmed up and melted some of the ice.

Mimas is just one of many moons that scientists think could have oceans below the surface Ganymede, which orbits Jupiter and is the largest moon in the solar system, has more water in its ocean than all of the oceans on the Earth. Titan, another of Saturn’s moons, is believed to have a salty ocean beneath the surface.

Space agencies want to study these oceans because they might be home to living organisms. However, the ocean on Mimas might not be old enough for life to have emerged there yet. It took hundreds of millions of years for life to develop on the Earth and the ocean on Mimas is relatively young; it is less than 25 million years old.

For years, people have wondered whether there's life on other planets. Scientists may now be closer than ever to answering that question.

Using powerful telescopes, a team of astronomers in South America discovered a new planet, called Proxima b. It circles a star named Proxima Centauri, in the same way Earth circles the sun. Proxima Centauri is the closest star to our solar system.

Scientists believe the new planet has a rocky surface and is similar in size to Earth. More important, they’ve determined that the distance between Proxima b and its “sun” gives the planet a similar temperature to Earth’s.This means it could have liquid water. The presence of water on a planet makes it possible for life to exist there. Scientists refer to planets like Proxima b as “Goldilocks planets” because they are not too hot or too cold, but just right to possibly support life.

Astronomers have found other Goldilocks planets in the past, but none are as close to Earth as Proxima b. Still, the new planet is 4.2 light years from Earth—that is about 25 trillion miles away.

Despite the long distance, astronomers hope to get a much better look at our new-found neighbor one day. But they’ll need to wait until more advanced telescopes are developed. They may also send a robotic spacecraft to investigate the planet.