How did supermassive black holes form in the early epochs of the universe? More importantly, how did they have enough time to grow as large as they did? The answer requires a very different universe. And back then, conditions were much different than they are now. There was a lot of gas, little dust, no stars, and a plethora of dark matter. Astronomers have spent decades observing early quasars, massive active galaxies powered by huge black holes feeding on surrounding gas. But these galaxies are seen so early in the universe’s history, one starts to wonder how a black hole finds sufficient...
A direct consequence of Einstein’s theory of general relativity, and an observational way to prove it, is gravitational lensing. It requires a powerful gravitational source to work, such as a galaxy or cluster of galaxies. It works in a similar way to a lens of glass, where rays of light are bent toward a single source, increasing the brightness. In this case, instead of glass, the bending of the rays is due to the curvature of space. Light rays coming from the source would otherwise miss Earth, but instead are bent toward us when there is a massive object in front of it. It’s...
How do stars lose mass? For a star like the Sun, it shoots out a swath of charged particles into space and sheds mass at a rate of 4 million tons per second! Though even at this rate, the Sun only loses 1% of its total mass every 160 Billion years, so it’s not disappearing anytime soon. For more massive stars, the process can become complex and strange. The red hypergiant VY Canis Majoris, one of the largest known stars, is about 40 times as massive as the Sun, but humungous in scale. If this star were to replace the...
When the launch of the James Webb Space Telescope comes a few years from now, we will have then opportunity to probe deeper into the cosmos than ever before, to see things we had only dreamed of seeing previously. Among the prime targets for this modern marvel of human ingenuity are potentially habitable exoplanets, where future humans could live, provided there isn’t already life occupying the real estate. To help astronomers assign importance to the growing number of exoplanets, researchers at the University of Washington’s Virtual Planetary Laboratory have devised an index to represent the habitability of worlds, near and...
For years there has been talk of a subsurface ocean present within Saturn’s icy moon Enceladus. Many have simply assumed it to be fact, but the reality is, something so complex on a world so far away is very difficult to prove conclusively. But now, using data from over a decade of observations by the Cassini spacecraft, mission scientists have shown conclusively that Enceladus must have a global ocean beneath a surface of ice. Previous data analysis suggested that there was a lens-shaped liquid ocean beneath the south polar region of the planet, giving a source for the observed plumes...
Welcome to a new series of posts that will characterize 1000 amazing facts about the Universe. There is so much out there that we have yet to learn, and every day, astronomers across the globe are using their research to reveal the deepest secrets of the cosmos. This series will look at the strangest, coolest, most exciting facts that we have discovered in hundreds of years of modern science. Fact #2: There are more Galaxies than you could possibly count. Our night sky is jam-packed with stars. If you’ve ever left the city to go far beyond the reach of...
A vast number of Galaxies in the Universe have a central black hole that is incredibly massive. The Black Hole at the centre of the Milky Way, dubbed Sag A*, is estimated to have a mass as high as three Million Suns. We generally can’t see black holes, but when they start to pull in matter from surrounding gas and dust clouds, the material forms a disk around the star. This accretion disk can heat up to incredible temperatures and emit X-rays and other high energy light, allowing us to see where the black holes are. Sometimes the light from...
