Hubble has captured an image of the first-ever predicted supernova explosion. The reappearance of the supernova dubbed "Refsdal" was calculated by different mass models of a galaxy cluster whose immense gravity is warping the supernova's light as the light travels toward Earth. The supernova was previously seen in November 2014 behind the galaxy cluster MACS J1149.5+2223, part of Hubble's Frontier Fields program. Astronomers spotted four separate images of the supernova in a rare arrangement known as an Einstein Cross. This pattern was seen around a galaxy within MACS J1149.5+2223. While the light... Read more

Hunting for faraway galaxies that existed long, long ago is like a fishing trip for astronomers. So far only the "big fish" have been found, bright galaxies that existed just a few hundred million years after the big bang. Now, using the Hubble and Spitzer space telescopes, astronomers have caught a "smaller fish," a very compact and faint early galaxy that was forming 400 million years after the big bang, which happened 13.8 billion years ago.

As there are many smaller fish than big fish in the sea, the new finding is evidence for an underlying population of dim galaxies that must have been common... Read more

Astronomers have discovered a rare beast of a galaxy cluster whose heart is bursting with new stars. The unexpected find, made with the help of NASA's Spitzer and Hubble space telescopes, suggests that behemoth galaxies at the cores of these massive clusters can grow significantly by feeding on gas stolen from other galaxies. The cluster in the new study, referred to by astronomers as SpARCS1049+56, has at least 27 galaxy members, and a combined mass equal to nearly 400 trillion suns. It is located 9.8 billion light-years away in the Ursa Major constellation. The object was initially discovered using... Read more

Astronomers have long wondered how the universe's largest elliptical galaxies continue making stars long after their peak years of star birth. By combining data from NASA's Hubble Space Telescope with observations from a suite of ground-based and space telescopes, two independent teams have uncovered a unique process to explain how this star birth continues. The teams found that that the galaxy's central black hole, jets, and newborn stars are all parts of a self-regulating cycle. In that cycle, jets shooting out of the galaxy's center heat a halo of surrounding gas, controlling the rate at which it... Read more

In particle physics labs, like the Large Hadron Collider in Geneva, Switzerland, scientists smash atoms together to study the underpinnings of matter and energy. On the scale of the macrocosm, nature provides a similar experiment by crashing clusters of galaxies together. Besides galaxies and gas, the galaxy clusters contain huge amounts of dark matter. Dark matter is a transparent form of matter that makes up most of the mass in the universe. During collisions, the clouds of gas enveloping the galaxies crash into each other and slow down or stop. Astronomers found that the dark matter continued... Read more

Three-leaf clover plants abound everywhere: on lawns, in gardens, and in forests. But spotting a four-leaf clover is a rare, lucky find. Astronomers using the Hubble Space Telescope have found the equivalent of a four-leaf clover with the discovery of four images of the same supernova. The images are arranged around a giant foreground elliptical galaxy embedded in a cluster of galaxies. The arrangement forms a cross-shaped pattern called an Einstein Cross. The powerful gravity from both the elliptical galaxy and its galaxy cluster magnifies the light from the supernova behind them in an effect called... Read more

Peering through a giant cosmic magnifying glass, NASA's Hubble Space Telescope has spotted one of the farthest, faintest, and smallest galaxies ever seen. The diminutive object is estimated to be more than 13 billion light-years away. This new detection is considered one of the most reliable distance measurements of a galaxy that existed in the early universe, said the Hubble researchers. Hubble detected the galaxy due to the lensing power of the mammoth galaxy cluster Abell 2744, nicknamed Pandora's Cluster. The cluster is so massive that its powerful gravity bends the light from galaxies far behind... Read more

It seems like our compulsive universe can be downright capricious when it comes to making oddball-looking things in the cosmos. The latest surprise to Hubble astronomers is a 100,000-light-year-long structure that looks like a string of pearls twisted into a corkscrew shape. This Slinky-like structure forms a bridge between two giant elliptical galaxies that are colliding. The "pearls" on the Slinky are superclusters of blazing, blue-white, newly born stars. The whole assembly, which looks like a tug-of-war, must result from the gravitational tidal forces present in the collision.

If that's not... Read more

If you need to check whether the prescription for your eye glasses or contact lenses is still accurate, you visit an ophthalmologist for an eye exam. The doctor will ask you to read an eye chart, which tests your visual acuity. Your score helps the doctor determine whether to change your prescription.

Astronomers don't have a giant eye chart to check the prescription for natural cosmic lenses, created by galaxy clusters. The gravity of these cosmic lenses warps space around them, magnifying and brightening the light from distant objects behind them. Without these lenses, background objects would be... Read more

If someone told you there was an object in space called "El Gordo" (Spanish for "the fat one") you might imagine some kind of planet-eating monster straight out of a science fiction movie. The nickname refers to a monstrous cluster of galaxies that is being viewed at a time when the universe was just half of its current age of 13.8 billion years. This is an object of superlatives. It contains several hundred galaxies swarming around under a collective gravitational pull. The total mass of the cluster, and refined in new Hubble measurements, is estimated to be as much as 3 million billion stars like... Read more