We all know that a humongous black hole exists at the center of our galaxy. It’s called Sagittarius A* (Sgr A* for short) and it has the mass of 4 million suns. We’ve got to see a radio image of it a few weeks back, showing its accretion disk. So, we know it’s there. Astronomers can chart its actions as it gobbles up matter occasionally and they can see how it affects nearby stars. What astronomers are still trying to understand is how Sgr A* formed.Continue reading “The Building Blocks for Supermassive Black Holes are Found in Dwarf Galaxies”
The planets in our Solar System all rotate on axes that roughly match the Sun’s rotational axis. This agreement between the axes of rotation is the typical arrangement in any system in space where smaller objects orbit a larger one.
But in one distant binary system, the large central object has an axis of rotation tilted about 40 degrees compared to its smaller satellite. This situation is even more strange because the main body isn’t a star but a black hole.Continue reading “Astronomers Find a Black Hole That was Somehow Pushed Over Onto its Side”
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The confirmation of gravitational waves back in 2017 continues to unlock whole new worlds of physics but also continues to elicit further questions. The detection of each gravitational wave brings a new challenge – how to find out what caused the event. Sometimes that is harder than it sounds. Now a team led by Alejandro Vigna-Gomez of the University of Copenhagen thinks they found a model of star death that helps to explain some previously inexplicable findings – and points to a galaxy with many more massive neutron stars than previously thought.Continue reading “Gravitational Waves Reveal Surprising Secrets About Neutron Stars”
A supermassive black hole (SMBH) likely resides at the center of the Milky Way, and in the centers of other galaxies like it. It’s never been seen though. It was discovered by watching a cluster of stars near the galactic center, called S stars.
S stars’ motions indicated the presence of a massive object in the Milky Way’s center and the scientific community mostly agreed that it must be an SMBH. It’s named Sagittarius A*.
But some scientists wonder if it really is a black hole. And one of the S stars could answer that question and a few others about black holes.Continue reading “One Star Could Answer Many Unsolved Questions About Black Holes”
What happens when you slam a neutron star (or black hole, take your pick) into a companion star? A supernova, that’s what. And for the first time ever, astronomers think they’ve spotted one.Continue reading “A Black Hole or Neutron Star Fell Into Another Star and Triggered a Supernova”
In 1916, Albert Einstein put the finishing touches on his Theory of General Relativity, a journey that began in 1905 with his attempts to reconcile Newton’s own theories of gravitation with the laws of electromagnetism. Once complete, Einstein’s theory provided a unified description of gravity as a geometric property of the cosmos, where massive objects alter the curvature of spacetime, affecting everything around them.
What’s more, Einstein’s field equations predicted the existence of black holes, objects so massive that even light cannot escape their surfaces. GR also predicts that black holes will bend light in their vicinity, an effect that can be used by astronomers to observe more distant objects. Relying on this technique, an international team of scientists made an unprecedented feat by observing light caused by an X-ray flare that took place behind a black hole.Continue reading “A Black Hole Emitted a Flare Away From us, but its Intense Gravity Redirected the Blast Back in our Direction”
Wormholes are a popular feature in science fiction, the means through which spacecraft can achieve faster-than-light (FTL) travel and instantaneously move from one point in spacetime to another. And while the General Theory of Relativity forbids the existence of “traversable wormholes”, recent research has shown that they are actually possible within the domain of quantum physics.
The only downsides are that they would actually take longer to traverse than normal space and/or likely be microscopic. In a new study performed by a pair of Ivy League scientists, the existence of physics beyond the Standard Model could mean that there are wormholes out there that are not only large enough to be traversable, but entirely safe for human travelers looking to get from point A to point B.Continue reading “One Theory Beyond the Standard Model Could Allow Wormholes that You Could Actually Fly Through”
In the center of our galaxy, hundreds of stars closely orbit a supermassive black hole. Most of these stars have large enough orbits that their motion is described by Newtonian gravity and Kepler’s laws of motion. But a few orbits so closely that their orbits can only be accurately described by Einstein’s general theory of relativity. The star with the smallest orbit is known as S62. Its closest approach to the black hole has it moving more than 8% of light speed.Continue reading “Fastest Star Ever Seen is Moving at 8% the Speed of Light”
In the 1960s, astronomers began theorizing that there might be black holes in the Universe that are so massive – supermassive black holes (SMBHs) – they could power the nuclei of active galaxies (aka. quasars). A decade later, astronomers discovered that an SMBH existed at the center of the Milky Way (Sagitarrius A*); and by the 1990s, it became clear that most large galaxies in the Universe are likely to have one.
Since that time, astronomers have been hunting for the largest SMBH they can find, in the hopes that can see just how massive these things get! And thanks to new research led by astronomers from the Australian National University, the latest undisputed heavy-weight contender has been found! With roughly 34 billion times the mass of our Sun, this SMBH (J2157) is the fastest-growing black hole and largest quasar observed to date.Continue reading “There’s a Black Hole With 34 Billion Times the Mass of the Sun, Eating Roughly a Star Every Day”
It’s a truism to point out that modern humans have only been around for the blink of an eye, relative to the age of the Universe. But the Universe was an active place long before we were around to observe all of that activity. And about 3.5 million years ago, it’s possible—if only remotely—that our ancient ancestors noticed something change in the night sky.
Would it have stirred something inside them? Impossible to know.Continue reading “About 3.5 Million Years Ago, a Stream of Gas Outside the Milky Way Would Have Lit Up the Night Sky”