black hole Archives

October 6, 2021October 6, 2021 by Evan Gough

One Star Could Answer Many Unsolved Questions About Black Holes

Detection of an unusually bright X-Ray flare from Sagittarius A*, a supermassive black hole in the center of the Milky Way galaxy. Credit: NASA/CXC/Stanford/I. Zhuravleva et al.

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.

September 7, 2021September 7, 2021 by Paul M. Sutter

A Black Hole or Neutron Star Fell Into Another Star and Triggered a Supernova

Artist's conception of the ring of material surrounding a star shortly after engulfing a dense companion. Credit: Bill Saxton, NRAO/AUI/NSF

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.

August 1, 2021August 1, 2021 by Matt Williams

A Black Hole Emitted a Flare Away From us, but its Intense Gravity Redirected the Blast Back in our Direction

Artist's impression of a black hole, as indicated by its bright accretion disk. Credit: NASA

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.

August 26, 2020August 26, 2020 by Matt Williams

One Theory Beyond the Standard Model Could Allow Wormholes that You Could Actually Fly Through

Molecular clouds scattered by an intermediate black hole show very wide velocity dispersion in this artist’s impression. This scenario well explains the observational features of a peculiar molecular cloud CO-0.40-0.22. Credit: Keio University

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.

August 13, 2020August 14, 2020 by Brian Koberlein

Fastest Star Ever Seen is Moving at 8% the Speed of Light

This artist's impression shows part of the orbit of one of the stars very close to the supermassive black hole at the centre of the Milky Way. Analysis of data from ESO’s Very Large Telescope and other telescopes suggests that the orbits of these stars may show the subtle effects predicted by Einstein’s general theory of relativity. There are hints that the orbit of this star, called S2, is deviating slightly from the path calculated using classical physics. This close-up of the orbit of star S2 shows how the path of the star is slightly different when it passed the same part of its orbit for the second time, 15 years later, due to the effects of general relativity.

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.

July 6, 2020February 17, 2023 by Matt Williams

There’s a Black Hole With 34 Billion Times the Mass of the Sun, Eating Roughly a Star Every Day

Close-up of star near a supermassive black hole (artist’s impression). Credit: ESA/Hubble, ESO, M. Kornmesser

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 (Sagittarius 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 they can see just how massive these things can 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.

June 3, 2020June 3, 2020 by Evan Gough

About 3.5 Million Years Ago, a Stream of Gas Outside the Milky Way Would Have Lit Up the Night Sky

An illustration of our hominid ancestors, likely Australopithecus, walking at night, under the lit up stream of gas about 3.5 million years ago. Image Credit: NASA, ESA, G. Cecil (UNC, Chapel Hill), and J. DePasquale (STScI)

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.

April 16, 2020April 16, 2020 by Matt Williams

Light Behaves Really Strangely Around a Black Hole

Combining observations done with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. The black hole blows a huge bubble of hot gas, 1,000 light-years across or twice as large and tens of times more powerful than the other such microquasars. The stellar black hole belongs to a binary system as pictured in this artist's impression. Credit: ESO/L. Calçada — Artist's impression of a Star feeding a black hole. Credit: ESO/L. Calçada

Black holes are famous for being inescapable. Within the event horizon of these celestial objects, matter and even light enter and then disappear forever. However, beyond the event horizon, black holes are known to form accretion disks from which light can escape. In fact, this is how astronomers are able to confirm the presence of black holes and determine their properties (i.e. mass, spin rate, etc.)

However, according to a recent NASA-funded study led by researchers from the California Institute of Technology (Caltech), there is evidence that not all light emanating from a black hole’s disk simply escapes. According to their observations, some of the light escaping from the disk is pulled back in by the black hole’s gravity and reflected off the disk again. These observations confirm something astronomers have theorized for about forty years.

February 21, 2020February 26, 2020 by Brian Koberlein

How Interferometry Works, and Why it’s so Powerful for Astronomy

Three of the dishes that make up the Atacama Large Millimeter/submillimter Array (ALMA). Image Credit: H. Calderón – ALMA (ESO/NRAO/NAOJ)

When astronomers talk about an optical telescope, they often mention the size of its mirror. That’s because the larger your mirror, the sharper your view of the heavens can be. It’s known as resolving power, and it is due to a property of light known as diffraction. When light passes through an opening, such as the opening of the telescope, it will tend to spread out or diffract. The smaller the opening, the more the light spreads making your image more blurry. This is why larger telescopes can capture a sharper image than smaller ones.

January 7, 2020January 7, 2020 by Evan Gough

M87’s Black Hole is Firing Out Jets that Travel 99% the Speed of Light

Using NASA’s Chandra X-ray Observatory, astronomers have seen that the famous giant black hole in Messier 87 is propelling particles at speeds greater than 99% of the speed of light. Image Credit: NASA/CXC/SAO/B. Snios et al.

Can black holes be famous? If they can, then the one at the heart of the M87 galaxy qualifies. And this famous black hole is emitting jets of material that travel at near the speed of light.