Black hole

Feb 22 2021

When a star rips apart …

... a muon deep under the ice of Antarctica creates a trace in a gigantic detector. The muon was created because a high-energy neutrino interacted with an atom in the detector. The neutrino began its journey about 700 million years ago, around the time the first animals evolved on Earth. That's the travel time it took for the particle to get from the distant, unnamed galaxy (cataloged as 2MASX J20570298+1412165) in the constellation of The Dolphin to Earth. It occurred as a result of "AT2019dsg." This is what astronomers call an event in which a star was ripped apart…

Premature birth? The most distant quasar raises questions

Astrophysics

Ene 13 2021

Premature birth? The most distant quasar raises questions

Astronomers have discovered the most distant quasar yet. The monstrous celestial object called J0313-1806, which existed 670 million years after the Big Bang, shines thousands of times brighter than the Milky Way and is powered by another extreme, the earliest supermassive black hole, more than 1.6 billion times the mass of the Sun. This fully formed distant quasar with a redshift of z = 7.64, formed more than 13 billion years ago, is also the earliest quasar discovered to date, giving astronomers a glimpse of how massive galaxies formed in the early universe. Quasars, powered by the feeding orgies…

Were the first black holes born in the form of baby universes?

Astrophysics

Dic 30 2020

Were the first black holes born in the form of baby universes?

Shortly after the Big Bang, the universe was still impenetrable. Its density was so high that a variation of only 50 percent - a coffee bean in a cake batter - would have been enough to produce a black hole immediately. The density was at least variable enough to let grow whole galaxies from the differences later. However, there seem to have been no "coffee beans" at that time - this is revealed today by the rather uniform cosmic background radiation. Nevertheless, so-called promordial black holes could have been formed at that time, just on other ways. They could…

Massive black hole turns star in solar size into spaghetti

Astrophysics

Oct 25 2020

Massive black hole turns star in solar size into spaghetti

About 215 million years ago the fate of a star was fulfilled: It was swallowed by a black hole with a million solar masses. The death struggle dragged on for a whole month. Meanwhile, the dying star was bidding farewell, a high-energy flare that emitted enough energy in the X-ray range alone to accelerate the Earth to one percent of the speed of light. This flare, called AT2019qiz and registered on Earth in 2019, was a gift to terrestrial astronomers. It is the first star death of this kind that was discovered so close to the Earth (although 215…

Black holes reveal themselves in the X-ray spectrum

Astrophysics

Oct 3 2020

Black holes reveal themselves in the X-ray spectrum

Black holes are the remnant of stars with more than eight solar masses. Everything we know points to their existence – the theory of relativity, cosmology, etc. And yet, only one supermassive black hole – with a mass of more than 6 billion solar masses – has been “photographed” to date with the help of surrounding radiation in the radio wavelength range. But stellar-mass black holes have not yet been seen. That’s why scientists are pleased that an international team of astrophysicists has now found distinct signatures of the event horizon of black holes that clearly distinguish them from…

Too heavy to be a neutron star, too light to be a black hole

Astrophysics

Jul 25 2020

Too heavy to be a neutron star, too light to be a black hole

Sometimes (always?), new research instruments like the Ligo-Virgo gravitational wave detector collaboration not only provide long expected answers to old questions, but also create completely new questions too. Take, for example, GW190412, which is the designation given to the latest conundrum, for which physicists can thank Ligo-Virgo. It refers to a gravitational wave burst that reached Earth on 14 August 2019. From the measured data, the researchers determined that a relatively lightweight object and a significantly more massive object must have merged together to form a black hole with a mass of now 25 solar masses. There’s no question about…

Einstein was right – and Sagittarius A* is a giant black hole

Astrophysics

Abr 29 2020

Einstein was right – and Sagittarius A* is a giant black hole

Physical theories have one downside that physicists are very aware of: they cannot be proven true for always. Instead, they can be considered correct just until someone can demonstrate that they’re wrong. That applies to Einstein’s theories too. His General Theory of Relativity, however, has been amazingly robust so far. Einstein himself proposed three tests for his revolutionary theory, which wasn’t based on experimental findings, but on an almost philosophical line of thinking. His first test concerned the orbit on which the planet Mercury moved around the Sun. Its point closest to the sun (perihelion) changes in a very…

50,000 solar masses – and that’s just a midsize black hole

Astrophysics

Abr 9 2020

50,000 solar masses – and that’s just a midsize black hole

Astronomers have been looking for medium-sized black holes for a long time. You’ve probably heard about the giant black holes at the center of galaxies and those that start with the mass of one star as a result of a supernova. But as small black holes, like from a supernova, gradually grown into giants, they must pass through intermediate stages sometime. The only problem is that these midsize black holes are not very easy to find. The Hubble Space Telescope has now delivered some important evidence that such black holes actually exist. In 2006, the Chandra and XMM-Newton X-ray…