Astrophysics

Nov 22 2020

How the universe heats up

Shortly after the Big Bang, in the Planck era, the universe was about 1032 Kelvin hot. Afterwards it expanded rapidly and cooled down as the energy spread over an ever larger space. By and large, this process should continue as long as the universe expands - an end to the expansion is not yet in sight, on the contrary. But there is a process that counteracts this cooling - at least temporarily. It is easy to understand. When 10,000 people go home from a football stadium, the mood cools down initially as the density of people decreases. But when…

Why the brain and the cosmos are structurally similar

Astrophysics

Nov 18 2020

Why the brain and the cosmos are structurally similar

The human brain has a volume of a about one liter (0,26 gallons, man: 1.27 l, woman: 1.13 l), i.e. one cubic decimeter or 0.001 cubic meter. The universe, on the other hand, has a volume of 2.3 million billion trillion cubic light years. Obviously, this is a huge difference of over 30 orders of magnitude. Nevertheless, both structures, the network of galaxies that criss-crosses the universe and the neural network in the brain, have surprising similarities, as Franco Vazza (astrophysicist at the University of Bologna) and Alberto Feletti (neurosurgeon at the University of Verona) note in a paper…

Astrophysics

Oct 29 2020

In search of dark matter with pendulums

Current experiments that search for dark matter are mostly based on the idea that dark matter should somehow show up, i.e. by interacting with normal matter. Now, however, the only thing we really know about this important part of the universe is that an interaction with normal matter occurs via gravity. This is what first made researchers realize that dark matter exists. Is it perhaps because the search has so far been fruitless? Then a method could help, which researchers of the NIST and their colleagues presented now. "Our proposal is based purely on gravitational coupling, the only coupling…

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…

Galaxies in a cosmic spider web made of dark matter

Astrophysics

Oct 24 2020

Galaxies in a cosmic spider web made of dark matter

Using ESO's Very Large Telescope (VLT), astronomers have found six galaxies orbiting a supermassive black hole when the universe was less than a billion years old. The galaxies are in a kind of cosmic "spider web" of gas that covers an area 300 times the size of the Milky Way. "The filaments of the cosmic web are like spider web threads," explains Marco Mignoli, astronomer at the National Institute of Astrophysics (INAF) in Bologna, Italy, and lead author of the new research published today in Astronomy & Astrophysics. "The galaxies grow where the filaments cross, and gas flows -…

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…

Astrophysics

Sep 28 2020

The giant and the dwarf

Size alone is not always the most important factor. Sometimes, large things also orbit small things – because the details of a system matter. Astronomers have now found a real example for this situation in space, about 80 light-years from us, using the TESS telescope. The discovery published in Nature shows the likely presence of a planet the size of Jupiter orbiting the white dwarf, WD 1856+534, once every 34 hours. “This planet is roughly the size of Jupiter, but it also has a very short orbital period – one year on this planet is only 1.4 days long, so…

Astrophysics

Sep 27 2020

How the Magellanic Stream was formed

The Milky Way does not travel through the universe alone. It is accompanied on its journey by smaller galaxies. The two largest are the Small Magellanic Cloud and the Large Magellanic Cloud, which are both visible as dusty twin smudges in the southern hemisphere. When the Magellanic Clouds started orbiting the Milky Way billions of years ago (astronomers are not certain about the timing and the gravitational bond, it’s possible that they are still on their first approach to the Milky Way), an enormous stream of gas known as the Magellanic Stream was ripped out of them. The stream…