Astrophysics

Mar 13 2021

News from the warp drive: one problem less

Sometimes there are strange coincidences. Yesterday I reported here that "passable" wormholes could be realizable also without the addition of negative energy. This is an important advance because there is no natural source for negative energy. The only thing we can do to get a little bit of negative energy is to trick the universe. We take the negative energy from it while it is not looking and give it back before it has even noticed. This gap offers us the uncertainty principle of quantum physics. But in order to obtain negative energy in quantities such as would be…

Quasar transmits from the early days of the universe

Astrophysics

Mar 8 2021

Quasar transmits from the early days of the universe

In the 1950s, astronomers discovered radio sources to which point-like, i.e. star-like objects could be assigned in the visible light range. Until then, whole galaxies had been identified as radio sources. The findings were called "quasi-stellar objects", or quasars for short. Later, however, researchers realized that quasars are embedded in galaxies after all, and in fact constitute their active nuclei radiating in many wavelength ranges. That they had been seen only as point sources was simply because they are very, very distant. In fact, they are the most distant objects in the universe that we can observe. This is…

Merging boson stars instead of colliding black holes?

Astrophysics

Feb 27 2021

Merging boson stars instead of colliding black holes?

Bosons are particles with an even spin. They include the fundamental particles that mediate the individual interactions (such as photons for electromagnetism), but also composite particles such as helium-4 atoms. Their peculiarity is that any number of them can occupy the same ground state. They are then indistinguishable from each other and form a Bose-Einstein condensate with unusual properties. Among other things, the density of the condensate can approach infinity. This would make bosons good candidates for very heavy celestial bodies, where huge masses crowd into a small space. Who doesn't think of a black hole? But a celestial…

Can supermassive black holes collapse directly from dark matter?

Astrophysics

Feb 25 2021

Can supermassive black holes collapse directly from dark matter?

At first glance, a black hole and dark matter sound like a perfect combination. However, there is a problem: dark matter is mainly found in the outer regions of galaxies, in massive halos. Supermassive black holes, on the other hand, form the core of a galaxy. Does there nevertheless go something together, which belongs together? Perhaps. As far as supermassive black holes are concerned, cosmology still has a problem. Because how exactly they originally formed is one of the biggest problems in the study of galaxy evolution today. Supermassive black holes were observed as early as 800 million years…

Astrophysics

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…

Astrophysics

Feb 3 2021

How heavy is dark matter?

Dark matter is a mysterious phenomenon. We do not know what it looks like or what it is made of. But physicists are convinced that it exists, because the effect of its gravitational pull can be observed in many examples in the cosmos. The visible universe - ourselves, the planets and stars - accounts for 25 percent of the total mass in the universe. The remaining 75 percent of its mass consists of dark matter. The fact that it interacts via gravity at least gives researchers a clue as to how heavy its particles might be. It was previously…

Astrophysics

Jan 25 2021

Six exoplanets in unusual resonance

If one leaves multi-body systems to themselves, sometimes a strange order appears. The distances of the planetary orbits are integer multiples of a basic value, moons and planets move in unison, celestial bodies always turn to the same side - what we then perceive as cosmic order are all no miracles, but merely results of the effect of gravity in a system built up in a certain way. This is also true of TOI-178, a star about 200 light-years away in the constellation Sculptor. When researchers first observed the star, they initially suspected they had discovered two planets orbiting…

In search of the axion, a hypothetical elementary particle

Astrophysics

Jan 16 2021

In search of the axion, a hypothetical elementary particle

For some time now, physicists have been thinking about an elementary particle that has very little mass, no electric charge and no spin (quantum angular momentum). It would interact very little with other particles because of these properties and would therefore be a good candidate for dark matter, which is characterized by just that. But the axion is also used in physics because in the neutron, a neutral nuclear particle, the charge of the quarks of which it is composed is so perfectly distributed that it is not at all apparent to the outside world that there are balancing…