Astrophysics

Apr 30 2020

Searching for the super supernova

A supernova is a powerful explosion at the end of the life of many stars. All massive stars with an initial mass greater than eight solar masses will eventually be torn apart by a supernova, but that fate also awaits smaller stars that are unlucky enough, after their actual end as a white dwarf, to accrete more material from a partner star, with which they form a binary system. Without supernovae, there would be no life, because it’s the only way heavy elements can be spread around the cosmos. On the whole, this process is understood. Particularly energetic supernovae,…

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

Astrophysics

Apr 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…

Kepler-1649c: an Earth twin with a short-tempered host star

Astrophysics

Apr 28 2020

Kepler-1649c: an Earth twin with a short-tempered host star

The Kepler telescope has already been shut down, but astronomers are still finding new exoplanets in its data. Kepler-1649c, which is 300 light-years from Earth, is one of these recently discovered treasures. The planet was overlooked by the first, automated search through the data. The rocky planet has one very intriguing characteristic: it is the most Earth-like exoplanet discovered to date. Kepler-1649c is only 1.06 times larger than Earth. Its host star supplies it with about three-quarters of the energy that the Earth receives from the Sun. That means that water, if it exists there, would be liquid on…

Dark matter: on the trail of the Zʹ boson

Astrophysics

Apr 18 2020

Dark matter: on the trail of the Zʹ boson

Almost 1000 physicists from 26 countries have committed themselves to one collective task: using the Belle-2 experiment to search for signs of a new model of physics, a model that might explain, among other things, dark matter. This phenomenon, whose existence has been observed many times already, has stubbornly refused to be explained using the current standard model of physics. In the Belle-2 experiment, researchers collide electrons with their antiparticles, positrons (identical mass, but opposite charge), in the SuperKEKB accelerator in Tsukuba, Japan. They hope to use these collisions to find traces of a new elementary particle, the Zʹ…

The Sun as a lens: A new method for taking high-resolution photographs of exoplanets

Astrophysics

Apr 17 2020

The Sun as a lens: A new method for taking high-resolution photographs of exoplanets

The universe is damn large and, in comparison, everything that exists inside it is extremely small. Sometimes, astronomers are lucky and get some help in their observations of, for example, an individual star in a far-away galaxy: help delivered by the gravity of other massive objects, which refract and amplify the light of even-more distant objects like a lens. The effect is called a gravitational lens. This effect, however, has one big disadvantage: we can’t intentionally create a gravitational lens for any object we want. To be able to use this effect to view a certain object, there must…

Can the special theory of relativity explain the strangeness of quantum physics?

Astrophysics

Apr 16 2020

Can the special theory of relativity explain the strangeness of quantum physics?

Physics has had a problem for some time. Its basic theories, the General and Special Theories of Relativity and theories of quantum physics, have proven correct in many cases. But they don’t fit together – in extreme cases, like in black holes or the big bang, where you would need to use both relativity and quantum physics, the math doesn’t work out. Quantum physics appears to be the more fundamental theory, so scientists have assumed that the theory of relativity would need to be modified to quantum relativity. But that might not have to be the case. Dr. Andrzej Dragan…

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

Astrophysics

Apr 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…

Astrophysics

Apr 6 2020

Axions to the rescue?

The neutron is, as suggested by its name, electrically neutral. Nevertheless, it still contains electrical charges. More specifically, it is made up of one up quark (charge: 2/3 of an electron charge e) and two down quarks (charge: -1/3 e each). In total, 2/3 + 2*(-1/3) equals exactly 0. But the neutron is not one-dimensional. It has a diameter of at least 1.7 * 10-15 meters, and when three components have to be spread out over any distance, even with an overall zero charge, some difference in charge should still be detectable. Calculations from theory say that a neutron should have an electrical dipole…