Astrophysics

May 12 2021

What is hard science fiction, anyway?

Brandon Q. Morris writes hard science fiction. But what does that actually mean? I like to explain it this way: What happens in my books could happen in reality. There are no laws of physics that would prevent it. You could also call it "realistic" science fiction, although the fiction remains, of course. In the end, it is a story that I tell. Apart from the degree of hardness (more on that below), hard science fiction also tends to depict the conflict between the hero and the environment (in the form of the universe and its manifold phenomena) instead of…

Astrophysics

May 11 2021

The noise of interstellar space

The vacuum between the stars is not empty. The interstellar medium consists of dust and gas, which in turn can be in atomic, molecular and ionized form. Its density varies widely. Interestingly, it is greatest in cool, dense regions where matter is mainly in molecular form and one could count up to 1 million molecules per cubic centimeter. In hot, diffuse regions, on the other hand, matter is mainly ionized and one finds only a single ion per 10,000 cubic centimeters. Compared to, say, the capabilities of a vacuum chamber constructed by humans, with still ten billion particles per…

Astrophysics

May 7 2021

How to make the invisible visible

Astronomers have a lot in common with forensic scientists. They infer from traces the events that might have led to the formation of these traces. They take photographs and look at what is visible of these events in order to then also be able to capture their invisible parts. Very much remains invisible in the universe: Black holes, dark matter or dark energy, which we all see only through their effects, are certainly the most prominent. But also magnetic fields play an important role. They provide the framework in which charged particles move in galaxies. For example, when clusters…

Astrophysics

Apr 22 2021

Older stars rotate faster than expected

Not only humans lose mobility in old age - stars also rotate more slowly then. All stars are born with angular momentum that comes from the rotation of the protostellar cloud. Then, as they get older, their rotation slows in a process called "magnetic braking." A study published in 2016 by scientists at Carnegie Observatories provided the first evidence that stars at a similar stage of life as the Sun are spinning faster than magnetic braking theories predict. The results of that study were based on a method in which scientists locate dark spots on the surface of stars and…

Two pairs of quasars in the early universe

Astrophysics

Apr 6 2021

Two pairs of quasars in the early universe

Quasars are loners. This is not because they do not get along with their colleagues, but has something to do with their nature. They are nuclei of active galaxies. And every galaxy has only one nucleus. Billions of stars can rotate badly around several cores. Nevertheless, astronomers have now found two quasar pairs at a distance of about ten billion light years as they report in Nature Astronomy. (more…)

Even the core of the Milky Way gives birth to stars

Astrophysics

Apr 1 2021

Even the core of the Milky Way gives birth to stars

Since Star Trek V we know that the core of the Milky Way is a very special area. There is no galactic barrier there, but there is a gigantic black hole (Sagittarius A*) with the fields it produces and a lot of stars in a small space. With average distances of less than one light year the night sky of a planet must be very bright there. New stars are formed from clusters of gas and dust clouds. The process is disturbed when magnetic fields waft through it or passing stars deform the cloud with their gravitational pull. In…

Astrophysics

Mar 28 2021

The very first structures of the cosmos

In one of my newest books astronomers are trying to use a solar gravitational lens to look at the beginning of the universe. Whether they succeed, I will not reveal here. But physicists at the Universities of Göttingen and Auckland (New Zealand) have now determined what they would see with the help of greatly improved computer simulations. The scientists discovered that a complex network of structures can form in the first trillionth of a second after the Big Bang. But these are not just any random structures: the behavior of these objects already mimics the distribution of galaxies in…

Basic structure of the cosmos pictured for the first time

Astrophysics

Mar 21 2021

Basic structure of the cosmos pictured for the first time

Stars group together to form galaxies. Galaxies form galaxy clusters. These form superclusters, between which vast, largely empty regions extend, the voids. All superclusters are connected by a honeycomb-like basic structure, the "cosmic web", which consists of filamentary gas structures of hydrogen. That these filaments must exist has been known for some time. On the one hand, they are known from simulations based on theories of the structure of the universe, which predict such a basic structure. On the other hand, they become visible when energetic quasars illuminate them like car headlights illuminating the nebula. However, the regions thus…