Astrophysics

Fascinating images from the beginning of the universe Astrophysics

Fascinating images from the beginning of the universe

Next to theory and experiments, simulations are one of the most important tools used in research today. Occasionally, scientists develop theories that cannot be tested using today’s practice or technology. Here, a simulation might then be able to point the theoretical physicist where he or she needs to look. Other times, it might happen that there are two different theories that could be suitable for describing reality. If simulations are built based on both theories, their results can sometimes separate the significant from the useless. And sometimes it also happens that there isn’t any theory yet, only data from…
How much energy can we borrow from a vacuum? Astrophysics

How much energy can we borrow from a vacuum?

Negative energy doesn’t exist; that’s what we learned in school. If it did, then there’d also have to be negative mass – and thus a repulsive gravitational force, because energy and mass are directly linked with each other, as Einstein showed in his theory of relativity. At the micro-level, however, that’s not true (and that’s one of the reasons why physicists are still having a lot of fun trying to unite relativity and quantum theory). In extremely small areas, it is possible for energy to fall below zero for a short time, so that we are essentially borrowing energy…
How a universe made out of fuzzy dark matter might look Astrophysics

How a universe made out of fuzzy dark matter might look

The exact composition of 84 percent of all the matter in the universe is unknown. That is the portion, called dark matter, which neither emits radiation nor interacts with conventional matter that we already know of in any other way than through gravity. Cosmologists believe they can use the standard model of the universe, Lambda-CDM, to get to the bottom of dark matter. This model assumes that dark matter is “cold” (cold dark matter - CDM). In physics, “cold” means that something is moving slowly. So-called “WIMPs” (weakly interacting massive particles) would have to be previously unknown particles, heavier…
At the end of the Solar System, there’s a surprisingly high pressure Astrophysics

At the end of the Solar System, there’s a surprisingly high pressure

Our Sun emits particles and radiation around the clock. These emissions propagate far into space in all directions and form the heliosphere. At the same time, our Solar System is constantly bombarded from interstellar space by cosmic radiation from a wide range of sources. Way out in the far outer edges of our Solar System, a few billion kilometers from the Sun, these streams of radiation meet each other from both directions in the so-called heliosheath. The pressure appears to be significantly higher there than researchers previously thought. This was discovered by astronomers with the help of the two…
How, not that long ago, the center of the Milky Way exploded Astrophysics

How, not that long ago, the center of the Milky Way exploded

Right now, despite its 4.2 million solar masses, Sagittarius A*, the gigantic black hole at the center of the Milky Way, appears to be a harmless, sleeping giant. But that wasn’t always the case. If one of our ancestors, Australopithecus, had been able to observe the skies over Africa 3.5 million years ago (thus, long after the extinction of the dinosaurs) just as intensively as we can, he might have been able to witness a gigantic, approximately 300,000-year-long explosion in the center of the Milky Way, which created conical bursts of radiation extending through both poles of the galaxy…
Big baby stars grow the same way as small baby stars Astrophysics

Big baby stars grow the same way as small baby stars

The protostellar object, G353.273+0.641, which is located 5500 light-years from Earth in the constellation Scorpio, is still a baby. It ignited only around 3000 years ago; astronomically, that is an extremely short amount of time. Nevertheless, G353 is already ten-times heavier than the Sun, and it’s still growing. For the first time, researchers were able to catch a direct glance from above of such a massive protostar and its surroundings using the Atacama Large Millimeter/submillimeter Array (ALMA). In this way, they were able to determine that apparently size doesn’t matter. G353, in any case, acts no different than other…
Structures in the cosmic mist Astrophysics

Structures in the cosmic mist

The Milky Way has existed for at least 13 billion years. Since then, it has continued to produce more and more new stars; one generation gives way to the next. To do this, it needs gas – more than it contains itself. That applies to all other galaxies too. But where do the Milky Way, Andromeda, and their like find more gas? In the intergalactic medium, which, at first glance, looks like just empty space between the galaxies. (more…)
A radio view into a black hole’s backyard Astrophysics

A radio view into a black hole’s backyard

By definition, black holes themselves remain shut off from direct observation. But astronomers have been able to precisely image the sphere of influence of a black hole – the area in which its gravity is the dominant force. In the case of a supermassive black hole in the interior of a galaxy, this area can be up to 500 light-years across. For comparison, the closest star to the Sun is a good four light-years away. This imaging was done by the Atacama Large Millimeter/submillimeter Array (ALMA) in the Atacama desert of Chile. NGC 3258, a giant elliptical galaxy about…