Astrophysics

Nov 1 2019

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

Nov 1 2019

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

Sep 10 2019

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…

Astrophysics

Sep 6 2019

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

Aug 20 2019

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…

Astrophysics

Aug 14 2019

How our Milky Way was born

13 billion years ago, the universe looked quite different. Stars formed in rapid sequence and joined to form dwarf galaxies that grew bigger through collisions with each other, in order to finally become the massive galaxies we see today. Our Milky Way was formed through a similar process. Spanish researchers at the Instituto de Astrofísica de Canarias (IAC) have now succeeded in retracing the development of our home galaxy using data from the Gaia satellite. To do this, the astronomers compared the position, brightness, and distance of a million stars within a 6,500 light-year sphere. In this way, they…

Astrophysics

Aug 13 2019

Have you ever seen a moon being born?

It starts with a cloud of gas and dust. The cloud contracts into a disk and a star ignites at its center. Planetoids form around the star in the protoplanetary disk and grow into planets. Around the planets, in turn, are dust disks that eventually form moons. Up to that last step, this theory of solar system formation had long been confirmed by observations. But no telescope had yet discovered a dust disk around a planet. Now one has. ALMA, the Atacama Large Millimeter/submillimeter Array made the first such observation in the young solar system of PDS 70, which is…

Old and young at the same time? The mystery of red giants

Astrophysics

Jul 17 2019

Old and young at the same time? The mystery of red giants

At the end of their life, main sequence stars (which also include our Sun) develop into red giants. This fate is predestined for them. However, it’s not so easy to figure out the true age of a red giant. This is because there are many individual factors that can accelerate or slow down their development. Astronomers have gotten rather good at this in recent years, but there are always exceptions. Four years ago, researchers of the Leibniz Institute for Astrophysics and the Max Planck Institute for Astronomy discovered red giants whose age estimates differed by up to four billion…