Who polluted the globular clusters? Space

Who polluted the globular clusters?

Globular clusters are very dense, spherical collections of stars with a radius of a dozen to a hundred light-years. They can contain up to a million stars and are found in all kinds of galaxies. There are about 180 of them in our galaxy. One of their great mysteries is the composition of the stars they contain. Although they were all born at the same time in the same gas cloud, the proportions of oxygen, nitrogen, sodium and aluminum, for example, vary from one star to another. A team from the Universities of Geneva (UNIGE) and Barcelona and the…
More life at the first stars? Life

More life at the first stars?

The very first stars consisted only of hydrogen and helium - there were no other elements in the still young cosmos. When they died in gigantic explosions, they released what had accumulated in them: heavier elements, which were needed so that planets could form. The more heavy elements (cosmologists call them "metals," although chemically they aren't necessarily), the more planets can form, the better chance life has, right? Not quite. Whether life has a chance depends on more than just the composition of a celestial body. In fact, planets located in the habitable zones of metal-poor stars may be…
85,000 volcanoes on Venus Space

85,000 volcanoes on Venus

You are planning a trip to Venus? Then you'd better avoid the numerous volcanoes there. This works better with good map material, as it is now finally available: Planetologists Paul Byrne and Rebecca Hahn from Washington University have counted 85,000 volcanoes on our neighboring planet Venus - and entered them on a map for the first time. The accompanying database is publicly available. "This work is the most comprehensive map of all volcanic structures on Venus ever produced," says Byrne, associate professor of earth and planetary sciences at Washington University in St. Louis. "It provides researchers with an enormously…
Why ‘Oumuamua accelerated Space

Why ‘Oumuamua accelerated

Comet (?) 'Oumuamua is the first known object formed outside the solar system that astronomers could observe on its way through our solar system. Its nature is still not conclusively explained - at least for some researchers. What we do know: It has not shown any radiation. Measurements in this regard are so accurate that even a cell phone transmitting on the object would have been noticed. But 'Oumuamua also shows a small non-gravitational acceleration. So it didn't move exactly as would have been expected based on mass and velocity. This is not unusual for comets. They typically release…
Rocky planets from the planet factory Space

Rocky planets from the planet factory

Why do rocky planets in a given star system usually look relatively similar? A new theory developed by Konstantin Batygin, professor of planetary science at Caltech, along with Alessandro Morbidelli of the Observatoire de la Côte d'Azur in France, may explain. "With the increase in exoplanet observations over the past decade, it has become clear that the standard theory of planet formation needs to be revised, starting with the basics. We need a theory that can explain both the formation of terrestrial planets in our solar system and the formation of self-similar systems of super-Earths, many of which have…
Why Venus died the heat death – and the Earth did not Life

Why Venus died the heat death – and the Earth did not

Venus, Earth's hot little sister, was probably once habitable, too, a long time ago. It basically orbits in the habitable zone. Surface temperatures of 450 degrees would actually not be expected there, were it not for the dense CO2 atmosphere that heats up the planet with its greenhouse effect. But why did this happen on Venus - and not on Earth so far? Volcanism is probably to blame, as researchers show in a new paper. According to the paper, volcanic activity that lasted hundreds to thousands of centuries and ejected massive amounts of material may have helped transform Venus…
Neutron star light – or something completely different? Space

Neutron star light – or something completely different?

Stars that are at least about three times heavier than the sun suffer a spectacular end. They manage to use all elements up to iron as fuel in different shells in their interior. Their core, which is only 10,000 kilometers across, then usually consists of iron and heavier elements. What happens to the dying star now depends mainly on this core. When it exceeds the Chandrasekhar limit of 1.44 solar masses, its matter can no longer resist its own gravity - and the star collapses into a neutron star. (more…)