Neutrinos prove the Sun is doing a second kind of fusion in its core

Like all stars, our Sun is powered by the fusion of hydrogen into heavier elements. Nuclear fusion is not only what makes stars shine, it is also a primary source of the chemical elements that make the world around us. Much of our understanding of stellar fusion comes from theoretical models of atomic nuclei, but for our closest star, we also have another source: neutrinos created in the Sun’s core.

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Gravitational lenses could be the key to measuring the expansion rate of the Universe

One of the tenets of our cosmological model is that the universe is expanding. For reasons we still don’t fully understand, space itself is stretching over time. It’s a strange idea to wrap your head around, but the evidence for it is conclusive. It is not simply that galaxies appear to be moving away from us, as seen by their redshift. Distant galaxies also appear larger than they should due to cosmic expansion. They are also distributed in superclusters separated by large voids. Then there is the cosmic microwave background, where even its small fluctuations in temperature confirm cosmic expansion.

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Astronomers think they’ve seen a magnetar form for the first time; the collision of two neutron stars

A magnetar is a neutron star with a magnetic field thousands of times more powerful than those of typical neutron stars. Their fields are so strong that they can generate powerful, short-duration events such as soft gamma repeaters and fast radio bursts. While we have learned quite a bit about magnetars in recent years, we still don’t understand how neutron stars can form such intense magnetic fields. But that could soon change thanks to a new study.

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Do neutron star collisions produce black holes?

In principle, creating a stellar-mass black hole is easy. Simply wait for a large star to reach the end of its life, and watch its core collapse under its own weight. If the core has more mass than 2 – 3 Suns, then it will become a black hole. Smaller than about 2.2 solar masses and it will become a neutron star. Smaller than 1.4 solar masses and it becomes a white dwarf.

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One Mars Trojan asteroid has the same chemical signature as the Earth’s moon

Although Mars is much smaller than Earth, it has two moons. Deimos and Phobos were probably once asteroids that were captured by the gravity of Mars. The red planet has also captured nine other small bodies. These asteroids don’t orbit Mars directly, but instead, orbit gravitationally stable points on either side of the planet known as Lagrange points. They are known as trojans, and they move along the Martian orbit about 60° ahead or behind Mars. Most of these trojans seem to be of Martian origin and formed from asteroid impacts with Mars. But one of the trojans seems to have a different origin.

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Even older red dwarf stars are pumping out a surprising amount of deadly radiation at their planets

Most of the potentially habitable exoplanets we’ve discovered orbit small red dwarf stars. Red dwarfs make up about 75% of the stars in our galaxy. Only about 7.5% of stars are g-type like our Sun. As we look for life on other worlds, red dwarfs would seem to be their most likely home. But red dwarfs pose a serious problem for habitable worlds.

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Something other than just gravity is contributing to the shape of dark matter halos

It now seems clear that dark matter interacts more than just gravitationally. Earlier studies have hinted at this, and a new study supports the idea even further. What’s interesting about this latest work is that it studies dark matter interactions through entropy.

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