Future Telescopes Could be Seeing the Wrong Planets

We have discovered thousands of exoplanets in recent years, including some that are Earth-sized and potentially habitable. But we haven’t seen many of those worlds. Most of the exoplanets we’ve found have been discovered using the transit method, which involves watching the brightness of a star dip as a planet passes in front of it. We can learn the size and sometimes the mass from these dips, but we have no idea what the world looks like, or whether it has a breathable atmosphere.

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Aging White Dwarfs Become Even More Magnetic

In a few billion years the Sun will end its life as a white dwarf. As the Sun runs out of hydrogen to fuse for energy it will collapse under its own weight. Gravity will compress the Sun until it’s roughly the size of Earth, at which point a bit of quantum physics will kick in. Electrons from the Sun’s atoms will push back against gravity, creating what is known as degeneracy pressure. Once a star reaches this state it will cool over time, and the once brilliant star will eventually fade into the dark.

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Astronomers Find a Giant Cavity in Space, Hollowed out by an Ancient Supernova

Star formation is a topic astronomers are still trying to fully understand. We know, for example, that stars don’t form individually, but rather are born within vast interstellar molecular clouds. These stellar nurseries contain gas dense enough for gravity to trigger the formation of stars. In spiral galaxies, these molecular clouds are most commonly found within spiral arms, which is why stars are most often born in spiral arms.

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Finally an Answer to why Gamma Rays are Coming From Seemingly Empty Space

Gamma rays strike Earth from all directions of the sky. Our planet is bathed in a diffuse glow of high-energy photons. It doesn’t affect us much, and we don’t really notice it, because our atmosphere is very good at absorbing gamma rays. It’s so good that we didn’t notice cosmic gamma rays until the 1960s when gamma-ray detectors were launched into space to look for signs of atomic weapons tests. Even then, what we noticed were intense flashes of gamma rays known as gamma ray bursts.

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We Knew Black Holes Have a Temperature. It Turns out They Also Have a Pressure

In the classical theory of general relativity, black holes are relatively simple objects. They can be described by just three properties: mass, charge, and rotation. But we know that general relativity is an incomplete theory. Quantum mechanics is most apparent in the behavior of tiny objects, but it also plays a role in large objects such as black holes. To describe black holes at a quantum level, we need a theory of quantum gravity. We don’t have a complete theory yet, but what know so far is that quantum mechanics makes black holes more complex, giving them properties such as temperature and perhaps even pressure.

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Researchers Generate an Entire Virtual Universe and Make it Available for Download (if you Have 100 Terabytes of Free Hard Drive Space)

Astronomy is a bit different from many sciences because you only have a sample size of 1. The cosmos contains everything we can observe, so astronomers can’t study multiple universes to see how our universe ticks. But they can create computer simulations of our universe. By tweaking different aspects of their simulation, astronomers can see how things such as dark matter and dark energy play a role in our universe. Now, if you are willing to spring for a fancy hard drive, you can keep one of these simulations in your pocket.

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Heavier Stars Might not Explode as Supernovae, Just Quietly Implode Into Black Holes

A supernova is a brilliant end to a giant star. For a brief moment of cosmic time, a star makes one last effort to keep shining, only to fade and collapse on itself. The end result is either a neutron star or a stellar-mass black hole. We’ve generally thought that all stars above about ten solar masses will end as a supernova, but a new study suggests that isn’t the case.

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Brown Dwarfs are Probably Much More Common in the Milky Way Than Previously Believed

Brown dwarfs are strange things. They are in the middle ground between planets and stars. A star is defined as an object massive enough for helium to fuse into hydrogen into its core, while a planet is too small for core fusion to occur. It seems a simple distinction until you learn about fusion. Anything with a mass below about 13 Jupiters is too small for fusion to occur, and is thus a planet. If your mass is about about 80 Jupiters, then you can fuse helium and are therefore a star. But if your mass is between 13 and 80 Jupiters, things get interesting. You can’t fuse hydrogen to shine brightly, but you can fuse lithium into other elements. This is known as lithium burning. It doesn’t provide lots of energy, but it is technically nuclear fusion.

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