How do black holes emit light?

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If there’s one thing everyone knows about black holes, it’s that they give off no light. These behemoths of time and space erase objects from history, swallowing everything in their paths. Yet a few minutes of research will tell you we can detect black holes through their radiation. In fact, black holes are supposedly some of the brightest objects in the universe. Welcome to the bizarre world of astrophysics.

First of all, your science teachers were telling the truth: black holes give off no light. As their namesake implies, these objects have grown so massive not even light can escape their gravity. If a rogue black hole flew between us and the stars, the only way to detect it would be through its gravity. Astrophysicists have shown, however, that most matter in the universe clumps together. Stars live in galaxies, and galaxies move in clusters. Black holes often live at the centers of galaxies or alongside stars throughout them.

Black Hole Accretion Disc Light Massive Color Picture Artist's Rendition Weekly Show

An artist’s rendition of an accretion disc. Scientists have yet to understand why the black hole emits particle streams on polar axes.

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Breakthough study finds remnants of Big Bang

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The universe is a big place. Most physicists say it is infinite, and estimates of our observable universe fall around 93 billion lightyears across. Fortunately, math and science give us the tools to unravel what we cannot see, such as last week’s breakthrough discovery of the “echo” from the Big Bang.

The Big Bang theory posits the universe burst from a single point some 13.7 billion years ago. In a fraction of a second it underwent staggering expansion, growing exponentially at speeds faster than light. Early phases of the universe contained plasma so “dense” (high-energy) that photons could not escape. About 380,000 years later, the plasma cooled enough to let light push through, giving the universe its first moment of transparency. This theory is widely accepted by the scientific community and explains many properties of our universe, such as cosmic background radiation, large-scale structures, and the large presence of light elements (more on these in future posts).

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Stephen Hawking: there are no black holes

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Famed physicist Stephen Hawking announced last week there are no black holes—at least not the way we think of them. His new, not-yet-peer-reviewed paper says the idea of an event horizon—the point of no escape—violates quantum mechanics and therefore does not exist. In doing away with the event horizon, Hawking claims to have solved the firewall paradox, one of the most pressing problems in modern physics.

First, some background. Stephen Hawking is a theoretical physicist and cosmologist and the Director of Research at the Centre for Theoretical Cosmology at Cambridge University. His work in quantum mechanics and general relativity is a cornerstone of modern physics and has made him one of the most famous scientists of the past century.

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The scale of the universe

Of all the secrets and mysteries of science, I find myself most fascinated by the universe. It’s birth and evolution,  its future and unexplored depths–these stories keep me coming back for more. Perhaps the most exciting part is that there is so much we do not know. We sit on our lonely planet, pondering how everything came to be and where it is going. If one phrase can describe the history of cosmology, it is the proverbial “the more we learn the less we know.”

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The Rosette nebula, a stellar nursery approximately 5,000 light years away. How can we possibly understand scales that leave everything we know incomprehensibly large or small?

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You are made of beautiful stardust

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Stars. They are such stuff as dreams are made on. They shine in the night sky, reminders of our insignificance and the vastness of the universe. They may sit millions of light years away, but they are closer than you think.

Simply put, stars are massive balls of plasma held together by their own gravity. Once a critical mass of interstellar dust and debris and accumulates, its gravity pulls it together, heating its core enough to fuse hydrogen into helium. The heat from these reactions balances the gravitational force of the outer shells, preventing the star from collapsing under its own mass. Stars spend most of their lives on what is called the main sequence, fusing hydrogen into helium as they orbit galactic centers at incredible speed.

Stars Space Outer Beautiful Pictures Secrets Colorful Large Magellanic Cloud Star Forming Stellar Nursery Weekly Show Beautiful

Part of a stellar nursery in the Large Magellanic Cloud. Here interstellar debris and supernova remnants come together to form new stars and planets. (Photo: ESA/Hubble)

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