Eventually, by growing and consuming material — planets, stars, errant spaceships, other black holes — astronomers think they evolve into the supermassive black holes that they detect at the centers of most major galaxies. So astronomers also think the universe might have jumpstarted the process by creating giant primordial black holes in the moment just after the Big Bang — though this is just as weird and problematic as you might think.
Both tiny and enormous black holes do exist. What exoplanet is closest to Earth? Is there gravity in space? How do stars produce and release energy?
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Tonight's Sky — Select location. Tonight's Sky — Enter coordinates. UTC Offset:. Picture of the Day Image Galleries. As stars reach the ends of their lives, most will inflate, lose mass, and then cool to form white dwarfs. But the largest of these fiery bodies, those at least 10 to 20 times as massive as our own sun, are destined to become either super-dense neutron stars or so-called stellar-mass black holes.
In their final stages, enormous stars go out with a bang in massive explosions known as supernovae. Such a burst flings star matter out into space but leaves behind the stellar core. While the star was alive, nuclear fusion created a constant outward push that balanced the inward pull of gravity from the star's own mass. In the stellar remnants of a supernova, however, there are no longer forces to oppose that gravity, so the star core begins to collapse in on itself.
If its mass collapses into an infinitely small point, a black hole is born. Packing all of that bulk—many times the mass of our own sun—into such a tiny point gives black holes their powerful gravitational pull. Thousands of these stellar-mass black holes may lurk within our own Milky Way galaxy. Supermassive black holes, predicted by Einstein's general theory of relativity, can have masses equal to billions of suns; these cosmic monsters likely hide at the centers of most galaxies.
The tiniest members of the black hole family are, so far, theoretical. These small vortices of darkness may have swirled to life soon after the universe formed with the big bang, some Astronomers also suspect that a class of objects called intermediate-mass black holes exist in the universe, although evidence for them is so far debatable. No matter their starting size, black holes can grow throughout their lives, slurping gas and dust from any objects that creep too close.
Anything that passes the event horizon, the point at which escape becomes impossible, is in theory destined for spaghettification thanks to a sharp increase in the strength of gravity as you fall into the black hole. Objects must creep fairly close to one to lose this gravitational tug-of-war. For example, if our sun was suddenly replaced by a black hole of similar mass, our planetary family would continue to orbit unperturbed, if much less warm and illuminated.
Because black holes swallow all light, astronomers can't spot them directly like they do the many glittery cosmic objects in the sky. But there are a few keys that reveal a black hole's presence.
For one, a black hole's intense gravity tugs on any surrounding objects. Astronomers use these erratic movements to infer the presence of the invisible monster that lurks nearby. Or objects can orbit a black hole, and astronomers can look for stars that seem to orbit nothing to detect a likely candidate.
Scientists had found indirect evidence of black holes before, witnessing stars in the center of our Milky Way galaxy orbiting around a gigantic invisible object, Universe Today reported. How such supermassive black holes — which can have billions of times the mass of our sun — form is an outstanding question, Bahcall said.
Researchers believe that these supermassive black holes were once much smaller, forming as more modest-size black holes in the earliest days of our universe. Over cosmological time, these objects absorbed gas and dust and merged with one another to grow, ending up as colossal monsters. But many of this story's details remain fuzzy, Bahcall said.
Astronomers have observed objects called quasars, which glow brighter than thousands of galaxies put together and are thought to be powered by supermassive black holes consuming matter. Quasars have been seen back as far as the first billion years after the Big Bang , when our universe formed, leaving scientists to scratch their heads over how such enormous objects could form so quickly, Bahcall said. Adam Mann is a journalist specializing in astronomy and physics stories.
He has a bachelor's degree in astrophysics from UC Berkeley. He lives in Oakland, California, where he enjoys riding his bike.
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