- 2883 - BLACKHOLES - Black holes are scary? If you fell into a black hole left over when a star died, you would be shredded. The massive black holes seen at the center of all galaxies have insatiable appetites. Black holes are places where the laws of physics are obliterated.
--------------------------- 2883 - BLACKHOLES - Black holes are scary?
- Halloween is a piece of cake. Nothing in the universe is scarier than a black hole.
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- Black holes are regions in space where gravity is so strong that nothing can escape. The 2020 Nobel Prize in Physics was awarded to Roger Penrose for his mathematical work showing that black holes are an inescapable consequence of Einstein’s theory of gravity. A massive black hole sits at the center of our galaxy.
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- Super massive black holes lurk at the center of galaxies. Most of the time they are inactive, but when they are active and eat stars and gas, the region close to the black hole can outshine the entire galaxy that hosts them.
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- Galaxies where the black holes are active are called “quasars“. Black holes are expected to form when a massive star dies. After the star’s nuclear fuel is exhausted, its core collapses to the densest state of matter imaginable, a hundred times denser than an atomic nucleus.
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- The center is so dense that protons, neutrons and electrons are no longer discrete particles. Since black holes are dark, they are found when they orbit a normal star. The properties of the normal star allow astronomers to infer the properties of its dark companion, a black hole.
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- The first black hole to be confirmed was Cygnus X-1, the brightest X-ray source in the Cygnus constellation. Since then, about 50 black holes have been discovered in systems where a normal star orbits a black hole. They are the nearest examples of about 10 million Blackholes that are expected to be scattered through the Milky Way.
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- Black holes are tombs of matter; nothing can escape them, not even light. The fate of anyone falling into a black hole would be a painful “spaghettification,” an idea popularized by Stephen Hawking in his book “A Brief History of Time.” In spaghettification, the intense gravity of the black hole would pull you apart, separating your bones, muscles, sinews and even molecules.
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- The black hole at the center of galaxy M87 is outlined by emission from hot gas swirling around it under the influence of strong gravity near its event horizon.
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- Over the past 30 years, observations with the Hubble Space Telescope have shown that all galaxies have black holes at their centers. Bigger galaxies have bigger black holes.
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- Nature knows how to make black holes over a staggering range of masses, from star corpses a few times the mass of the Sun to monsters tens of billions of times more massive.
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- In 2019 astronomers published the first-ever picture of a black hole and its event horizon, a 7-billion-solar-mass beast at the center of the M87 elliptical galaxy.
It’s over a thousand times bigger than the black hole in our galaxy.
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- These black holes are dark most of the time, but when their gravity pulls in nearby stars and gas, they flare into intense activity and pump out a huge amount of radiation.
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- Massive black holes are dangerous in two ways. If you get too close, the enormous gravity will suck you in. And if they are in their active quasar phase, you’ll be blasted by high-energy radiation.
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- Quasars are the brightest objects in the universe. These super massive black holes are strange. The biggest black hole discovered so far weighs in at 40 billion times the mass of the Sun, or 20 times the size of the solar system.
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- Whereas the outer planets in our solar system orbit once in 250 years, this much more massive object spins once every three months. Its outer edge moves at half the speed of light.
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- Like all black holes, the huge ones are shielded from view by an event horizon. At their centers is a “singularity“, a point in space where the density is infinite. We can’t understand the interior of a black hole because the laws of physics break down. Time freezes at the event horizon and gravity becomes infinite at the singularity.
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- The good news about massive black holes is that you could survive falling into one. Although their gravity is stronger, the stretching force is weaker than it would be with a small black hole and it would not kill you.
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- The bad news is that the event horizon marks the edge of the abyss. Nothing can escape from inside the event horizon, so you could not escape or report on your experience. So, who really knows, and I can get away with telling you this.
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- According to Stephen Hawking, black holes are slowly evaporating. In the far future of the universe, long after all stars have died and galaxies have been wrenched from view by the accelerating cosmic expansion, black holes will be the last surviving objects.
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- The most massive black holes will take an unimaginable number of years to evaporate, estimated at 10 to the 100th power, or 10 with 100 zeroes after it. The scariest objects in the universe are almost eternal.
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----------------- Other reviews about mysterious Blackholes, request number to get a copy:
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- 2593 - BLACK HOLE - new techniques to study? In 2019 astronomers unveiled the first direct picture of a black hole. Now, astronomers have used a different technique involving x-ray “echoes” to peer even closer the edge of a black hole
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- 2573 - BLACKHOLES - everything we know? Blackholes are some of the strangest phenomena in our universe. One natural question to ask is how does Albert Einstein’s theory describe space and time around a massive spherical object like a star? The solution to this was found by Karl Schwarzschild. It is valid all around any static round object and, remarkably, only depends on its mass. That alone can define a black hole.
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- 2461 -- BLACKHOLES - first discoveries? Astronomers have discovered a strange black hole-star pair, a finding that could open our eyes to millions of new black holes that have been hidden in the cosmos. Astronomers have assumed that there are millions of these black holes in our Milky Way galaxy alone.
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- 2433 - Dark matter and blackholes.
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- 2338 - It is easy to claim you took a picture of a black hole because there is nothing to see. Its not just black it is blank. But, astronomers claim they have taken that first picture. What they took was a picture of the hot visible accretion surrounding the Black hole. But, it is a first! Here is how it was done:
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- 2331 - How the picture was taken? Actually, we can not see a black hole because no light escapes to see it with. You can not see a shadow either but you see the boundary of light round it. This is how we “see” a black hole . We see the accretion disk of hot material emitting light surrounding the black hole. We see the boundary not the black hole itself. It was not easy but here is how astronomers saw their first black hole
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- 2090 - Blackholes and white holes?
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- 2022 - Blackholes how to measure their mass? The more distant galaxies are more challenging. New techniques must be used to measure radius and rotation because they are so far away. A breakthrough was the finding of two blackholes orbiting each other
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- 2020 - Blackholes, when did they first appear? How did the first stars form and how did they create the first blackholes, called quasars? How old was the Universe when these first stars happened? How are colliding blackholes and detecting gravitational waves helping in our understanding the birth of the universe?
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- 1936 - Are there rogue Blackholes? Could primordial Blackholes be roaming our galaxy and could they explain the 26% of Dark Matter in the Universe? Massive Blackholes are at the center of most galaxies. Could smaller Blackholes be at the center of dwarf galaxies? Gravitational waves may be the new way to find some answers.
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- 1918 - Blackholes and Galaxies? How do galaxies evolve? Which came first the central Black hole or the galaxy? Is there a direct correlation between the size of the central Black hole and the size of the galaxy ?
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- 1908. - How the mass of a black hole is calculated?
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- 1926. - Are there rogue blackholes wandering through our galaxy? Are there blackholes that we calling Dark Matter?
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- 1891 - The Black hole is inescapable for stars greater than 20 Solar Mass. Blackholes are the evolution of natural stages in physics and astronomy. They are inevitable outcomes of interactions of mass and energy in the Universe. The mystery remains, what happens after the Black hole?
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- 1882 - Could Blackholes explain Dark Matter? More evidence that an expanding Universe is accelerating, but, also that super massive Blackholes are suppressing new star formation. A new theory has galaxies embedded in a halo of Blackholes that could account for Dark Matter.
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- 1869 - Black hole mysteries, how big can they get? How do you calculate their mass? Is the firewall of destruction actually visible? Can entangled particles actually escape the Black hole?
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- 1843 - Great Walls in space with Blackholes. Are there really holes in the Universe? Are there complete voids of only empty space? How to calculate and measure the rotation rate of Blackholes.
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- 1819 - The history of discovery of Blackholes. This review also lists 21 other Reviews on the subject of Blackholes.
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- 1753 - At the Event Horizon the spin would drag along space-time. Space-time would be distorted like a spoon spinning in honey.
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- 1646 - Schwarzschild Radius of a Black hole defines the Event Horizon is equal.
R = 2* G * M / c^2. Our Milky Way Galaxy Black hole has a 7,000,000 mile radius, and weighs 4 million Solar Mass.
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- 1628 - The math says that a 1 Solar Mass Black hole, our Sun, ( not rotating and not electrically charged) has a radius of 1.86 miles.
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- 1657 - Gravity slows down clocks, it is stronger than Time. The Black hole at the center of our Galaxy has orbiting stars that measure unseen mass to be 4,300,000 Solar Mass.
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- 1587 - Blackholes are real.
- 1551 - M87 the galactic black hole.
- 1508 - Are there more blackholes in our own galaxy?
- 1441 - Evidence to believe in blackholes?
- 1350 - Blackholes can get big and bright?
- 1244 - Blackholes explained?
- 1105 - How Small Can Blackholes Get?
- 1177 - Blackholes in Astronomy
- 1096 - Are Blackholes Monsters or Creators?
- 903 - Spinning Blackholes.
- 848 - Blackholes are Everywhere.
- 846 - Too Weird to Ponder
- 819 - Black hole of All Sizes.
- 774 - Seeing Blackholes.
- 578 - Blackholes
- 453 - Blackholes are Neither
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- October 30, 2020 2883
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--------------------- --- Friday, October 30, 2020 ---------------------------
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