Gmail : la messagerie de Google. Black hole's 'big meal' could spark fireworks. 10 January 2014Last updated at 07:23 GMT By James Morgan Science reporter, BBC News, Washington DC If the black hole "bites" the gas cloud, X-ray "fireworks" will flare out Astronomers are getting ready for their best ever glimpse of the mysterious black hole at the heart of our galaxy. "Fireworks" will flare if it gobbles up a giant gas cloud which is drifting perilously close. A collision is now likely in spring, according to scientists at the American Astronomical Society meeting. Stargazers will be able to see the climax on a new public monitoring website. "This could be our black hole's biggest meal in hundreds of years," said Leo Meyer, of the University of California, Los Angeles. "It might bring spectacular fireworks - and we want everybody to watch. " Front row seats The collision could give astronomers a unique window on one of the universe's great enigmas.
Black holes are so dense that not even light can escape them, once it passes their event horizon (point of no return). Mystery. The Formation of Stellar Mass Black Holes: Making energetic destroyers. (Image Credit: NASA / CXC / M. Weiss) The formation of a stellar mass black hole is a very chaotic and energetic event. Really though, there isn’t much that involves black holes that isn’t chaotic or energetic. Stellar mass black holes have a minimum mass of around 3.2 times that of our sun (3.2 solar masses).
I say “around” because, due to our lack of understanding of neutron degeneracy thresholds, we don’t quite know where the boundary is between neutron stars and black holes. At the moment, 3.2 solar masses is a good guesstimate, as it fits snugly in between the most massive neutron star and smallest black hole ever discovered. There are three processes that can form a stellar mass black hole; each one is amazing in its own right. These black holes can form from the following ways: Image Credit: NASA/AEI/ZIB/M. Today, we are going to take a look at mergers. Stars with the mass of: This tells us that, if a star is 7 solar masses, it will be ~900 times more luminous than our sun.
Wormholes" Theoretical Kerr black holes aren't the only possible cosmic shortcut to the past or future. As made popular by everything from "Star Trek: Deep Space Nine" to "Donnie Darko," there's also the equally theoretical Einstein-Rosen bridge to consider. But of course you know this better as a wormhole. Einstein's general theory of relativity allows for the existence of wormholes since it states that any mass curves space-time. To understand this curvature, think about two people holding a bedsheet up and stretching it tight. If one person were to place a baseball on the bedsheet, the weight of the baseball would roll to the middle of the sheet and cause the sheet to curve at that point.
Now, if a marble were placed on the edge of the same bedsheet it would travel toward the baseball because of the curve. In this simplified example, space is depicted as a two-dimensional plane rather than a four-dimensional one. Black hole. A black hole is defined as a region of spacetime from which gravity prevents anything, including light, from escaping.[1] The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole.[2] Around a black hole, there is a mathematically defined surface called an event horizon that marks the point of no return. The hole is called "black" because it absorbs all the light that hits the horizon, reflecting nothing, just like a perfect black body in thermodynamics.[3][4] Quantum field theory in curved spacetime predicts that event horizons emit radiation like a black body with a finite temperature. This temperature is inversely proportional to the mass of the black hole, making it difficult to observe this radiation for black holes of stellar mass or greater.
Objects whose gravity fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace. History General relativity.