In their paper submitted to Astrophysical Journal Letters, they describe a set of simulations investigating the collapse of a rotating gas cloud into a black hole. Credit: Ilya Mandel, ARC Centre of Excellence for Gravitational Wave Discovery The figure shows the formation of a rotationally-supported donut of gas around the black hole, as the initial gas rotates increasingly faster. They were particularly interested in understanding whether a rotating star could quietly collapse into a black hole. candidate at the University of California Santa Cruz, and involving OzGrav Chief Investigator Ilya Mandel, set out to answer this question. Theories suggest that these massive stars completely collapse into black holes, but is that possible?Ī team led by Ariadna Murguia-Berthier, a Ph.D. However, some massive stars seem to completely disappear without any explosion. Meanwhile, the outer layers of the star explode in a brilliant flash, observable as a supernova. A heavy iron star core contracts under gravity, creating a neutron star, or if it is heavy enough, a black hole. Beyond iron, energy is required to sustain fusion rather than being released by fusion. The energy produced by this nuclear fusion also provides pressure support inside the star, which balances the force of gravity and allows the star to remain in equilibrium. If light could go faster than the “speed of light”, then it could escape the event horizon, and would no longer qualify as a black hole.Stars produce energy by fusing lighter elements into heavier ones in their core: hydrogen into helium, then helium into carbon, oxygen, and so on, up to iron. Nothing can go faster than the speed of light, so nothing can escape a black hole. ![]() That is the point where the speed to escape becomes the speed of light. Now imagine compacting the mass of the Earth into the size of a thimble. However, if you built a machine to throw the ball fast enough (roughly 25,000 miles per hour) then it would overcome the Earth’s gravity and escape forever. Earth’s gravity will cause the ball to fall back down after a few seconds. As an example, imagine throwing a ball up in the air. A black hole is a region of space that is so warped that not even light can escape. Even when light travels on a curved path it does so at the “speed of light” which is a universal speed limit. However, light has no mass so it is not accelerated by gravitational forces. This is one reason that light may be affected by gravity. ![]() Matter such as stars and galaxies can warp the geometry of spacetime so the “shortest path” connecting two points may no longer be a straight line. In general relativity, the familiar three spatial dimensions combine with time to make up a four-dimensional “spacetime”. To explore the subtle aspects of this question, we will consider it in the context of Albert Einstein’s general theory of relativity, the simplest theory for gravity that is consistent with experimental observations. The short answer is no, the speed of light is always the same. Scientific Credit: James, O., von Tunzelmann, E., Franklin, P., & Thorne, K., 2015, Classical and Quantum Gravity 32, 6, 065001.ĭoes the speed of light increase as it nears the event horizon due to the influence of a black hole’s gravitational pull? ![]() A black hole with an accretion disc as envisioned by the Double Negative Visual Effects team in collaboration with Kip Thorne and other scientists for the movie, Interstellar.
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