What evidence do astronomers use to detect black holes? please help and thank you :)
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(1) Gravitational lensing (bending of light passing by black holes), and (2) (for black holes at the centers of galaxies such as our own) deduction based upon the speeds of stars going around the center, together with laws or gravity and motion.
Other indirect proofs or inferences can be made from the behavior of certain X-Ray stars with "accretion discs" where matter falls into black holes, and gamma ray bursts.
(Broken Link Removed)
http://en.wikipedia.org/wiki/Accretion_disk
help me like just tell us the frigin answer
Astronomers use several different types of evidence to detect and study black holes:
1. Stellar Motion: Astronomers can observe the motion of stars near compact objects suspected of being black holes. If a star is seen to orbit around an invisible object with no visible companion, it suggests the presence of a black hole. The strong gravity of a black hole can cause nearby stars to move in highly elliptical or fast orbits.
2. Gravitational Waves: Gravitational waves are ripples in the fabric of spacetime caused by the acceleration of massive objects. The Laser Interferometer Gravitational-Wave Observatory (LIGO) and other gravitational wave detectors have detected the merging of black holes by measuring the tiny changes in space caused by these events.
3. X-rays: When matter falls into a black hole, it forms an accretion disk, a hot, glowing region of gas and dust that spirals into the black hole. This accretion disk emits X-rays, which can be detected by X-ray telescopes such as the Chandra X-ray Observatory. The presence of intense X-ray sources with no visible star or other object in the vicinity suggests the existence of a black hole.
4. Time Dilation: The intense gravitational pull of a black hole causes time to slow down near its event horizon. Astronomers can measure the time dilation of light emitted by objects falling into a black hole, known as gravitational redshift. By studying the change in the frequency of light, astronomers can infer the presence of a black hole.
It is important to note that detecting a black hole directly is difficult because they do not emit any light. Instead, astronomers rely on their effects on the surrounding matter and space in order to indirectly observe and study them.