Circle the correct statements
8. 5ptsBlackholes: Blackholes are the remnants of the most massive stars, formed...
8. 5ptsBlackholes: Blackholes are the remnants of the most massive stars, formed after their supernovae explosions. Supermassive blackholes, which may form by mergers of stellar blackholes, are thought to reside at the center of nearly all galaxies. (a) The size of its event horizon (within which even light cannot escape its gravity) is deter- mined by the mass, and is known as Schwarzschild radius. (b) According to general relativity, the space-time continuum is distorted by gravity near a blackhole characterized by the Schwarzschild metric. To an observer at an infinite distance from a blackhole, any event occurring near the event horizon speeds up to infinity, making it impossible for us to observe it. (c) Even the most supermassive blackholes, it is impossible to resolve them from Earth because they are too small. (d) Some blackholes are 'active' and emit electromagnetic radiation in the X-ray, 9-ray, and radio wavelength; these wavelength regimes are expected to have a negligible contribution from stellar emission. (e) Radio emission from active blackholes likely is thought to originate from inverse Compton scattering of electrons.