THE FRANKLIN The Science Magazine of Notting Hill & Ealing High School ◆ Spring 2025
What are Black Holes and what are their properties? By Aswini K, Sixth form which is normally a straight line. The light gets amplified and distorted due to the large gravitational forces from black holes.
What are black holes ? Despite what the name suggests, black holes aren’t actually holes, they’re actually the opposite. The inside of a black hole is theoretically an area of extremely concentrated matter, which is very dense and has no volume.This is stated in Einstein’s General Theory of Relativity. This density allows black holes to have such a strong gravitational pull that not even light can escape them, giving them its black appearance. This boundary, which “traps light” is known as the event horizon. This boundary is where the velocity needed to escape the black hole equals light speed. Therefore, we believe that once something has entered a black hole, it cannot leave the black hole. This is also why we do not know what happens in a black hole past the event horizon.
A light curve which does not contain a distinctive peak therefore does not suggest the presence of a black hole. These peaks can sometimes be caused by nearby asteroids or natural variations in the star’s brightness.
How do we find black holes ? Although we do not have any non-theoretical information regarding what the inside of a black hole contains, we do have many ways of being able to find them by observing a black hole’s effects on nearby objects in space. We look for signals that might have been produced by a black hole passing in front of a star. We look for the light of a star being magnified as the gravitational field of the black hole can act like a lens. This effect produces a distinctively shaped peak in the light curve of the star. These peaks in the light curves are caused by an effect called gravitational lensing. Gravitational lensing leads to a bend in the path of light in space, 1