So we’ve all heard Einstein’s famous “E=MC^2”, right?
Energy equals mass times the speed of light squared. Since light is of course, energy, it’s worth considering that light and mass are two sides of the same coin and that perhaps light, like mass, can be influenced by gravity.
In 1919 astronomers Arthur Eddington and Frank Dyson observed a solar eclipse where they tried Einstein’s idea of gravity-bent light. To the endless excitement of the scientific community, when the eclipse became total and the stars behind the sun became visible as during the night - the sky was all wrong.
It turned out that (surprise) Einstein was correct and the stars behind the Sun were having their light pulled by the Sun’s gravity just as the planets are pulled. This effect is called gravitational lensing, and there are some pretty big plans for it.
When the Hubble Space Telescope took some of its well known portraits of space it became obvious that there were objects behind the things we were looking at whose light was being twisted and magnified along the side of what we were looking at. It’s like this:
The dashed line is the light from the galaxy behind the object we’re looking at, the thing we shouldn’t be able to see due to both distance and location (it’s behind something).
The = sign is the light from the galaxy far away and the nearer galaxy cluster, which pulled and magnified more light towards us than would’ve otherwise come in our direction. The light from both objects then come parallel towards us.
Galaxy on the edge of visible universe ——-< (Galaxy cluster) ====== Us
Gravitational lensing is basically a naturally occurring telescope. This is an incredible circumstance of nature. If things aren’t aligned correctly then the phenomenon either won’t happen, or won’t happen to a useful degree.
Since NASA’s budget is relatively nonexistent (please take a moment to sign this petition for funding! The Planetary Society needs all the help it can get), gravitational lensing is a very useful tool to increase the power of our telescopes but the frequency of being able to view an object this way is so rare that it can’t be counted as an efficient primary method of investigating the cosmos.
Jaguar (Wild Brazil - BBC)