Wednesday, 29 April 2009

(What is?) Gravitational Lensing

This is quite a rare phenomenon but occurs naturally. It happens when two astronomical bodies of extreme mass (like stars, galaxies or free-floating planets) are almost perfectly aligned as we, the observers, see them from our standpoint. What you then observe, when one star passes in front of the other, is not a dimming of the light or an eclipse, but multiple distorted images of the background star appearing in a "ring" like structure around the edge of the gravitational influence of the foreground star!

The reason that happens is because the gravity of the star that is closer to the observer bends the light rays from the further away object, acting as a kind of astrophysical "lens". This phenomenon is called gravitational lensing.

Astronomers take advantage of this rare effect to look for new exo-planets orbiting other stars.


george said...

what about travelling to these worlds?
any chance?

HooLooVoo said...

Short answer, no. We will visit Mars in the next few decades but going anywhere outside our Solar system is an immense challenge. The distances are just too large. Even when travelling at the speed of light (300,000 km/s), if that were possible for a spacecraft, it would still take hundreds of years. This raises interesting questions about what's going on on THIS planet right now in terms of sustainability.

But that is not why we're looking for new planets. I'll write another post at some point sbout that.