Space Now!
Something Old or Something New?
- 24-09-12
- Written by Josh
As NASA approach their 54th birthday they have announced the discovery of one of the oldest and most distant galaxies.
The inspiringly named MACS 1149-JD was discovered using the Hubble and Spitzer space telescopes. It is thought that this tiny galaxy, just 1% the mass of the Milky Way, formed from the very first stars just 500 million years after the big bang. Galaxies this small and old are incredibly difficult to spot as they require levels of sensitivity usually out of reach of even our best telescopes.
We were able to spot MACS 1149-JD as we had a little help. Back in 1924 Owest Chwolson discussed something called 'Gravitational Lensing', and this concept was revisited by Albert Einstein in 1936.
Gravitational lensing is the bending of light by gravity to form a natural lens. This can result in odd optical tricks, the most notable being 'Einstein Rings' these are where the object being observed is seen as a ring surrounding the object being used as the gravitational lens.
These lenses, despite producing cool optical tricks, are also very useful. They can magnify light from sources as well as using the bending of the light to identify previously unseen or obscured objects. It is this magnification that was so important in the case of MACS 1149-JD, with its light being amplified nearly 15 times. This enabled the telescopes to collect a wide array of light in different wavelengths. This sort of data is critical so that we can unlock the secrets of the early universe.
Discoveries like this pave the way for Hubble and Spitzer's eventual replacement, the James Webb Space Telescope. This telescope will investigate the first galaxies and stars to form. Discovering how the first stars formed is the next major step in understanding the Big Bang and out Universe's origin.
