When humans think about distances in space, it is almost impossible to comprehend the vast expanse in between different masses. In a humans mind circumnavigating the globe is a huge deal, the time it would take is almost inconceivable let alone the distance. Scientists however will continue to strive in order to see further into the universe and therefore longer back in time. Images are just starting to reach us of some of the oldest known bodies within the universe and lots more discoveries are sure to come; hopefully with the notion of letting us understand where we come from.
Until recently the oldest known objects in space, except the universe itself, have thought to be stars, or gamma ray bursts as these stars explode, but now there is evidence to suggest that the galaxies, containing these stars are much older than thought previously. The universal limit for age is set by the boundaries of the universe, which is considered to be as old as 13.75 billion years old. These galaxies come pretty close to this age, in astrological terms.
Galaxies consist of a huge collection of stars orbiting a central core; this is thought to be a super-massive black hole, although this is not yet official. Galaxies range in sizes, our galaxy, the ‘Milky Way’, is thought to contain between 100 billion and 400 billion stars. Our closets neighboring galaxy ‘Andromeda’ is thought to have a mass of three trillion stars with a diameter of 250,000 light-years.
A light year is a measurement of distance, unsurprisingly, the distance it takes light to travel in one year. Light travels at a speed of 186,000 miles per second that is 671 million miles an hour. Keep that astronomical speed in mind as we delve further into the cosmos.
In September 2009 a group of astronomers handling the ‘Hubble Ultra Deep Field Telescope’ (HUDF) came across what was soon to be spectroscopically confirmed as the furthest, and therefore the oldest, object to be discovered in the universe.
What the scientist had found was a galaxy some 13.1 billion light-years away, meaning it was only 600 million years younger than the universe itself. Scientists believe that galaxies only start to form at a limit of 200 million years after the Big Bang, meaning that this galaxy was formed during what is known as the ‘Reionization Epoch’, a period in which galaxies were forming at the fastest rate.
This galaxy was soon to be named by those who found it as UDFy-38135539 or HUDF.YD3 and it even featured on the television series presented by Professor Brian Cox, ‘Wonders of the Universe’.
Arguably it is a small galaxy registering one billion stars that covers just one- tenth the diameter of the Milky Way. However when thinking about those numbers it gives even the experienced travellers amongst us severe jet lag.
Now here is the even more exciting bit…
As soon as January of the next year an even older galaxy was discovered and this now holds the record for the oldest known object in the cosmos. Similarly named UDFj-39546284 is roughly 150 millions years older than the previous, although it has not yet been spectroscopically verified.
It is thought confirmation of this galaxy will occur when NASA and ESA launch the James Webb Space Telescope (JWST) planned for 2018. ESA also have another telescope in range in which they hope to have operational at the beginning of the next decade. The European-Extremely Large Telescope (E-ELT) will help us not only understand how galaxies and planets are formed but should aid us in looking into the recesses of the universe in a hope to understand where we came from and ultimately where we are going.
- Astronomers find that galaxies are the ultimate recyclers (eurekalert.org)
- Our humble home (didyouknow.org)
- How do we know how many galaxies are in the Universe? [Starts With A Bang] (scienceblogs.com)