A few months ago I blogged about an amazing shuttle mission that set off to perform maintenance on one of the most important pieces of scientific equipment for humanity, the Hubble Space Telescope. Up until now the Hubble team has been performing calibration tests and making sure that everything is working properly after its last trip into space. Well now the time has come for them to release the images that they’ve acquired over the past few months, and I must say they are stunning.
Before you gallivant off and ogle the 56 pictures NASA has released to us I want to show you something that really drove home just how important the Hubble is. First off let’s have a look at a ground based observation of Stephan’s Quintet, a cluster of 5 galaxies who are very close together and have been very well studied over the past decade:
That picture was taken from the Kitt Peak National Observatory using a 2.1 meter telescope back in 1998. Whilst its not the most amazing picture it does give away some detail about the galaxies and their relationships with each other. For instance the one in the bottom left hand corner (NGC7320) looks very blue in relation to the others. This is due to a process called redshift where as light travels towards the observer it stretches to the lower energy (red) side of the spectrum. This would lead us to believe that NGC7320 is probably closer to us than its neighbours, although you can’t say that definitively with this picture.
Let’s step into the future 2 years from when this picture was taken and have a look at this beauty:
Well hello there gorgeous! The picture is basically a zoomed in version of the last one, but boy look at the detail! This really demonstrates the power of putting a telescope in space as the primary mirror on Hubble is only 2.4m big, a mere 30cms more than the previous picture. We can now quite clearly see the redshift in 3 of the galaxies visible here, with NGC7320 hiding off in the corner. This was even before its last camera upgrade in 2002 with the Advanced Camera for Surveys. 7 years later NASA gave Hubble its last upgrade and it seems that it was money very well spent.
Oh dear, could you all give me 5 minutes alone with this picture? 😉
But seriously just….look…at….that! The detail is phenomenal and even with these galaxies being so far away (most are above 200 million light years away) we can still pick out individual stars. The Hubble team has also kindly added some information to this picture and you can probably guess what my earlier ramblings have been leading up to. The numbers on the respective galaxies are the amount of redshift the light has undergone before it has reached us. Looking at NGC7320 we can see it is significantly lower than the rest, which means it is actually a lot closer to us at about 39 million light years. There’s also another clue as to why NGC7320 is close to us, can you guess what it is?
Have a gander at NGC7318A/B and NGC7319, aren’t they a little unusual? For starters NGC7318A/B are two galaxies in the last stages of merging. You can see some of the starts and other stellar material being thrown off towards the right side of the picture. NGC7319’s lower spiral arm is significantly distorted towards NGC7318A/B, showing that their combined masses are pulling them in. But what of NGC7320? It looks like your normal galaxy and that’s because it’s so far away from the other three that their gravity has little effect. There’s so much that this one picture shows us!
It’s things like this that really inspire me. In just a little over 10 years we’ve gone from a fuzzy picture of distance galaxies we can make guesses on to something like this which shows amazingly distance objects in spectacular detail. We still have another 5 years before the next space telescope takes off and it looks like Hubble will be doing a fantastic job until it comes online.
Now I just need to convince NASA to bring Hubble back to earth, as was their original intention.