Mortal as I am, I know that I am born for a day. But when I follow at my pleasure the serried multitude of the stars in their circular course, my feet no longer touch the earth - Ptolemy
Cosmic Trainwreck Arp 274
I'm delighted to announce that the winner of the public vote to choose the last Hubble picture was won by Arp 274, the triple interacting galaxies, which astronomers call a 'cosmic trainwreck'. The picture has now been released and it is truly spectacular.
The HubbleSite link allows you to download the correct version for your monitor for a screensaver or desktop wallpaper. Their image is also zoomable, which is great fun to play around with. It's hard to comprehend that what we are looking at spans about 200,000 light years. (A light year is the distance light travels in one year, roughly 5.88 trillion miles or 9.46 trillion km.) In case you're wondering what the two very bright objects above the galaxy on the right are, they are unrelated foreground stars in our own Milky Way galaxy.
The Astronomy Picture of the Day people weren't slow at publishing it either, go to the main page and select 7 April, or click the direct link. When the page has loaded, right-click the image and "select as desktop wallpaper" — it's as simple as that. It has been my new wallpaper since it was released last week, I didn't think I'd change from The Milky Way Over Mauna Kea so soon!
Galactic collisions take place over hundreds of millions of years — the ultimate slow dance. While the galaxies do collide, the individual stars within them (usually) do not. If the galaxies have black holes at their cores, they will eventually gobble each other up and form one supermassive black hole. Arp 274, also known as NGC 5679, is around 400 million light years in the direction of the constellation Virgo 'the Virgin'. Motion is a marriage of time and space, so the amount of time light takes to reach us is a measure of the distance.
It is difficult to imagine that the snapshot we see is actually what was happening 400 million years ago from our perspective — if we could see Arp 274 as it really is now — it might have completed the gravitational dance to form one mighty galaxy with little or no clue remaining of what took place before. I feel immensely privileged to be witness to this awesome spectacle and I wonder what the astronomical giants of the past would have thought if they could have seen such a sight. I like to think I am seeing it on their behalf, and I'm honoured to share it with you.
Future collision for the Milky Way
In April 2002 a Hubble team member played around with some computer graphic software and projected what the future (far, far, far — billions of years into the future, so don't panic) collision between our own Milky Way and our neighbour the Andromeda Galaxy might look like. The result was shown at the Einstein Planetarium but the image of the computer-generated local cosmic trainwreck of the far future is still available to download for disaster junkies. Here is the extraordinary image of the clash of the titans, if you can bear to look!
Chat about your celestial observances at the H2G2 Astronomy Society. Comment on anything in this edition of Babe Among the Stars by starting a new conversation below.