Edd didn't want his slot back . . .
What do all these galaxies have in common?
They're all spirals? Hah - sorry, tricked you.
These all have the same thing in common . . .
The fact that I have been lazy and not given the Object IDs? YES!
And what has that got to do with this?
"The Cosmic Scarf" 588011501535495237
(zoom out as far as you can!)
Well, it's the boundary of where our beloved picture provider, the SDSS telescope
, has taken its pictures. Night after night, for many years, it has slowly worked its way across the sky. It's a digital camera, older than the ones in our mobile phones today (some astronomers, unlike me, somehow keep up with technology!). But its exposure times are long. It works slowly and carefully. And of course, as the Earth rotates on its own axis and around the Sun, it won't always be able to go back to the spot to fill in the gaps.
Here is the pattern that it has built up over this time:
Not only can you see a few blue scarves, but you can also see the Plough. So now we can look up at the sky ourselves and have a clearer idea of where all these beautiful galaxies we see come from - and just how tiny they are compared to the small foreground that is the beautiful roof over our heads every clear night.
That is part of this beautiful, Crab-Nebula-Like splash of, for want of a better phrase, photograph-history:
The good news is that there is more of the sky to photograph . . . perhaps for Galaxy Zoo III . . . May we never
run out of galaxies.
I have many people to thank for the sudden inspiration I had for this little story. Firstly, Jules
and all the other people who have contributed to the wonderful Galaxies from the Edge thread
- a great little project I never would have thought of; but - as Chris and a member of the audience commented towards the end of this great talk
- 150,000 brains combined make for many, many great ideas.
Secondly, Bob Nichol
from Portsmouth University - effectively a zookeeper without a zookeeper name on this forum.
Thank you very much, Bob, for giving a brilliant talk at Herstmonceux Festival
(which not only taught me an awful lot about the SDSS Telescope but, more importantly, prompted at least one member of the audience to tell me that he and his son would join the zoo!), and for letting me crib those SDSS pictures.
Now, doubtless I have got one or two details slightly wrong, so any corrections welcomed.