A while ago I wrote about the Mars rover Spirit, and the fact that it’s been stuck unable to move for the better part of a year. Earlier this week NASA and the Jet Propulsion Laboratory at Caltech announced that they were giving up on attempts to free her: Spirit will now remain in place as a ’stationary research station’.
Although Spirit did a sterling job - over 2200 days on a mission originally scheduled to last only 90! - it’s hard not to find the news sad. I confess I’ve always had a tendency to over-anthropomorphize objects, and especially to feel sorry for them when they break, but with Spirit at least I’m not the only one.
Just a short one this week, as I’m very busy at work. I’m also working on a couple of astronomy podcasts, the first of which will be online in a few weeks. I’ll let you know when they’re up.
Stephan's Quintet, by Hubble. Click to enlarge.
This beautiful group is a cluster of galaxies called Stephan’s Quintet. Its members are orbiting each other in a slow dance which, many millions of years in the future, will most likely end with a series of mergers to form a single super-galaxy. Two of them, near the centre, are already quite easy to mistake for a single object.
But one of the galaxies here is an odd one out, not really part of the cluster at all: in fact it’s about seven times closer to Earth than the others, at a mere 40 million light years instead of 290 million. Can you tell which one?
I don’t think I’ll ever get bored of these visual demonstrations of how vast the universe is. Here’s a nice one from the American Museum of Natural History:
I’m not sure which is more impressive: the idea of all that staggeringly complex structure stretched out across the cosmos surrounding our little home - or the fact that a race of inquisitive apes has managed to discover, to map and to understand so much of it in such a comparatively short time. Remember that the universe comes with no user’s guide or FAQ: everything we know about it is a testament to our own powers of inquiry, deduction and organisation. As a species, we have a lot to be proud of.
Although five gold rings would be perhaps more appropriate, here’s a somewhat late Christmas tree on the fifth day of the festival:
The Christmas Tree Nebula, aka NGC 2264
Unlike the names of some nebulae, the ‘Christmas Tree Nebula’ is one which actually fits pretty well. Both the shape and the colour used to represent the light in this image are evocative of a tree, and it’s even complete with baubles - hot new stars forming from gas collapsing out of the clouds in the nebula.
Spirit is the name of a robot which lives on Mars. It’s from Earth originally, but it moved there almost six years ago and since then has been helping us to study the rocks and dust of the planet’s surface, as well as some of the geological activity going on there. When NASA sent it there it’s mission was planned to last for 90 Martian days (or ‘sols‘ as they’re named - each is about 40 minutes longer than an Earth day because of Mars’s slightly slower rotation). Those 90 days were a success, as were the next 90 and the next: the mission has now been going on for over 2000 sols.
That’s a long time to spend in such an arid, dusty environment, crawling over and around rocks at the whim of people 300 million miles distant, with no access to repair teams or cleaning. It would change anyone, and it’s certainly changed Spirit. Here’s a composite self-portrait, formed from many small pictures taken by the rover’s cameras pointing down at itself:
Spirit, a self-portrait
And here’s another self-portrait, showing the build-up of red Martian dust on Spirit’s clean, shiny exterior:
Simon Page has designed a series of retro-style posters for the International Year of Astronomy, which the IYA committee has apparently decided to use. I think they all look really nice - perhaps partly because they remind me of the covers of old editions of Scientific American and Martin Gardner books I used to read as a child. It’s just a shame he made them so late in the year.
And what’s not to like about astronomy-inspired art?
(This was meant to come out on Tuesday as is traditional, but some sort of vengeful internet gnome seems to have prevented it. Well, here it is.)
Here’s a new image from the Hubble Space Telescope - specifically, the Wide Field Camera 3 which was successfully installed this May. The picture’s of an area that Hubble’s photographed before, producing the famous Ultra Deep Field image containing some 10,000 distant galaxies. This new picture repeats the feat in near infrared light (for the benefit of human eyes the colours have been shifted, so the light which now appears red is really in the farther infrared, while the blue is only just outside our visible range).
New Hubble Ultra-Deep Filed in infrared. Click for credit and larger versions.
Take a moment to look into that picture. Each of those tiny blobs is a galaxy.
Lots of galaxies are spiral-shaped like our Milky Way. Some we see face-on and some edge-on, depending on their orientation towards the Earth. Those which look edge-on are generally pretty flat, sometimes with a pronounced bulge in the disk’s centre.
ESO 510-G13. Click for Hubblesight release.
But not this galaxy, the charmingly-named ESO 510-G13. Its disk, which we can see perfectly edge-on, has a definite warp to it as though someone had grabbed the edges and given it a twist. In fact this is evidence of a recent collision with another galaxy, whose gravitational effect has shifted millions of stars huge gas clouds off their orbits. The disk is being rippled through by titanically slow waves of density, like a pool’s surface after a bucket of water’s dumped into it. Although the shape of the starry and gassy components of the disk is hard to make out against the bright glow of the central bulge, the warp is easy to spot because of the dark dust lanes running through the disk. This dust, made up of tiny particles a fraction of a millimeter in diameter, absorbs and scatters the starlight from behind it.
My name's Olaf Davis, and I'm a PhD student in the Astrophysics group at Oxford. This blog is mainly about astronomy and mainly aimed at the layman (no physics or maths training required!) but I sometimes stray into other areas which interest me, particularly maths and science reporting and communication.
