Chris Lintott’s Universe

The star(s) of the show today have been those making up the Milky Way, the structure of which has been revealed like never before by the results of a survey conducted by the Spitzer Space Telescope. The result is currently displayed right across the exhibition hall, as you can see in the Universe Today report.

For those of you who aren’t here, go and play with the Alien Earths interface which lets you zoom around and into the image, head for highlights selected by the team and switch between wavelengths with the slide of a mouse. Excellent eye candy for the end of a very long day.

I like the United Kingdom InfraRed Telescope (UKIRT); they do amazing work and have been doing so for 25 years. However, they’ve just released one of the most stunning data sets I’ve seen for a long time – the first release from their deep infrared survey, UKIDSS. This is the deepest and largest infrared survey ever made, the result of work that’s been going on since 2005. Sadly I missed the press conference as I was working on my talk, but luckily, Pamela has the full story here. And if you’re more a pictures than a words person, I recommend you jump straight into the site here and explore the gallery. The images are great, but my favourite UKIRT image is still the one below – the Chicken nebula.

Update Stuart reminds me that there’s an amazing Zoomable image from the part of the survey that looks along the plane of the Milky Way.

We’re just scanning for stories for the next Sky at Night news roundup, and apparently ESA think this image of hot gas in the middle of the Orion nebula (as seen in x-rays) looks ’somewhat like Santa Claus’. I can’t see it at all…

Just a very brief update on Galaxy Zoo. We’ve reached our target of more than 30,000 users and have just upgraded the hardware behind the site to make sure we can cope with as many people as once. We’re hoping to get a couple of new features up on the site in the next 24 hours, and first priority is a discussion forum so people can compare images.

We’ve just been mentioned on slash dot so please bear with us during the tsunami of traffic currently heading our way. If the site goes down again then I’ll try and post updates here and if you’re into that sort of thing, there’s a Galaxy Zoo group on facebook.

Today’s pretty image is a ring galaxy - if you see one of these, we want to know about it.

At about five am this morning, two thirds of the way through my second shift on the telescope, I went outside to watch the dawn. The peak immediately behind the JCMT is called Pu’u Poliahu and I decided that would be the perfect spot to watch the Sun come up. Poliahu is the Hawai’ian snow goddess, who was constantly at war with her sister, the volcano god Pele. Pele’s home is the still active Mauna Loa, whereas Poliahu lived on the summit of Mauna Kea which is frequently snow covered. Pu’u Poliahu is therefore a sacred site, but as the place where the first astronomical site testing on the mountain was done, I suppose it might be considered sacred to astronomers too!

The sky was already bright when I stepped out of the door, with a crescent moon hanging about the summit ridge which is home to Gemini, UKIRT and several other telescopes. I walked through one of the JCMT’s neighbours down here in ’sub-mm valley’, the SMA which consists of eight small dishes, and began climbing the mountain. I could see Jupiter extremely low on the horizon, and off to the right I could see the neighbouring island of Maui sticking above the clouds.

As I climbed higher, I began to feel the effects of the altitude. Climbing even a small hill at more than 14,000 feet above sea level is not easy, and I found myself becoming short of breath. I was also being blown about a bit by an extremely strong wind cutting across the summit, gusts of which blew me from one side of the track to the other. I had my back to the West, and between concentrating on breathing and resisting the wind I didn’t turn round to look at the dawn until I reached the top.

My pictures - taken while crouching down trying to shelter the camera from the wind - don’t do the sight justice. With the crescent moon above the greatest collection of professional telescopes anywhere in the world, the colour of the dawn was a deep red, purple low on the horizon rising to a golden yellow higher up. There were still stars visible in the sky as well as the Moon, and most of the telescopes were still open, most of them pointing toward me, away from the rising Sun.

I know it may be hard to believe, but sitting up there I was thinking of all the times when doing research feels like a hard slog, a prison sentence in front of a computer which won’t cooperate. Combined with the excellent data we got last night, it’s trips like this that remind me why I’m doing any of this in the first place. All I could think about (apart from the need to avoid being literally blown away) was how incredibly, incredibly lucky I am. I think I stayed up there for about twenty minutes, not able to tear my eyes away from the colours laid out in front of me (and realising that clouds are useful for something!).

And walking back down, frozen but ecstatic, I thought about how unique this wonderful island is. On the way up to the telescope, we’d looked over and seen the glow of the vents from one of the world’s most active volcanoes. Where else in the world could you find such an amazing variety within an area not much bigger than greater London? I also think I found the perfect spot to capture almost all of Mauna Kea’s telescopes on pixels.

From left to right: Subaru, Keck, IRTF (NASA), Canada-France-Hawaii Telescope, Gemini North, Uni. Hawaii, UKIRT, small Uni. Hawaii dome and in valley JCMT and CSO.

I love my job.

It’s not always easy being an astronomer whose work is based on observations in the sub-mm, even though this part of the electromagnetic spectrum (think of it as very short wave radio) is perfect for spotting the signatures of the more than 100 molecules which have been detected in space. The problems start when we have to deal with molecules closer to home, however; microwave ovens operate at these frequencies because they can excite the water molecules in food and that also means that it’s especially important for sub-mm telescopes to be high above sea level, away from most of the atmosphere. In one of my early observing runs I managed to make a completely independent detection of ozone in the Earth’s atmosphere which, suffice it to say, was not what I was looking for!

Even after we’ve got over that problem, though, applied for and got our fabulous data of huge scientific importance, when it comes to presenting results it’s hard not to be jealous of everyone else. My office neighbours produce incredible images from optical, infrared, ultraviolet and X-ray telescopes, but the largest sub-mm camera in the world until recently, SCUBA has a few tens of pixels. Not megapixels, but pixels. So when it comes to giving research talks we’ve been rather left behind as far as flashy pictures go.

However, things are changing. When the Sky at Night was last in Hawaii, we featured the new instruments being prepared for the JCMT. SCUBA’s successor, SCUBA2, is moving slowly in the right direction, but the spectral line receiver, HARP, is up and running. Instead of taking a spectrum at each point in a field, HARP makes maps which can be quickly converted into visual representations. I’ve already got my first data, and the first press release came out last week.

This is the centre of the Orion nebula, as seen in emission from Carbon Monoxide (the most common molecule in the Universe behind molecular hydrogen). The real beauty of this data, though, is that we can tune to different frequencies as this schematic shows

When you do that, as in this movie, you get a sense of the motion of the gas. The movie starts with a frequency corresponding to material moving rapidly toward us, at about 200 km/s (half a million miles an hour), and tunes through the different frequencies to end up with material rapidly receeding from us. This is a beautiful illustration of a ‘champagne flow’, as gas is forced away from the central part of the nebula, where star formation is most vigorous.

There will be a lot more from HARP, and from the JCMT in the next few years, and the ability to actually see in the sub-mm will certainly help us get a grip on the surprisingly complicated story of star formation.

Working with Pete Lawrence has been one of the most eye-opening parts of the Sky at Night over the last couple of years. As well as being blessed with unbelievable luck with clouds, he comes up with some of the most interesting projects I’ve seen.

His latest images of The Shadow of Venus are a case in point.

We had a fantastic production meeting yesterday morning, and I’m really looking forward to the rest of the year. We also had a quick rundown of what we’ve missed in the two months without news notes, and I was generally mocked for suggesting that NASA’s announcement on dark matter yesterday was likely to be interesting.

I was right. Here’s what they’ve done. Take this image of a cluster of galaxies:

Then spend a long time looking at the shapes of all the small background galaxies, looking for the distortion caused by the passage of their light through the massive foreground galaxy cluster. Then use those distortions to work out where the mass is in the cluster - not just the mass that happens to shine, but all the dark matter too. Colour the result a pretty shade of blue.

The first thing you notice is that it really is a very nice shade of blue, and that NASA’s graphics are getting better and better. Then you notice that the matter in the cluster forms a ring around the centre. This is a slightly crazy result, and the astronomers involved spent a year refusing to believe their eyes (or slightly more accurately, their computers). What seems to have happened is that this is a collision between two clusters, which we’re viewing head-on. The ring is a ripple moving outwards as an aftershock of the collision. There’s a simulation of this here, or you can look at high resolution images (and non-quicktime movies) here.

It’s a stunning result, and the observers deserve a huge amount of credit for what must have been a massive (pun intended) amount of work. But I’m not sure this quote, from first author Myungkook James Jee, is correct

“This is the first time we have detected dark matter as having a unique structure that is different from the gas and galaxies in the cluster”

Have a look at my article on the Bullet Cluster over on the Bang! site.

I think out of everything we do, I most enjoy talking about Mars and Saturn. The missions to both have brought back amazing pictures over the last few years, and it’s great that for the last program of the first 50 years of the Sky at Night, we’re going to back to Saturn. The latest results from Cassini are incredible and in John Zarnecki and Michele Dougherty we have two of our best interviewees.

It’s on Sunday night, on BBC2 at 23.45, followed by the extended edition on BBC 4 on Monday evening at 7pm (repeated at 00:50 in the early hours of Tuesday).

Althought I was clouded out last night, I’ve been enjoying the many pictures which arrived in my inbox overnight. Here are some sent to BBC News, and very lovely they are too.

Or at least, they are until we click through to picture 5, where we’re told that

Comet McNaught is passing close to the Sun, whose gravity pulls material off, giving it a big and visible ‘debris field’

which happens to be complete rubbish (as well as annoying english teachers around the world by only mustering ‘big’ and ‘visible’ as adjectives). It is the warming of the comet as it approaches the Sun that leads to the expulsion of material, which is then driven away from the Sun by the solar wind. Nothing to do with gravity at all. But I didn’t need to tell you that, did I?

UpdateBBC site now corrected.