Last week there was a horrific Panorama programme about the ‘dangers’ of WiFi. It centered on a claim that the radiation from WiFi devices was much stronger than that from mobile phone masts, and later turned out that what they meant was the signal from a WiFi device 1 metre away was stronger from a mobile phone mast 100 metres away. Anyway, why do I mention this now? Because this is fanatastic.
This week’s Carnival of Space is up, over at Universe Today. Nice to see a few British bloggers appearing here and there.
I’ll be giving a free public talk at Green College in Oxford tomorrow night. It starts at 6.30, and the title is
Who, what and when? : Progress in the BIG questions in astronomy.
You’re welcome to reserve a seat via the link above, or just come along on the night.
I’ll also be co-host of Bill Heine’s Radio Oxford show tomorrow evening, from 4 until about 5.30. You can listen online via the above link; I’m normally extremely nervous about radio, so we’ll see how it goes.
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.
I thought you might want to be the first to see my new research project. We need your help!
I don’t have time for much writing today, but over at Universe Today it’s the Carnival of Space. I must get round to submitting something for next week.
Dizzy has what looks to be an advert for NASA’s return to the moon programme. It’s pretty flashy, but is it me or does it look like a Lego advert?
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”
It seems to be the month for stunning Mars images. Not just from the spacecraft, but from amateurs too. Damian Peach, who gets amazing and incredible results whenever he looks at the sky, sent me this animation. It’s a compilation of his 2005 images of Mars, comprising a full rotation of the planet. As Mars sails into the morning skies ahead of its opposition at the end of the year, it’s a reminder of just how good Earthbound views can be.