"German satellite hurtling towards Earth"

ROSAT, a German satellite is indeed "hurtling towards Earth", as the Guardian and many other news outlets have been telling us in recent days. Well, "hurtling" isn't quite accurate, but it'll reach us sometime in the next few days as its orbit gradually decays (in fact, since I typed this it looks as though it's come down).

I was slightly surprised to learn it hadn't come down a long time ago. It was a pioneering X-ray astronomy space mission of the early 1990s. When the first X-ray detectors were thrown briefly up above the atmosphere on rockets, there were no great expectations. This was in 1962 and imaginations stretched only to a faint glow from the Sun's million-degree outer atmosphere, or possibly from the Moon's surface as energetic particles in the solar wind smashed into it. As the world knows, the results were much more exciting: bright, point sources of X-rays beyond the solar system, among the stars of the Milky Way; a cosmic "background", X-rays coming from all directions on the sky; X-radiation from the Crab Nebula. A new window had opened on the high-energy universe of black holes and neutron stars; nobody thought much about X-rays from the Moon for a long time.

ROSAT closed this particular historical circle by detecting, for the first time, X-rays from the Moon. The ROSAT image of the Moon, illuminated only on its sunward side, looks so familiar that you might need to look twice and think about it to realise just how amazing it is. It is lit up only on the sunward side because the Moon's surface is reflecting X-rays from the Sun (strictly, scattering those X-rays, and apparently also fluorescing).

ROSAT was used to make many important advances in X-ray astronomy; a brief list is here. I always had a soft spot for it because it closed the lunar loose end. None of this prevented its fiery doom, however, which no doubt is as it should be. None of us escapes his doom, watery, fiery or otherwise, no matter what sort of songs we've sung in the meantime.

None of the news reports let us forget it was a German space mission, rather than, say an "X-ray telescope", "orbiting X-ray laboratory" or some such border-less phrase. I wonder why? If it had actually fallen on somebody's head, would the German nation have been held to account? Would we have seen invoked the ghost of Wernher van Braun? I'm really not sure what's behind this.

Tribes of Science

A dentist appointment this morning made it easiest for me to travel by car, and also meant I was coming to work after 9.30. So I happened to hear a very nice, short programme on Radio 4. It is probably not the first time that an anthropologist has looked at a group of scientists, but it's the first time I've come across such a thing away from academic literature. So the programme mixed little snippets of Diamond Light Source science with words from the staff scientists: how they worked together and interacted, both among themselves and with visitors using the facility, how they felt about their role of service (as opposed to leading and driving scientific projects), their dress code: a "tribe of science". Perhaps he viewed them from a vantage point similar to Margaret Mead in Samoa - and I wonder how far they told him what they thought he wanted to hear, or should hear. No sex though, at least on the radio.

So I very much appreciated a scientific story humanised by the voices of the scientists themselves, and the agenda of an outside view. Just the sort of thing you also get in a forum where scientists themselves will tell their stories, where you can inquisite them, change the agenda, ask them how they feel as humans about geeky and abstract pre-occupations; in university adult education in fact. Good thing the brochure will be out soon.

all round the Sun

it seems to me that vague feelings about the world and how it works become more firmly held and acted on as one gets older. So I find myself at last turning into a Guardian reader. It has to be admitted there are many sorts of entertainment on the Guardian's website particularly, such as today's article on Isabella Rossellini's series of animal sex short films. Also catching my more professional eye is this item on the first 360° view of the Sun's surface. Will we learn something uniquely new form this? Of course not: no dragons or UFO's or day-glo sunspots have been lurking in the unseen parts of the Sun's surface, always furtively avoiding our cameras and telescopes. It's a symbolic moment, a point where our monitoring of the Sun and its outputs can attain a new level of sophistication; a small step for routine science, the kind that eventually and unspectacularly leads to changes in thinking. It's certainly a media friendly step, however, even if there is no media-friendly huge new discovery,and the Guardian's article is only one of many all over the internet. That incremental process will lead to new things - or not - in its own sweet time, and in the meantime everybody can enjoy the continually improving view of our nearest star.

Total eclipse of the Moon

"This is a very rare event. It only happens every 400 years," said the glossy lady on ITV this morning. "Oh, dear," I said - or maybe something worse. "Text them!" said my wife. But I had to press on with the day so I hope somebody else commented.

Lunar eclipses are visible somewhere on Earth most years. Statistically that means we can see one in Britain on average once every year or two. Sometimes we'll see them in successive years and sometimes we might have to wait two or three years. In 2011 we'll be able to see lunar eclipses on 15 June and 10 December, but then we'll have to wait until 2015.

So, what's this "every 400 years" about? Well, it is apparently more than 400 years since the last time a total eclipse coincided with the winter solstice. This is a coincidence of so little import that nobody has yet bothered to work out when it will happen next but it certainly isn't a recurring event every 400 years. It is equally valid to get excited because a lunar eclipse falls on your birthday, on the birthday of Sun Myung Moon, or on a day when American Werewolf in London is being shown on TCM. But I'm not sure that poor Kate Garraway appreciated any of this and somebody glancing only briefly at that channel - like myself - could easily have come away with the impression that lunar eclipses in general were extremely rare events. I'm really not sure if this was her own impression.

I shouldn't complain; it's great to see a celestial event receiving this much attention. But it's hard not to feel uneasy at some of what gets said on these occasions, and the degree of cosmic ignorance that gets revealed.

Anyway, regardless of which day it falls on, a lunar eclipse is a beautiful and only slightly unusual sight and you won't have to wait 400 years to see the next one.

Life in the Cosmos

Are there living things elsewhere in the universe? Barring the arrival of the flying saucers over the capital cities of the world, we'll have to try to answer this tantalising question using the same tactics employed for any of the big scientific questions, a bit like the assembly of a very large jigsaw puzzle of an unusual character. We have lots of little, detailed pieces for some bits of the picture but there are other, big sections we have few or no pieces for and we're going to have to go out to try to find them. Sometimes we'll come back with a handful of pieces that turn out to be wrong, or to belong in a different jigsaw. We're not really sure of the ultimate size or shape of the picture and there may be entire sections we're not yet aware of, whose existence will only become clear because they're needed to fit into the bits we've completed in detail. At the present time the sizes of the pieces also vary enormously: some parts of the picture are represented in detail by lots of teensy pieces, other bits are like the big, chunky pieces of a toddler's jigsaw, drawing crude, unsubtle shapes in primary colours. We'd love to take the jig saw to those bits and render them more finely, in particular to see if there are big new, unsuspected bits that border them. People will spend their entire scientific careers filling in wee bits of the jigsaw and they may even turn out not to be so important - they were smaller bits, making a smaller part of the picture, than we thought at the time.

There might never come a time when the jigsaw is definitively finished.

Astronomers are working very hard at the extraterrestrial life jigsaw right now, on several different fronts, and there are stories in the media all the time. So in the last couple of days we have learnt that there has been liquid water on Mars in "recent" times; and we've heard that one quarter of observed Sun-like stars harbors a close-in terrestrial-mass planet (these links are to the American journal Science - you can read the abstracts but you'll have to be inside an organisation with a subscription to go further).

The presentation of these stories in the mass media often causes problems, however. "Scientists might possibly have found a new Earthlike planet" is not nearly as attention-grabbing a headline as "At last, an Earthlike planet that could harbour life!" The widely reported discovery of such a planet a couple of weeks ago has turned out to be more tentative than most reports suggested, with an inevitable backlash as foolish as the initial hype. The mystery of the disappearing planet in the Guardian deals really well with this, highlighting the perennial clash between the demands of journalism and the long, painstaking process of completing the jigsaw puzzle.

How can you find out what's behind the headlines? Come to our courses! We'll mention the caveats and uncertainties alongside the exciting results. There's time to ask questions and we're aiming to explore the ideas, not propagandise. My starting point here is Astronomy - and we do have a "Life in the Cosmos" course after Xmas - but these comments apply to any of our science courses, and "explore the ideas", in science or otherwise, is what universities are for.

It's too beautiful a day to sit in the house. But before I stop, here's a very different, I think wonderful sort of science communication: "Dance your PhD 2010".