Skip to main content

When space isn't cold enough

Not a Blue Peter model - the actual Herschel Space Observatory
We are used to thinking of space as a cold place. And it is, sort of - but not always in the ways you might expect.

For instance, if you were suddenly dropped into space you might assume that the minimal temperature out there would mean that your blood would freeze solid in your veins, while simultaneously trying to boil where any is exposed due to a lack of pressure. But here's the thing. It won't boil - your circulatory system will keep it under pressure - and it won't freeze because a vacuum makes a great insulator. Remember vacuum flasks - there's a lesson there. The only heat you will lose is through radiation and you aren't hot enough to do that quickly.

Even so, it's rather ironic that space just isn't cold enough for the Herschel Space Observatory. It was sent up with 2160 litres of liquid helium to keep it cool. but that is due to run out by the end of March, leaving the Herschel to die of warmth in space - without that helium, the electromagnetic radiation emitted by the satellite itself will be enough to mask the subtle stream of photons it has been detecting.

The Herschel has done great work on helping us understand how stars and galaxies are formed, peering back around 10 billion years in time, picking up weak sub-millimetre light from the dust around newly formed stars. The good news, though, is that although the Herschel is soon to stop functioning, according to Steve Eales at the University of Cardiff, an astronomer who leads one of the telescope’s largest surveys,  'the treasure trove of Herschel data will be picked through by astronomers for years to come.' That's good to know.

Thanks to Physics World (also featuring an excellent article by me (ahem) on the need for double blind experiments in physics to deal with experimenter bias in the January edition) for this info.

Comments

Popular posts from this blog

Is 5x3 the same as 3x5?

The Internet has gone mildly bonkers over a child in America who was marked down in a test because when asked to work out 5x3 by repeated addition he/she used 5+5+5 instead of 3+3+3+3+3. Those who support the teacher say that 5x3 means 'five lots of 3' where the complainants say that 'times' is commutative (reversible) so the distinction is meaningless as 5x3 and 3x5 are indistinguishable. It's certainly true that not all mathematical operations are commutative. I think we are all comfortable that 5-3 is not the same as 3-5.  However. This not true of multiplication (of numbers). And so if there is to be any distinction, it has to be in the use of English to interpret the 'x' sign. Unfortunately, even here there is no logical way of coming up with a definitive answer. I suspect most primary school teachers would expands 'times' as 'lots of' as mentioned above. So we get 5 x 3 as '5 lots of 3'. Unfortunately that only wor

Why I hate opera

If I'm honest, the title of this post is an exaggeration to make a point. I don't really hate opera. There are a couple of operas - notably Monteverdi's Incoranazione di Poppea and Purcell's Dido & Aeneas - that I quite like. But what I do find truly sickening is the reverence with which opera is treated, as if it were some particularly great art form. Nowhere was this more obvious than in ITV's recent gut-wrenchingly awful series Pop Star to Opera Star , where the likes of Alan Tichmarsh treated the real opera singers as if they were fragile pieces on Antiques Roadshow, and the music as if it were a gift of the gods. In my opinion - and I know not everyone agrees - opera is: Mediocre music Melodramatic plots Amateurishly hammy acting A forced and unpleasant singing style Ridiculously over-supported by public funds I won't even bother to go into any detail on the plots and the acting - this is just self-evident. But the other aspects need some ex

Mirror, mirror

A little while ago I had the pleasure of giving a talk at the Royal Institution in London - arguably the greatest location for science communication in the UK. At one point in the talk, I put this photograph on the screen, which for some reason caused some amusement in the audience. But the photo was illustrating a serious point: the odd nature of mirror reflections. I remember back at school being puzzled by a challenge from one of our teachers - why does a mirror swap left and right, but not top and bottom? Clearly there's nothing special about the mirror itself in that direction - if there were, rotating the mirror would change the image. The most immediately obvious 'special' thing about the horizontal direction is that the observer has two eyes oriented in that direction - but it's not as if things change if you close one eye. In reality, the distinction is much more interesting - we fool ourselves into thinking that the image behind the mirror is what's on ou