cosmolog

The Space Station

Proposal for an installation for "radiographic", g39, Cardiff, April 2004

Beaming down from the all corners of the universe are radio transmissions that have been broadcasting 24 / 7 for billions of years. No jingles, no phone ins, no traffic news, no personalities, no adverts, no competitions, no aesthetic . . . or maybe there is, the aesthetic of raw data . . . "a steady hiss type static of unknown origin" *

Visible light includes only a small range of wavelengths and frequencies of energy. At higher frequencies and shorter wavelengths lie ultra violet light, x -rays and gamma rays, at lower frequencies, infra red and radio frequencies. Given the right "eyes" and "ears" we can detect these bands of radiation emitted by extraterrestrial sources.

In radio astronomy the aural can be seen to meet the graphic. RF radiation (radio frequency radiation) induces a very weak electric current in an antenna. This can be amplified by a radio receiver until its strong enough for us to listen to. Just like the BBC or pirate radio . . .

For the purposes of interpreting this data radio astronomers convert it into the visual domain, mapping frequencies, their strength and location.

The Space Station starts from the idea of receiving an extraterrestrial radio source and playing it back alongside a graphic interpretation of the broadcast. Sound can be analyzed in various ways - relative strength of different frequency bands, amplitude, rhythmic content etc - and this information used to modulate and / or create visual information.

An uncompromising approach is to play a live radio source* at high volume and fidelity, allowing it to create a literal visual interpretation of itself through frequency analysis.

In this incarnation various recordings of different radio sources - among them meteor bursts, solar flares, pulsars, broadcasts from Jupiter - are part of a playlist including songs and music selected according to references to space and the universe in their titles. The Space Station orders these tracks according to random selection, music / sound non stop, radio without human interference.

Analogous to the interpretation of radio astronomical data, an analysis of frequency and amplitude is used to both create visual artifacts and affect parameters of found film footage and stills, rendering a real time visual counterpart to the sonic dimension.

*( Karl Jansky 1931)
*direct from radio telescope or internet stream

ten million volts

Leaving the building in the small hours I came across this little nook near the exit. Funny I'd never noticed it before. A display concerning the history of the department and in particular the van der graf generator that had been housed in the weird architectural feature in the photo below, the concrete fan like tower. Now cleared of its particle accelerator (shipped to China) the innards have been reconfigured into office space.

the pole star

Polaris: or by an other name, Alruccabah, Cynosura, Phoenice, Lodestar, Pole Star, Tramontana, Angel Stern, Navigatoria, Star of Arcady, Yilduz, Mismar, the North Star, Alpha Ursae Minoris . . . in the names of stars lie the histories and myths of ancient civilizations, of navigation and poetry.

a cold night in the observatory

Setting off at 10 pm we walked the 5 minutes or so to the observatory through a warren of buildings, heads cricked to the heavens. The night was freezing and clear, perfect weather to visit the telescope.

I was hoping for a glimpse of Jupiter, which we'd spied above us on the walk, but first we had to align the telescope. This meant pointing it at certain highly visible stars of known coordinates and synchronising its computer control - so that we could then find objects invisible to the naked eye, simply by typing in their location.

The first star targeted was Capella. The telescope records what it sees as a digital image but there is a small optical telescope attached to help roughly align it. Seen through it the star assumed a physicality previously lacking. Not exactly 3D but an exagerated 2D, a new spherical clarity, floating against a background of previously unseen stars.

Captured in the optical telescope its image was brought up on the screen and the telescopes orientation fine tuned until the star glowed in the dead centre of the monitor.

A time consuming business, and a chilly one, under the open dome of the telescope, the cold air falling in. The procedure was repeated for Polaris and now ready for serious observation, the telescope was cooled down to -25 degrees centigrade ( to improve its focus ) and the coordinates of the nights objective typed in, GRC 188.

Viewed through the optical telescope there lay a field of stars, 5000 light years away.

Chilled to the bone, colder than a supercooled lens, I left my companions to their observation as they fine tuned the focus to take a pristine 100 second exposure. I never did get to see Jupiter.

bass

A few days ago David Whittle (see 17th March) emailed me to say that he'd converted a power point presentation on the sound of the early universe into a web page. I looked at it on my mac but the sounds wouldn't play. Here in the astrophysics department I've tried it on a windows machine and, lo and behold, it works.

(This mac/windows incompatibility is really annoying : looking at this site on the same windows machine none of the movies play, infact looking at the prescribed file types for the windows media player it's hard to see what file types the two different platforms have in common . . . it seems .mpg should work but my movie exporter doesn't do .mpg . . . . )

Listening to David's sounds and reading his approach to creating them is very interesting. Most sound like noise, weighted towards various frequencies depending on the size of the universe / interpretation of data, which is kind of like I'd expected. Very different from John Cramers sound (17th February). More like the Cramer interpretation is a sound created by simplifying the data down to just the peaks in the power spectrum, giving a more harmonious combination of frequencies.

Pedro's getting into this - he's slowly turning into a sound artist ! - now full of ideas as to alternative ways of interpreting the data and experiments with low frequencies to create localised spaces of silence and loudness where waves cancel each other out / reinforce each other, a la wave interference patterns.

The cmb sounds are really low - in the region of 48 to 54 octaves below middle c. That's wavelengths of between 20,000 and 200,000 light years.

Another thing Pedro is asking is what size would the universe have to be - or have been - for these frequencies to be in the audible range, starting around 60 hz. A rough calculation suggests a volume similar to that of the earth.

ding dong merrily on high

Today was going to be the day I visited the telsecope but the sky is overcast so it'll have to wait.

The project to create the sound of the CMB (documented over the last few months) has jumped the rails. I've been thinking that my idea of using an IFFT on the CMB power spectrum was misconceived and various conversations today seem to confirm that. I never really understood what a power spectrum was and thought I could use it as a plot of frequency and amplitude but I now realise that though this is possible, a number of different sounds could give rise to the same power spectrum. So - it's necessary to look at the data in a different way, to look at it before its made into a power spectrum. Pedro has ideas about this which I don't fully understand yet.

Talking about this I learned of a past visitor to the department, David Whittle, who had worked on the same idea, although from the basis of actually understanding the problem in a much more rigourous way. I tracked him down on the www and emailed him.
His reply suggests that the way to proceed is indeed complicated and involves starting by simulating the early universe.
I look forward to hearing his results of which he says: "I now have sounds not just for the CMB as observed, but also the evolution of the sound spanning the first 1 million years of the life of the universe --- starting about 50 years after the Big Bang, up to recombination (about 380,000 years) and then on past recombination when the normal matter, once freed from being trapped by the radiation, is free to follow the structure of the dark matter."

I've finally got hold of a book I was shown back in October, "An Introduction to Modern Astrophysics", which weighs in at half a ton. Deep within lies a description of the subtle pulsation of some stars and their modes of oscillation. Again and again reading about such chiming stars, their ringing is likened to that of a bell. I'd like to hear what a sky full sound like all dinging away. Of course their oscillations are too low to hear even if our ears where to be in the right place (which is a ridiculous notion, the bodies to which they are attached would have long been reduced into a fiery heap of cinders). Transposed up into our audible range and simulated on a computer though they may be safely heard.

Jodrell Bank

Six miles off the M6, down winding country roads, sits Jodrell Bank, bowl pointing straight up to the heavens. On the last day of our tour of the Midlands, Bob and I drove up from Stafford to check it out.

I've been there before, years ago. A lot of things remembered from childhood appear to have shrunk but it still seems pretty big. It bought to mind something my friend Ansuman Biswas once said in connection with radio telescopes, that they are like a monks bowl quietly waiting for whatever might fall into them.

Perfectly still under the low grey clouds, carefully sculpted to collect whatever information might fall from the far flung reaches of the universe, it radiated a patient tranquility.

By contrast the visitors centre had all the charm of a motorway service station restroom. The mysteries of cosmology are overshadowed by the question as to how they managed to turn such inspiring subject matter into such a mess.

The website is probably a better bet . . . these timelapse movies for example : 1 2 3

DM Bob phones home.

Music of the Steers

I'm away from Oxford for a couple of weeks travelling the ring roads of Britain with DM Bob. Playing songs about tractors, hogs, fugitives, losers, cattle, love, loss and little green men (as in extra terrestials).

What has this to do with astrophysics ? DM Bob is a space alien.