March 09, 2006

Hardcore Science 

Sod the politics, and let's talk about some cool scientific stuff!

The Sandia Z Accelerator is a brute of a machine built for the explicit purpose of producing flashes of X-rays of extremely high power - a matter of terawatts for nanoseconds*. This machine has broken record after record in its operation, but recently it achieved something absolutely astonishing: a plasma temperature exceeding 2 GK - billions of degrees, much hotter than the core of stars. And, even more interestingly, an energy output as X-rays considerably higher than the energy input. This energy must come from somewhere, and the researchers involved hypotesized that micro-scale turbulence in the compressed plasma causes intense viscous heating. Yes, also plasma has its own viscosity. Now, I'm no expert of plasma (I produced a bit of it years ago, when I closed a circuit with a short piece of thin steel wire, plugged it into a 220V mains socket and flicked the switch: the wire exploded with a loud pop and a small violet fireball.), but I know that high-temperature plasma is involved in nuclear explosions, astrophysical phenomena and fusion reactions that could be used to produce energy.

In a completely different field, Italian and other researchers discovered new organisms and divisions of bacteria in a particular habitat at the bottom of the Mediterranean Sea. The place is known as the Bannock basin, and it's a depression in the sea bottom filled with brine (close to 30% w/v NaCl). Naturally, there is an interface between this brine and the seawater above: in this 2.5 m thick layer, a rich and diverse bacterial ecosystem lives receiving methan from below and sedimenting particulate from above. This discovery is interesting in itself, but it has more implications: there probably is liquid water underneath the ice layer covering Jupiter's moon Europa, and conditions similar to the Bannock lake-seawater interface may exist there too. Moreover, bacterial and enzimatic processes are interesting from an industrial standpoint, but their drawback is delicacy: if the process conditions deviate even slightly from the correct setting, entire bacterial cultures or enzyme catalyst can be severely damaged. Bacteria living in these extreme conditions, on the other hand, will be less delicate.

Update 10/03: Boy, you can't finish an article about science that some other new discovery or invention pops up. And fortunately so.

The Cassini spacecraft has observed a plume of water and other substances erupting into space from Saturn's moon Enceladus, and a hot spot at it south pole. A plume - or geyser - means that liquid water is present under the icy surface, and a hot spot means energy. Together with the rock forming Enceladus, these are ingredients that may produce life - even if just microrganisms.

Finding lifeforms out of Earth would mean that life does not need the particularly mild conditions of our planet to emerge: the universe is therefore full of life, and other intelligent species will be out there, somewhere. However, such a discovery could also open another huge interrogative. If microrganisms eventually found on Titan, Europa or Enceladus are radically different from the Earthly ones, it means that they just evolved locally**. But what if those lifeforms were similar enough? Coincidence or common origin? And what common origin, then?

Later today, beginning at 21:25 GMT, the Mars Reconnaissance Orbiter will begin its orbital insertion manouvre: it is a delicate stage, because if the spacecraft does not decelerate enough or it's too far from the planet, it will slingshot around Mars and be lost; if it decelerates too much or gets too close, it will plunge to the surface and be destroyed. We will know in a few hours how it goes. The MRO carries a sizable array of instruments, among them a high-resolution (1 m) camera; a ground-penetrating radar (this one produced in Italy); a sounder for atmospheric/weather observations and and infrared/visible spectrometer for identification of the minerals on Mars' surface.

* This means an energy in the kJ range. The reason for the existence of the Z Accelerator is to reproduce the conditions encountered during nuclear explosions without actually detonating nuclear devices.

** Go on, try to make sense in discussing these matters using Creationism or Intelligent Design models...


meraviglioso blog :-D

finalmente un po' di realta' in tutta la politicaccia che c'e' in giro - v.
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