Archive | December 2011

This might be my next computer

A bare-bones computer that costs $25 (£16, or €19) is going to be on sale very soon. It uses a chip similar to the one in your mobile (well, that depends on whether you have a “smart” phone or not), and it’s based on Linux.

What really is going to grab attention is the price, especially when money is short. $25: that’s a very low price for something that could spark interest in computing and microelectronics amongst teenagers – just like the Arduino boards I used earlier this year. Maybe I’ll get one myself, but if anyone’s interested, here is the project’s site.

Update on the Final Year Project

I should have posted this earlier, but I made my choice for the dreaded Final Year Project a few weeks ago. The project concerns the Fermi Large Area Telescope, a gamma-ray space-based telescope used by NASA to view the universe at gamma-ray wavelengths. If you want an idea of what that might look like if we could see gamma rays, this site might interest you.

Back to the project I have. Fermi has detected pulsars (neutron stars that spin at a fast enough rate to appear to pulse) in the past, but it’s spatial resolution is too low for them to be optically identified. What my supervisor, Andy Shearer, wants to do is to investigate deconvolution techniques to see if this can be improved. Deconvolution is the opposite of convolution (thank you, Captain Obvious), which is when two signals are “mixed”, for lack of a better word. An example of this is a motion-blurred photo; or the Hubble Space Telescope, which originally had a flawed mirror distorting photos which could be corrected after the photos had been taken.

Here is a picture (I suspect in false colour) of what Fermi has shown us. If you were to zoom in on individual bright spots, they’d be too blurred to be any use for identifying the pulsars. Deconvolution algorithms should be able to get around this, and the department has their own programmes to do it. All I’ll have to do is to run the programmes on the data from the Fermi catalogue, and maybe tweak them. A bit like game modding, really!

New particle found

It’s not the Higgs Boson AKA The God(damn) Particle, but the LHC has found a new particle, composed of a “beauty” quark and an “anti-beauty” quark.

Quarks are the smallest particles that we know of, so small that they have no known structure. They’re called “quarks” because Murray Gell-Mann apparently decided to break with the traditional “-on” ending for particle names and used the following line from Finnegan’s Wake:

Three quarks for Muster Mark!

They come in six flavours (yes, you read that correctly): up, down, top/beauty, bottom/truth, strange and charm. Now, these names may sound like something that was invented while drinking or playing darts (which is how the Penguin diagram was invented), but there is a method to the madness. Up and down quarks are named after their components of isospin (this is a quantum number that exists, for instance, to distinguish between neutrons and protons, both of which have similar masses); top and bottom are their logical counterparts. Charm apparently fascinated and pleased (or charmed) the physicists who proposed it because of the symmetry it brought. Strange came from the fact that it appears in certain particles in cosmic rays, which have unusually long lifetimes and where detected before the quark model was even proposed by Gell-Mann and independently by George Zweig.

Another strange thing about quarks is that their electrical charges are not integers: they are either -(1/3)e or +(2/3)e, where e is the charge of an electron. Their antiparticles will have the opposite charge: i.e. a quark with a charge of -1/3 will have an antiquark associated with it with a charge of 1/3. The total charge has to add up to 0 or 1, forming the positively or neutrally charged particles that are known as hadrons (for example, protons and neutrons).

This is pure blue-sky research. It’s unlikely to have any practical use for a long time, if ever, but so bloody what? It expands human knowledge and gives us a better understanding of the universe, which is part of what I love about science: that moment when you realise “Oh, so that’s how it works”.

Tim Minchin’s new piece

Tim Minchin has created a new piece that he’s titled “Woody Allen Jesus”. For some reason, ITV refused to play it – the director of television, Peter Fincham, demanded it be cut. All he’s done is bring more attention to it, when it’s not very offensive.

Cello Wars

Olwen showed me this video a few days ago. Star Wars themes using cellos? Brilliant!

The uses of plasma

Okay, what’s plasma? It’s an ionised form of matter similar to a gas, or a gas which has lots of ionised particles in it (to put it a bit simply). Most people will have heard of plasma-screen TVs, or maybe plasma being used in experimental fusion reactors such as ITER. But there’s more than that.

Artificial plasmas include your TV (if you’ve got a plasma-screen, which I don’t) or fluorescent lighting in more everyday life, and this may include plasma brushes in dentistry. More exotic or specialist varieties include plasma torches, arcs from Tesla coils, or even in ITER, like I mentioned earlier. Of course, the problem with fusion is that we’ll need to wait a while before it becomes practical: research has been going on for over 50 years and it’s still quite hard to get it to work. The general idea with fusion reactors is that lighter elements (anything with an atomic number less than iron (56), which appears to be the cut-off between fusion and fission) are fused together at high temperatures, releasing nuclear binding energy. The inherent advantage in this is that if the temperature is not maintained, the plasma cannot sustain itself and the reaction will be quenched by itself – this means it’s much less likely to go catastrophically wrong.

But plasmas can occur quite naturally. Lightning is one type which can reach a temperature of around 30000°C – for comparison, the surface of the Sun is around 6000°C! Ball lightning is another phenomenon, characterised by spherical lights in the sky accompanied by a thunderstorm, and it has been suggested that this might be a form of plasma – if it even exists, that is.

But if you really want beautiful naturally-occuring plasmas, then you need look no further than the polar lights. What happens here is that charged particles from the solar wind in the higher levels of the atmosphere collide with each other; the collisions produce photons with a particular frequency/wavelength in the visible spectrum. Photographic film and possibly digital cameras are sensitive to a higher range of frequencies than the human eye, so they can see more colours. Why am I mentioning this? Well, photos often show more red in aurorae than the humans themselves saw, mainly because the red photons produced are just outside the range of the human eye.

Plasma often shows up in science-fiction as weapons, usually as a form of superheated gas or liquid that causes some nasty burns – almost like a futuristic form of napalm. Some works use this as hand weapons (Covenant weapons in the Halo series, for instance), or as ship-to-ship weapons. I think the latter is slightly more likely, but I wouldn’t exactly hold my breath about it: plasmas need to be confined to a particular space to prevent dissipation, and even if that weren’t a problem, there’s other obstacles. For instance, such weapons would generate a LOT of heat (dual plasma rifles overheating in Halo 2/3, anyone?), and even today we have materials that can withstand such levels of heat. They were used in the Space Shuttle, and the ceramic plates used by some bullet-resistant vests. Finally, blackbody radiation means that they would lose their heat very rapidly and, because they’re glowing, there is a risk of blinding the operator.

Old school rock = enjoyment

If you haven’t heard of, well here you go! It’s a site dedicated to handcrafted Internet radio, and I came across this mix of old school rock classics while studying for the exams. It’s got stuff by The Doors, The Rolling Stones and other giants of rock. Do I need to say more?