On Thursday Flavio took us to the big Co-op on Thursday so we could stock up on cheap food. This guy was the "keeper of the sausage" - apparently this sausage is the second largest sausage ever made? Naturally I had to pose with him.
This week in the lab consisted of lots and lots of reading. I think I probably read about 20 or so hefty scientific articles - one of which was 66 pages long (eughhhh) but I feel like I have a much better grasp on thermal noise and my project now. By the way, if any of you are interested in what I'm actually doing in Italy this summer, I thought I should provide a little run down!
Gravitational waves (GWs) are perturbations in space-time caused by accelerated masses (...this is why I usually just say "physics research" when people ask me what I am doing with my summer...). Essentially, an accelerating mass in one location - like the Earth in free fall around the Sun - causes masses elsewhere to accelerate by means of gravitational waves. Gravitational radiation was originally predicted by Einstein as a consequence of general relativity, and affirmative, indirect observations have been made by observing the energy loss of binary star systems. However, to this day no direct observation of gravitational radiation has been made. Why is this, you say? Because the changes in distance that even the most massive accelerating objects create are still utterly tiny. About 1/1000th of the diameter of a proton, in fact! So how do we measure a distance so small? That's where we come in.
In an international effort, physicists from all over the world have rallied to build several large scale gravitational wave detectors. Examples include LIGO in the USA, GEO600 in Germany, TAMA in Japan, and the VIRGO detector in Italy. There is even an initiative in motion to build a gravitational wave detector, called LISA, in space! Most of these detectors are highly sensitive, large-scale Michelson interferometers - these machines use laser light to measure very precise distances. Laser light is sent down two perpendicular tunnels, reflected off mirrors at the end of the tunnels, and the information about the distance these lasers have traveled is recorded and analyzed.
Inescapably, measuring such small distances requires that all materials in the interferometer be absolutely still. Specifically, the mirrors at the end of the tunnels are subject to large amounts of thermal fluctuations that are the predominant source of "noise" - or fluctuations that obscure the GW data. This is where my project takes off - I am testing materials for the mirror's suspension to determine which ones contain the least amount internal friction. So far, we have a pretty good idea of what this material should be - fused silica - but there are lots of variations as far as size, arrangement and suspension techniques that need to be explored. Pretty cool stuff.
If you are more interested in gravitational waves and their detection, or just want a better explanation, LIGO has a great website that does a much better job than me at explaining all of this.
The people we are working for - Luca Gammaitoni and his crew - are considered the authorities on thermal noise, so working with them is very exciting. If you want to check out more of what they're involved with you can visit the lab's website! I am also excited about attending the NiPS summer school after my project is over. My aunt was asking me how I even found my internship this summer, so for all of you who are interested, I went to the NSF website - then applied to basically everything I found interesting. There aren't that many international REUs but there are tons of domestic internships!
P.S. I just found out I can't drink the milk here or I throw up! Wooo!
...hovercars?
ReplyDeleteExactly.
ReplyDelete