October 29, 2012
Just been marking some Physics 1A coursework. In one question about frames of reference, the expected answer to “what is the key assumption necessary for this to be valid” is apparently “time is simple”. In this case this means relative motion is slow, so no nasty relativistic effects; an identical time co-ordinate can be used in both frames. But “time is simple” made me giggle.
(a) I have just listened to several deadlines whooshing by, when only a moment ago they were nowhere near. It seems obvious that space-time is non-linear. Not just curved but crinkled. We need some kind of adaptive optics equivalent for straightening out the space-time curvature. We must get Doc Brown working on it.
(b) I have been noting further signs of entropy in the old bod. Most distressing. How did this happen? I am still eighteen, obviously. As the Thin White Duke used to sing, Time may change me, but I can’t trace Time. Or maybe Sandy Denny had it down – Who knows where the time goes? Perhaps as her chum RT used to sing, we’ll all meet on the ledge. (Stop now, getting depressing – Ed.)
(c) Meanwhile the Government makes it worse with all this clock changing tomfoolery. My apprentice Jack tells there is an old Navaho saying – only the government can believe that cutting a foot off the bottom of the blanket and sewing it onto the top of the blanket, you get a longer blanket. Whats more, technology has made it more confusing.
Saturday night I wanted to set an alarm, as I had to get up reasonably early to go do something. I stared at several different digital devices and I really didn’t know whether they would automatically adjust themselves in the middle of the night or not. What should I set the alarm for? When I woke up, how would I know if the change had been made or not? I could easily blow it by an hour in either direction. So I put three different devices on the bedside table and crossed my fingers. Luckily, in the morning, two had changed and one had not, so the conclusion was clear. But Jeez, how nervewracking. Why haven’t I got a CLOCK???
Now you can guess. Device A = radio alarm. Device B= ancient Palm LifeDrive. Device C = mobile phone. Which one was thankfully the dumbest?
August 20, 2008
So whats with the neutrino puzzle thing ?
A little while back I wrote an article about astronomical discovery space, and speculated on whether the golden age of discovery was over. I wrote a blog post about it too. My conclusion was that the best hopes for real discoveries was time, neutrinos, and the internet. Two out of three of those (time and the internet) are exactly where I have been putting my personal efforts. Neutrinos are tempting too, but thats big experiment stuff and I haven’t been in that club and don’t have the experience.
Since pushing that line, I had found myself cooling on the neutrino front. Amanda clearly detects atmospheric neutrinos, but no sources yet; IceCube may just, but even then it hardly seems likely to turn into a rich and diverse skymap, like X-ray astronomy. IceCube is already a cubic kilometre of ice – what more can we do ? Looks like a brick wall.
I got re-invigorated last week listening to two excellent lectures by David Saltzberg from UCLA. This was part of the SLAC Summer Institute on “Cosmic Accelerators”. You can find his talks uploaded here. (Scroll down to Aug 13th and 14th). There are lots of very good and ambitious projects going on, but some just seemed really fun, and potentially hugely promising. Do check out Salzberg’s talk, cos I might give you a slightly garbled version as this was all new to me.
The first thing is that radio Cherenkov can be easier to detect than optical. ANITA is an experiment on a balloon that flies high above the Antarctic looking for backscattered radio pulses from the collision of UHE neutrinos with the ice. Its effectively looking at over a million cubic km of detector. It has had a preliminary flight, with more to come. Even groovier is the idea of looking for radio pulses from the Moon. This has been tried by Parkes and by the GLUE project. There’s even a suggestion of using a Europa orbiter.
Next lovely idea is acoustic detection, in principle using huge volumes of water. Early attempts are being made by SAUND in the Bahamas, and ACORNE off the coast of Scotland. No GZK neutrinos yet, but these experiments are in early development stages.
Or perhaps we take Martin E’s suggestion, and just wait for some random person to suddenly say “Ow !! What was that ??”