I don't know if you've been following the ongoing saga of the Ivory-Billed Woodpecker. It's been running (at least to my mind) in corners of the press since the Spring. I love the story: Some preliminary evidence was found that this bird, which was thought to be extinct, had resurfaced in Arkansas. The scientists on the quest were so happy they cried real tears, apparently. But then there was a series of counter-claims that it was a mistake, a misidentification....and so the discussion went on and on. (Drawing at right was obtained from this site.) This morning, there was another story about the matter on NPR (I've heard about 5 of them on NPR so far...there are at least 9) giving an update on the matter. Several more people have been convinced by new evidence collected by several recording devices that have been left in the forests. Christopher Joyce, in the Radio Expeditions series (lovely name), does an excellent report on the new evidence in the story "Audio Evidence of Ivory-Billed Woodpecker". (There are links there to several earlier stories on the saga.) There are fascinating highlights in the story, such as when they're listening to a known recording of the bird, and comparing it to the recording made in the forest. You see, that's not good enough, since the recording was made in the forest with the bird far away from the microphone. The sound is distorted by trees, leaves, distance, etc. So to do a proper comparison, they have to figure out what the known recording would be like if it had all those obstructions as well..... Besides the fact that it is a rather lovely story for its own sake, I like it because it reminds me of the processes we go through in fields of physics, especialy Particle (or "High Energy") Physics, and Cosmology. Most of the objects, events, and phenomena we care about are not directly accessible (and that is the biggest understatement on this blog so far). So people spend a lot of time looking for clear means of identifying what we're looking for by indirect means.
A clear example is the Cosmic Microwave Background (CMB). The universe is over 13 billion years old, but a lot of focus on the science of the origins, structure and fate of the universe requires knowledge of the nature the very early universe - physics back from when the universe was in its first tens or hundereds (at most) of thousands of years. Well, we can't go back to that time, and we can't make a universe in the lab, so instead we must listen to the echoes of that time (the CMB) using various delicate instruments such as the WMAP or Planck satellites, or the Boomerang balloon experiments. (Image above right is CMB data. Part of it makes our banner image. See a quick explanation here.) Those recordings then allow us to attempt to identify what the features of the physics of the universe were so astonishingly long ago. And people argue, just as they do in the woodpecker story. Other examples include looking for elusive, very massive particles such as the top quark, the Higgs particle(s), and supersymmetric particles, the latter two categories still being ongoing quests. (JoAnne is our resident expert on these searches, and no doubt she'll be talking more about this sort of thing.) In cases such as these, in laboratories such as CERN, or SLAC, or Fermilab, (see those labs' websites for nice tours) we collide together known particles at extraordinary energies, which -because of E=mc^2- allows for the creation of all sorts of other, more massive, particles - more energy, more massive. Among those -fleetingly- will be created the particle we're looking for. But how do we know? There's no detector designed to look directly for this new particle. Instead, we detect the lower mass-energy particles into which it decays - of a type that we know very well (electrons, muons, etc) - and we look for the particular patterns those particles make in the detector. A particular pattern or patterns is just like the song of the woodpecker. You don't see the woodpecker directly, you listen for its song. Same for the particles. -cvj
