Tuesday, April 17, 2007

The last post (from the APS)

This will be my last post from the APS meeting. I'll just take a moment comment on a few more of the talks I've seen.

One of the most entertaining talks of the meeting was on Selling Physics to Unwilling Buyers given by Lawrence Krauss (of The Physics of Star Trek fame). Krauss is well known for his public understanding of science work and is very good at it due to his enthusiasm and understanding of the problems that the general public have with science. He doesn't shy away from saying that the vast majority of people think that science is dull, difficult and that scientists are untrustworthy. But he thinks that the apprehensions are things that you can get past by showing science in its true light. We need to show that science isn't some abstract thing that has no impact on people's lives, but is in fact integral to pretty much every area of life, and basic science is in fact easy to demonstrate and understand. Also people need to be shown that by applying the basics of scientific, or experimental principles, they are able apply a better filtering of ideas or views that are obvious crap from those which have a weight of evidence. I can't do justice to all the things he said here, but the main new thing I came away with was that I should use more video clips in public talks.

At the moment I'm sitting in the morning plenary talks session and have heard a couple of very good talks. The first talk was by Jacqueline Hewitt from MIT and was about looking from a 21 cm background from neutral Hydrogen in the dark ages. The 21 cm line (the wavelength of the electromagnetic wave) is a radio frequency emission line from neutral Hydrogen (i.e. an electron bound to a proton), and the dark ages represent a period in the universe between the production of the CMBR (i.e. the time at which protons and electrons first are able to stay bound within Hydrogen atoms, without being disassociated by the radiation field) and the reionisation of that Hydrogen by radiation from the first stars after they form. I'd not really heard much on this subject before and was very interested to here about the methods for going about trying to detect this emission. I'll keep an eye on this stuff in the future as they should be able to learn a lot about structure formation in the early universe from such observations.

The next talk in the plenary session was about global warming by James Hansen - I think it's probably more useful to hear this stuff from a scientist who works on the subject than from Al Gore. I've never really been confronted (or looked out myself) the evidence for human induced global warming, so this talk was very enlightening. He showed how the Earth's climate (temperature, sea levels, greenhouse gas levels) has fluctuated by large amount over periods of hundred of thousands of years and the reasons for this. The main point being that these changes are very gradual and the feedback mechanisms of the Earth take a long time to respond to them, whereas now the man-made release of greenhouse gases is well over and above natural level and the planet can't deal with these as part of the natural long term trends. The idea that short term variations in the solar flux have lead to the current warming don't seem to hold up much weight after you've seen the long term trends. He proposed many of the main ideas to deal with energy consumption and emission problems, but obviously these need governments to introduce proactive policies or nothing will get done.

Anyway I need to make a move and head to the airport soon. Next post will be back from blighty.