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steuard: (physics)
Saturday, May 24th, 2014 04:19 am
We live in a remarkable era. If you brought an ancient Greek astronomer to the present day and dropped him off in a field somewhere, he would be awestruck, and maybe terrified. (Heck, it probably wouldn't even need to be an astronomer: I think that most people were quite familiar with the night sky until recent times.)

The meteor shower was pretty much a bust: I was outside for a decent stretch and only saw two for sure, plus a couple more "maybes" that were too brief and dim for me to judge whether they came from the expected radiant point. (To be fair, from where I was in our backyard I was seeing far less than the full sky.)

But in the same time, I saw at least half a dozen satellites, ranging from "almost too dim to see" to "easily the brightest object in the sky". It's obviously been too long since I just lay back to watch the stars: those things are now a near-constant presence. So I really do wonder how that Greek time traveler would react to the modern sky: what would those swift-moving, variable brightness points of light mean to him? What would Plato make of it? What stories would Homer tell?

For that matter, I'm sure that there are still plenty of societies and communities today that have little knowledge of high technology, from isolated tribes to rural villages. What do *they* make of the satellites that now pass constantly over their heads? This is a recent phenomenon: its origin is easily within living memory, and it has only gradually become as frequent as it is today. What stories do those people tell? Do they know or guess that these are the work of human beings? Do they fear that the newly mobile stars are an omen of some approaching doom?

And what stories might we tell about ourselves, as we alter the face of the heavens so deeply without ever pausing to think what an astounding achievement that is?
steuard: (physics)
Tuesday, May 31st, 2011 05:11 pm
It's been a long, long time since I wrote anything here: I've just finished teaching an intensive one month "Spring Term" class on Medical Physics that met two to three hours a day, five days a week. This might have been less stressful if I'd ever taught (or taken) a class on the subject before (or if I hadn't spent the whole week between my previous final exams and the class starting writing and giving a conference talk in Chicago). But it seems to have gone well, and I've now officially hit summer vacation! That means that I get to procrastinate on baby preparation and paper writing by sharing cool recent science tidbits.

The first is serious physics, and has the potential to be tremendously exciting if it pans out: the CDF experiment at Fermilab may have found the first direct evidence of physics beyond the Standard Model of particle physics! For a nice layman's summary, my friend Sean Carroll has a good writeup at Cosmic Variance; for some more detail, follow the links to posts at R├ęsonaances. I won't try to repeat them here; I'll just show the exciting data:

and comment that the red line is the expected Standard Model result and the blue bump above would presumably correspond to an entirely new neutral particle about 150 times heavier than a proton. This result still isn't 100% solid: it's a "4.8 sigma" result, which is extraordinarily unlikely to happen by chance, but until it's reproduced by Fermilab's D0 experiment or by the LHC there's always the chance that someone forgot to carry a two during the data analysis.

The second thing to share is a beautiful time-lapse video of the Earth rotating under the stars that was recently adapted from an earlier video of stars rotating in the sky. It's a vivid demonstration of the Earth's motion through the heavens that makes you rethink your assumptions about what's really moving when you watch the sky. Here's the video; seriously consider watching it full-screen in HD!
steuard: (Default)
Monday, July 2nd, 2007 09:53 pm
Kim and I are on our way back to LA from my mother's wedding in North Platte, Nebraska. The trip has been great so far; along the way, we've visited quite a few national parks (and national monuments and a national memorial). This evening we arrived at our hotel just outside Bryce Canyon National Park in southern Utah (we'll be spending a chunk of tomorrow there), and I talked Kim into going out between sunset and moonrise to look at the stars.

Stargazing on a dark night with a clear sky far from city lights is one of the most awe inspiring experiences that I've had; I don't get the opportunity often at all. Bryce Canyon turns out to be an absolutely top-notch viewing location: it's far from major light sources, and the dry air makes for tremendously clear viewing. The glory of seeing the stars at a place like this is the sheer number of them that you can see: not just the brightest few but countless thousands in every direction. And yet, those rare dark sky opportunities are also the times when I turn out to most wish that I knew more about which stars are which and even about the constellations (which my rational side usually dismisses as insignificant historical artifacts).

I really have to do this more often. And when I have kids, I'll make a point of taking them to see the stars as often as we can manage.