In my previous post, I talked about how not all astronomers use photons. Well, neither do all astronomers look up from Earth or Earth orbit. A new telescope aims to look down at the Earth — precisely so that it can see the sky.

JEM–EUSO proposes fixing a downward looking camera on the space station. It would stare at Earth — primarily the oceans — and watch for ultra high energy cosmic rays (charged particles, typically protons) as they hit. It would work very much like the Pierre Auger Observatory in Argentina, which detects fluorescent showers of secondary particles caused by the cosmic rays colliding with atmospheric particles, followed by a final flash as the particles hit detectors on the Earth. Auger astronomers have detected the most energetic things in the universe, and asserted with bare bones statistics that they probably emanate from the supermassive black holes at the centers of galaxies. But some want better proof than that given by a few dozen high energy cosmic rays, and, for that, they need more hits.

Looking down from the space station, JEM–EUSO could monitor an area between 50 to 250 times as large as Pierre Auger. The 5-year mission goal would be to detect at least 1,000 particles with greater than 7×10e19 eV energies. Particles like that would be probes of energy regimes 10 million times bigger than those explored by the LHC. Maybe JEM–EUSO could even detect a few particles with 10e21 eV energies. Because then we could use my favorite prefix in the world, and talk about the Zev scale: Zettaelectronvolt particle physics. Yoshiyuki Takahashi, of University of Alabama Huntsville, and Mark Christl, of Marshall Space Flight Center gave a talk on JEM–EUSO on Saturday. They say it would take 20 years for Pierre Auger and its successor, Pierre Auger North (proposed for nearby southeastern Colorado), to do what JEM–EUSO could do.

The total cost? $220 million — and that includes the rocket ride that it needs. ESA and NASA were once enthusiastic. But then, with the space shuttle retirement, NASA couldn’t find a ride for EUSO. ESA also liked it but its transport vehicle, the ATV, can’t deal quite handle it. Thankfully, JAXA, the Japanese space agency, seems to like the idea. And it may have a rocket, the new H-IIB, to fly it up — if test flights later this year prove successful.

Takahashi says JAXA will make a final decision on JEM–EUSO in September, and it could launch sometime in 2013. It would be nice to get a real astrophysical experiment on the space station. Nobel prize winner Sam Ting seems to have found a way to get his $1.5 billion AMS up to the station on the shuttle’s last flight. Why can’t these guys fly a novel experiment that costs a fraction as much?

Image: JEM–EUSO

Astronomers typically use photons of some sort to figure out what’s happening up there. Sure, some astronomers look for cosmic rays (which are not rays but in fact charged particles like protons), and eventually, gravitational waves are going to be important. But light is the way 99% of astronomy has been done. Now, a new window on the heavens is about to open — and the window goes through the center of the Earth.

The $271 million IceCube project, stuck in the Antarctic ice, would be the largest observatory to use neutrinos — chargeless, high-energy and nearly massless elementary particles. IceCube is a cubic kilometer array consisting of strings of detectors dropped down into ice cores made with hot-water drills. The detectors see the secondary effect of neutrinos colliding with atoms of ice. Neutrinos are terrific for astronomers because, lacking a charge, they aren’t bent by galactic magnetic fields. They may provide some of the only evidence of what happens in the center of supernovae. But they are incredibly elusive — they only rarely interact with matter. Thus the need for a cubic kilometre telescope.

On Saturday, Laura Gladstone of the University of Wisconsin showed that, based on data with only half of the telescope’s 86 strings installed, IceCube was working pretty well: It could see the Moon’s shadow. Common neutrinos particles called muons rain down on Antarctica — some 9 million a lunar month land on IceCube. A much smaller signal was observed when the Moon passed overhead and absorbed some of those muons.

But what Gladstone and her colleagues really want to do is look for the neutrinos that, speeding through the Earth, come up and hit IceCube from underneath. That way, the Earth would blot out most of the common, lower energy muons that fill the galaxy, and instead filter for the zippy high-energy neutrinos that could be coming from pulsars and supernovae, maybe even extragalactic sources. Michael Baker, in the previous talk, said he didn’t quite have the statistics yet to show any point sources in his through-the-Earth looking glass. They’ll have to wait a little longer; IceCube is expected to have all 86 strings installed by 2011.

Image: NSF

Peter Michelson, head of the Large Area Telescope team on Fermi, the gamma ray telescope formerly known as GLAST, gave the opening talk this morning. He went through all the amazing things that it has found in its first 8 months: gamma-ray only pulsars, milli-second pulsars, and active galactic nuclei. But he saved the news for last: Fermi, like two other experiments PAMELA and ATIC, is seeing way too many electrons and positrons all around us — which could be an indirect signal from the annihilation or decay of dark matter, the stuff that makes up up to a quarter of the mass of the universe, but has yet to be detected directly as a particle.

Last year, the PAMELA and ATIC teams showed rises in positrons and electrons – far more than are expected to be in the diffuse galactic background. Now, Fermi, shows not just a rise, but a bump –– centered around 300 or 400 gigaelectronvolts. That bump could mark the center of mass for a dark matter particle, such as a WIMP (Weakly Interacting Massive Particle). The results of the different experiments are not exactly the same (Fermi counts the total electrons and positrons, whereas PAMELA can distinguish between the two), but they seem to be compatible. Michelson isn’t ready to rule out a conventional source just yet — the extra particles could be generated from nearby pulsars, and then whipped into a diffuse background by galactic magnetic fields — but he says that there is a good chance that they could be observing new physics. “Exciting stuff,” he says. Symmetry Breaking has their take on the discovery here. More news to come — after I learn some more myself.

[Editor’s update: that full story is now available here.]

Well here we are in Denver, at the American Physical Society April meeting, which this year just so happens to be in May. Denver, the mile-high city, should be in springtime bloom, all alpine sunshine and wildflowers. But it is colder than a Bose-Einstein condensate. Oh well — there’s so much good stuff going on in the basement of the Sheraton here that I probably won’t be leaving the hotel. There are 1,025 preregistered attendees — about the same as last year, says Don Wise of APS. But the number of abstracts are down slightly: 1,089, compared to 1,194 from last year.

With all the excitement about the imminent turning on of the LHC, people are forgetting that the Tevatron at Fermilab will be nipping at the LHC’s heels for a while. Brian Winer, of Ohio State University, gave an update on the Tevatron and explained how the scientists there are using every trick they can think of to wring more sensitivity out of the machine, such as using artificial neural networks to combine information from two different detection experiments. Also, the Tevatron has been running long enough now, at high enough luminosities, that they are getting enough collisions to make interesting statistics.

As early as this summer, Winer expects that Fermilab will be able to to statistically rule out the existence of a 160 GeV Higgs boson, one of the theoretically likely masses for the so-called “God particle.” (Barring a positive detection, of course.) It will be a lot harder for them to detect a lower-mass Higgs boson before the LHC starts pumping out data. But who knows?

As a tantalizing treat, Winer put up a picture, a couple years old, of a detection of a particle that had the perfect characteristics of the Higgs. Only problem was, the particle was four times as likely to be noise.

Now, if they could only get four or five more detections in the same spot, then they’d be in business.

Winer repeated the exhortation of a colleague: “We’re one good idea away from finding this thing.”

I came across an interesting little poster the other day. John Stewart, a physics professor at the University of Arkansas at Fayetteville, decided to look at lexical trends in physics textbooks. He used a method developed by the late, great Don Hayes, a sociologist at Cornell University, who looked at trends in all sorts of texts — from school books to SATs — to explain both the dumbing down of America and the jargoning up of science and technology.

Stewart examined trends between two physics texts, Halliday and Resnick 3rd edition, published in 1988, and Halliday, Resnick and Walker, 7th edition, from 2004. The lexical difficulty — a measure of the book’s readability — increased by almost a grade level. The newer edition was prettier — the amount of blank space in the book doubled — but the addition of another author may have made the textbook worse, something along the lines of too many cooks in the kitchen. Stewart’s conclusion? “The old Halliday and Resnick was a better object to read,” he says. “It’s very noticeable.”

Now I haven’t seen the 7th edition, but I do remember Halliday and Resnick 3rd edition — it was the physics textbook I used in college. And it was plenty tough to read. I didn’t realize I had it so good.

At APS, there are the invited talks, and then there are the talks that might affectionately be known as the “crackpot” talks. Any member of APS, regardless of their background or affiliation, can submit an abstract and give a 10 minute talk. Nothing is rejected.

So about once a day, there’s a session with a coded title like “Unconventional ideas in XXXX.” That’s where the weird ones go. Sunday morning, Sunil Thakur, with an affiliation of “Individual Research”, was scheduled to give a talk on the “Nature of Reality.” In the abstract, Thakur promised to explain that “how the reality is revealed does not depend only on the properties of the reality itself but also depends on the properties of the medium through which the object is manifested.”

It looks like last year, Thakur submitted an abstract on black holes, where he claimed that temperature affects the speed of light. But today he didn’t show up, and the session ended early. Everyone filed out of the room, maybe a touch disappointed.

“I wanted to learn the nature of reality,” muttered one young physicist, not without sarcasm. “Now I have to find something else to do.”

Many physicists are still smarting from the blows they took after Congress slashed various high-energy physics programs in the fiscal year 2008 budget. In the main conference area on Saturday morning, five computers sat beckoning. They weren’t for quick email checks, but for physicists to sign and send form letters to their representatives in Congress. The form letter calls for a total of $510 million in emergency supplemental appropriations: $180 million for the NSF, $30 million for the NIST Core program, and $300 million for the DOE Office of Science.

Many Washington insiders think chances of this happening are quite slim, but APS officials are still pushing hard.

They collected 1,753 signatures at the March meeting in New Orleans, and in the first morning in St. Louis, they had garnered 142. Don Engel, a science policy fellow at APS in Washington, DC, was giving out stickers that read “I support science funding” to everyone that signed the form letter. “You want a sticker?” Engel asked his latest petitioner. “Then we know not to bother you again.”

This is a bit of a homecoming for me; it has been almost exactly a year since I left the St. Louis Post-Dispatch. And so I was feeling fairly nostalgic as I walked the streets of downtown on this blustery Friday evening. My mood wasn’t brightened at all by the utter desolation of downtown. With the Cardinals out of town, the streets were deserted, save for an empty beer can rattling in the wind. Attention physicists! Get out of downtown! The charm of St. Louis is hidden within its neighborhoods and side streets. Hop in a cab and say “Lafayette Square” or “Central West End” — the cabbie will drop in the right place, and you won’t be disappointed. I also hear that Schlafly, the local brewmeister (in addition to the local brewmeister, Anheuser-Busch), has a “Repeal of Prohibition” festival going on Saturday afternoon, if anyone is already looking to play hooky. I’m willing to trade more St. Louis tips for story tips — email me at e.hand@nature.com. Looking forward to the conference!

Posted on behalf of Rachel Courtland:

Greetings from New Orleans, which is likely jazzed to host the American Physical Society March Meeting, dedicated to all things solid state and condensed matter. Some conference-goers arrived over the weekend, enjoying sunny weather and steam-calliope music along the riverbank. But the weather turned cloudy this morning, driving everyone in to 40 early-morning sessions dedicated to everything from the latest results on graphene properties to the dynamics of shaking cat paws.

Conference organizers are waiting for registration to finish before declaring this physics conference 2008’s largest (it’s met with some rivals in recent years). But the program, which tops out at 665 pages, no longer has room to display short abstracts for each talk, an indicator there’s lots of great physics to be discussed.

After a quick cup of press room coffee, I’m off for round two of sessions. Stay tuned for more as the conference gets into a groove.