Wednesday, August 30, 2006

Fog inhibits diurnal convection

Today's satellite image and animation for the tri-state area of Wisconsin, Iowa, and Minnesota shows a prime example of the power of sun-heated land. There is a pool of colder air aloft in the western Great Lakes that by itself isn't enough to cause instability. But add heating from the Sun at ground level and the gradient is enough to produce convection and clouds.

A fog bank was present overnight and into the middle of the day over the tristate region, as seen in this morning image. The fog was burned off by the sun but it took until the early afternoon to do so and kept the ground cooler. Ergo, no cumulus where the fog was earlier.

This animation is during the afternoon as the bank slowly dissipated, leaving a kidney-shaped hole in the cumulus field.

Friday, August 25, 2006

An animation of Pluto

Pluto as seen at Ryerson Observatory, University of Chicago, five years ago. Click on the link to see the apparent motion of Pluto against the background stars.

Zelia parallax

Two astronomers were imaging the same globular cluster at the same time, from a continent apart, when an asteroid passed in front. Combining their images by time shows the powerful concept of parallax in astronomy:

The asteroid (er, I'm sorry, Small Solar System Body), was about 100 million kilometers from Earth when the images were taken.

Images taken by Adam Block, Daniel Versatche, and Bill Patterson.

Thursday, August 24, 2006

IAU and the planet definition

The IAU has passed a resolution about what to define as a planet, and the previously maligned idea of a "dwarf planet" came back to win. The public will think dropping Pluto as a planet is somehow a bad thing despite the illogical definitions required to keep it as a planet. I leave it to Astronomy Blog to mention the details. I believe most astronomers will just ignore the issue and call objects by what they want to. Witness the fact that the term "asteroid" has been unofficially removed, replaced by "minor planet", then today replaced by "Small Solar System Body", except everyone still uses the term asteroid.

Wednesday, August 23, 2006

Amateur nuke detectors

Wired is reporting on a group that built their own scintillation detector to look for radioactive cargo in San Francisco, to compete with Homeland Security.

With sodium iodide (and other inorganic crystals), a gamma-ray will interact with one of the electrons bound deep inside one of the atoms and liberate it, producing an electron with some energy, plus an X-ray with the excess energy of the reaction. The photoelectron can then interact with normally bound electrons in the crystal, liberating them into what is called the "conduction band" and allowing them to migrate through the crystal. They and the positively-charged hole can move around until they meet with an impurity in the crystal. This can, if the impurity is chosen correctly, cause a fluorescence of visible photons. In sodium iodide, Thallium is added as the impurity at about 1 part per thousand. While a great scintillator, NaI(Tl) is expensive and absorbs water.

Certain organic molecules will also directly fluoresce when given excess energy from these passing photoelectrons or other energetic charged particles. Certain plastics can also be used: in fact, polystyrene, a very cheap material, can be used.

Once visible photons are produced, they are measured via a photomultiplier tube or other light-measuring device.

The amount of visible photons developed in these materials is directly proportional to the energy of the original gamma-ray. This is great, as you can detect precisely what radioactive decay was responsible for the gamma-ray, and therefore what radioactive element you may be looking at.

You can see a terrestrial gamma-ray map of the United States here. They separate out three common radioactive that are present in nearly all rocks and soils via this proportional energy measurement. A more detailed description of airborne radioactivity mapping is here.

Friday, August 18, 2006

Geologist causes a ruckus

Canadian geologist violates Danish sovereignty.
Bloggers might write reams and reams about Israel and Lebanon, but what might really cause an international dispute is Canada and Denmark!

Green Gabbro has the best link title for this story.

Cell phones, terrorists, and Tuscola County, Michigan: update

I see that prosecutors are indeed trying to cover their ass in the embarrassing Tuscola County, Michigan case in Caro.

"There's real suspicion on my part, when you get these other charges, that you get this face-saving, 'Well, we've locked them up and we've got to charge them with something."'

--David A. Moran, associate dean at Wayne State University Law School

When they realize how they have no case, they will do their best to have the men plea bargain something, however light, to prove the case wasn't the amazing reach it is.

Boing-boing missed the part where the terrorism charges were dropped and replaced with fraud charges.

Doctrine of first sale indicates there is no fraud here. Unfortunately some people don't get it.
For instance, using the term "black-market" in a story implies that somehow it's illegal to sell goods you've bought legally. It isn't. Nor is it illegal to remove a possibly illegal restriction on use of the phone (The carriers block your ability to use your phone with other carriers' SIM cards, yet you can get the carriers or a third-party store to unblock the phone... usually for a fee). How is doing this by yourself then illegal?

Wednesday, August 16, 2006

The definition of a planet: IAU conference and the issue of 2003 UB313

It's been expected for a long time now; the IAU meeting has attempted to produce the definition of what a planet is.

Pluto was long too small to really match into the classical planets without letting other bodies like 2003 UB313 in, and now a committee has suggested simply the "spherical body not orbiting another object" suggestion, which includes some other minor planets in it including Pluto. You can't have Pluto in a real definition as a planet and not Ceres and some of the big Kuiper Belt objects without putting an arbitrarily size limit on the definition and this drove astronomers to impasse.

The "Spherical bodies" idea was agreed by some as a radical definition that would bestow planet status on many objects; some argued it would dilute the idea of what a planet was. Keeping the old 9 planets and restricting 2003 UB313 was cruel and decidely the wrong thing to do. Putting a higher size limit to keep 2003 UB313 out would have been physically arbitrary and would have forced Pluto out of major planet status.

Brian Marsden, who just retired, long argued that Pluto really was nothing more than a large Kuiper Belt Object. It was unfortunate in my opinion that public sentiment drove the arguments about was a planet was more than science. He makes the point that we will likely have a lot more planets in the near future when we prove the sphericity of the bigger minor planets and KBOs, and if the public doesn't like that, they chose to live with it by forcing Pluto into the issue.

UPDATE: Mike Brown's thoughts. And his NYTimes Op-ed.

Search this blog for "Pluto"

Search this blog for "2003 UB313"

UPDATE: Looks like they've come to their senses.

Monday, August 14, 2006

Tuscola County stupidity: cell phones and Arabs in Michigan

I sincerely hope that pride doesn't prevent Tuscola County, Michigan prosecutor Mark E. Reene from dropping the outrageously stupid charges against three Americans whose only crime was to attempt to make a profit and have dark skin. When they realize how they have no case, they will do their best to have the men plea bargain something, however light, to prove the case wasn't the amazing reach it is. Will Caro, Michigan police chief Benson Page think of the huge waste of resources in pointless extra patrols of the bridge? Why would a terrorist buy a thousand cellphones for a detonator when he needed only one? Why not arrest every tourist who buys a cellphone and takes a photo of the Mackinac? My guess is that no tourists ever go to Caro or Tuscola County, because I surely never will.

Friday, August 04, 2006

Weather is not climate

It was a hot one on Monday and Tuesday here in Chicago--hot enough that I avoided getting a coffee to keep me warm in my cold office and opted for a iced drink. The heat wave affecting the Midwest finally broke and those in Chicago generally didn't do the following--

Those who can't remember the weather always say "It's never been so hot before". They tend to forget last year, or 1995, or 1988, etc. They tend to forget 1916, 1911, 1918. The entire Dust Bowl.

It's really important point: Weather is not climate. A heat wave is not the result of a change in climate. Weather is a day-to-day variation in temperature, humidity, etc. Climate is the long-term average of weather. On average, the climate of Chicago gives us 34 inches of water. On average. Look at the variation in yearly precipitation here. Even after averaging over 365 days, the average precipitation varies over +-10 inches of rain each year.

Look at the other graphs on the Chicago climate page.

The whole point is, you can't blame a single event, a single drought, a single year's weather on global warming. You can't. You can make statistical statements, but the natural variability of weather will mask any contribution by forced warming until you look at a long-term average (or some other greatly averaged variable).

Problematic web pages:
Treehugger: The Heatwave is On: Global Warming?
Bruce Sterling: Global Warming Knocks Out MySpace
Washington Post: More Frequent Heat Waves Linked to Global Warming

Someone took the research about reducing the well-known urban heat island effect and blame increasing nighttime temperatures on global warming, rather than accounting for the continued growth in urban areas.

Some comments here: Climate Science:Roger Pielke Sr. Research Group Weblog

Thursday, August 03, 2006

Adventures in Shortwave: more Radio Havana Cuba

In light of the news about Fidel Castro's health and the future of Cuba, here are two recordings from last night's Radio Havana Cuba.

Radio Habana Cuba end of editorial, religious response, music at end(04:14, 1.7MB mp3)
Essentially, the statement was, the Cuban people will continue to do all the good things they do now, and imperialist conspirators and their evil plans will not work.

Well wishes from world leaders and imprisoned Cubans in the U.S. (07:35, 3.5MB mp3)

Both were recorded on 9820kHz. There were thunderstorms in the vicinity. I used Audacity to record and removed some hum and nearby carrier whistles with some notch filters.

P.S. See also recordings from 2006-12-18 and 2006-07-13

Tuesday, August 01, 2006

NEXRAD radar and cars

The NEXRAD radar near Chicago is bending back down to ground and lighting up cars on the highways south of town. I've labeled the image above with arrows to the returns. This image adds the highway overlay to the radar, showing the returns to be from I-65, I-57, and I-39. Earlier you could see I-55 on the return as well.

Looking at a balloon sounding from the nearest area (Lincoln, IL) shows an inversion at about 6000ft (1800m):
This could be bouncing the beam back onto the ground on this hot steamy night.

The smallest arrow on the annotated radar image--what is that sitting out in eastern Lee County? It's static in the animation.

UPDATE: Google Earth link. What's at the corner of Beemerville Rd, Compton Rd, and 251?
2nd UPDATE: Silos on a topographic high?
Or a tall AM antenna? Probably the antenna.

3rd UPDATE: The antenna is 150m tall, listed in the FCC Antenna database, owned by ComEd.

Radiation readings

My long-term radiation average for my basement Geiger counter here at the Regenstein Library is 7.6uR/hr. Lately it's been elevated a touch. For the last 1372 minutes (or roughly a day), it's 7.95uR/hr. Over the last hour, it's at 8.38 (EDIT: in the space of writing this the last 60 count rate went down to 7.67. Love them statistics). All of this is so small that it doesn't matter but it's an interesting variation. Merely putting a simple aluminum can near the Geiger counter can drop the reading by 0.5uR/hr, so these changes aren't significant. I wonder if I've made some change in my office (or perhaps in the next office) that has changed the local background rate. The air is off too; perhaps that's allowing a small amount of radon to appear (which is normally non-existant in the library).

The popular Geiger Counter post. In which I graph the radiation on an airplane flight. And radon decay.

See the Genesis-1 spacecraft tonight in Chicago

The inflatable and privately-owned Genesis-1 spacecraft will be visible tonight from Chicago. It was built by Bigelow Aerospace, headquartered in Las Vegas (my hometown).

The spacecraft rises in the northwest at 10:08PM, and passes the Big Dipper on its way to its maximum altitude of 62 degrees above the horizon in the southwest, above Arcturus, at 10:12PM. It enters the Earth's shadow at 10:13.

It should appear as a faint star, not much brighter than the faintest stars you can see (in Chicago), so get away from light sources and let you eyes adapt. It would be dimmer than most of the stars in the Big Dipper. Binoculars should help.

Don't confuse it with the Helios 1A rocket, which will be visible at nearly the same place and same time. You will be able to discern between them because the rocket body is moving to the north while Genesis-1 will be moving south-ish.

Pass details