Musings on optics, physics, astronomy, technology and life

Archive for March, 2013

Still more on space rocks

We on the East Coast of the USA had some more “freaky space rock” excitement a week ago yesterday (March 22). Shortly after 8 p.m., Facebook and Twitter lit up about a flash in the sky that looked like a fireball or bolide. I didn’t see it personally because I was indoors at the time. (Drat!)

The next morning, I learned from Jonathan McDowell‘s Facebook page that the American Meteor Society had aggregated reports of the fireball and made them into a “heat map.” The latter shows that the reports ranged all along the Northeast Corridor from DC to Boston (boy, that is a familiar trek for me). Via Facebook I asked Jonathan whether he thought that any leftovers from that blast landed in the Atlantic, and he replied that that was his guess. I’m glad that nobody got hit by that thing — who knows, it might have been pretty big.

Incidentally, should you see a bright moving flash in the sky, the Meteor Society has a handy Web form for reporting your observation. And the organization reported one amateur astronomer’s spectacular photos of the event.

Finally, if you’re wondering about the aftermath of the Chelyabinsk explosion last month, the New York Times did a follow-up article that describes the intruder as a stony meteorite — an ordinary chondrite. There’s more evidence that the people of the Russian city “dodged a bullet,” so to speak. Whew.

(Edited later on March 31 to fix a typo.)


Ask a physicist!

If you want to boost attendance at your local religious congregation, just ask a Nobel Prize-winning physicist to deliver the weekly sermon. This actually works!

Folks at Paint Branch Unitarian Universalist Church (Adelphi, Md.) were honored to have Dr. John C. Mather of NASA Goddard Space Flight Center in the pulpit yesterday. Dr. Mather had been at the church a few months ago to attend the memorial service of Frank McDonald, a retired NASA GSFC high-energy astrophysicist, and once he got talking to the minister, she invited him back for a Sunday service.

You can read both his talks during the service — first some comments to the children at the beginning of the service, and then his sermon for the adults. The sanctuary was full!

After the service, Dr. Mather stuck around for a discussion circle in one of the church’s classrooms. About 35 folks got a chance to ask him questions about space-time, the origins of life, the spirituality of scientists, and the James Webb Space Telescope. I didn’t take notes, but I enjoyed the session thoroughly. How often do folks get to sit around and chat with a Nobel laureate?

Great citizen science

Want to bring the science of light to the masses? This week I found a fascinating example of demonstrating Thomas Young’s double-slit experiment with a big cardboard box, an eyepiece and bright sunlight. The ScienceDump blog got the video from Veritasium.

Yes, to those of us who actually have studied physics, the competing theories of light as waves and particles might be old hat. But, as you can see in the video, it’s not old hat to the passersby  who haven’t thought about the subject since grade school.

I’m certainly going to check out these websites to see what other interesting demonstrations of “citizen science” are out there. If you have had a chance to bring science to the masses, I’d love to hear about your experiences.

And then there was one

Once upon a time — literally, in 1960 — Time magazine chose 10 “American Scientists” as its “Men of the Year” (the award would become “Person of the Year 39 years later). Of the 10 scientists chosen to represent their rather broad common profession — George Beadle, Charles Draper, John Enders, Donald A. Glaser, Joshua Lederberg, Willard Libby, Linus Pauling, Edward Purcell, Isidor Rabi, Emilio Segrè, William Shockley, Edward Teller, Charles Townes, James Van Allen, and Robert Woodward — eight of them either had won or would win a Nobel Prize. Considering that such other giants as Albert Einstein were already dead by 1960, this is still a pretty impressive list.

When I was blogging for Optics & Photonics News, I looked up these “1960 Men of the Year” and found that only two of them, physicists Glaser and Townes, were still alive. I met Townes on several occasions during my years at the Optical Society, most recently at the celebration for the 50th anniversary of the laser in May 2010.

Today, while surfing the Web, I stumbled upon an obituary for Glaser; he died in his sleep a few days ago at the age of 86. His official Berkeley obituary goes into more detail about his subsequent careers in molecular biology and neurobiology (after all, when one wins a Nobel at age 34, what else can one do in one’s original career?).

So Townes is the last guy left from the 10 Men of 1960. He’s 96 and will turn 97 later this year. And he’s still not “emeritus.”

Two weeks later

It’s been two weeks since a “freaky space rock” blasted out of the sky above Chelyabinsk, Russia. At the time, the worldwide press breathlessly reported the extent of the amateur video footage and the ground-level damage and then moved on to other flavors of the moment. Meanwhile, what have we learned about our cosmic visitor?

A week after the event, Sky & Telescope reporters blogged about the composition and trajectory of the Chelyabinsk meteoroid. The recovered fragments are “ordinary chondrites,” the most common type of stony meteorites. These ordinary chondrites do contain flecks of metals, but also lots of silicates, as opposed to iron meteorites, which really are chunks of iron. The space rock was moving in a completely different direction from the asteroid that nearly missed the Earth the same day, so the events were unrelated, as much as our pattern-seeking human brains would like to deny.

S&T also reported that a scientist at the University of Western Ontario calculated that the near-Earth object (NEO) was cruising at 20 km/s when it hit the atmosphere. The “infrasound” detectors that are supposed to enforce the nuclear test-ban treaty picked up the blast waves — equal to about 30 Hiroshima bombs — from as far away as Antarctica.

Scientists suspect that the space rock came from (or was) an Apollo asteroid, a specific class of minor planets that cross Earth’s orbit. So, yeah, this should really point out the need to keep watch on the other Earth-crossers that may be whizzing by. The University of Hawaii is developing a “last-alert system” to complement PanSTARRS. And, as Chelyabinsk cleans up, local officials are figuring out how to market the newly famous city as a hot tourist destination. (It even has a travel agency called Sputnik!)