How can I force myself to write?

Great thread on Ask Metafilter

October 6 2008

It's Donkey Day. Today in history.

I've taken a couple of days off work since Christine got home on Thursday from the hospital. Her total knee replacement surgery, performed a week ago today, though she still has to take pain meds. She left the house today for the first time since Thursday. I took her to Longmont Clinic to get her blood drawn (she's on warfarin, aka coumadin), then to Lowe's. Our neighbor Ray the Handyman started painting our house today - just in time, as we're expecting our first frost tonight, and possibly our first snow next weekend.

This afternoon I read Planet Migration through a Self-Gravitating Planetesimal Disk, a preprint by a group at the University of Rochester. The main interest of the paper is that they performed N-body simulations on a GPU. We've talked about doing this at SwRI. It sounds like Moore, Quillen, and Edgar have figured out how to do it, using a C development environment from NVIDIA called CUDA. There's no connection with Sarah Palin, so far as I know.

Fixing Climate, Part 2

Phil Orr took Broecker to Pyramid Lake in Nevada, which is a remnant of Lake Lahontan, one of the largest lakes in North America during the last Ice Age. Orr had found human and animal bones in Fishbone Cave on the eastern shore of the dry bed of nearby Lake Winnemucca. Orr believed that man had entered North America during the Ice Age, and suspected that the bones dated to that time. In 1955, "scholars" favored a more recent date. Orr was interested in having Broecker perform carbon-14 dating on the human bones and artifacts that he had found. Broecker also took samples of tufa, a form of calcium carbonate, from Pyramid Lake. Broecker and Orr collaborated for the rest of the 1950s. Orr's intuition proved to be correct, and the rises and falls of the lakes in the Great Basin got Broecker interested in climate.

Fixing Climate, Episode 1

Last weekend I read Fixing Climate, by Wallace S. Broecker and Robert Kunzig. Broecker is a scientist at Lamont-Doherty Earth Observatory who is known for his work on the ocean conveyer belt and rapid climate change. Kunzig is a terrific science writer. I liked the book so much that I’m going to write about it here for a while.

Episode 1 (text from the book is given in italics):

Broecker gave his first scientific talk, as a graduate student, at an archeology meeting in Los Angeles on September 1, 1955. It was the hottest day ever to that point in LA – 110 degrees. He had been asked to give the talk by J. Laurence Kulp, who was a pioneer in the newly developed field of Carbon-14 dating. The archeologists were arguing about when people first arrived in the New World. After Broecker’s talk, Phil Orr of the Santa Barbara Museum of Natural History came up to him:

Phil Orr … was clearly more of a digger than a scholar; although he smoked a pipe, it had a cigar butt in it. He was a short man with a potbelly stuffed into jeans and cowboy boots. His face was shaped like an interstate highway shield – a wide forehead, uncluttered by hair, narrowing to a pointy, straggly bearded chin. That forehead overhung deep-set eyes that seemed made to squint. Orr eyeballed Broecker.

“Kid,” he said, for he was plenty old to be Broecker’s father. “I can see that you know a lot about physics and math. But I also see that you don’t know a goddamned thing about the earth.”

He paused to let that sink in, and to relight the cigar butt.

“Come with me for three weeks and I’ll change your life.”

Words That Make Me Stop Reading

sheeple
blood and treasure
boots on the ground
speak truth to power
maverick
muscular foreign policy
chattering classes
executive experience
quick study
leverage
world-class

However, I do like the Educational Jargon Generator and the Automatic Computer Science Paper Generator.

2008 DDA meeting, Part 2

Monday, April 28, 2008
Session 2: The Yarkovsky and YORP Effects
Invited Talk: Analytic Theory of the YORP Effect for Near-Spherical Objects

















David Nesvorný, Southwest Research Institute

SwRI's own David gave a nice invited talk on YORP, a thermal effect that changes the spins of small bodies. The YORP effect was confirmed for two Near-Earth Asteroids (NEAs) in 2007, resulting in fame, fortune, and papers in Nature and Science for two groups. YORP may be the main mechanism that forms binaries among the NEAs. Most modeling of YORP has been done numerically, but David and David derived an expansion of the YORP torque in spherical harmonics that agrees well with numerical results for reasonably round bodies such as 1998 KY26.

In the same session, Steve Chesley of JPL gave a talk describing his work with David on a clever approach to look for the Yarkovsky effect in NEAs by modeling it as a transverse acceleration (a_t), just as he does to model nongravitational forces in comets. The model value of a_t translates into a drift rate in semi-major axis, which is the key effect he's looking for. As I recall, he has tentative detections for over a dozen NEAs. It just goes to show how prescient I was a decade ago when I got a proposal to review on how Yarkovsky might affect the orbits of asteroids. Many years before, I had learned of the Yarkovsky effect in a course taught by Joe Burns while he was on sabbatical in Berkeley. I had Yarkovsky pigeonholed as one of those strange radiation effects like Poynting-Robertson that applies to dust and rocks, but certainly not to mountains in space. Now there's a veritable Yarkovsky industry. If you want to read all about it, here's a review paper by Bill Bottke and the Davids. As Bill likes to say, with two Davids we can Czech and re-Czech our results.

Non-liveblogging the 2008 DDA meeting, part 1

This year's Division on Dynamical Astronomy meeting seems to have been a success. Now that the meeting is over, I'm going to free-associate about one talk each day. We'll see how far I get!

Monday, April 28, 2008
Session 1: Stars and Galaxies
Invited Talk: Telling Tales with Tidal Tails

Kathryn V. Johnston, Columbia University

From Kathryn's abstract: In the last decade, the stellar halos of the Milky Way and Andromeda galaxies have been mapped in exquisite detail, revealing that they are actually richly substructured in phase-space due to the presence of debris from tidally disrupted satellites.

The Local Group consists of Andromeda, the Milky Way, and at least 33 smaller galaxies, which is appropriate since M33 is the largest of the nieces and nephews. As the eons pass, Andromeda and the Milky Way are engaging in galactic cannibalism, with the Clash of the Titans likely to occur in about 3 billion years. Until that large meal, we must subsist on snacks such as the Sagittarius stream. Streams are produced by tidal disruption of dwarf galaxies; similar tails are seen in simulations of the Moon-forming impact. The structure of the streams provides a sensitive probe of the Galactic potential at large distances. Ultimately, we will be able to compare aspects of the outer Galaxy, such as the shape of the halo, with that predicted by cosmological N-body simulations, some of which now follow over 10¹⁰ particles, i.e., more than one for every man, woman, and child on Earth. One of the key projects of NASA's planned Space Interferometry Mission telescope will be to determine Galactic structure out to hundreds of kiloparsecs, a region containing a number of tidal tails.

astro-ph search for papers about tidal streams and tidal tails

Lance Melting, 1968-2008

Our friend Lance Melting, a special education teacher in Longmont, died in a car crash on I-70 just west of the Eisenhower Tunnel on Monday, March 31, 2008. April 5 would have been his 40th birthday. On that Monday, we had flown to Chicago to spend spring break with Christine's family. We had just enjoyed a lovely dinner with Christine's sister Cathy and her boyfriend Ron when I got a phone call from a friend in Longmont. She told me that Lance had died in a car accident that day, and that they might not know for days exactly what had happened. We looked on the Internet and found that there had been a fatality on Vail Pass. We knew it must be Lance, but couldn't imagine why he would have been driving in snowy conditions. Eventually we learned that he was driving his wife Jamie and their four kids to a vacation in Disneyland. Apparently the weather worsened abruptly on the west side of the tunnel. Lance was the only fatality in a series of three pileups that involved at least 60 cars. Jamie was released from the hospital five days after the accident. She faces a long recovery, but I think she will recover fully. Fortunately, the children only suffered bruises and scratches.

Lance worked with our son Joey, who has Asperger Syndrome, at Rocky Mountain Elementary School from kindergarten through 6th grade. Lance had amazing patience and empathy. Lance had to work with many kids, some with disabilities far more severe than Joey's, and yet we always felt that Joey got all the time he needed with Lance. I think Lance deserves a lot of the credit for the way Joey has turned into a kind, calm, thoughtful 14-year-old.

Yesterday Christine, Joey, and I went to Lance's memorial service at Skyline High School. About 1,000 people attended. There was a performance of martial arts by students, including two of his sons, from a school in Boulder at which Lance had been a student since 1993. A number of family members and friends spoke. I hadn't realized what a jock Lance had been! I hadn't figured him to be a football or rugby player. Finally, there was a slide show of Lance and his family. He always had a smile on his face, even though he had an incredibly difficult job that requires an amount of dedication I can't fathom.

Lance is survived by his wife Jamie Lathrop and their children Aaron, Andrew, Alex, and Abby. Contributions to the Lathrop-Melting Scholarship Fund, for the four children, can be sent in care of Ahlberg Funeral Chapel, 326 Terry St., Longmont, CO 80501.

Lance was born one day after the death of Martin Luther King, Jr. I am consoled by the hope that somewhere in the world, a child was born this month who will do as much good as Lance did. He was one of the greatest people I have ever met.