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8 thursday, april 19, 2012

The california Aggie

Solar eclipse to appear over northern California in May Special glasses will be sold on Picnic Day

Evan Davis / Aggie

Fourth year Kevin DeLano (right) and fifth year Rachael Johnson (left) model the eclipse glasses.

By BRIAN RILEY Aggie Science Writer

Students and members of the UC Davis community are preparing for a special type of solar eclipse that will occur in the evening sky in northern California this coming May 20. This eclipse will be an “annular” (meaning “ring-like”) type of solar eclipse, which is when the moon passes directly in front of the sun without completely cover-

ing it and appears as a complete disk within a disk. “We don’t get to see it often because our moon isn’t on the right plane. [The plane of orbit] is 5 degrees off, so to catch it on the right plane is really spectacular,” said Jared Clapham, a senior communication major at UC Davis who is currently taking an astronomy class. People who view the eclipse from the city of Davis will only see a partial

eclipse on May 20, beginning at 5:15 p.m. and ending at 7:38 p.m. Pacific Daylight Time. Maximum eclipse will occur at 6:31 p.m., viewing from Davis, when the moon will appear to cover 86 percent of the sun’s disk somewhat low in the western sky. Kevin Delano and Rachael Johnson, both senior geology majors, are co-presidents of the UC Davis Geology Club. “We see this as an opportunity to educate people about a real cool natural phenomenon they will experience,” Delano said. The Geology Club will be offering special solar eclipse glasses on the Quad during Picnic Day for a $2 donation, and afterward by special arrangement. “One cannot view the eclipse without the glasses,” Delano stressed, “because the sun will damage your eyes.” The other type of eclipse is a lunar eclipse, when the earth casts a shadow on the moon. “A lunar eclipse is seen by half of the entire planet,” said Howard Spero, who is a professor of geology and chair of the geology department at UC Davis. “Even though solar eclipses are more frequent, much fewer people see [total solar eclipses] because you have to be on a specific part of the planet at a specific time to be able to see one,” Spero said. The upcoming annular eclipse will be able to be seen in the U.S. from within a wide band that stretches from northern California southeastward toward western Texas. To see the disk-within-a-disk, ring-

Heat up and wiggle Researchers discover how desert squirrels protect their newborns

Desert squirrel

By HUDSON LOFCHIE Aggie Science Writer

How does a squirrel tell a rattlesnake to stay away from its babies? It heats up its tail. Using a robotic model of a squirrel, researchers at UC Davis and UC San Diego have been trying to find out how squirrels communicate aggression to their most dangerous predator. This heated communication is just part of the behavior that researchers are trying to mimic in an effort to understand how such a small animal manages to ward off such a large adversary. In the arid desert, the squirrel is not trying to protect itself, but its babies, or pups. During the late spring and early summer, the pups are born, and the rattlesnakes go hunting. Normally, a squirrel would be outmatched and simply run away from the rattlesnake. But when it comes to protecting the pups, running away is not an option. The squirrel needs some way of alerting the snake that it is willing to fight if necessary. “By heating its tail, [the squirrel] is saying ‘Hey! We are here! We know you are there,’” said Sanjay Joshi, a professor of mechanical and aerospace engineering at UC Davis and one of the researchers on the project. “We dis-

courtesy

covered that tail-heating is a very important component of communication.” Heating is an effective signaling method for the squirrels because it drastically increases the squirrel’s visibility to the rattlesnake’s “sight” with infrared. In other words, snakes have heat vision. This observation is the first-ever discovery of animals actively communicating with heat signals. When a snake encounters a squirrel that is displaying a heated tail, it avoids getting into strike position and getting near the pups. However, sometimes the tail-heating is not enough on its own, so squirrels must use other methods to ward off the serpentine danger. In these occasions, squirrels perform what is called “flagging,” or waving their tail a certain way. “Snakes will rarely strike at a flagging adult squirrel,” said Rulon Clark, a researcher at the UC San Diego department of biology and another of the head researchers on the project. In addition to tail-heating and flagging, squirrels have two more defense methods they can employ against rattlesnakes. Squirrels have incredible agility as well as a strong resistance to snake venom. In addition to the biological and behavioral questions the researchers

Have a safe Picnic Day!

were trying to answer, they have also been looking to answer a more basic question about robot-animal interaction — how closely to the rattlesnake does the robot have to resemble an actual squirrel to pull off a successful mimicry? “Simulations in a lab are always different from the true performance in the field,” said Ryan Johnson-Masters, a graduate student in Joshi’s lab. In both laboratory and field settings, the snake seemed unable to tell the difference between real squirrels and the robotic squirrels that had been designed to mimic the tail-heating and flagging behavior. Engineers had to work closely with biologists to get the design of squirrel characteristics right, and biologists worked with the engineers to gather and analyze the data that the robot delivered. Much of what is known about squirrel psychology was discovered by UC Davis professor of psychology Donald Owings, who passed away last year. However, the researchers are continuing the work that he started and hope that they will discover many more previously unknown intricacies of animal behavior. HUDSON LOFCHIE can be reached at science@theaggie. org.

like effect, viewers can drive to any area along Interstate 5 between Willows, Calif. and Glendale, Ore. and look for clear skies, or anywhere along Highway 101 between Garberville, Calif. and Bandon, Ore. A Google interactive map of the solar eclipse path can be found on the NASA.gov website. “It’s silly not to [drive north]. This is an opportunity of a lifetime,” Spero said, referring to the short one-hour drive. According to Sky & Telescope magazine, although the sky doesn’t turn dark during an annular eclipse, the sky will turn dark blue, allowing the planet Venus to be seen to the left of the sun. Spero is an “eclipse chaser” and has traveled all over the world to see seven total solar eclipses in 21 years on four continents, when day becomes night for a span of a few or several minutes. He has also seen one annular eclipse. Kenneth Verosub, also a professor in the geology department, traveled to China with Spero to see a total eclipse there in July 2009. Verosub teaches a course called “Earth Science, History, and People,” which, he explained, involves studying the interactions between geologic processes and human activity. “I believe that people need to look up at the sky more than they do,” Verosub said. “To me it’s a connection to the long span of human history and to the way that earlier people related to or responded to these kinds of events.” BRIAN RILEY can be reached at science@theaggie.org.


April 19, 2012