New gamma-ray eyes spot hidden pulsars
NASA’s new Fermi gamma-ray telescope has captured the faint gamma-ray glimmer of pulsars invisible to radio telescopes. The enhanced ability to detect pulsars may help theorists flesh out the life stories of massive stars.
Pulsars are spinning neutron stars, the dense and fiercely magnetized remnants of massive stars that underwent gravitational collapse. Astronomers can observe them with a radio telescope only when the slender streams of radio waves broadcast from their magnetic poles point Earthward. The newly identified pulsars appear to emit gamma-rays in broad plumes originating in their intense magnetic atmospheres well above the neutron stars’ surfaces.
The new pulsars weren’t simple to spot. To detect periodic patterns in emissions from extremely faint objects rotating at an unknown rate, a team led by the Santa Cruz Institute for Particle Physics (SCIPP) ran five months of data through a series of brute force guess-and-check calculations. Their computations turned up 16 pulsars rotating between 2 and 20 times per second (Science, DOI: 10.1126/science.1175558). Since then, they have identified at least 8 more. The newly discovered pulsars are 10,000 to 100,000 years old, young by astronomical standards.
“Certainly there are a lot that we haven’t seen,” says Robert Johnson, the SCIPP physicist who designed the telescope’s gamma-ray sensors. Astronomers have already identified more than 1800 radio pulsars, but Johnson said the new gamma-ray telescope may double the number of pulsars they can detect.
Caption: New pulsars: blink and you’ll miss them.
I'm currently the Idaho National Laboratory Research Communications fellow, meaning I develop web features and multimedia about INL research in energy, environment, and everything else. This is my published and unpublished writing, done for coursework, internships, freelance, and the hell of it.
Tuesday, October 27, 2009
Saturday, October 24, 2009
soft lede exercise
SANTA CRUZ - In Jacob Rosen’s operating room, the nurses might quit if they stray too far from the wall sockets.
In a videotaped demonstration of Rosen’s robotic operating room, two robotic arms stitched and snipped sutures across a wound on the patient’s torso. Rosen pointed at a third arm as it retrieved a tool and passed it to one of the surgeon arms.
“This is the nurse, by the way,” said Rosen.
The UC Santa Cruz computer engineer is making real surgery look more like the surgery in video games and science fiction movies.
In a videotaped demonstration of Rosen’s robotic operating room, two robotic arms stitched and snipped sutures across a wound on the patient’s torso. Rosen pointed at a third arm as it retrieved a tool and passed it to one of the surgeon arms.
“This is the nurse, by the way,” said Rosen.
The UC Santa Cruz computer engineer is making real surgery look more like the surgery in video games and science fiction movies.
Tuesday, October 20, 2009
in the style of Smithsonian's Wild Life
Timed Flight
How do tiny monarch butterflies migrate more than 2,000 miles without a map and end up in the same grove of fir trees in central Mexico, year after year? They navigate by the sun, just as the Vikings did. The monarchs’ internal sun compass needs a clock to work correctly because the sun is “a moving target, and butterflies need to compensate for that movement,” says Steven Reppert of the University of Massachusetts. Until recently, scientists assumed that butterflies navigated with a light-sensitive clock built into their brains. Reppert and his colleagues discovered that monarchs have two such clocks – and that they navigate with the one in their antennae.
The researchers put tiny leashes on the monarchs and let them take wing in an outdoor flight simulator. Normal butterflies flew southwest, toward Mexico. Butterflies with their antennae snipped off couldn’t orient properly and took off every which way. Painting the monarchs’ antennae black didn’t affect their brain clocks, but a few days without time cues from the sun set the butterflies and their antenna clocks adrift. Bees, ants, and other insects that navigate by the sun may rely on antenna clocks, too.
How do tiny monarch butterflies migrate more than 2,000 miles without a map and end up in the same grove of fir trees in central Mexico, year after year? They navigate by the sun, just as the Vikings did. The monarchs’ internal sun compass needs a clock to work correctly because the sun is “a moving target, and butterflies need to compensate for that movement,” says Steven Reppert of the University of Massachusetts. Until recently, scientists assumed that butterflies navigated with a light-sensitive clock built into their brains. Reppert and his colleagues discovered that monarchs have two such clocks – and that they navigate with the one in their antennae.
The researchers put tiny leashes on the monarchs and let them take wing in an outdoor flight simulator. Normal butterflies flew southwest, toward Mexico. Butterflies with their antennae snipped off couldn’t orient properly and took off every which way. Painting the monarchs’ antennae black didn’t affect their brain clocks, but a few days without time cues from the sun set the butterflies and their antenna clocks adrift. Bees, ants, and other insects that navigate by the sun may rely on antenna clocks, too.
Saturday, October 17, 2009
News: tsunami science
A story of watery destruction, written in sand
SANTA CRUZ – Mention the word “tsunami,” and many people envision a towering wall of water. But according to U.S. Geological Survey oceanographer Bruce Jaffe, tsunamis don’t have to be very tall to be deadly.
“Once it starts getting above your knees, you’re in trouble,” Jaffe said.
On Sept. 29, an underwater earthquake sent a series of massive waves hurtling toward the South Pacific island of Samoa. When the tsunami slammed into the coast and surged ashore, it knocked down trees, buildings, and people, hauling away the wreckage with terrible speed.
Jaffe was fresh from a research trip to the tsunami aftermath when he lectured about it to a UC Santa Cruz audience Tuesday afternoon. He was still reeling from the destruction and human toll, which the Associated Press reported at more than 160 dead.
Tsunami education and evacuation drills paid off for Samoans, Jaffe said. On the day of the tsunami, children waiting for the school bus noticed the water receding. The children recognized the classic tsunami sign and persuaded adults to sound an alarm. Many residents were able to evacuate to the safety of high ground before the tsunami hit.
“The good news is that nearly everywhere on the island, people knew about tsunamis,” Jaffe said. “Had there not been that knowledge, I think there would be probably several thousand if not more people who got killed.”
Jaffe and his colleagues are adding to the body of tsunami knowledge with their research on tsunami sand deposits. They learned that sand particles can ride tsunamis a half mile or more inland before settling out into deposits. They can measure how far inland the sand travels and use that figure to estimate the speed and depth of the waves as well as the strength of the earthquake that produced them.
Jaffe and his colleagues know a tsunami deposit when they see one. The deposits are typically a few inches to one foot deep, and often contain chunks of dirt torn up by the powerful waves. In some cases they may be preserved for millions of years as sandstone.
The oldest tsunami deposit ever found is 65 million years old, Jaffe said. It may have been set off by the same asteroid impact that caused the extinction of many dinosaurs.
More tsunami history may be recorded in sandstone deposits buried in our own backyards, Jaffe said. Using those deposits to fill in the gaps in our patchy tsunami records can help scientists construct a tsunami forecast.
“People don’t believe that a tsunami’s going to hit them,” Jaffe said. “But then when they see the deposit and you show them, here’s what a modern tsunami deposit looks like and this looks very similar, then they pay attention.”
SANTA CRUZ – Mention the word “tsunami,” and many people envision a towering wall of water. But according to U.S. Geological Survey oceanographer Bruce Jaffe, tsunamis don’t have to be very tall to be deadly.
“Once it starts getting above your knees, you’re in trouble,” Jaffe said.
On Sept. 29, an underwater earthquake sent a series of massive waves hurtling toward the South Pacific island of Samoa. When the tsunami slammed into the coast and surged ashore, it knocked down trees, buildings, and people, hauling away the wreckage with terrible speed.
Jaffe was fresh from a research trip to the tsunami aftermath when he lectured about it to a UC Santa Cruz audience Tuesday afternoon. He was still reeling from the destruction and human toll, which the Associated Press reported at more than 160 dead.
Tsunami education and evacuation drills paid off for Samoans, Jaffe said. On the day of the tsunami, children waiting for the school bus noticed the water receding. The children recognized the classic tsunami sign and persuaded adults to sound an alarm. Many residents were able to evacuate to the safety of high ground before the tsunami hit.
“The good news is that nearly everywhere on the island, people knew about tsunamis,” Jaffe said. “Had there not been that knowledge, I think there would be probably several thousand if not more people who got killed.”
Jaffe and his colleagues are adding to the body of tsunami knowledge with their research on tsunami sand deposits. They learned that sand particles can ride tsunamis a half mile or more inland before settling out into deposits. They can measure how far inland the sand travels and use that figure to estimate the speed and depth of the waves as well as the strength of the earthquake that produced them.
Jaffe and his colleagues know a tsunami deposit when they see one. The deposits are typically a few inches to one foot deep, and often contain chunks of dirt torn up by the powerful waves. In some cases they may be preserved for millions of years as sandstone.
The oldest tsunami deposit ever found is 65 million years old, Jaffe said. It may have been set off by the same asteroid impact that caused the extinction of many dinosaurs.
More tsunami history may be recorded in sandstone deposits buried in our own backyards, Jaffe said. Using those deposits to fill in the gaps in our patchy tsunami records can help scientists construct a tsunami forecast.
“People don’t believe that a tsunami’s going to hit them,” Jaffe said. “But then when they see the deposit and you show them, here’s what a modern tsunami deposit looks like and this looks very similar, then they pay attention.”
Tuesday, October 13, 2009
in the style of New Scientist expert Q&A
How does ultraviolet light kill microbes in drinking water?
-J. Welsh, Santa Cruz, Calif.
Sandra Chung, who wrote her master’s thesis on microbial drinking water quality at the University of North Carolina School of Public Health, shines a spotlight on waterborne germs:
Many municipal wastewater treatment plants use ultraviolet, or UV, light to disinfect wastewater. The particles in raw sewage absorb or scatter UV light and make it less effective, so UV disinfection usually happens after crude steps like settling and filtration remove most of the solids from the water. UV light disinfects by penetrating the outer membranes of bacteria and viruses and frying the DNA inside. Massive DNA damage kills the microbes or prevents them from reproducing; either way, they’re unlikely to make you sick.
UV light is simpler to use than chlorine, and it doesn’t change the way water tastes or smells. But it’s expensive and requires a lot of energy to do on a large scale. If you have time to spare in a sunny climate, you can leave drinking water in clear plastic bottles on a hot tin roof or other reflective surface. After six or more hours in direct sunlight, a healthy dose of solar UV and heat should kill most of the harmful bacteria in the water.
-J. Welsh, Santa Cruz, Calif.
Sandra Chung, who wrote her master’s thesis on microbial drinking water quality at the University of North Carolina School of Public Health, shines a spotlight on waterborne germs:
Many municipal wastewater treatment plants use ultraviolet, or UV, light to disinfect wastewater. The particles in raw sewage absorb or scatter UV light and make it less effective, so UV disinfection usually happens after crude steps like settling and filtration remove most of the solids from the water. UV light disinfects by penetrating the outer membranes of bacteria and viruses and frying the DNA inside. Massive DNA damage kills the microbes or prevents them from reproducing; either way, they’re unlikely to make you sick.
UV light is simpler to use than chlorine, and it doesn’t change the way water tastes or smells. But it’s expensive and requires a lot of energy to do on a large scale. If you have time to spare in a sunny climate, you can leave drinking water in clear plastic bottles on a hot tin roof or other reflective surface. After six or more hours in direct sunlight, a healthy dose of solar UV and heat should kill most of the harmful bacteria in the water.