Explorer of the 'cool universe'

Artist's impression of the Herschel space telescope, which is revealing a surprising array of activity in cold, dark regions where interstellar material condenses. Credit: ESA, D. Ducros.

Emory astrochemist Susanna Widicus Weaver will soon begin one of the first broad spectral surveys of small organic molecules in deep space. Her lab’s research proposal – to search for the raw materials of life in star-forming regions – recently won 42 hours of observing time on the Herschel Space Observatory.

“The process for applying is incredibly competitive, and 42 hours is a huge amount of time, so we’re ecstatic,” Weaver said. “I actually watched the Herschel instrument evolve over the past 10 years, so I have to pinch myself that this is actually happening.”

Astrochemistry draws on astronomy, laboratory spectroscopy and chemical modeling to study chemical mechanisms in space. Weaver is skilled in all three of these specialized areas.

Weaver studies chemical mechanisms in space.

As a graduate student at Caltech, she would visit the NASA Jet Propulsion Laboratory and marvel at the technology going into building the Herschel instruments. Headed by the European Space Agency, Herschel became the largest telescope in space when it launched last year. The scope’s 3.5 meter-diameter mirror offers an unprecedented view of the “cool universe,” the domain of objects like tiny stars and molecular clouds that barely emit light. It may not seem as glamorous as looking for new planets, but scientists believe that the cool universe holds secrets for how life forms. Herschel operates in the far-infrared range, penetrating the veil of gas and dust shrouding these cooler realms by bridging the gap between infrared and radio astronomy.

Weaver’s research is focused on that gap, in the terahertz frequency range. At Emory, she is developing the technology to search for the building blocks of life in this largely unexplored area of deep space. Students are helping her build a high-sensitivity spectrometer to record the terahertz transmission frequency of transient molecules that are key building blocks to forming simple molecules of sugars and amino acids.

Weaver theorizes that these transient molecules are present in deep space. On Earth, however, they are unstable, existing only for the blink of an eye. So Weaver is developing methods to make the molecules and keep them stable in a laboratory environment. Using spectroscopy to record the spectral “fingerprints” of the molecules gives the lab a guide to search for them in space.
Stellar pregnancy and birth in the Milky Way. Credit: ESA/HiGAL Cosortium.

Weaver and her students are frequent visitors to the Caltech Submillimeter Observatory on the Mauna Kea volcano of the Big Island of Hawaii, where they acquire terahertz spectra with a 10.4-meter radio astronomy dish. This dish is a powerful device, situated in a high, dry and dark location, but observations are still hampered by the Earth’s atmosphere, which blocks most far-infrared wavelengths, while also producing its own far-infrared radiation. Observing terahertz radiation from the ground is like trying to see stars on a cloudy night.

“That’s the reason that the Herschel telescope is so incredible. This is the first time we can observe molecules in the terahertz range from space,” Weaver says.

Weaver and her students will use their time on the Herschel observatory to search for a range of simple molecules that they have identified as key to prebiotic pathways in interstellar chemistry, such as acetic acid, methyl formate, glycolaldehyde and methanol.

“Most previous observations have targeted a few specific molecules, but we want to open that up and get a better idea of the average composition of the clouds in star-forming regions,” Weaver explains.

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Tapping secrets of the social brain

Gary Stix writes in Scientific American:

Emory University just announced at this week's Society for Neuroscience meeting that it is establishing a Center for Translational Social Neuroscience.

The objective will be to bring in bigwig scientists like psychologist Frans de Waal from the school's Yerkes National Primate Research Center to marshal a body of basic research on social bonding and translate it into drugs or behavioral interventions that can help autistic children and those suffering from the kinds of social deficits that can occur with schizophrenia. These studies will also shed light on how the normal social brain works.

"The overall goal is to foster collaboration between people trying figure to out how to treat autism patients and people who are working with animals who can come up with clever ways of stimulating the social brain and bring these people together to make translation happen," says Larry Young, the center's director, who uses prairie voles (unusual because they are monogamous mammals—see photo) to study social relationships.

Read the whole article in Scientific American.

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Entering the era of living machines

Imagine being able to program an innocuous organism to clean up hazardous waste. Or generate a clean, cheap fuel. Or destroy cancer cells.

Emory scientists are among those working at the forefront of synthetic biology – the engineering of biological functions and systems not found in nature. This rapidly accelerating field holds tremendous promise, but raises challenging questions about ethics, security and safety.

Have an interest or concern about synthetic biology? Now is the time to express it. On Nov. 16-17, Emory is hosting a public meeting of the Presidential Commission for the Study of Bioethical Issues. (Watch videos of the event by clicking here.) It’s the third and final meeting of the commission before it issues recommendations to President Obama on synthetic biology.

“We look for a good turnout from interested members of the public, as well as teachers, students and practitioners in fields that touch on synthetic biology,” said Emory President James Wagner, vice chair of the commission.

If you are unable to attend, you can still have your say. Written comments on the topic can be emailed to info@bioethics.gov.

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Physics flies off the rails in 'Unstoppable'

It’s a gripping premise: “1 million tons of steel. 100,000 lives. 100 miles to impact.”

The new movie “Unstoppable,” features a runaway train, loaded with toxic chemicals, speeding towards a town with a bend in the tracks. It’s actually loosely based on a 2001 incident when a renegade locomotive was halted just short of Kenton, Ohio.

But is the science in “Unstoppable” accurate? Could the train’s impact decimate a town?

Emory physicist Sidney Perkowitz applies the basic formula of kinetic energy – one-half the mass times the speed squared – to compare the impact of the “Unstoppable” train to nuclear bombs and an asteroid.

A hydrogen bomb carries energy equivalent to 20 million tons of TNT. A train weighing one million tons, traveling at 50 miles per hour, as the movie’s publicity describes it, would carry the equivalent of 60 tons of TNT. “That would be a major explosion,” Perkowitz says.

But can a train really weigh 1 million tons?

“I think whoever wrote the publicity forgot the difference between tons and pounds,” Perkowitz says. If the train had a weight of 1 million pounds, then it would only have the energy of 60 pounds of TNT.

“That’s certainly enough to take out a building,” he says. “It would turn an SUV into molecules and it would be a terrible crash, but not enough to take out a whole city block.”

Interesting science, but not likely to stop movie goers in their tracks. “It sounds like a fun film,” Perkowitz says. “I would sit back and munch some popcorn and let the train run over me, and not worry too much about the math.”

Check out this video of Perkowitz talking about the physics in the movie “Iron Man,” and how it has some basis for reality in the U.S. military.

Sound too far-fetched? Watch this news video from CNN, below, about a half-man, half-robot contraption developed by the defense contractor Raytheon:

Are astronauts at risk for lung cancer?

NASA photo

Researchers from Emory's Winship Cancer Institute and the Medical College of Georgia are launching a new cancer research initiative – into space.

NASA awarded a team of investigators from both institutions $7.6 million to study how space radiation may induce lung cancer. The award establishes a NASA Specialized Center of Research (NSCOR), consisting of a team of scientists with complementary skills.

Interplanetary space travel could expose astronauts to conditions where they are chronically exposed to types of radiation not normally encountered on earth. One of these is high energy charged particles (HZE), which results in complex damage to DNA and a broader stress response by the affected cells and tissues.

There is no epidemiological data for human exposure to HZE particles, although some estimates have been made studying uranium miners and Japanese atomic bomb survivors, says Ya Wang, a radiation oncologist and director of the NSCOR at Emory.

Animal experiments show that HZE particle exposure induces more tumors than other forms of radiation such as X-rays or gamma rays. Because it is a leading form of cancer, lung cancer can be expected to be prominent among increased risks from radiation even though astronauts do not smoke. However, the risk for astronauts remains unclear because the dose of HZE astronauts are expected to receive is very low, Wang says.

Read more in this Winship news release.

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