Image of the Day: ALMA sees a baby solar system

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Observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope of the disc of gas and cosmic dust around the young star HD 142527 show vast streams of gas flowing across the gap in the disc. These are created by giant planets guzzling gas as they grow. The dust in the outer disc is shown in red. Dense gas in the streams flowing across the gap, as well as in the outer disc, is shown in green. Diffuse gas in the central gap is shown in blue. The gas filaments can be seen at the three o’clock and ten o’clock positions, flowing from the outer disc towards the center.

Image credit: ALMA (ESO/NAOJ/NRAO), S. Casassus et al.

Image of the Day: Cambrian embryo fossil

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The Cambrian Period is a time when most phyla of marine invertebrates first appeared. Also dubbed the “Cambrian explosion,” fossilized records from this time provide glimpses into evolutionary biology. Most fossils show the organisms’ skeletal structure, which may give researchers accurate pictures of these prehistoric organisms. Now, researchers at the University of Missouri have found rare, fossilized embryos they believe were undiscovered previously. Their methods of study may help with future interpretation of evolutionary history. This image shows the Cambrian embryo fossil exposed by acid etching on rock surface. The polygonal structure on the surface is indicative of blastula-stage of development.

Image credit: Broce, et al.

A river of plasma, guarding against the sun

The Earth’s magnetic field, or magnetosphere, stretches from the planet’s core out into space, where it meets the solar wind, a stream of charged particles emitted by the sun. For the most part, the magnetosphere acts as a shield to protect the Earth from this high-energy solar activity.

But when this field comes into contact with the sun’s magnetic field — a process called “magnetic reconnection” — powerful electrical currents from the sun can stream into Earth’s atmosphere, whipping up geomagnetic storms and space weather phenomena that can affect high-altitude aircraft, as well as astronauts on the International Space Station.

Now scientists at MIT and NASA have identified a process in the Earth’s magnetosphere that reinforces its shielding effect, keeping incoming solar energy at bay.

By combining observations from the ground and in space, the team observed a plume of low-energy plasma particles that essentially hitches a ride along magnetic field lines — streaming from Earth’s lower atmosphere up to the point, tens of thousands of kilometers above the surface, where the planet’s magnetic field connects with that of the sun. In this region, which the scientists call the “merging point,” the presence of cold, dense plasma slows magnetic reconnection, blunting the sun’s effects on Earth.

“The Earth’s magnetic field protects life on the surface from the full impact of these solar outbursts,” says John Foster, associate director of MIT’s Haystack Observatory. “Reconnection strips away some of our magnetic shield and lets energy leak in, giving us large, violent storms. These plasmas get pulled into space and slow down the reconnection process, so the impact of the sun on the Earth is less violent.”

Foster and his colleagues publish their results in this week’s issue of Science. The team includes Philip Erickson, principal research scientist at Haystack Observatory, as well as Brian Walsh and David Sibeck at NASA’s Goddard Space Flight Center.

Mapping Earth’s magnetic shield

For more than a decade, scientists at Haystack Observatory have studied plasma plume phenomena using a ground-based technique called GPS-TEC, in which scientists analyze radio signals transmitted from GPS satellites to more than 1,000 receivers on the ground. Large space-weather events, such as geomagnetic storms, can alter the incoming radio waves — a distortion that scientists can use to determine the concentration of plasma particles in the upper atmosphere. Using this data, they can produce two-dimensional global maps of atmospheric phenomena, such as plasma plumes.

These ground-based observations have helped shed light on key characteristics of these plumes, such as how often they occur, and what makes some plumes stronger than others. But as Foster notes, this two-dimensional mapping technique gives an estimate only of what space weather might look like in the low-altitude regions of the magnetosphere. To get a more precise, three-dimensional picture of the entire magnetosphere would require observations directly from space.

Toward this end, Foster approached Walsh with data showing a plasma plume emanating from the Earth’s surface, and extending up into the lower layers of the magnetosphere, during a moderate solar storm in January 2013. Walsh checked the date against the orbital trajectories of three spacecraft that have been circling the Earth to study auroras in the atmosphere.

As it turns out, all three spacecraft crossed the point in the magnetosphere at which Foster had detected a plasma plume from the ground. The team analyzed data from each spacecraft, and found that the same cold, dense plasma plume stretched all the way up to where the solar storm made contact with Earth’s magnetic field.

A river of plasma

Foster says the observations from space validate measurements from the ground. What’s more, the combination of space- and ground-based data give a highly detailed picture of a natural defensive mechanism in the Earth’s magnetosphere.

“This higher-density, cold plasma changes about every plasma physics process it comes in contact with,” Foster says. “It slows down reconnection, and it can contribute to the generation of waves that, in turn, accelerate particles in other parts of the magnetosphere. So it’s a recirculation process, and really fascinating.”

Foster likens this plume phenomenon to a “river of particles,” and says it is not unlike the Gulf Stream, a powerful ocean current that influences the temperature and other properties of surrounding waters. On an atmospheric scale, he says, plasma particles can behave in a similar way, redistributing throughout the atmosphere to form plumes that “flow through a huge circulation system, with a lot of different consequences.”

“What these types of studies are showing is just how dynamic this entire system is,” Foster adds.

Tony Mannucci, supervisor of the Ionospheric and Atmospheric Remote Sensing Group at NASA’s Jet Propulsion Laboratory, says that although others have observed magnetic reconnection, they have not looked at data closer to Earth to understand this connection.

“I believe this group was very creative and ingenious to use these methods to infer how plasma plumes affect magnetic reconnection,” says Mannucci, who was not involved in the research. “This discovery of the direct connection between a plasma plume and the magnetic shield surrounding Earth means that a new set of ground-based observations can be used to infer what is occurring deep in space, allowing us to understand and possibly forecast the implications of solar storms.”

By Jennifer Chu, MIT News Office

Image of the Day: Meandering Mississippi

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In the picture at left, small, blocky shapes of towns, fields and pastures surround the graceful swirls and whorls of the Mississippi River. Countless oxbow lakes and cutoffs accompany the meandering river south of Memphis, Tennessee, on the border between Arkansas and Mississippi, USA. The “mighty Mississippi” is the largest river system in North America.

Image credit: USGS / NASA

MIT students dominate Putnam Mathematical Competition, winning team event

The recently announced results of the annual William Lowell Putnam Mathematical Competition, the prestigious undergraduate mathematics contest that this year included more than 4,100 students from 557 colleges and universities across the U.S. and Canada, represented a sweeping victory for MIT.

The Institute not only won the team competition — placing ahead of runners-up Carnegie Mellon University and Stanford University — but also placed four students in the top five individual spots, an achievement that earns those contestants designation as “Putnam Fellows”: sophomore Mitchell Lee, junior Zipei Nie, freshman Bobby Shen, and freshman David Yang.

A large number of other MIT students also delivered strong performances on the famously challenging six-hour, 12-question exam.

“The Putnam exam is brutally graded,” explains Henry Cohn, an adjunct professor of applied mathematics who helped students prepare for the Putnam by teaching — along with Abhinav Kumar, an associate professor of applied mathematics — 18.A34 (Problem Solving Seminar). “There’s almost no partial credit given, so, for example, on question B6 this year, exactly zero students received full credit. This year’s median score was around one point out of 120 points available, so even students who scored zero were in good company.”

“There were 87 MIT students in the top 442 this year, which is amazing,” Cohn adds. “No other school had even half that many.”

Cohn and members of MIT’s team first learned of the Putnam triumph via Wikipedia.

“We noticed a day or two before we received the ‘official’ results in the mail that somebody had altered the Wikipedia entry for the Putnam Competition to reflect that MIT had won, but we didn’t know if it was a prank,” he says. “When the ‘official’ results finally came, I was thrilled.”

Winning MIT team of Lee, Nie, and Gunby

The three members of MIT’s winning team — Lee, Nie, and junior Benjamin Gunby, also a mathematics major — competed in Putnam for a variety of reasons.

“I find the Putnam Competition to be a fun experience,” explains Lee, a mathematics major and two-time Putnam Fellow. “Besides that, I hope that my performance will help me if I apply for graduate school. I also appreciate the prize money.” (Lee won $3,500 for his efforts.)

Lee also enjoys the team camaraderie. He attributes MIT’s performance this year to “the overall strength of the math community here at MIT.”

“We enjoy talking about math,” he says. “We all support each other and congratulate each other. The things I have learned from other competitors undoubtedly played a role in my own performance.”

Nie, also a mathematics major and two-time Putnam Fellow, says that math contests provide a sense of belonging. As a high school student in China, Nie says, he felt “pessimistic day after day, so I decided to let math be the meaning of my life. Math and the support of my high school teachers cured me. Math Olympiad training became my main work during those years. Fortunately, I made great progress.”

Gunby, a Putnam Fellow last year and a member of the winning MIT trio this year, says math contests represent an intellectual challenge. “Math competitions have played a big part of my life,” he says, “especially during high school. Before college, math classes didn’t do much to improve my problem-solving skills. But everyone in college can find a math class that’s interesting and challenging.”

Michael Sipser, the Barton L. Weller Professor of Mathematics, head of the Department of Mathematics, and interim dean of the School of Science, says: “I’m proud that our department has attracted such a high caliber of student. We had an extraordinary number of top performers on the Putnam: 80 percent of the top five and 60 percent of the top 25.”

“Word has gotten out that MIT is the place to be for competitive math,” Sipser says, “and success breeds even more success. Winning helps us attract even more strong students, and not just math competitors, but smart kids in general.”

Sipser hopes that attention on events like the Putnam Competition can trigger larger public conversations about math. “It helps us celebrate math in a playful way,” he says.

Contest math vs. research math

How well does success at “contest math,” like the Putnam Competition, correlate with later achievement in math? As Sipser puts it, comparing time-limited contest math to research math “is like comparing regular chess to blitz chess.”

Bjorn Poonen, the Claude E. Shannon Professor of Mathematics and one of just eight students ever to be a four-time Putnam Fellow (as an undergraduate at Harvard University), agrees: “The Putnam differs from math research in that it rewards speed more than the ability to develop deep insights over time. There is some overlap in the skills, but there are many excellent mathematicians who didn’t do well on the Putnam. Also, as far as content goes, math majors at MIT learn much more than what is covered on the Putnam.”

Cohn, who received his SB in mathematics from MIT in 1995 and who participated in the Putnam Competition as an undergraduate, says: “While we rightfully celebrate these clever and quick problem-solvers who did so well on the Putnam, there are amazing MIT students who don’t even take the exam, as well as wonderful students who are going to accomplish fantastic things in mathematics even though they scored one point on the Putnam. The mathematics department doesn’t value students who win contests any more than we value the rest of our great students.”

By Chuck Leddy, MIT News correspondent

Image of the Day: Growing & glowing

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This map shows photosynthetic activity across North America during the growing season, with the United States Midwest proving to be the most active spot on the continent. The pink glow in the satellite photo represents fluorescence measured from land plants in early July, from 2007 to 2011. Plants convert light into energy in a process known as photosynthesis. During this process, vegetation emits a difficult-to-detect fluorescent glow that is invisible to the naked eye. The magnitude of the glow indicates the amount of photosynthesis within a given region, NASA officials said in a statement.

Image credit: NASA’s Goddard Space Flight Center / (description) LiveScience Staff

Image of the Day: Mapping polarization of ferroelectric materials

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At the atomic scale, engineering researchers at the University of Michigan (U-M) have for the first time, mapped the polarization of a cutting-edge material for memory chips. The researchers found a way to improve the performance of ferroelectric materials.

Image credit: Chris Nelson and Xiaoqing Pan, Department of Materials Science and Engineering, University of Michigan

Image of the Day: Surface systems: Engineering nanoparticles to improve human health

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This image depicts a model of the interactions of engineered nanoparticle surfaces (blue) with fluorescent (green) and serum proteins (gold) used for a rapid-response blood test. University of Massachusetts Amherst nanochemist Vincent Rotello (Chemistry) is engineering nanoparticle surfaces for widespread applications in therapeutics, diagnostics, and tissue engineering. One key challenge Rotello and his research group are addressing is how to design materials to interact in controlled fashion with proteins. Rotello has developed new systems for delivering proteins into cells, as well as surfaces that are highly resistant to protein adhesion, with applications for implantable sensors and other biomedical devices. For his creative and translational research, Rotello has been appointed Distinguished Professor. This research is being conducted through the campus’ Center for Hierarchical Manufacturing, an NSF Nanoscale Science and Engineering Center.

Image credit: Rotello Research Group

Image of the Day: At the edge of NGC 2174

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This fantastic skyscape lies near the edge of NGC 2174, a star-forming region about 6,400 light-years away in the nebula-rich constellation of Orion. It follows mountainous clouds of gas and dust carved by winds and radiation from the region’s newborn stars, now found scattered in open star clusters embedded around the center of NGC 2174, off the top of the frame. Though star formation continues within these dusty cosmic clouds, they will likely be dispersed by the energetic newborn stars within a few million years. Recorded at infrared wavelengths by the Hubble Space Telescope, the interstellar scene spans about 6 light-years. The image celebrates the upcoming 24th anniversary of Hubble’s launch onboard the space shuttle orbiter Discovery on April 24, 1990.

Image credit: NASA, ESA, Hubble Heritage Team (STScI/AURA)

Image of the Day: Sakurai’s Object

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Stellar lifetimes are measured in billions of years, so changes in their appearance rarely take place on a human timescale. Thus an opportunity to observe a star passing from one stage of life to another on a timescale of months to years is very exciting, as there are only a very few examples known. One such star is Sakurai’s Object (V4334 Sgr). Using the Altair adaptive optics (AO) system with the Gemini North Telescope on Mauna Kea in Hawai’i to compensate for distortions to starlight caused by the Earth’s atmosphere, two National Optical Astronomy Observatory astronomers were able to observe the shell of escaping material around the star. This oil painting represents what the present expanding shell of gas and dust around the star may look like.

Image credit: Stephen Mack, National Optical Astronomy Observatory

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