ACS Applied Materials &Interfaces, Volume 9, Issue 34, Page 28139-28143, August 30, 2017.Continue reading →
On August 21, for about two minutes across a swath of North America, Earth’s moon will pass in front of and completely block out the sun, causing a total solar eclipse. Countless people are expected to witness this rare phenomenon, the first total solar eclipse in North America in 38 years. Just this week, scientists at Caltech and JPL decided that a small space telescope will be watching with them.
NuSTAR (Nuclear Spectroscopic Telescope Array) is a NASA mission led by Caltech and principal investigator Fiona Harrison, the Benjamin M. Rosen Professor of Physics and Kent and Joyce Kresa Leadership Chair of the Division of Physics, Mathematics and Astronomy. As the telescope orbits around Earth, it stares deep into the cosmos to measure the X-rays emitted from energetic phenomena such as supernovas. Occasionally, scientists will turn NuSTAR toward our sun, measuring X-rays from so-called active regions—spots where solar magnetic field lines collide, often causing plasma to blast into space, in a process called reconnection.
“Because it orbits near the equator, NuSTAR will only see a partial solar eclipse, about 30 percent of totality,” says Brian Grefenstette, a research scientist on the NuSTAR team at Caltech. “However, we got lucky in that this partial eclipse will block out a single active region. As the moon’s edge progressively covers the region, scientists will be able to determine with unusual precision how both the brightness and temperature of the region vary over its extent.” Because of the unpredictability of where the active regions will fall relative to the regions blocked by the moon, NuSTAR’s scientists only determined that they would be able to make these measurements a week before the eclipse.
Understanding the X-ray energy contained in an active region may be an important step toward solving a long-standing mystery: why the sun’s corona—the vast, diffuse aura of plasma particles visible during a total eclipse—is so much hotter than its surface.
“Active regions are where the heating of the corona is most violent,” says David M. Smith of UC Santa Cruz, who leads the NuSTAR solar science team. “Many small magnetic reconnection events may be the underlying cause. Using the eclipse to help us map out the region in X-rays will give us a unique data set to help test this theory.”
NuSTAR is a Small Explorer mission led by Caltech and managed by NASA’s Jet Propulsion Laboratory for NASA’s Science Mission Directorate in Washington.
The meeting focused on the people, programs, and ideas that have helped to break down the barriers to being a female physicist.[Physics 10, 94] Published Wed Aug 16, 2017Continue reading →
An analysis of electron-positron collision data has determined the spin and parity of a particle thought to consist of four quarks.[Physics] Published Wed Aug 16, 2017Continue reading →
Langmuir, Volume 33, Issue 42, Page 11603-11610, October 24, 2017.Continue reading →
A single-electron transistor carries more heat than that predicted by the Wiedemann-Franz law linking thermal and electrical conductivities.[Physics] Published Tue Aug 15, 2017Continue reading →
Author(s): Philip BallTwo research teams have created the coldest molecular ion beams ever, putting molecules in their ground states of rotation and providing improved experimental stand-ins for interstellar gas clouds.[Physics 10, 93] Published Mon Au…Continue reading →
Author(s): Michael ZaiserSimulations of porous materials exhibit internal stress patterns like those in granular materials, despite the fact that these two systems are practically “negative images” of each other.[Physics 10, 92] Published Mon Aug 14, 2…Continue reading →
Network scientist Daniel Larremore draws on his diverse interests to make sense of patterns in sporting records, hiring decisions, and the spread of diseases.[Physics 10, 91] Published Fri Aug 11, 2017Continue reading →
Theorists have used lattice-QCD calculations to predict two weak-force-driven reactions—proton fusion and tritium decay.[Physics] Published Thu Aug 10, 2017Continue reading →
Chemistry of Materials, Volume 29, Issue 16, Page 6936-6946, August 22, 2017.Continue reading →
Following the 2017 American Physical Society (APS) general election, Philip Bucksbaum will be vice president of APS in 2018 – an election that places him in the presidential line. He will become president-elect in 2019 and president in 2020.Continue reading →