This vivid twist represents a solar cyclone, made of plasma, or ionized gas, moving along swirling magnetic fields on the Sun. It is a computer simulation of the storms on the Sun, created using data from a space telescope at NASA’s orbiting Solar Dynamics Observatory and the Swedish 1-meter Solar Telescope on Earth.
These solar cyclones may help to answer a question that scientists had long wondered about: why is the sun’s atmosphere more than 300 times hotter than its surface? Scientists previously thought that the heat came from the surface of the sun, but how it traveled to the surface was unclear. Now, researchers think that these solar storms, as many as 11,000 at once, funnel heat from the sun’s surface to the corona, as they reported in Nature.
Image via Wedemeyer-Böhm et al/Nature Publishing Group
The Sun’s atmosphere, or corona, is spectacularly hot—far, far hotter than the Sun’s surface. Why this is is still something of a mystery, and scientists watching the Sun’s surface have built software that looks at the heating and cooling occurring in the corona in an attempt to understand how fast temperature changes happen.
Above is an ultraviolet image of a small patch of the sun’s corona. The right half has been processed with a computer program so sections that are growing cooler over a 12-hour period are colored yellow, orange, and red, while heating sections are labeled blue and green.
What’s the News: An international team of researchers, led by the National Center for Atmospheric Research, has learned that large magnetic waves are partly to blame for the Sun’s immensely hot corona. The study, published in the journal Nature, also suggests that the waves could be the driving force behind the solar wind.
Starting this week, NASA will have a new eye in the sky to better sort out the way that greenhouse gases, air pollution, and solar activity interact to affect the climate of our planet. The Glory satellite, currently set to launch on Friday, will spy on changes both in our atmosphere and in the sun.
Its main job will be to study fine airborne particles known as aerosols. Smaller than the diameter of a human hair, these specks can move great distances across the globe and are largely responsible for hazy skies. [The New York Times]
Greenhouse gases and their contribution to climate change have been the subject of much research, of course, but aerosols remain murkier. Climate scientist James Hansen, a member of the Glory team, says researchers must use an uncertainty range for modeling aerosols that’s three to four times greater than what they use with greenhouse gases, simply because the contribution of aerosols is much less understood.
The Glory mission will, if all goes according to plan, collect data on the micro-physical, chemical and optical properties of aerosols using two instruments—an Aerosol Polarimetry Sensor (ARS) and a Total Irradiance Monitor (TIM)—that will monitor the climate system and provide new data for scientists working on the issue of climate change. The APS will collect visible and near-infrared data scattered from aerosols and clouds and the TIM, mounted on a special track that allows it move independent of the satellite, should record total electromagnetic radiation given off by the sun that hits the top of Earth’s atmosphere. [The Atlantic]
The pair of observers that make up NASA’s Solar Terrestrial Relations Observatory (STEREO) have been traveling since 2006 to reach opposite sides of our star, and they just beamed back the first 360-degree solar images.
The satellites are in the same orbital path as Earth, more or less, and have just taken up their final positions — one is where we’ll be in three months, and the other where we were three months ago. (The first has NASA’s least imaginative name to date: STEREO A, for “ahead.” The second is called STEREO B, for…you can probably guess.) [TIME]
Seeing the far side of the sun isn’t just a scientific curiosity. It could also helps researchers figure out the sun’s violent outbursts, like the coronal mass ejections that could endanger astronauts and foul up satellites if one headed for Earth.
Good news, solar sail enthusiasts: the NASA experimental spacecraft that was feared to be a dud sprang into life last week.
NanoSail-D was launched aboard a small satellite in December; once the satellite was in orbit the engineers back on Earth ordered the cargo door opened, and waited for NanoSail-D to pop out as planned. But the solar sail craft remained stubbornly inside the cargo bay. As weeks passed with no action, NASA’s hopes for the craft sunk.
But last Wednesday, NASA announced that NanoSail-D had spontaneously emerged.
“We knew that the door opened and it was possible that NanoSail-D could eject on its own,” Mark Boudreaux, FASTSAT project manager at the Marshall Center, said in a press release. “What a pleasant surprise this morning when our flight operations team confirmed that NanoSail-D is now a free flyer.” [CNN]
When Apollo 11 astronauts Neil Armstrong and Buzz Aldrin stepped onto the lunar surface in 1969, they did more than make history and utter unforgettable words. They also deployed seismic sensors that would allow scientists back on Earth to monitor the activity on the moon. Crews from the 12th, 14th, 15th, and 16th iterations of Apollo also deployed sensors, the lot of which took measurements until 1977. Using recently developed techniques of analysis, two teams working independently say they have gone back into that catalog of data and sorted through the statistical noise that has confounded researchers, creating a clear picture of the moon’s core.
The new study provides the first confirmation of layering of the moon’s core and suggests that the moon, like Earth, has a solid inner core surrounded by a molten outer core, researchers said. But the moon’s interior also has another layer of partially melted material – a ring of magma – around its outer core, the study found. [MSNBC]
The moon shakes with moonquakes, but those are more scattered and weaker than the quakes we experience here on the home world, and the moon’s busted-up surface made the signals difficult for Apollo seismic monitors to read. Through a statistical technique called waveform stacking, the new teams could better identify how seismic waves move through the moon, and especially how the core affects them. That, in turn, shows the size and density of the core.
Whales don’t wear sunscreen. And because these massive sea mammals must surface to breathe, they are being exposed to more and more ultraviolet radiation sneaking through the weakened ozone layer. According to Karina Acevedo-Whitehouse, lead author of a study in the Proceedings of the Royal Society B, some whales are getting serious sunburns at an alarming rate.
From 2007 to 2009, her team sampled fin, sperm, and blue whales in the sun-drenched Gulf of California, which is the long, skinny expanse of water between mainland Mexico and Baja California.
Nearly all of the skin samples contained “sunburn cells,” abnormal cells associated with ultraviolet-induced DNA damage. These indicators were even found in the lowest layer of skin on the whales, suggesting that those individuals were suffering from very severe sunburns. [Discovery News]
The edge of the solar system is not some static line on a map. The boundary between the heliosphere in which we live and the vastness of interstellar space beyond is in flux, stretching and shifting more rapidly than astronomers ever knew, according to David McComas.
McComas and colleagues work with NASA’s Interstellar Boundary Explorer (IBEX), a satellite orbiting the Earth with its eye turned to the edge of the heliosphere—the bubble inflated by the solar wind that encapsulates the solar system and protects us from many of the high-energy cosmic rays zinging across interstellar space. This week in the Journal of Geophysical Research, the team published the results of IBEX’s second map of the region, and found that its makeup has changed markedly over the span of just six months. Says McComas:
“If we’ve learned anything from IBEX so far, it is that the models that we’re using for interaction of the solar wind with the galaxy were just dead wrong.” [National Geographic]