Studying The Sun’s Dramatic Temperature Variations
Posted by Sean Meade 7:18 AM on Jul 08, 2013
This story by Michael Mecham and Frank Morring, Jr. ran in the July 8 edition of Aviation Week & Space Technology.
Spaceborne study of the Sun has produced spectacular images like these over the years, but still leaves much about our nearest star cloaked in mystery. Now an ultraviolet (UV) telescope with unusually high spectral bandwidth will try to solve one of the most puzzling—why temperatures vary so dramatically between the Sun’s surface and the upper limits of its turbulent atmosphere.
IRIS will focus on the interface region in the Sun’s atmosphere , shown in this image collected by Japan’s Hinode spacecraft, in the hope it will reveal why the corona above it gets so much hotter. Credit: JAXA/Hinode
NASA ‘s Interface Region Imaging Spectrograph (IRIS) mission received “a great insertion orbit” from its three-stage Orbital Sciences Pegasus XL air-launched booster June 27, hitting a 400-mi.-high Sun-synchronous orbit that should carry it well beyond its nominal two-year operational life.
NASA ‘s IRIS spacecraft will image about 1% of the Sun with each shot of its ultraviolet telescope , resolving images as small as 150-mi. across. Credit: Lockheed Martin
The $170 million mission fields a 20-cm (8-in.) UV telescope and spectrograph designed to record the ultraviolet light emitted in the transitional region that stretches from the Sun’s surface —where temperatures are a mere 10,000F—to its corona, or upper atmosphere, where they reach several million degrees. The mission will study solar and plasma physics, space weather and astrophysics to gain a better understanding of how the Sun’s internal convective flows power its atmospheric activity. Spikes in that activity can interrupt electrical grids and disrupt communications satellites.
Astronomers combined images taken with Europe’s Proba-2 spacecraft and from the ground at Atoll Hao in French Polynesia during a total solar eclipse in July 2010 to produce this illustration of the extended corona . Credit: ESA/Proba-2 consortium/SWAP team/Institut d’Astrophysique de Paris (CNRS & UPMC), S. Koutchmy/J. Mouette
With a liftoff weight of 140 kg (300 lb.), IRIS has a power rating of 200 watts. Its most prominent feature is its 3-meter (9.8-ft.)-long UV telescope built by the Smithsonian Astrophysical Observatory.
A massive coronal hole in blue shows a 400,000-mi.-wide opening in the Sun’s magnetic field that lets the solar wind spew out at 400-500 mi./sec., twice its normal speed. Credit: NASA /SDO
The spacecraft’s multi-channel imaging spectrograph , built by Lockheed Martin Sensing and Exploration Systems from a design collaboration with Montana State University, will observe in the extreme ultraviolet wavelengths between 1,200-3,000 angstroms, far higher than previous missions.
Solar particles from an Earth-directed coronal mass ejection (CME) March 15 show up clearly in these occluded images from the Solar Heliospheric Observatory. Credit: ESA/NSA/SOHO
The instrument’s mirrors, polished by L-3 Communications SSG-Tinsley Inc. in Richmond, Calif., have a quality better than the Hubble Space Telescope’s, says Principal Investigator Alan Title, a senior fellow at the Lockheed Martin Advanced Technology Center in Palo Alto, Calif.
The CME above produced this aurora over Prudhoe Bay, Alaska, two days later, reflecting a geomagnetic storm rated G2 fading to G1 on a five-point scale. Storms that are more severe can damage satellites and disrupt power grids.
“IRIS will show the solar chromosphere in more detail than has ever been observed before,” says Adrian Daw, deputy project scientist. “My opinion is that we are bound to see something we didn’t expect to see.”
Those campers in Yellowstone sure look happy inlast weekend’s Look. And why shouldn’t they? Fresh air and land, lots of land, under starry skies above, no fences or hobbles, and so on.
Obviously they didn’t read — or have forgotten — the cover story that National Geographic published almost exactly three years ago, “Yellowstone Supervolcano: What Lies Beneath the Park.” So what lies beneath? Just “one of the biggest volcanoes on Earth,” is all.
There are volcanoes, and then there are supervolcanoes. The latter have no agreed-on definition — the term was popularized in a BBC documentary in 2000 — but some scientists use it to describe explosions of exceptional violence and volume. The U.S. Geological Survey applies the term to any eruption ejecting more than 1,000 cubic kilometers (240 cubic miles) of pumice and ash in a single event — more than 50 times the size of the infamous Krakatau eruption of 1883, which killed more than 36,000 people. Volcanoes form mountains; supervolcanoes erase them. Volcanoes kill plants and animals for miles around; supervolcanoes threaten whole species with extinction by changing the climate across the entire planet.
Now, these “supereruptions” don’t happen all that often — not once in recorded human history, in fact. But when they do, one place they regularly go off is Yellowstone. One of them, 2.1 million years ago, created a Rhode Island-size ditch. The most recent blow up was 640,000 years ago. But that one was only a thousand times as big as the Mount St. Helens eruption in 1980.
So how can those happy campers sit there in the park, blithely untroubled by, as one National Geographic caption puts it, the “hellish column of superheated rock — mostly solid, some viscous, some molten — ris[ing] from hundreds of miles within the Earth”? (The magma chamber is 30 miles wide and its contents are 2,500 degrees, by the way.) It’s not as if the evidence isn’t there in plain sight:
The land to this day is literally boiling over. The trout that riot in the rivers would not be so abundant without the warming effects of the hydrothermal springs at the bottom of frigid Yellowstone Lake. The park roils with geysers, fumaroles, mud volcanoes and other hydrothermal activity. Half the geysers on the planet are in Yellowstone. The hydrothermal features change constantly in temperature and behavior, with new ones popping up in the forests, spewing clouds of steam visible from airplanes, exuding vapors that have been known to kill bison on the spot.
Hephaestus may keep a spare anvil or two under Mount Etna, but his boiler room has been moved to Wyoming, apparently.
The way I see it, there are three possible explanations for the parkgoers’ serenity.
1. They didn’t read the article. That issue went straight to the National Geographics pile in the den.
2. Nature teaches acceptance.
3. They saw the movie “2012.” Which means:
(a) Since 2012 came and went without geological incident, we’re in the clear; or,
(b) If Magmageddon comes, no worries: As John Cusack shows, you can outrun eruptions in your R.V.
It has been revealed that the sun has released coronal mass ejection. The solar phenomenon, which can send billions of tons of particles into space that can travel to Earth, were released on July 16, 2013.
Through the help of experimental NASA research models, it has been found that the CMEs have left the sun at the speed of around 560 miles per second.
Experts were of the view that it is the general speed of CMEs. They continued by affirming that the CMEs do not harm humans, but they have capacity to affect electronic systems in satellites.
Authorities concerned were of the view that they have already informed the Messenger and Juno spacecraft that the recently released CMEs can cross them. Experts said that it is always better to warn them so that mission operators can put the spacecrafts into safe mode.
In addition, it has also been found that the CMEs can cause a space weather phenomenon, which is known as a geomagnetic storm. This phenomenon takes place when Earth-directed CMEs fill energy in to the magnetic envelope of Earth.
This envelope known as the magnetosphere is then remained funneled with energy for a long time, said experts.