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Author Topic: NASA Announcements  (Read 7472 times)

Offline zorgon

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Re: NASA Announcements
« Reply #15 on: March 08, 2013, 04:38:40 PM »
Solar Wind Energy Source Discovered

March 8, 2013: Using data from an aging NASA spacecraft, researchers have found signs of an energy source in the solar wind that has caught the attention of fusion researchers. NASA will be able to test the theory later this decade when it sends a new probe into the sun for a closer look.

The discovery was made by a group of astronomers trying to solve a decades-old mystery: What heats and accelerates the solar wind?


Solar wind flows away from the sun at speeds up to and exceeding 500 km/s (a million mph).

The solar wind is a hot and fast flow of magnetized gas that streams away from the sun's upper atmosphere.  It is made of hydrogen and helium ions with a sprinkling of heavier elements.  Researchers liken it to the steam from a pot of water boiling on a stove; the sun is literally boiling itself away.

“But,” says Adam Szabo of the NASA Goddard Space Flight Center, “solar wind does something that steam in your kitchen never does.  As steam rises from a pot, it slows and cools.  As solar wind leaves the sun, it accelerates, tripling in speed as it passes through the corona. Furthermore, something inside the solar wind continues to add heat even as it blows into the cold of space."

Finding that "something" has been a goal of researchers for decades.  In the 1970s and 80s, observations by two German/US Helios spacecraft set the stage for early theories, which usually included some mixture of plasma instabilities, magnetohydrodynamic waves, and turbulent heating.  Narrowing down the possibilities was a challenge. The answer, it turns out, has been hiding in a dataset from one of NASA's oldest active spacecraft, a solar probe named Wind.

Launched in 1994, Wind is so old that it uses magnetic tapes similar to old-fashioned 8-track tapes to record and play back its data.  Equipped with heavy shielding and double-redundant systems to safeguard against failure, the spacecraft was built to last; at least one researcher at NASA calls it the "Battlestar Gallactica" of the heliophysics fleet. Wind has survived almost two complete solar cycles and innumerable solar flares.

"After all these years, Wind is still sending us excellent data," says Szabo, the mission’s project scientist, “and it still has 60 years' worth of fuel left in its tanks.”




Using Wind to unravel the mystery was, to Justin Kasper of the Harvard-Smithsonian Center for Astrophysics, a "no brainer." He and his team processed the spacecraft's entire 19-year record of solar wind temperatures, magnetic field and energy readings and ...

"I think we found it," he says.  "The source of the heating in the solar wind is ion cyclotron waves."

Ion cyclotron waves are made of protons that circle in wavelike-rhythms around the sun's magnetic field.  According to a theory developed by Phil Isenberg (University of New Hampshire) and expanded by Vitaly Galinsky and Valentin Shevchenko (UC San Diego), ion cyclotron waves emanate from the sun; coursing through the solar wind, they heat the gas to millions of degrees and accelerate its flow to millions of miles per hour. Kasper's findings confirm that ion cyclotron waves are indeed active, at least in the vicinity of Earth where the Wind probe operates.
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Ion cyclotron waves can do much more than heat and accelerate the solar wind, notes Kasper.  "They also account for some of the wind's very strange properties."

The solar wind is not like wind on Earth.  Here on Earth, atmospheric winds carry nitrogen, oxygen, water vapor along together; all species move with the same speed and they have the same temperature.  The solar wind, however, is much stranger.  Chemical elements of the solar wind such as hydrogen, helium, and heavier ions, blow at different speeds; they have different temperatures; and, strangest of all, the temperatures change with direction.

"We have long wondered why heavier elements in the solar wind move faster and have higher temperatures than the lighter elements," says Kasper.  "This is completely counterintuitive."

The ion cyclotron theory explains it: Heavy ions resonate well with ion cyclotron waves. Compared to their lighter counterparts, they gain more energy and heat as they surf.



An artist's concept of Solar Probe Plus approaching the sun where it can test the ion cyclotron theory.

 The behavior of heavy ions in the solar wind is what intrigues fusion researchers. Kasper explains: "When you look at fusion reactors on Earth, one of the big challenges is contamination.  Heavy ions that sputter off the metal walls of the fusion chamber get into the plasma where the fusion takes place.  Heavy ions radiate heat. This can cool the plasma so much that it shuts down the fusion reaction."

Ion cyclotron waves of the type Kasper has found in the solar wind might provide a way to reverse this process. Theoretically, they could be used to heat and/or remove the heavy ions, restoring thermal balance to the fusing plasma.

"I have been invited to several fusion conferences to talk about our work with the solar wind," he says.

The next step, agree Kasper and Szabo, is to find out if ion cyclotron waves work the same way deep inside the sun's atmosphere where the solar wind begins its journey.  To find out, NASA is planning to send a spacecraft into the sun itself.

Solar Probe Plus, scheduled for launch in 2018, will plunge so far into the sun's atmosphere that the sun will appear as much as 23 times wider than it does in the skies of Earth. At closest approach, about 7 million km from the sun's surface, Solar Probe Plus must withstand temperatures greater than 1400 deg. C and survive blasts of radiation at levels not experienced by any previous spacecraft.  The mission's goal is to sample the sun's plasma and magnetic field at the very source of the solar wind.

"With Solar Probe Plus we'll be able to conduct specific tests of the ion cyclotron theory using sensors far more advanced than the ones on the Wind spacecraft," says Kasper.  "This should give us a much deeper understanding of the solar wind's energy source."

The research described in this story was published in the Physical Review Letters on February 28, 2013: "Sensitive Test for Ion-Cyclotron Resonant Heating in the Solar Wind" by Justin Kasper et al.


Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit: Science@NASA

http://science.nasa.gov/science-news/science-at-nasa/2013/08mar_solarwind/

Offline zorgon

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There’s a Hole in the Sun, NASA Says
« Reply #16 on: June 07, 2013, 03:31:07 AM »
There’s a Hole in the Sun, NASA Says

Quote
By Ian O’NeillPublished June 04, 2013Discovery News

During the latter part of last week, a huge void rotated across the face of the sun.

But never fear, it isn’t a sign of the “end times” or some weird sci-fi stellar malnourishment: This particular hole is a coronal hole.

Though it may be a well-known phenomenon, it is noteworthy — it’s the largest coronal hole to be observed in the sun’s atmosphere for over a year.

Snapped through three of NASA Solar Dynamics Observatory’s (SDO) extreme ultraviolet filters, this coronal hole is caused by a low density region of hot plasma.


 Image: NASA-SDO

Quote
The sun’s lower corona is threaded with powerful magnetic fields. Some are looped — or “closed” — very low in the corona, creating the beautiful, bright coronal loops that trap superheated gases that generate vast amounts of extreme ultraviolet light, radiation that is produced by multimillion degree plasma (the bright regions in the image, top).

However, there are also “open” field lines that have one end of their magnetic flux anchored in the solar photosphere.

These lines fire solar plasma into interplanetary space at an accelerated rate, often intensifying space weather conditions.

These regions of open field lines, or coronal holes, act like fire hoses, blasting plasma into space.

These regions are the source of the the fast solar wind that accelerates solar material toward Earth, which often only takes 2-3 days to travel from the sun to Earth.


Image: NASA-SDO

Quote
Through the SDO’s eyes, coronal holes appear dark as there is a very low density of the multimillion degree plasma generating the EUV radiation. And as this dramatic observation demonstrates, to the eyes of the SDO, the sun really does appear to have a hole.

We are currently going through an uptick in solar activity as our nearest star experiences “solar maximum” — the peak of its natural 11-year cycle.

At this time, we can expect an increased frequency of solar flares and coronal mass ejections as the sun’s magnetic field becomes increasingly stressed.
 Although this solar maximum is less active than predicted, it is producing some powerful flares and CME’s.
 
Now we’re seeing huge coronal holes, all a consequence of the twisted turmoil our sun is currently enduring.

http://beforeitsnews.com/space/2013/06/theres-a-hole-in-the-sun-nasa-says-2460822.html

http://www.foxnews.com/science/2013/06/04/there-hole-in-sun-nasa-says/

[youtube]ZwgaW0yjfZ0[/youtube]

Offline zorgon

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Re: NASA Announcements
« Reply #17 on: February 08, 2014, 10:38:42 PM »
Mars Curiosity Rover Finds 'Substantial' Water

Nasa learns there is more water on the red planet than previously thought - which could one day sustain human life.


There are around two pints of water in every square foot of Martian soil

Quote
The first scoop of Martian dust, dirt and finely grained soil analysed by Nasa's Curiosity rover suggests there is a "substantial" amount of water on Mars.

Scientists confirmed the soil sample was about 2% water, increasing the chance that a manned mission to the red planet would be able to survive.

In a cubic foot (0.03 cubic meters) of Martian soil "you can get maybe a couple of pints (0.47 litres) of water out of that," said Laurie Leshin, lead author of the study in the journal Science.

Mr Leshin, who is dean of science at Rensselaer Polytechnic Institute said the discovery offered hope for hydrating humans were a mission to Mars go ahead some day.

"We saw Mars as a very dry desert and while this is not as much water you will find in Earth soil ... it's substantial," he said.

No space agency has any concrete plans to send astronauts to Mars but the United States has said it hopes to launch the first humans there by the 2030s.

Signs of water on Mars are nothing new.

Previous space agency rovers and orbiters have found evidence Mars likely had water - whether in the form of ice, below-ground reservoirs or even the drinkable kind - perhaps billions of years ago.

But the latest evidence comes from some of the most sophisticated instruments ever sent to the red planet.

The soil analysed by Curiosity was collected from a portion of the Gale Crater known as Rocknest.

"We now know there should be abundant, easily accessible water on Mars," Mr Leshin said.

"We probably can find it almost anywhere right on the surface under your feet if you are an astronaut."

http://news.sky.com/story/1146964/mars-curiosity-rover-finds-substantial-water

 


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