NASA SDO: Sun Monitoring Satellite captures 100 millionth image

The Atmospheric Imaging Assembly on NASA's Solar Dynamics Observatory captured its 100 millionth image of the sun on Jan. 19, 2015. 

The dark areas at the bottom and the top of the image are coronal holes, areas of less dense gas, where solar material has flowed away from the sun. 

Credit: NASA/SDO/AIA/LMSAL

On Jan. 19, 2015, at 12:49 p.m. EST, an instrument on NASA's Solar Dynamics Observatory captured its 100 millionth image of the sun.

The instrument is the Atmospheric Imaging Assembly (AIA), which uses four telescopes working parallel to gather eight images of the sun, cycling through 10 different wavelengths -- every 12 seconds.

The Atmospheric Imaging Assembly (AIA) images the solar atmosphere in multiple wavelengths to link changes in the surface to interior changes. 

Data includes images of the Sun in 10 wavelengths every 10 seconds. 

Credit: NASA SDO, Lockheed Martin Solar Astrophysics Laboratory

The Helioseismic and Magnetic Imager extends the capabilities of the SOHO/MDI instrument with continual full-disk coverage at higher spatial resolution and new vector magnetogram capabilities.

Credit: NASA SDO, Lockheed Martin Solar Astrophysics Laboratory

Between the AIA and two other instruments on board, the Helioseismic Magnetic Imager (HMI) and the Extreme Ultraviolet Variability Experiment (EVE), SDO sends down a whopping 1.5 terabytes of data a day.

The Extreme Ultraviolet Variability Experiment measures the solar extreme-ultraviolet (EUV) irradiance with unprecedented spectral resolution, temporal cadence, and precision. 

EVE measures the solar extreme ultraviolet (EUV) spectral irradiance to understand variations on the timescales which influence Earth's climate and near-Earth space.

Credit: NASA SDO, Lockheed Martin Solar Astrophysics Laboratory

AIA is responsible for about half of that. Every day it provides 57,600 detailed images of the sun that show the dance of how solar material sways and sometimes erupts in the solar atmosphere, the corona.

In the almost five years since its launch on Feb. 11, 2010, SDO has provided images of the sun to help scientists better understand how the roiling corona gets to temperatures some 1000 times hotter than the sun's surface, what causes giant eruptions such as solar flares, and why the sun's magnetic fields are constantly on the move.

NASA SDO: Tracking a gigantic sunspot across the Sun

Super sunspot AR2192 produced 10 significant solar flare while traversing the Earth-side of the sun; six X-class and four above M5-class. 

Credit: NASA/SDO

An active region on the sun, an area of intense and complex magnetic fields, rotated into view on Oct. 18, 2014.

Labeled AR2192, it soon grew into the largest such region in 24 years, and fired off 10 sizable solar flares as it traversed across the face of the sun.

The region was so large it could be seen without a telescope for those looking at the sun with eclipse glasses, as many did during a partial eclipse of the sun on Oct. 23.

"Despite all the flares, this region did not produce any significant coronal mass ejections," said Alex Young a solar scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland."

"Coronal mass ejections, or CMEs, are giant clouds of solar particles that can affect technology when they reach near-Earth space."

"You certainly can have flares without CMEs and vice versa, but most big flares do have CMEs. So we're learning that a big active region doesn't always equal the biggest events."

The largest sunspot since November 1990 is seen traveling across the front of the sun in these images from NASA's SDO, captured Oct. 17-Oct 29, 2014. 

Credit: NASA/SDO

Such active regions are measured in millionths of a solar hemisphere, where 1 micro-hemisphere, or MH, is about 600,000 square miles.

This region topped out at 2,750 MH, making it the 33rd largest region out of approximately 32,000 active regions that have been tracked and measured since 1874.

It is the largest sunspot seen since AR 6368, which measured 3,080 MH on Nov. 18, 1990.

The largest five active regions ever observed were between 4,000 and more than 6,000 MH and they all appeared between 1946 and 1951.

On the other hand, the region that produced one of the biggest solar flares of all time on Sep. 1, 1859, in what's known as the Carrington event, wasn't even one of the top 50 at only 2,300 MH.

During its trip across the front of the sun, AR 12192 produced six X-class flares, which are the largest flares, and four strong M-class flares. M-class flares are one tenth as strong as X-class flares.

The number provides more information about its strength. An M2 is twice as intense as an M1, an M3 is three times as intense, etc.

"Having so many similar flares from the same active region will be a nice case study for people who work on predicting solar flares," said Dean Pesnell, project scientist for NASA's Solar Dynamics Observatory at Goddard.

"This is important for one day improving the nation's ability to forecast space weather and protect technology and astronauts in space."



This movie shows fireworks on the sun as 10 significant flares erupted on the sun from Oct. 19-28, 2014. 

The graph shows X-ray output from the sun as measured by NOAA’s GOES spacecraft. The X-rays peak in sync with each flare. 

Credit:  NASA/SDO/NOAA/GOES

AR 12192 rotated onto the far side of the sun on Oct. 30, 2014, however as it evolves, we may see a new version of it rotating back into view in two weeks.

Solar Photosphere: Hot explosions on the cool sun

Sizzling star: Hot explosions in an active region of the Sun. 

In this image of the photosphere that was obtained at the end of September 2013 with the help of IRIS, the explosions are the bright spots. 

The image shows a sector with a size of 50,000 kilometers by 25 000 kilometers. 

Credit: NASA

The Sun is more spirited than previously thought. Apart from the solar eruptions, huge bursts of particles and radiation from the outer atmosphere of our star, also the cooler layer right below can be the site of explosions: in some areas magnetic energy builds up and discharges within only a few minutes in temperature eruptions of up to 100000 degrees.

Researchers under the lead of the Max Planck Institute for Solar System Research have now for the first time found evidence of such short-lived heat pockets in data from NASA's space telescope IRIS (Interface Region Imaging Spectrograph).

The Sun is an incredibly hot place, but even though in all its layers the temperatures are daunting, some are hotter than others.

With a temperature of approximately 5000 degrees, the Sun's visible surface, the photosphere, for example, is comparatively cool.

Going outward from there, the temperatures within the Sun's atmosphere rise, first moderately and then sharply, until they reach one million degrees.

"Our analysis shows, that this temperature distribution is not the same everywhere, and is constantly in motion", says Prof. Dr. Hardi Peter from the MPS, the paper's first author.

Together with an international team of scientists, Peter analyzed data from the space telescope IRIS taken from active regions on the Sun.

These regions within the photosphere are characterized by high magnetic field strengths and are the "birth places" of the dark sunspots, which cover the Sun's surface, at some times more, at others less abundantly.

"In these regions we found heat pockets as big as half of Germany. They are up to 20 times as hot as their surroundings", the astrophysicist describes. The heat pockets flash up for only minutes and then return to their normal state.

The amount of energy released during these explosions would be sufficient to provide all of Germany with electrical power for 8000 years.

The massive photospheric explosions cannot be spotted in visible light, but leave traces in the ultraviolet radiation the Sun emits into space.

IRIS can split this ultraviolet radiation into its constituting wavelengths more precisely than any other solar observatory before. In addition, it offers an unprecedented spatial resolution.

When IRIS opened its eyes to the Sun for the first time in July of last year, it could discern structures with a size of only 250 kilometers and examine radiation from such small regions separately.

"To our great surprise, we found well-defined areas within the active regions emitting radiation quite unlike the radiation from their vicinity", says Peter.

The researchers discovered characteristic wavelengths that special highly ionized atoms within the solar plasma such as triply ionized silicon ions emit into space.

"The presence of these wavelengths within the spectra points to very high temperatures", says Peter.

Only under such conditions can silicon loose three of its electrons, but in which of the Sun's layers did this temperature arise? Truly within the cool photosphere? Or maybe, and this would be much less spectacular, farther outside in the much hotter atmosphere?

The spectral data from IRIS proved to be so detailed that the researchers could extract further decisive clues.

For example, they were able to infer the density of the solar plasma where the radiation originated. In addition, they showed that the radiation had encountered singly-ionized iron ions on its way outward. These ions occur only in cooler regions.

"All in all, we found a coherent picture: the unusual radiation must originate in the cool outer photosphere" says Peter.

The researchers believe that the strong magnetic fields in the photosphere provide the necessary energy for the explosions.

In the area of the sun spots, the magnetic field lines protrude in a loop-like fashion from the Sun's surface; hot plasma flows there. When these flows are short-circuited, the explosions occur.

"The new results have fundamentally changed our understanding of the Sun's outer buildup", says Peter. "Instead of a stable temperature distribution, there are apparently dynamical processes within the cool photosphere that can turn everything topsy turvy."

Already in 1917, the American physicist Ferdinand Ellermann discovered areas with higher temperatures within the photosphere.

However, they differed from their surroundings only by a few thousand degrees and can therefore be considered rather minor temperature deviations. Whether the newly discovered explosions are linked to this phenomenon, is still unclear.

One of the other publications in Science magazine, to which scientists from the MPS have contributed, also paints a new picture of the processes on the Sun.

Researchers under the lead of the Harvard-Smithsonian Center for Astrophysics found that the solar wind, the continuous stream of particles from the Sun, does not leave the Sun's surface uniformly, but locally in highly energetic jets. These observations, too, are based on data from IRIS.

More information: 
H. Peter et al. "Hot Explosions in the Cool Atmosphere of the Sun." Science, 17 October 2014 - DOI: 10.1126/science.1255726

H. Tian et al. "Prevalence of Small-scale Jets from the Networks of the Solar Transition Region and Chromosphere." Science, 17 October 2014 - DOI: 10.1126/science.1255732

Fluorine formed in stars and our Sun

The Sun by the Atmospheric Imaging Assembly of NASA's Solar Dynamics Observatory. Credit: NASA

The fluorine that is found in products such as toothpaste was likely formed billions of years ago in now dead stars of the same type as our sun.

This has been shown by astronomers at Lund University in Sweden, together with colleagues from Ireland and the USA.

Fluorine can be found in everyday products such as toothpaste and fluorine chewing gum.

However, the origins of the chemical element have been somewhat of a mystery.

There have been three main theories about where it was created. The findings now presented support the theory that fluorine is formed in stars similar to the sun but heavier, towards the end of their existence.

The sun and the planets in our solar system have then been formed out of material from these dead stars.

Nils Ryde

"So, the fluorine in our toothpaste originates from the sun's dead ancestors", said Nils Ryde, a reader in astronomy at Lund University.

With doctoral student Henrik Jönsson and colleagues from Ireland and the US, he has studied stars formed at different points in the history of the universe to see if the amount of fluorine they contain agrees with the predictions of the theory.

By analysing the light emitted by a star, it is possible to calculate how much of different elements it contains. Light of a certain wavelength indicates a certain element.

In the present study, the researchers used a telescope on Hawaii and a new type of instrument that is sensitive to light with a wavelength in the middle of the infrared spectrum. It is in this area that the signal is found in this case.

"Constructing instruments that can measure infrared light with high resolution is very complicated and they have only recently become available", said Nils Ryde.

Different chemical elements are formed at high pressure and temperature inside a star.

Henrik Jönsson

Fluorine is formed towards the end of the star's life, when it has expanded to become what is known as a red giant. The fluorine then moves to the outer parts of the star.

After that, the star casts off the outer parts and forms a planetary nebula. The fluorine that is thrown out in this process mixes with the gas that surrounds the stars, known as the interstellar medium.

New stars and planets are then formed from the interstellar medium. When the new stars die, the interstellar medium is enriched once again.

The researchers are now also turning their attention to other types of stars.

Among other things, they will try to find out whether fluorine could have been produced in the early universe, before the first red giants had formed.

They will also use the same method to study environments in the universe that are different from the environment surrounding the sun, such as close to the supermassive black hole at the centre of the Milky Way.

There, the cycle of stars dying and new ones being born goes considerably faster than around the sun.

"By looking at the level of fluorine in the stars there, we can say whether the processes that form it are different", said Nils Ryde.

NASA Studies of the ultraviolet sun

Four of the telescopes on the Solar Dynamics Observatory observe extreme ultraviolet light activity on the sun that is invisible to the naked eye. 

Credit: NASA/SDO

You cannot look at the sun without special filters, and the naked eye cannot perceive certain wavelengths of sunlight.

Solar physicists must consequently rely on spacecraft that can observe this invisible light before the atmosphere absorbs it.

"Certain wavelengths either do not make it through Earth's atmosphere or cannot be seen by our eyes, so we cannot use normal optical telescopes to look at the spectrum," said Dean Pesnell, the project scientist for the Solar Dynamics Observatory (SDO), at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Several spacecraft can observe these invisible light wavelengths. SDO for example has four telescopes that image the sun in the ultraviolet spectrum.

As beams of ultraviolet light pass into the telescope, a mirror with special coatings filters and amplifies the ultraviolet light's otherwise poor reflection.

The incoming photons are then recorded as pixels and converted into electrical signals, similar to how your cell phone camera sees visible light.

"It's exactly the same process, whether it's ultraviolet light, infrared light, visible light, or radio," said Joseph Gurman, project scientist for both the Solar and Heliospheric Observatory (SOHO) and the Solar Terrestrial Relations Observatory (STEREO) at Goddard.

"In this case we're trying to understand how the sun changes and how those changes affect life here on Earth."

Ultraviolet light causes molecular radiation damage to our skin, seen as sunburns that can lead to cancer.

Its cousin, extreme ultraviolet radiation, and the associated solar storms have the potential to disrupt communications and spacecraft navigation.

"These are very damaging, energetic photons, and we want to understand what chain of events produces these photons," Pesnell said.

The Solar Dynamics Observatory (SDO) observed a solar flare (upper left) and a coronal mass ejection (right) erupting from the sun’s limb in extreme ultraviolet light on August 6, 2010. 

Credit: NASA/SDO

Thankfully our planet's atmosphere absorbs much of this solar radiation, making life on Earth possible.

However, this means that to study extreme ultraviolet light, instruments must do it from the vacuum of space.

"Ultraviolet light from the sun can show us the origins of solar storms that can lead to power outages, cell phone disruptions, and delays in shipping packages due to the rerouting of planes from over the pole," Gurman said.

By understanding what occurs in the sun's atmosphere, scientists hope to predict when powerful solar events such as coronal mass ejections and solar flares may occur.

Spacecraft record solar activity as a binary code, 1s and 0s, which computer programs can translate into black and white. 

Scientists coloroured the images for realism, and then zoom in on areas of interest. 

Credit: NASA/Karen Fox

"You really want to know what's happening on the sun as soon as you can," said Jack Ireland, a solar visualization specialist at Goddard.

"We can then use computer models to estimate how solar events will affect Earth's space environment."

The information can then be used by NOAA's Space Weather Prediction Center, in Boulder, Co. to alert power companies and airlines to take the necessary precautions, thus avoiding power outages and keeping airplane passengers safe.

ACRIMSat: Sun sets for NASA solar monitoring spacecraft

Artist's rendering of the AcrimSat spacecraft.

Image Credit: NASA

After 14 years of monitoring Earth's main energy source, radiation from the sun, NASA’s Active Cavity Radiometer Irradiance Monitor satellite has lost contact with its ground operations team at NASA's Jet Propulsion Laboratory, Pasadena, California, and its mission has been declared completed.

AcrimSat's ACRIM 3 instrument was the third in a series of satellite experiments that have contributed to a critical data set for understanding Earth's climate: the 36-year, continuous satellite record of variations in total solar radiation reaching Earth, or total solar irradiance.

The three ACRIM instruments have supplied state-of-the-art data during more than 90 percent of that time. Three other satellite instruments launched in 1995, 2003 and 2013 continue to monitor total solar irradiance.

Launched on Dec. 21, 1999, for a planned five-year mission, AcrimSat went silent on Dec. 14, 2013. Attempts since then to reestablish contact have been unsuccessful. The venerable satellite most likely suffered an expected, age-related battery failure.

The sun puts out a fairly stable amount of energy compared with many other stars.

"That's where the term 'solar constant' comes from," said AcrimSat project manager Sandy Kwan of JPL, referring to a standard unit of measurement in astronomy.

Dark sunspots and bright areas around them called faculae, visible in this 2001 solar image, cause most of the variation in total solar irradiance. 

Image Credit: NASA/GSFC/SVS

Over the sun's 11-year cycle, the average variation in visible light is about one-tenth of one percent, a change so small that scientists only discovered it when they were able to observe the sun from satellites above our light-scattering atmosphere.

Kwan pointed out that AcrimSat's grandfather, the ACRIM 1 instrument on the Solar Maximum Mission satellite launched in 1980, was the first instrument to show clearly that solar irradiance does vary.

Although the percentage of change is minuscule, the energy it represents can have important effects on Earth.

Scientists believe that sustained changes of as little as 0.25 percent in total solar irradiance over periods of decades to centuries caused significant climate change in Earth's distant past.

Today, as greenhouse gases accumulate in the atmosphere, it's critical to understand the relative contributions of variations in solar irradiance and human-produced greenhouse gases to changes in Earth’s climate. To gain that knowledge, a long, continuous series of solar observations is an essential tool.

"The data record from the ACRIM series remains valuable for studying solar variability," said Greg Kopp, a senior research scientist at the University of Colorado's Laboratory of Astrophysics and Space Physics in Boulder.

"This more than three-decade-long data series exceeds the duration of any other irradiance instruments."

Sun sends more 'shock waves' to Voyager 1 - Video

Credit: NASA/JPL-Caltech

NASA's Voyager 1 spacecraft has experienced a new "shock wave" from the sun as it sails through interstellar space.

Such waves are what led scientists to the conclusion, in the fall of 2013, that Voyager had indeed left our sun's bubble, entering a new frontier.

"Normally, interstellar space is like a quiet lake," said Ed Stone of the California Institute of Technology in Pasadena, California, the mission's project scientist since 1972.

"But when our sun has a burst, it sends a shock wave outward that reaches Voyager about a year later. The wave causes the plasma surrounding the spacecraft to sing."

Data from this newest tsunami wave generated by our sun confirm that Voyager is in interstellar space, a region between the stars filled with a thin soup of charged particles, also known as plasma.

The mission has not left the solar system, it has yet to reach a final halo of comets surrounding our sun, but it broke through the wind-blown bubble, or heliosphere, encasing our sun.

Voyager is the farthest human-made probe from Earth, and the first to enter the vast sea between stars.

"All is not quiet around Voyager," said Don Gurnett of the University of Iowa, Iowa City, the principal investigator of the plasma wave instrument on Voyager, which collected the definitive evidence that Voyager 1 had left the sun's heliosphere.

"We're excited to analyze these new data. So far, we can say that it confirms we are in interstellar space."




The first two tsunami waves to reach Voyager 1 caused surrounding ionized matter to ring like a bell at frequencies expected in interstellar space. 

The third tsunami caused similar ringing, confirming that Voyager 1 continues it journey into interstellar space. 

Image Credit: NASA's Voyager 1 spacecraft

Our sun goes through periods of increased activity, where it explosively ejects material from its surface, flinging it outward. These events, called coronal mass ejections, generate shock, or pressure, waves.

Three such waves have reached Voyager 1 since it entered interstellar space in 2012. The first was too small to be noticed when it occurred and was only discovered later, but the second was clearly registered by the spacecraft's cosmic ray instrument in March of 2013.

Cosmic rays are energetic charged particles that come from nearby stars in the Milky Way galaxy. The sun's shock waves push these particles around like buoys in a tsunami.

Data from the cosmic ray instrument tell researchers that a shock wave from the sun has hit.

Meanwhile, another instrument on Voyager registers the shock waves, too. The plasma wave instrument can detect oscillations of the plasma electrons.

"The tsunami wave rings the plasma like a bell," said Stone. "While the plasma wave instrument lets us measure the frequency of this ringing, the cosmic ray instrument reveals what struck the bell—the shock wave from the sun."

This ringing of the plasma bell is what led to the key evidence showing Voyager had entered interstellar space. Because denser plasma oscillates faster, the team was able to figure out the density of the plasma.

In 2013, thanks to the second tsunami wave, the team acquired evidence that Voyager had been flying for more than a year through plasma that was 40 times denser than measured before, a telltale indicator of interstellar space.

Why is it denser out there? The sun's winds blow a bubble around it, pushing out against denser matter from other stars.

Now, the team has new readings from a third wave from the sun, first registered in March of this year.

These data show that the density of the plasma is similar to what was measured previously, confirming the spacecraft is in interstellar space.

Thanks to our sun's rumblings, Voyager has the opportunity to listen to the singing of interstellar space, an otherwise silent place.

Voyager 1 and its twin, Voyager 2, were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn.

Voyager 2 also flew by Uranus and Neptune. Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft and is expected to enter interstellar space in a few years.

Under the bright lights of an aging sun

Venus can be seen as a black dot eclipsing the Sun in this image from 2012. 

Venus orbits too close to the Sun to the planet to be habitable for life as we know it. 

Venus experiences a runaway greenhouse and the average surface temperatures are thought to be around 864ºF. 

Credit: NASA/SDO & the AIA, EVE, and HMI teams; Digital Composition: Peter L. Dove

Life as we know it on Earth is linked to our star, the Sun, which provides our planet with just the right amount of heat and energy for liquid water to be stable in our lakes, rivers and oceans.

However, as the Sun ages, it is steadily growing brighter and brighter. Eventually, the sunlight that supports life will become too great, and it will bring an end to habitability on our planet.

A Star is Born and Ages
The Sun formed some 4.5 billion years ago when gravitational attraction caused a massive cloud of gas and dust to collapse.

Currently the Sun is stable and has been for billions of years. The bright ball of light in our sky goes about its days generating energy by fusing hydrogen atoms in its core.

As the Sun ages it will enter another stage of stellar evolution where it's atmosphere begins to inflate. This is when the Sun will expand into a red giant star, swallowing planets in the inner Solar System, possibly including the Earth.

As time goes on, the Sun will start shedding its atmosphere and will continue to grow into a massive planetary nebula, which is like a large cloud of gas ejected from the old star.

This is a sort of recycling stage, where elements created by the star are sent back to the interstellar medium, thereby providing new materials for more stars to form.

Next, the old core of the Sun will cool and collapse into a dense but small hunk of mass known as a white dwarf star.

Eventually, it will cool to the point where only a cold, dark husk remains.
Life as we know it is intrinsically tied to the life-cycle of the Sun because we rely on its light for energy. Right now, things are perfect for biology. In the future, this will change dramatically.

As the Sun heats up and expands, life on Earth will become increasingly difficult. Long before the Sun becomes a red giant some 4 or 5 billion years from now, our planet will be rendered uninhabitable.

Dying in a Future Solar System
The fate of the Earth as the Sun grows old is not an old topic. For decades, scientists have studied various scenarios for how an ageing Sun will affect Earth's future habitability. Writers and artists, on the other hand, have explored the idea for centuries.

However, humankind will be gone long before a red giant star fills our skies.

Rather than leading us to a rocky ball of ice, an ageing Sun will instead blast the Earth with ever-increasing heat. Before the Sun expands to a red giant, this increased heat will cause dramatic climatic change on our planet.

The Atmosphere in 3-D
Previous models have predicted that an increase of just 6 percent in the solar constant (a measure of incoming solar electromagnetic radiation) would cause a runaway greenhouse effect on Earth that would render the planet uninhabitable as the oceans boil away to space.

Based on this number, Earth's habitability could come to an end in around 650 million years from now. However, a more recent study has extended the expected lifetime of Earth as a habitable world.

Discover the lifecycle of stars with this activity and handout. 

Many people think the different stages in the life of a star are actually different types of stars, rather than just stages in the life of a single star. 

Credit: NASA/JPL, Astronomical Society of the Pacific

New research shows that the accuracy of previous studies, which were based on 'one-dimensional' models of Earth's climate, could be improved.

"One-dimensional models treat the atmosphere as a single vertical column. This single column is meant as a representative average of all points on the Earth," explains Eric Wolf of the Department of Atmospheric and Oceanic Sciences at the University of Colorado Boulder.

"While one-dimensional models can treat radiative transfer well (i.e. solar energy and the greenhouse effect), they completely ignore many important aspects such as clouds, dynamics, and the pole to equator gradients of energy which ultimately describe our climate."

Wolf and his colleague Brian Toon, also of UC Boulder, used complex, three-dimensional climate models in order to bring more detail into the picture.

"Three-dimensional models, as we refer to them, are general circulation models of climate. They include a fully, spatially-resolved, rotating planet, with clouds, oceans, sea-ice, weather, etc.," Wolf told Astrobiology Magazine.

"The three-dimensional general circulation model I used has also been used for problems of modern climate. General circulation models are considered the most advanced type of climate models."

The added detail of the 3-D models showed that the Earth could remain habitable for longer than previously expected.

"According to my work, the Earth may remain 'habitable' for at least another 1.5 billion years, when the Sun is approximately 15.5 percent brighter than today," said Wolf. "This is the limit of our current study."

It's important to note that a habitable Earth in terms of astrobiology is not necessarily habitable for human beings.

Read the full article here

Giant Sun Plasma Tendril: Solar Eruption - SDO Video

A massive formation on the sun made of super-hot magnetic plasma erupted this week in an explosive solar storm captured on video by NASA's SDO spacecraft.

The huge plasma tendril, known as a solar filament, erupted on Wednesday (June 4), blowing part of itself out into space in what astronomers call a coronal mass ejection (CME).

NASA's powerful Solar Dynamics Observatory recorded a video of the solar filament eruption while the Solar and Heliospheric Observatory (SOHO) tracked the subsequent CME.

Astronomer Tony Phillips of Spaceweather.com, a website that tracks solar flare events, wrote in a post Thursday (June 5) that amateur and professional astronomers had watched the filament for more than a week to see how it would meet its end.

"Astronomers had been bracing for the possibility that the filament would collapse, causing a Hyder flare when it landed on the solar surface," Phillips wrote in the June 5 post. "Instead, it erupted and hurled part of itself into space."

Phillips added that the solar eruption was not aimed directly at Earth, but could deal a "glancing blow" to the planet's magnetic field on Saturday (June 7), possibly amplifying northern lights displays.

A giant solar plasma filament on the sun rising up off the star's surface on June 4, 2014 in this full-disk view from NASA's Solar Dynamics Observatory. 

The filament ultimately triggered a solar eruption known as a coronal mass ejection.

Credit: NASA/SDO

NASA's Solar Dynamics Observatory and SOHO, a joint mission by NASA and the European Space Agency, are part of a fleet of space observatories regularly watching the sun for signs of solar storms, eruptions and flares.

The most powerful solar eruptions can pose a danger to astronauts and spacecraft in space, as well as interrupt satellite navigation and communications systems. They can also interfere with ground-based power and communications systems.

Strong and moderate solar storms can also supercharge the Earth's auroras, triggering dazzling northern lights shows.

NASA SDO: Giant Solar 'Tornado' Whirl Off the Sun - Video

A NASA spacecraft has captured spectacular video of an enormous plasma "tornado" spinning off the sun.

NASA's Solar Dynamics Observatory probe (SDO), watched the dark-hued twister churn and ultimately erupt over the course of one day, from April 29 to 30.

Mission scientists used the spacecraft's imagery to create an 18-second-long video of the dramatic solar tornado.

"The suspended plasma is being pulled and stretched by competing magnetic forces until something triggers the breakaway," NASA officials wrote on SDO's Facebook page, assuming the voice of the spacecraft.

"This kind of activity is fairly common on the sun, but we have only been able to view them at this level of detail since I began operations just four years ago."

The plasma appears dark in this ultraviolet-light view because it is cooler than the material surrounding it, NASA officials added.

The $850 million Solar Dynamics Observatory launched in February 2010 on a five-year mission to study the variations in solar activity that influence life on Earth.

The probe uses three different instruments to observe the sun, gathering data that is helping scientists better understand the solar magnetic field and space weather.

Over the course of its operational life, SDO has recorded many stunning images of solar flares, coronal mass ejections and other sun phenomena.

NASA Wise: Brown Star is discovered to be a close neighbour of our Sun

This image is an artist's conception of the brown dwarf WISE J085510.83-071442.5. 

The Sun is the bright star directly to the right of the brown dwarf. 

Credit: Robert Hurt /JPL, Janella Williams /Penn State University

A "brown dwarf" star that appears to be the coldest of its kind, as frosty as Earth's North Pole, has been discovered by a Penn State University astronomer using NASA's Wide-field Infrared Survey Explorer (WISE) and Spitzer Space Telescopes.

Images from the space telescopes also pinpointed the object's distance at 7.2 light-years away, making it the fourth closest system to our Sun.

Kevin Luhman

"It is very exciting to discover a new neighbor of our solar system that is so close," said Kevin Luhman, an associate professor of astronomy and astrophysics at Penn State and a researcher in the Penn State Center for Exoplanets and Habitable Worlds.

"In addition, its extreme temperature should tell us a lot about the atmospheres of planets, which often have similarly cold temperatures."

Brown dwarfs start their lives like stars, as collapsing balls of gas, but they lack the mass to burn nuclear fuel and radiate starlight.

The newfound coldest brown dwarf, named WISE J085510.83-071442.5, has a chilly temperature between minus 54 and 9 degrees Fahrenheit (minus 48 to minus 13 degrees Celsius).

Previous record holders for coldest brown dwarfs, also found by WISE and Spitzer, were about room temperature.

Although it is very close to our solar system, WISE J085510.83-071442.5 is not an appealing destination for human space travel in the distant future.

"Any planets that might orbit it would be much too cold to support life as we know it" Luhman said.

Add caption

WISE J085510.83-071442.5 was discovered through its rapid motion across the sky in two infrared images the WISE satellite taken six months apart in 2010. 

Two additional images were taken with the Spitzer Space Telescope in 2013 and 2014 to measure its distance via the parallax effect. 

Credit: NASA/JPL/IPAC

NASA SDO: Sun Unleashes Major X1.3 Class Solar Flare - Video

The sun erupted with a massive solar flare late Thursday (April 24), triggering a temporary communications blackout on some parts of Earth.

The powerful flare peaked at 8:27 p.m. EDT Thursday (0027 April 25 GMT), and ranked as an X1.3-class solar storm, one of the strongest types of flares the sun can experience, according to a report from the U.S. Space Weather Prediction Center (SWPC).

NASA's Solar Dynamics Observatory captured video of the intense solar flare in several difference wavelengths.

The solar flare erupted from an active sunspot region known as Region 2035 located on the far western side (or limb) of the sun as seen from Earth.

Because of its position, the flare sparked a high-frequency radio blackout for about an hour on the daytime side of Earth, most likely over the Pacific Ocean and Eastern Pacific Rim, according to the SWPC update.

An X1.3-class solar flare (far right) erupts from the surface of the sun on April 24, 2014 EDT (April 25 GMT).

Credit: NASA /Solar Dynamics Observatory

"Region 2035 is rotating out of view and won't pose any danger for much longer, but could in the immediate future," SWPC officials wrote in the update.

When aimed directly at Earth, X-class solar flares can endanger astronauts in space, as well as interfere with communications and navigation satellites in orbit.

The most powerful X-class flares can also affect power grids and other infrastructure on the Earth.

Thursday's solar flare was the fourth X-class solar flare of 2014. It followed an X1.2 solar flare on Jan. 7, a monster X4.9 solar flare on Feb. 24, as well as an X1 solar flare on March 29.

Solar System: Sun, Earth and Mars Align

Mars takes the celestial stage Tuesday night (April 8) when it lines up with the Earth and our Sun, in a kind of cosmic preview to the Red Planet's closest approach to Earth during a total lunar eclipse later this month.

The alignment between Mars, the Earth and the sun is called "opposition" because Mars and the sun are opposite to each other in our sky.

Opposition and the date of closest encounter are slightly different because Earth and Mars are not in perfectly circular orbits.

Oppositions between Earth and Mars happen about every 26 months because the planets are relatively close to one another.

NASA and other agencies often take advantage of these close approaches to send spacecraft that way.

A recent example is NASA's Mars Atmosphere and Volatile Evolution probe (MAVEN), which launched in November 2013 and will arrive this September.

India's space agency, ISRO's first Mars orbiter will also arrive at the Red Planet in September after its own launch last year.

The opposition of Mars comes just seven days ahead of the planet's closest approach to Earth on the night of April 14.

The Red Planet and Earth are converging ever closer to their cosmic encounter at a rate of about 186 miles (300 kilometers) a minute, according to a NASA skywatching advisory.

On April 14, Mars and Earth will be only 57 million miles (92 million kilometers) apart. This is a bit more than half the distance between Earth and the sun, which is about 93 million miles (150 million km).

By coincidence, Mars' closest approach to Earth occurs on the same night as a total lunar eclipse.

Weather permitting, observers could see a blood-red appear to glide just south of ruddy Mars as it passes through Earth's shadow in the late-night sky.

This should make the planet easy to spot in the constellation Virgo while the moon, just a few degrees south, is in total eclipse as seen from North America.

The total lunar eclipse starts at 2 a.m. EDT (0600 GMT) on April 15. The moon will spend 78 minutes in total starting around 3 a.m.

The moon will turn a Martian-looking red during the eclipse due to light from the sun shining through the Earth's atmosphere.

NASA STEREO: UNH detector illuminate cause of sun's 'perfect storm'

This image combines data from two coronagraphs and an extreme ultra-violet imager (green) on STEREO A. 

The CME is the bright streaks emanating from the sun. 

A coronagraph is a telescope that uses a disk to block the sun's bright surface revealing the solar corona. 

Credit: NASA.

An international team of scientists, including three from the University of New Hampshire's (UNH) Space Science Center, uncovers the origin and cause of an extreme space weather event that occurred on July 22, 2012 at the sun and generated the fastest solar wind speed ever recorded directly by a solar wind instrument.

The formation of the rare, powerful storm showed striking, novel features that were detected by a UNH-built instrument on board NASA's twin-satellite Solar TErrestrial RElations Observatory (STEREO) mission.

An instrument led by the University of California, Berkeley also made key measurements.

The 2012 storm was so powerful that had it been aimed at Earth instead of at the STEREO A spacecraft, which was located 120 degrees off to the side of Earth, the consequences would have been dramatic: widespread aurora, satellite malfunctions, and potential for failures with ground-based electricity grids.

To date, it has been unclear how extreme space weather storms form and evolve.

Developing a better understanding of their causes is vital to protect modern society and its technological infrastructures, and is one of the goals of the STEREO mission.

"These results provide a new view crucial to solar physics and space weather as to how an extreme space weather event can arise from a combination of multiple solar eruptions," says research assistant professor Noe Lugaz of the UNH Institute for the Study of Earth, Oceans, and Space (EOS) and a coauthor on the Nature Communications paper.

Lead author is Ying D. Liu of the State Key Laboratory of Space Weather, National Space Science Center and Chinese Academy of Sciences.

The authors suggest it was the successive, one-two punch of solar eruptions known as coronal mass ejections (CMEs) that was the key to the event, which blasted away from the sun at 3,000 kilometers per second-a speed that would circle the Earth five times in one minute.

Detecting the successive eruptions would not have been possible prior to STEREO.

"In a sense, this was the 'perfect storm'," Lugaz says. "The first, fast eruption greased the skids for the quick propagation of the subsequent, extremely fast eruptions through interplanetary space."

More Information: Nature Communications Journal - 'Observations of an extreme storm in interplanetary space caused by successive coronal mass ejections' Ying D. Liu, Noé Lugaz, et al. doi:10.1038/ncomms4481

NASA Cassini: Rhea's Day in the Sun

A nearly full Rhea shines in the sunlight in this recent Cassini image. 

Rhea (949 miles, or 1,527 kilometers across) is Saturn's second largest moon.

Lit terrain seen here is on the Saturn-facing hemisphere of Rhea. 

North on Rhea is up and rotated 43 degrees to the left. 

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 10, 2013.

The view was obtained at a distance of approximately 990,000 miles (1.6 million kilometers) from Rhea. 

Image scale is 6 miles (9 kilometers) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. 

The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. 

The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. 

The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission, and saturn.jpl.nasa.gov. 

The Cassini imaging team homepage.
Image Credit: NASA/JPL-Caltech/Space Science Institute

NASA's Solar Dynamics Observatory (SDO): Massive Sunspot AR1944

One of the largest sunspots in the last nine years, labeled AR1944, was seen in early January 2014, as captured by NASA's Solar Dynamics Observatory (SDO). 

An image of Earth has been added for scale. 

Credit: NASA/SDO

An enormous sunspot, labeled AR1944, slipped into view over the sun's left horizon late on Jan. 1, 2014.

The sunspot steadily moved toward the right, along with the rotation of the sun, and now sits almost dead center, as seen in the image above from NASA's Solar Dynamics Observatory (SDO).

Sunspots are dark areas on the sun's surface that contain complex arrangements of strong magnetic fields that are constantly shifting.

The largest dark spot in this configuration is approximately two Earths wide, and the entire sunspot group is some seven Earths across.

For comparison, another giant sunspot, five to six Earths across, is shown below from 2005. The image was captured by the European Space Agency and NASA's Solar and Heliospheric Observatory (SOHO).

Sunspots are part of what's known as active regions, which also include regions of the sun's atmosphere, the corona, hovering above the sunspots.

Active regions can be the source of some of the sun's great explosions: solar flares that send out giant bursts of light and radiation due to the release of magnetic energy, or coronal mass ejections that send huge clouds of solar material out into space.

As the sunspot group continues its journey across the face of the sun, scientists will watch how it changes and evolves to learn more about how these convoluted magnetic fields can cause space weather events that can affect space-borne systems and technological infrastructure on Earth.

Two of the largest sunspots in the last nine years: the one on the left is from Jan. 17, 2005, captured by ESA/NASA's Solar Heliospheric Observatory; the one on the right is from Jan. 7, 2014, captured by NASA's Solar Dynamics Observatory. 

Credit: ESA/NASA SOHO and NASA SDO

NASA SDO: Quiet Corona and Upper Transition Region of the Sun

This image, taken on Dec. 31, 2013 by the AIA instrument on NASA's Solar Dynamics Observatory at 171 Angstrom, shows the current conditions of the quiet corona and upper transition region of the Sun.

AIA will image the outer layer of the Sun's atmosphere, the corona, at all temperatures from 20 thousand to 20 million degrees. 

Image Credit: NASA/SDO