Can Solar Flares Hurt Astronauts?

[/caption]

Solar flares, coronal mass ejections, high-energy photons, cosmic rays… space is full of various forms of radiation that a human wouldn’t want to be exposed to for very long. Energized particles traveling into and through the body can cause a host of nasty health problems, from low blood count to radiation sickness to cataracts and cancer… and potentially even death. Luckily Earth’s magnetic field and atmosphere protects us on the surface from much of this radiation, but what about the astronauts aboard the Space Station? How could events such as today’s powerful near-X-class solar flare and last week’s CME affect them, orbiting 240 miles above Earth’s surface?

Surprisingly, they are safer than you might think.

M8.7-class solar flare erupting on the Sun's northeastern hemisphere at 03:49 UT on Jan. 23, 2012. (Courtesy NASA/SDO and the AIA team. Edited by J. Major.)

The M8.7-class flare that erupted from the Sun early on Jan. 23 sent a huge wave of high-energy protons Earthward, creating the largest solar storm seen since 2005.  The cloud of energetic particles raced outwards through the Sun’s atmosphere at speeds well over a million miles per hour, blowing past our planet later the same day. (More slower-moving charged particles will impact the magnetosphere in the coming days.) We are safe on Earth but astronauts exposed to such radiation could have faced serious health risks. Fortunately, most solar protons cannot pass through the hull of the Space Station and so as long as the astronauts stay inside, they are safe.

Of course, this is not the case with more dangerous cosmic rays.

According to the NASA Science site:

Cosmic rays are super-charged subatomic particles coming mainly from outside our solar system. Sources include exploding stars, black holes and other characters that dwarf the sun in violence. Unlike solar protons, which are relatively easy to stop with materials such as aluminum or plastic, cosmic rays cannot be completely stopped by any known shielding technology.

Even inside their ships, astronauts are exposed to a slow drizzle of cosmic rays coming right through the hull. The particles penetrate flesh, damaging tissue at the microscopic level. One possible side-effect is broken DNA, which can, over the course of time, cause cancer, cataracts and other maladies.

In a nutshell, cosmic rays are bad. Especially in large, long-term doses.

Now the astronauts aboard the ISS are still well within Earth’s protective magnetic field and so are shielded from much of the cosmic radiation that passes through our solar system daily. And, strangely enough, when solar flares occur – such as today’s – the amount of cosmic radiation the ISS encounters actually decreases.

Why?

The solar particles push them away.

Decrease in cosmic radiation during a CME recorded in 2005.

In an effect known as the “Forbush decrease”,  magnetically-charged particles ejected from the Sun during flares and CMEs reduce the amount of cosmic radiation the ISS experiences, basically because they “sweep away” other charged particles of more cosmic origin.

Because cosmic rays can easily penetrate the Station’s hull, and solar protons are much less able to, the irony is that astronauts are actually a degree safer during solar storms than they would be otherwise.

And it’s not just in low-Earth orbit, either: Wherever CMEs go, cosmic rays are deflected. Forbush decreases have been observed on Earth and in Earth orbit onboard Mir and the ISS. The Pioneer 10 and 11 and Voyager 1 and 2 spacecraft have experienced them, too, beyond the orbit of Neptune. (via NASA Science.)

Due to this unexpected side effect of solar activity it’s quite possible that future manned missions to the Moon, Mars, an asteroid, etc. would be scheduled during a period of solar maximum, like the one we are in the middle of right now. The added protection from cosmic rays would be a big benefit for long-duration missions since we really don’t know all the effects that cosmic radiation may have on the human body. We simply haven’t been traveling in space long enough. But the less exposure to radiation, the better it is for astronauts.

Maybe solar storms aren’t so bad after all.

Read more about solar radiation and the Forbush decrease on NASA Science here.

Aurora Alert! Sun Sends CME in Earth’s Direction

As seen here by the Solar Dynamics Observatory, a long duration M3-class flare began erupting on the Sun from sunspot region 1401 at 13:42 UTC (8:42 AM ET) today, Thursday, January 19, 2012, sending a coronal mass ejection (CME) directly towards Earth. Scientists predict the CME will arrive at around 16:00 UTC on January 21, 2012 GMT. Spaceweather.com says strong geomagnetic storms are possible and high-latitude (and possibly middle-latitude) skywatchers can be on the lookout for increased aurora.

Continue reading “Aurora Alert! Sun Sends CME in Earth’s Direction”

Giant “Surfing” Waves Roll Through Sun’s Atmosphere

[/caption]

Surf’s up on the Sun! Our favorite gnarly spacecraft, the Solar Dynamics Observatory (SDO) has caught conclusive evidence of classic “surfer waves” in the Sun’s atmosphere. But these waves trump ‘Hawaii Five-O’ surfing big time, as they are about the same size as the continental U.S. Spotting these waves will help our understanding of how energy moves through the solar atmosphere, known as the corona and maybe even help solar physicists be able to predict events like Coronal Mass Ejections.

Just like a surfing wave on Earth, the solar counterpart is formed by the same fluid mechanics — in this case it is a phenomenon known as a Kelvin-Helmholtz instability. Since scientists know how these kinds of waves disperse energy in water, they can use this information to better understand the corona. This in turn, may help solve an enduring mystery of why the corona is thousands of times hotter than originally expected.

“One of the biggest questions about the solar corona is the heating mechanism,” says solar physicist Leon Ofman of NASA’s Goddard Space Flight Center, Greenbelt, Md. and Catholic University, Washington. “The corona is a thousand times hotter than the sun’s visible surface, but what heats it up is not well-understood. People have suggested that waves like this might cause turbulence which cause heating, but now we have direct evidence of Kelvin-Helmholtz waves.”

Even though these waves occur frequently in nature here on Earth, no one had seen them on the Sun. But that was before SDO.

Ofman and colleagues spotted these waves in images taken on April 8, 2010 in some of the first images caught on camera by SDO, which launched in Feburary last year and began capturing data on March 24, 2010. Ofman & team have just published a paper in Astrophysical Journal Letters.

Kelvin-Helmholtz instabilities occur when two fluids of different densities or speeds flow by each other. In the case of ocean waves, that’s the dense water and the lighter air. As they flow past each other, slight ripples can be quickly amplified into the giant waves loved by surfers. In the case of the solar atmosphere, which is made of a very hot and electrically charged gas called plasma, the two flows come from an expanse of plasma erupting off the sun’s surface as it passes by plasma that is not erupting. The difference in flow speeds and densities across this boundary sparks the instability that builds into the waves.

On the sun, the two fluids are both plasmas — expanses of super hot, charged gases — which interact. One is erupting from the surface and shooting past a second plasma that is not erupting. The resulting turbulence is a Kelvin-Helmholtz wave form.

The erupting plasma is likely from a Coronal Mass Ejection, such as was seen earlier this week, where the Sun violently propels massive amounts of high-speed plasma particles into space. So, knowing more about the how the corona is heated and what the conditions are just before the KH waves form might give scientists the ability to predict a the next CME, which is a long-standing goal of solar scientists.

But figuring out the exact mechanism for heating the corona will likely keep solar physicists busy for quite some time. However, SDO’s ability to capture images of the entire sun every 12 seconds with such precise detail will certainly provide the data needed.

Source: NASA

You can follow Universe Today senior editor Nancy Atkinson on Twitter: @Nancy_A. Follow Universe Today for the latest space and astronomy news on Twitter @universetoday and on Facebook.

Sun Erupts with Enormous X2 Solar Flare

Just in time for Valentine’s Day, [and the Stardust flyby of Comet Tempel 1] the Sun erupted with a massive X-Class flare, the most powerful of all solar events on February 14 at 8:56 p.m. EST . This was the first X-Class flare in Solar Cycle 24 and the most powerful X-ray flare in more than four years.

The video above shows the flare as imaged by the AIA instrument at 304 Angstroms on NASA’s Solar Dynamics Observatory. More graphic videos below show the flare in the extreme ultraviolet wavelength of 193 Angstroms and as a composite with SOHO’s coronagraph.

Spaceweather Update: A CME hit Earth’s magnetic field at approximately 0100 UT on Feb. 18th (8:00 pm EST on Feb. 17th). Send me or comment your aurora photos

The eruption registered X2 on the Richter scale of solar flares and originated from Active Region 1138 in the sun’s southern hemisphere. The flare directly follows several M-class and C-class flares over the past few days which were less powerful. The explosion also let loose a coronal mass ejection (CME) headed for Earth’s orbit. It was speeding at about 900 Km/second.
CME’s can disrupt communications systems and the electrical power grid and cause long lasting radiation storms.

According to a new SDO update, the particle cloud from this solar storm is weaker than first expected and may produce some beautiful aurora in the high northern and southern latitudes on Feb. 17 (tonight).

According to spaceweather.com, skywatchers in the high latitudes should be alert for auroras after nightfall Feb. 17 from this moderately strong geomagnetic storm.

Send me your aurora reports and photos to post here

Sources: SDO website, spaceweather.com

NASA SDO – Big, Bright Flare February 15, 2011

Video Caption: Active region 1158 let loose with an X2.2 flare at 0153 UT or 8:50 pm ET on February 15, 2011, the largest flare since Dec. 2006 and the biggest flare so far in Solar Cycle 24. Active Region 1158 is in the southern hemisphere, which has been lagging the north in activity but now leads in big flares! The movie shows a close-up of the flaring region taken by the Solar Dynamics Observatory in the extreme ultraviolet wavelength of 193 Angstroms. Much of the vertical line in the image and the staggered lines making an “X” are caused by the bright flash overwhelming our imager. A coronal mass ejection was also associated with the flare. The movie shows activity over about two days (Feb. 13-15, 2011). Since the active region was facing Earth, there is a good chance that Earth will receive some effects from these events, with some possibility of mid-latitude aurora Feb. 16 – 18. Credit: NASA SDO

X2 flare Video combo from SDO and SOHO

Video caption: The X2 flare of Feb. 15, 2011 seen by SDO (in extreme ultraviolet light) enlarged and superimposed on SOHO’s coronagraph that shows the faint edge of a “halo” coronal mass ejection as it races away from the Sun. The video covers about 11 hours

[/caption]

This image taken by SDO's AIA instrument at 171 Angstrom shows the current conditions of the quiet corona and upper transition region of the Sun. Credit: NASA/SDO/AIA

Earths Entire Star for the First Time on Super SUNday

[/caption]

Super Bowl SUNday XLV marks a watershed moment in observing our Sun. Today, February 6, 2011, NASA’s twin STEREO solar observatories will reach locations on exact opposite sides of the Sun, called opposition, and they are beaming back uninterrupted images from both the entire front and rear side hemispheres of Earths star in three dimensions and 360 degrees for the first time.

“For the first time in history we can see the entire Sun at one time – both the far side and the near side,” said Joe Gurman, in an interview for Universe Today. Gurman is the Project Scientist for NASA’s STEREO mission at the NASA Goddard Spaceflight Center in Greenbelt, MD. This will significant aid space weather forecasting.

To mark this historic milestone, NASA today released images captured by STEREO on Feb. 2 – slightly prior to opposition – which gives humankind our first ever global look at the whole sphere of our Suns surface and atmosphere in extreme ultraviolet light (EUV). The probes were over 179 degrees apart. See location maps and images below

This article features even newer EUV images – compared to NASA’s press release – that were taken even closer to opposition by STEREO on Feb. 3 and today on Feb. 6 and which I downloaded from the STEREO website. The newer EUV images show an ever so slightly more complete solar view as the probes orbit reaches further to the suns far side.

Coincidentally, the STEREO duo may reach opposition – exactly 180 degrees apart – while the Super Bowl XLV half time show is ongoing, at roughly 7:30 p.m. EST in the evening of Sunday, Feb. 6.

The Sun from STEREO A and B on Feb. 3, 2011.
Images taken by the SECCHI Extreme Ultraviolet Imager (EUVI) at the 304 Angstrom bandpass which is sensitive to the He II singly ionized state of helium, at a characteristic temperature of about 80 thousand degrees Kelvin. These are the most current images used to create the spherical solar view on Feb 3, 2011. Credit: NASA

There is a tiny sliver of unseen solar surface on the far side of the sun at the extreme fringes of the far side EUV images that will fill in over the new few days to give an even better view. As of today that wedge is less than 1 degree. See the solar image collections above and below.

“The currently unseen far side wedge will disappear around February 12,” Gurman told me. “There might still be some small areas at high latitudes we won’t be able to see, but the view from the ecliptic is always limited. It takes about 3 days to get back the high resolution data.”

“On either side of the wedge, the features are smeared out because they’re from the “limbs” (edges) of the Sun as seen from each STEREO spacecraft.”

“The far side resolution will increase as the STEREO twins proceed around the sun.”

“On the near side, we can substitute the much higher resolution SDO AIA image data along the nearside “seam”, said Gurman.

SDO is in Earth orbit on the earth-facing side of the sun and will fill in the gap.

“For the next 8 years we will have a 360 degree view of the Sun by combining STEREO and SDO data,” said Gurman. “We will have that whole sun view until the STEREO spacecraft swing back to the earth side of the Sun.”

The Sun from STEREO A and B on Feb. 6, 2011 on SuperSUNday.
The probes were nearly at opposition 180 degrees apart. These images provide the first 360 degree global view of Earths Star. Images taken by the SECCHI Extreme Ultraviolet Imager (EUVI) at the 195 Angstrom bandpass is sensitive to the Fe XII ionization state of iron, at a characteristic temperature of about 1.4 million degrees Kelvin. Credit: NASA

Why is it important to image the far side of the sun?

Because scientists can now immediately detect active regions on the far side of the sun which were hidden from our view up until now.

“No active region can hide from us anymore because we will now have this 360 degree view.”

The new far side data will allow much faster detection of solar storms which in turn will enable faster predictions of space weather which potentially can severely impact sensitive technological infrastructure on Earth and throughout the solar system.


Until now, we had to wait about two weeks until the rear side active regions of the sun rotated into our view on the front side. But no longer. On average the sun rotates in about 27 days – faster at the equator and slower at the poles.

“We will now be able to detect the coronal mass ejections, or CMEs as they happen on the far side instead of waiting until they rotate around with no forewarning. The magnetic storms with energetic particles blast out at varying speeds of about 700 to 1000 km/sec and can reach Earth in one to three days,” said Gurman.

These magnetic storms are a threat to air traffic control of airliners, can disrupt the power grip, damage communications systems, space satellites in Earth orbit and around the solar system, effect other sensitive electronics systems and also harm astronauts working aboard the International Space Station.

An artist's concept shows both STEREO surrounding the sun on opposite sides. Credit: NASA

STEREO is comprised of two nearly identical STEREO spacecraft – dubbed STEREO Ahead and STEREO Behind –orbiting around our Sun. One probe – B – trails Earth around the sun and moves a bit slower; the other one – A – leads the Earth traveling slightly faster.

Each probe images half of the suns sphere and broadcasts the data back to Earth continuously, 24 hours each day. STEREO’s solar telescopes are tuned to four different wavelengths of extreme ultraviolet radiation (171, 195, 284, 304 Å) selected to trace key aspects of solar activity such as flares, tsunamis and magnetic filaments.

“The images are converted into a spherical projection by researchers on the science teams,” said Gurman. An international group of scientific institutions and governments from the U.S., UK, France, Germany, Belgium, Netherlands and Switzerland designed and built STEREO’s science imaging and particle detecting instruments.

The two probes have been slowly separating in opposite directions at about 45 degrees per year ever since they were launched together aboard a Delta II rocket on October 25, 2006 from Cape Canaveral Air Force Station (CCAFS) in Florida.

After hurtling past the moon, the solar powered spacecraft – weighing some 600 kg – were flung into solar orbit on opposite sides of the Earth and have been moving away from Earth and apart from each other. In this way the wedge of unseen solar territory has been diminishing as the probes gain more complete coverage of the sun, thus enabling us to formulate a more complete understanding of the solar environment.

STEREO stands for Solar TErrestrial RElations Observatory. Their mission is to provide the very first, 3-D “stereo” images of the sun to study the nature of coronal mass ejections.

The STEREO mission is currently funded until 2013.

“The probes have enough fuel to last 100 years,” said Gurman. “The lifetime limiting factor is the spacecraft electronics and funding. The solar arrays will only gradually degrade over decades.”

NASA/STEREO Reveals the Entire Sun

Launched in October 2006, STEREO traces the flow of energy and matter from the sun to Earth. It also provides unique and revolutionary views of the sun-Earth system. STEREO, when paired with SDO, can now give us the first complete view of the sun’s entire surface and atmosphere

On Super Bowl SUNday - Feb 6, 2011;
The two NASA STEREO spacecraft will see the entire Sun ! Super Bowl SUNday will truly mark a milestone for solar observations. On February 6, the two STEREO spacecrafts will be 180 degrees apart and for the next 8 years the STEREO spacecrafts and SDO will be able to observe the entire 360 degrees of the Sun. Credit: NASA
Positions of STEREO A and B for 6-Feb-2011 17:00 UT. This figure plots the current positions of the STEREO Ahead (red) and Behind (blue) spacecraft relative to the Sun (yellow) and Earth (green). The dotted lines show the angular displacement from the Sun. Units are in A.U.

Solar Explosions Spark Controversy

[/caption]

Nowhere in the Solar System are conditions more extreme than the Sun. Every second it converts millions of tons of matter into energy to create the intense levels of heat and light we expect of our local star. Study the Sun in different wavelengths and its violent nature can really become apparent. The STEREO satellite has been studying the Sun at a wavelength of 304Å and the results support a controversial solar theory.

Coronal Mass Ejections (or CMEs) are common on the Sun and they have a very real impact to us here on Earth. The solar explosions expel trillions of trillions of tons of super hot hydrogen gas into space, sometimes in the direction of the Earth. Traveling at speeds up to 2,000 kilometers per second it takes just a day for the magnetized gas to reach us and on arrival it can induce strong electric currents in the Earth’s atmosphere leading not only to the beautiful auroral displays but also to telecommunication outages, GPS system failures and even disturbances to power grids.

Solar flares, to use their other name, were first observed back in 1859 and since then, scientists have been studying them to try to understand the mechanism that causes the eruption. It has been known for some time that the magnetically charged gas or plasma is interacting with the magnetic field of the Sun but the detail has been at best, elusive.

In 2006, the international satellite STEREO was launched with the objective of continuously monitoring and studying the CMEs as they head toward the Earth and its data has helped scientists at the Naval Research Laboratory (NRL) in Washington, D.C., start to understand the phenomenon.

Using this new data, scientists at the NRL compared the observed activity with a controversial theory that was first proposed by Dr James Chen (also from the NRL) in 1989. His theory suggested that the erupting clouds of plasma are giant ‘magnetic flux ropes’, effectively a twisted up magnetic field line shaped like a donut. The Sun being a vast sphere of gas suffers from differential rotation where the polar regions of the Sun and the equatorial regions all rotate at different speeds. As a direct result of this, the plasma ‘drags’ the magnetic field lines around and the Sun and it gets more and more twisted up . Eventually, it bursts through the surface, taking some plasma with it giving us one of the most dramatic yet potentially destructive events in the Universe.

Dr Chen and a Valbona Kunkel, a doctorate student at George Mason University, applied Dr. Chen’s model to the new data from STEREO and found that the theory agrees with the measured trajectories of the ejected material. It therefore looks like his theory, whilst controversial may have been right all along.

Its strange to think that our nearest star, the Sun, still has secrets. Yet thanks to the work of Dr. Chen and his team, this one seems to have been unraveled and understanding the strange solar explosions will perhaps help us to minimise impact to Earth based technologies in years to come.

Mark Thompson is a writer and the astronomy presenter on the BBC One Show. See his website, The People’s Astronomer, and you can follow him on Twitter, @PeoplesAstro

Solar Activity is Picking Up

The current solar cycle (24) has been pretty boring, but a new sunspot — 1035 — is growing rapidly and now is seven times wider than Earth. Solar astronomers are predicting it could grow to be the largest sunspot of the year. There’s not been a lot of competition for the biggest sunspot, though: for 259 days (or 74%) of 2009, the sun has been spotless. But maybe the (solar) tide is turning. There’s been other action recently besides the new sunspot. A long-duration C4-class solar flare erupted this morning at 0120 UT from around the sunspot, which hurled a coronal mass ejection (CME) towards Earth. (See below for image of the CME that blasted off the sun on Dec. 14) Observers at high-latitude could see some aurora action when the CME arrives on or about Dec. 18th. Keep cheering; maybe the sun will come out of its doldrums.

CME on Dec. 14, 2009.  Credit: NASA, SoHO
CME on Dec. 14, 2009. Credit: NASA, SoHO

Remember, don’t look at the Sun directly to try and see the sunspot. NASA has a great site that gives real-time data and updated images of the Sun from SoHO (Solar and Heliospheric Observatory.) Or check out Spaceweather.com, which also provides updates. And if you have a safe way of observing and imaging the sunspot, feel free to post images here, or send to Nancy.