As the sun dips into extremely low levels of activity before the current cycle’s “solar minimum”, a vast coronal hole has opened up in the sun’s lower atmosphere, sending a stream of fast-moving plasma our way.
To the untrained eye, this observation of the lower corona — the sun’s magnetically-dominated multi-million degree atmosphere — may look pretty dramatic. Like a vast rip in the sun’s disk, this particular coronal hole represents a huge region of “open” magnetic field lines reaching out into the solar system. Like a firehose, this open region is blasting the so-called fast solar wind in our direction and it could mean some choppy space weather is on the way.
As imaged by NASA’s Solar Dynamics Observatory today, this particular observation is sensitive to extreme ultraviolet radiation at a wavelength of 193 (19.3 nanometers) — the typical emission from a very ionized form of iron (iron-12, or FeXII) at a temperature of a million degrees Kelvin. In coronal holes, it looks as if there is little to no plasma at that temperature present, but that’s not the case; it’s just very rarefied as it’s traveling at tremendous speed and escaping into space.
The brighter regions represent closed field lines, basically big loops of magnetism that traps plasma at high density. Regions of close fieldlines cover the sun and coronal loops are known to contain hot plasma being energized by coronal heating processes.
When a coronal hole such as this rotates into view, we know that a stream of high-speed plasma is on the way and, in a few days, could have some interesting effects on Earth’s geomagnetic field. This same coronal hole made an appearance when it last rotated around the sun, generating some nice high-latitude auroras. Spaceweather.com predicts that the next stream will reach our planet on March 28th or 29th, potentially culminating in a “moderately strong” G2-class geomagnetic storm. The onset of geomagnetic storms can generate impressive auroral displays at high latitudes. Although not as dramatic as an Earth-directed coronal mass ejection or solar flare, the radiation environment in Earth orbit will no doubt increase.
The sun is currently in a downward trend in activity and is expected to reach “solar minimum” by around 2019. As expected, sunspot numbers are decreasing steadily, meaning the internal magnetic dynamo of our nearest star is starting to ebb, reducing the likelihood of explosive events like flares and CMEs. This is all part of the natural 11-year cycle of our sun and, though activity is slowly ratcheting down its levels of activity, there’s still plenty of space weather action going on.
Last week, amateur astronomer Wayne Jaeschke noticed something peculiar in his observations of Mars — there appeared to be a cloud-like structure hanging above the limb of the planet.
Many theories have been put forward as to what the phenomenon could be — high altitude cloud? Dust storm? An asteroid impact plume?! — but it’s all conjecture until we can get follow-up observations. It is hoped that NASA’s Mars Odyssey satellite might be able to slew around and get a close-up view. However, it appears to be a transient event that is decreasing in size, so follow-up observations may not be possible.
For the moment, it’s looking very likely that it is some kind of short-lived atmospheric feature, and if I had to put money on it, I’d probably edge more toward the mundane — like a high-altitude cloud formation.
Despite the lack of a global magnetic field like Earth’s magnetosphere, Mars does have small pockets of magnetism over its surface. When solar wind particles collide with the Earth’s magnetosphere, highly energetic particles are channeled to the poles and impact the high altitude atmosphere — aurorae are the result. On Mars, however, it’s different. Though the planet may not experience the intense “auroral oval” like its terrestrial counterpart, when the conditions are right, solar particles my hit these small pockets of magnetism. The result? Auroral umbrellas.
The physics is fairly straight forward — the discreet magnetic pockets act as bubbles, directing the charged solar particles around them in an umbrella fashion. There is limited observational evidence for these space weather features, but they should be possible.
As the sun is going through a period of unrest, amplifying the ferocity of solar storms, popping off coronal mass ejections (CMEs) and solar flares, could the cloud-like feature seen in Jaeschke’s photograph be a bright auroral umbrella? I’m additionally curious as a magnetic feature like this would be rooted in the planet’s crust and would move with the rotation of the planet. It would also be a transient event — much like an atmospheric phenomenon.
The physics may sound plausible, but it would be interesting to see what amateur astronomers think. Could such a feature appear in Mars observations?
The video is actually composed of 22,000 high-definition photographs, stitched together is a finely crafted time lapse video. The photographer in question is Terje Sorgjerd who braved -22C temperatures in the Arctic Circle to bring us this stunning perspective of the Aurora Borealis, or the Northern Lights. Throw in the Hans Zimmer “Gladiator” theme tune “Now We Are Free” and we get a timeless classic video that can be watched over and over again and never get bored.
So, sit back and enjoy the Sun-Earth interaction at its most spectacular.
In 2009, I wrote about a fascinating idea: in the hunt for “Earth-like” exoplanets, perhaps we could detect the radio emissions from a distant world possessing a magnetosphere. This basically builds on the premise that planets in the solar system, including Earth, generate electromagnetic waves as space plasma interacts with their magnetospheres. In short, with the right equipment, could we “hear” the aurorae on extra-solar planets?
In the research I reviewed, the US Naval Research Laboratory scientist concluded that he believed it was possible, but the radio telescopes we have in operation aren’t sensitive enough to detect the crackle of distant aurorae. According to a new study presented at the RAS National Astronomy Meeting in Llandudno, Wales, on Monday, this feat may soon become a reality, not for “Earth-like” worlds but for “Jupiter-like” worlds.
“This is the first study to predict the radio emissions by exoplanetary systems similar to those we find at Jupiter or Saturn,” said Jonathan Nichols of the University of Leicester. “At both planets, we see radio waves associated with auroras generated by interactions with ionised gas escaping from the volcanic moons, Io and Enceladus. Our study shows that we could detect emissions from radio auroras from Jupiter-like systems orbiting at distances as far out as Pluto.”
Rather than looking for the magnetospheres of Earth-like worlds — thereby finding exoplanets that have a protective magnetosphere that could nurture alien life — Nichols is focusing on larger, Jupiter-like worlds that orbit their host stars from a distance. This is basically another tool in the exoplanet-hunters’ toolbox.
Over 500 exoplanets have been confirmed to exist around other stars, and another 1,200 plus exoplanetary candidates have been cataloged by the Kepler Space Telescope. The majority of the confirmed exoplanets were spotted using the “transit method” (when the exoplanet passes in front of its host star, thereby dimming its light for astronomers to detect) and the “wobble method” (when the exoplanet gravitationally tugs on its parent star, creating a very slight shift in the star’s position for astronomers to detect), but only exoplanets with short orbital periods have been spotted so far.
The more distant the exoplanet from its host star, the longer its orbital period. To get a positive detection, it’s easy to spot an exoplanet with an orbital period of days, weeks, months, or a couple of years, but what of the exoplanets with orbits similar to Jupiter (12 years), Saturn (30 years) or even Pluto (248 years!)? If we are looking for exoplanets with extreme orbits like Pluto’s, it would be several generations-worth of observations before we’d even get a hint that a world lives there.
“Jupiter and Saturn take 12 and 30 years respectively to orbit the Sun, so you would have to be incredibly lucky or look for a very long time to spot them by a transit or a wobble,” said Nichols.
By assessing how the radio emissions for a Jupiter-like exoplanet respond to its rotation rate, the quantity of material falling into the gas giant from an orbiting moon (akin Enceladus’ plumes of water ice and dust being channeled onto the gas giant) and the exoplanet’s orbital distance, Nichols has been able to identify the characteristics of a possible target star. The hypothetical, “aurora-active” exoplanet would be located between 1 to 50 AU from an ultraviolet-bright star and it would need to have a fast spin for the resulting magnetospheric activity to be detectable at a distance of 150 light-years from Earth.
As we’re talking about exoplanets, magnetospheres and listening for radio signals, let’s throw in some alien-hunting for good measure: “In our Solar System, we have a stable system with outer gas giants and inner terrestrial planets, like Earth, where life has been able to evolve. Being able to detect Jupiter-like planets may help us find planetary systems like our own, with other planets that are capable of supporting life,” Nichols added.
Although Nichols isn’t talking about directly detecting habitable alien worlds (just that the detection of Jupiter-like exoplanets could reveal Solar System-like star systems), I think back to the 2009 research that discusses the direct detection of habitable worlds using this method: Aliens, if you’re out there, you can be as quiet as you like (to avoid predators), but the screaming radio emissions from your habitable planet’s magnetosphere will give away your location…
There’s one recurring question I’ve been asking for nearly a decade: Why is the Sun’s corona (its atmosphere) so hot?
When asking this out loud I inevitably get the sarcastic “um, because the Sun is… hot?” reply. Yes, the Sun is hot, really hot, but solar physicists have spent the last half-century trying to understand why the corona is millions of degrees hotter than the solar surface.
After all, if the air surrounding a light bulb was a couple of magnitudes hotter than the bulb’s surface, you’d want to know why that’s the case, right? At first glance, the solar atmosphere is breaking all kinds of thermodynamic laws.
Using the SDO’s high-definition cameras and imagery from the awesome Japanese Hinode solar observatory, features previously invisible to solar astronomers have been resolved. The features in question are known as “spicules.” These small-scale jets inject solar plasma from the solar surface into the lower corona, but until now they’ve been considered too cool to have any appreciable heating effect.
That was until a new type of hot, high-speed spicule was discovered.
“It’s a little jet, then it takes off,” solar physicist Scott McIntosh, of the National Center for Atmospheric Research’s High Altitude Observatory, told Discovery News’ Larry O’Hanlon. “What we basically find is that the connection is the heated blobs of plasma. It’s kind of a missing link that we’ve been looking for since the 1960s.”
These Type II spicules blast hot multi-million degree Kelvin plasma at speeds of 100 to 150 kilometers per second (62 to 93 miles per second) into the corona and then dissipate. What’s more, these aren’t isolated events, they’ve been observed all over the Sun. “This phenomenon is truly ubiquitous and populates the solar wind,” said McIntosh.
While this research provides more clarity on coronal dynamics, McIntosh is keen to point out that Type II spicules probably don’t tell the whole coronal heating story.
NASA’s coronal physics heavyweight James Klimchuk agrees. “It is very nice work, but it is absolutely not the final story on the origin of hot coronal plasma,” he said.
“Based on some simple calculations I have done, spicules account for only a small fraction of the hot plasma.”
Klimchuk favors coronal heating through magnetic stresses in the lower atmosphere generating small reconnection events. Right at the base of the corona, loops of magnetic flux channeling multi-million degree plasma high above the Sun’s chromosphere become stressed and eventually snap. These reconnection processes produce sub-resolution nanoflare events — akin to small explosions releasing energy into the solar plasma, heating it up.
Another heating mechanism — a mechanism I studied during my solar research days (.pdf) — is that of wave heating, when magnetohydrodynamic waves (I studied high-frequency Alfven waves, or ion cyclotron waves) interact with the lower corona, heating it up.
But which heating mechanism injects the most energy into the corona? For now, although there’s plenty of theorized processes (including these new transient Type II spicules), we don’t really know. We can only observe the solar corona from afar, so getting a true grasp on coronal dynamics is very hard. We really need a probe to dive deep into the solar atmosphere and take a measurement in-situ. Although the planned Solar Probe Plus will provide some answers, it may still be some time before we know why the corona is so hot.
But it is most likely that it’s not one coronal heating mechanism, but a combination of the above and, perhaps, a mechanism we haven’t uncovered yet.
This morning, at 08:55 UT, NASA’s Solar Dynamics Observatory (SDO) detected a C3-class flare erupt inside a sunspot cluster. 100,000 kilometers away, deep within the solar atmosphere (the corona), an extended magnetic field filled with cool plasma forming a dark ribbon across the face of the sun (a feature known as a “filament”) erupted at the exact same time.
It seems very likely that both events were connected after a powerful shock wave produced by the flare destabilized the filament, causing the eruption.
A second solar observatory, the Solar and Heliospheric Observatory (SOHO), then spotted a huge coronal mass ejection (CME) blast into space, straight in the direction of Earth. Solar physicists have calculated that this magnetic bubble filled with energetic particles should hit Earth on August 3, so look out for some intense aurorae, a solar storm is on its way…
Alternative title: “Jumping to Conclusions and Bullshit”
Crop circles are amazing. They are, quite literally, works of art. And like all other known forms of art, they are constructed by people with time on their hands. No UFOs have been braiding our crops, no aliens have been playing let’s-confuse-the-stoopid-humans-with-this-cryptic-message-we-travelled-hundreds-of-light-years-to-deliver. Crop circles are made by hoaxers and enthusiasts.
So yesterday, I read a terribly fascinating, yet terribly painful article that seamlessly combines three disparate facts to arrive at a terribly flawed conclusion: a coronal mass ejection (CME) will hit us on July 7th, possibly causing global damage, according to a crop circle prediction.
This may seem a little shocking, considering this equivalent of a micro-doomsday is only two days from now, but the “Exopolotics Examiner” Dr. Michael Salla discusses it with great excitement:
The Alert is for Sunspot 1024 which suddenly appeared on July 3 and 4 […] It typically takes CMEs, traveling at around a million miles per hour, three to four days to reach the Earth. So if Sunspot 1024 does generate CMEs towards the Earth, they would arrive right on the predicted date of July 7.
Apparently, we now have an infallible space weather prediction method. Sunspot 1024 could generate a CME directed toward Earth, therefore fulfilling the prediction that we are going to get hit by a CME in two days. Amazing right? Obviously Salla is referring to the work of a solar physicist, with a new hi-tech computer simulation, or with access to cutting-edge observational data. Wow, it looks like we have found the Holy Grail of sunspot characterization methods!
Actually, the July 7th prediction is purely based on crop circles at Milk Hill, in Wiltshire, UK. How do we know these flattened fields of corn predict a CME? Actually, they don’t. Even the crop circle experts make no convincing connection with crop circles and the Sun, apart from pointing out that the patterns resemble an orrery — but even if it is an orrery, the corn has been flattened by a team of hoaxers, they could make it mean anything. (I’m still waiting for a massive Micky Mouse crop circle.)
Although I find all this highly entertaining, the thing that made me laugh the most was the point that the Milk Hill patterns were made in “3 Phases.” However, looking at the incredibly beautiful design of that thing, it’s little wonder the aliens had to build the design in shifts. After all, extraterrestrials need tea-breaks too… perhaps their little feet got tired stomping all that corn… or perhaps it was constructed by slacking crop circle hoaxers who couldn’t get it all done in one night?
My money is on the latter.
So, there is a dubious link between the crop circle and the Sun (apart from ‘it faces that way,’ directly along the tractor tracks… hmm, interesting), what could Salla be talking about? Oh that’s it! The Earth’s magnetosphere has a hole in it! Hell, dig your lead-lined bomb shelters now!
Now this is one point I’m actually a little annoyed about. Apparently Dr. Salla is also qualified in solar-terrestrial physics, as he seems to dredge up some pretty compelling science recently published by NASA. Salla says:
Importantly, scientists will be able to directly study the impacts of large amounts of solar plasma penetrating a breach in the magnetosphere first reported by NASA scientists in December 2008 […] If the interpretations of crop circle researchers are correct, then we will shortly directly observe the impact of solar energy from CMEs passing through the magnetosphere breach. –Dr Salla (emphasis not added by me, used for dramatic effect I suspect).
Now this is good stuff, perhaps this guy is on to something. In summary:
The Milk Hill crop circle predicts a solar storm on July 7th (but it’s not very clear where in the corn this is printed).
An active sunspot has appeared at a high latitude on the solar surface (this is true, although only B Class solar flares have been detected… not in Earth-killing leagues I’m afraid).
This sunspot could generate an Earth-directed CME (this is true, again, but the odds are pretty damn low).
The CME will hit us on July 7th (read #3).
Now that NASA has detected a hole in our magnetosphere, deadly solar particles could penetrate our atmosphere!
In other words, Salla has strung together some dubious “signs” from a crop circle, tied it into this new sunspot, gotten all excited that it could generate some pretty feeble CMEs, somehow assumed they will be Earth-directed and then chucked in a very incorrect opinion as to what this “hole in the magnetosphere” means.
Although the magnetospheric breach is certainly an amazing discovery — made by the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites in 2008 — I think Salla misses the point. The magnetospheric breach hasn’t just appeared, it wasn’t caused by human activity (like the hole in the ozone layer, which I think he thinks this is), it’s always been there in some way, shape or form.
NASA’s five THEMIS spacecraft have discovered a breach in Earth’s magnetic field ten times larger than anything previously thought to exist. Solar wind can flow in through the opening to “load up” the magnetosphere for powerful geomagnetic storms. But the breach itself is not the biggest surprise. Researchers are even more amazed at the strange and unexpected way it forms, overturning long-held ideas of space physics. —NASA release.
Obviously overcome with the NASA terminology “giant breach,” Salla assumes this is a new hole in the magntosphere leaving us open to the ravages of the Sun. Actually it doesn’t, it’s simply an observation of a previously unknown piece of magnetospheric dynamics. Yes, the breach is linked with solar storms and the aurora, but there’s every likelihood this phenomenon has always existed, even when the Earth’s magnetic field was battered by X-class solar flares and jumbo CME’s during the last solar maximum (are we still here? Yes, I think we are). To think we are going to even notice a make-believe low-energy CME produced by a feeble region of the Sun generating B-class solar flares is laughable.
So the physics is flawed, the prediction is totally far-fetched, and apparently you need a PhD in exopolitics to understand how crop circles come into it. It’s just a fear-mongering article that is becoming all too common on the Examiner these days.
No, this is another huge FAIL for the Examiner… where are all the Skeptical, Science and Common Sense Examiners?
Playing on our love for WALL-E, our amazement for the Pixar Lamp and some great animation, Chris Smith, an employee at NASA Goddard Flight Center, has given the upcoming Solar Dynamics Observatory a personality.
Apart from obviously having too much time on his hands, Smith is a very talented guy (as all NASA employees are) and is showing that, once again, the space agency is doing a fantastic job of reaching out to the public.
As proven by the efforts of the Phoenix Mars Lander team in 2008, communication goes a long way and by harnessing social media, NASA can make its missions household names. Phoenix was tweeting, blogging and podcasting to its hearts content for five months, from touchdown to frozen death; it was Big Brother for robots living on Mars.
Now most NASA missions have Twitter feeds and devoted blogs, ensuring everyone’s interest is piqued. It also helps to have a Twitter feed talking in first-person, giving these brave rovers, landers, orbiters and probes a much needed personality.
So now, Chris Smith has done something very cool with the SDO; he’s given it an animated personality in a short animation reminiscent of a movie teaser for an upcoming Disney-Pixar feature film. Behold, the Little SDO:
“It’s a really fun little piece,” says Wade Sisler, a television producer for NASA. “And we’re hoping to use it as a way of waking some kids and folks up to solar science.”
And so NASA should, I like it! It’s going to get people interested in a comparatively small mission, and let’s face it, the satellite lacks character (the boxy 4-eyed robot doesn’t do much for me). However, now that Smith has added squeaky solar panel wings, and blinking “eyes” (without changing the design of the craft at all), he’s boosted the SDO’s likeability. Suddenly I care for the little guy. I hope he doesn’t get hit by a solar flare.
Due for launch in October, the SDO will be inserted into a geosynchronous orbit above New Mexico, gathering data from the Sun, so solar physicists can better understand space weather. The cool thing is that with those four eyes, the SDO will capture high-definition images of the Sun continuously.
It might not have the dazzle of the Phoenix Mars Lander, but it has a personality and people will love him (I await the Twitter feed).
Sigmoids in the solar corona have been studied for many years, but little explanation of their formation or why they are often the seed of powerful solar flares have been forthcoming. Using high-resolution X-ray images from the Japanese-led solar mission Hinode (originally Solar-B), solar physicists have known that these very hot S-shaped structures are composed of many highly stressed magnetic flux tubes filled with energized plasma (also known as ‘fibrils’), but until now, little was known about the formation and flare eruption processes that occur in sigmoids.
Now, a team of solar physicists from the University of St Andrews believe they have found an answer using powerful magnetohydrodynamic (MHD) computer models, aiding our understanding of coronal dynamics and getting us one step closer to forecasting space weather… Continue reading “An Explanation For Solar Sigmoids”
It’s been a busy day with a range of topics posted on the Universe Today, but all have a common thread: the universe is a deadly place for man and galaxy. For starters, research into the radiation mankind will face when settling on Mars and the Moon could prove to be one of our main challenges in space. The threat of a massive dose of radiation from a solar flare is bad enough, but the gradual damage to our cells and increased risk of cancer is a problem we need to solve, or at least manage. But that’s nothing compared with what dwarf galaxies have to put up with; their larger spiral cousins like to eat them for dinner, leaving behind galactic ghosts of the dwarfs that were… Continue reading “The Sinister Side of the Cosmos: Killer Galaxies, Cosmic Forensic Science and Deadly Radiation”