Full disk view of the Sun on August 20, 2013. The prominences on the right side of the Sun in this image are the ones captured in the closeup image above. Credit and copyright: Michel Collart.
This close-up movie of looping, dancing prominences on the Sun looks like something you’d see from one of the spacecraft we have studying the Sun, such as the Solar Dynamics Observatory. However, the images were taken from Earth by amateur astronomer Michel Collart from France. He was able to capture incredible detail (see his list of equipment below) of this region on the Sun’s western limb, and in a series of 120 frames, shows a lot of activity taking place on the morning of August 20, 2013.
It is easy to become mesmerized watching the matter ejected at high speed from the surface, then falling back down due to the Sun’s gravity.
“We saw beautiful loops this morning, and as a bonus, we see a beautiful ejection of matter from the left and return to its starting point — great!” Collart posted on the WebAstro Forum.
And while these loops are huge – see the image below comparing the size of the Earth and Moon to the prominences — this is just a small area of the Sun.
See the full view of the Sun taken by Michel:
Full disk view of the Sun on August 20, 2013. The The ‘small’ prominences on the right side of the Sun in this image are the ones captured in the closeup image above — not the bigger prominences on the left side. Credit and copyright: Michel Collart.
And the comparison of sizes between the loops, Earth, the Moon and the distance between the Earth and Moon:
Size comparison of the looping prominences on the Sun on August 20, 2013. Credit and copyright: Michel Collart.
Michel told Universe Today that he’s been imaging the Sun for about 15 years and this is the first time he’s been able to take images of them. “These loops are very rare to catch,” he said.
The series of 120 frames (1 per 30 seconds, so 1 hour total) were taken by Michel on Tuesday August 20th, between 7:25 and 8:25 UTC on Tuesday, August 20, 2013, about the same time the Sun blasted a coronal mass ejection with billions of tons of solar particles toward Earth at the mind-boggling speed of 3.3 million km/h (2 million mph).
Here’s a video version of the loops, complete with music:
Michel Collart’s equipment and methods:
Michel Collart’s telescope and imaging set up. Image courtesy Michel Collart.
Takahashi Refractor TOA 130mm, Coronado Solarmax90 double stacked with Coronado PST etalon and blocking filter BF15, Televue 1.8x Barlow and Point Grey Camera Grasshopper3 ICX674 sensor.
120 videos of 10s spaced by 20s at 40 frames/s taken the 20/08/2013 between 7:25 and 8:25 GMT.
Processing: Autostakkert2 + Registax6 and export as video on Registax5, Finalizing the video in VirtualDub and export GIF
Thanks to Michel for allowing Universe Today to share his wonderful work!
A solar cycle montage from August 1991 to September 2001 in X-rays courtesy of the Yohkoh Solar Observatory. (Credit: David Chenette, Joseph B. Gurman, Loren W. Acton, image in the public Domain).
The Sun has provided no shortage of mysteries thus far during solar cycle #24.
And perhaps the biggest news story that the Sun has generated recently is what it isn’t doing. As Universe Today recently reported, this cycle has been an especially weak one in terms of performance. The magnetic polarity flip signifying the peak of the solar maximum is just now upon us, as the current solar cycle #24 got off to a late start after a profound minimum in 2009…
Or is it?
Exciting new research out of the University of Michigan in Ann Arbor’s Department of Atmospheric, Oceanic and Space Sciences published in The Astrophysical Journal this past week suggests that we’re only looking at a portion of the puzzle when it comes to solar cycle activity.
Traditional models rely on the monthly averaged sunspot number. This number correlates a statistical estimation of the number of sunspots seen on the Earthward facing side of the Sun and has been in use since first proposed by Rudolf Wolf in 1848. That’s why you also hear the relative sunspot number sometimes referred to as the Wolf or Zürich Number.
But sunspot numbers may only tell one side of the story. In their recent paper titled Two Novel Parameters to Evaluate the Global Complexity of the Sun’s Magnetic Field and Track the Solar Cycle, researchers Liang Zhao, Enrico Landi and Sarah E. Gibson describe a fresh approach to model solar activity via looking at the 3-D dynamics heliospheric current sheet.
The spiraling curve of the heliospheric current sheet through the inner solar system. (Graphic credit: NASA).
The heliospheric current sheet (or HCS) is the boundary of the Sun’s magnetic field separating the northern and southern polarity regions which extends out into the solar system. During the solar minimum, the sheet is almost flat and skirt-like. But during solar maximum, it’s tilted, wavy and complex.
Two variables, known as SD & SL were used by researchers in the study to produce a measurement that can characterize the 3-D complexity of the HCS. “SD is the standard deviation of the latitudes of the HCS’s position on each of the Carrington maps of the solar surface, which basically tells us how far away the HCS is distributed from the equator. And SL is the integral of the slope of HCS on that map, which can tell us how wavy the HCS is on each of the map,” Liang Zhao told Universe Today.
Ground and space-based observations of the Sun’s magnetic field exploit a phenomenon known as the Zeeman Effect, which was first demonstrated during solar observations conducted by George Ellery Hale using his new fangled invention of the spectrohelioscope in 1908. For the recent study, researchers used data covering a period from 1975 through 2013 to characterize the HCS data available online from the Wilcox Solar Observatory.
SD and SL parameters juxtaposed against the traditional monthly sunspot number (SSN). Note the smooth fit until the end of solar cycle #23 around 2003. (Credit: Liang Zhao/The Astrophysical Journal).
Comparing the HCS value against previous sunspot cycles yields some intriguing results. In particular, comparing the SD and SL values with the monthly sunspot number provide a “good fit” for the previous three solar cycles— right up until cycle #24.
“Looking at the HCS, we can see that the Sun began to act strange as early as 2003,” Zhao said. “This current cycle as characterized by the monthly sunspot number started a year late, but in terms of HCS values, the maximum of cycle #24 occurred right on time, with a first peak in late 2011.”
“Scientists believe there will be two peaks in the sunspot number in this solar maximum as in the previous maximum (in ~2000 and ~2002),” Zhao continued, “since the Sun’s magnetic fields in the north and south hemispheres look asymmetric, and the north evolved faster than the south recently. But so far as I can see, the highest value of monthly-averaged sunspot number in this cycle 24 is still the one in the November 2011. So we can say the first peak of cycle 24 could be in November of 2011, since it is the highest monthly sunspot number so far in this cycle. If there is a second peak, we will see it sooner or later.”
The paper also notes that although cycle 24 is especially weak when compared to recent cycles, its range of activity is not unique when compared with solar cycles over the past 260 years.
HCS curves plotted on the surface of the Sun. Comparisons are made for the solar maximum on October 2000 (CR 1968), descending phase on April 2005 (2029), solar minimum on September 2009 (CR 2087), and ascending phase on March 2010 (CR2094). CR=Carrington Rotation. (Credit: Liang Zhao, The Astrophysical Journal).
The HCS value characterizes the Sun over one complete Carrington Rotation of 27 days. This is an averaged value for the rotation of the Sun, as the poles rotate slower than the equatorial regions.
The approximately 22 year span of time that it takes for the poles to reverse back to the same polarity again is equal to two average 11 year sunspot cycles. The Sun’s magnetic field has been exceptionally asymmetric during this cycle, and as of this writing, the Sun has already finished its reversal of the north pole first.
This sort of asymmetry during an imminent pole reversal was first recorded during solar cycle 19, which spanned 1954-1964. Solar cycles are numbered starting from observations which began in 1749, just four decades after the end of the 70-year Maunder Minimum.
“This is an exciting time to study the magnetic field of the Sun, as we may be witnessing a return to a less-active type of cycle, more like those of 100 years ago,” NCAR/HAO senior scientist and co-author Sarah Gibson said.
A massive sunspot group that rotated into view in early July, 2013, one of the largest seen for solar cycle #24 thus far. (Credit: NASA/SDO).
But this time, an armada of space and ground-based observatories will scrutinize our host star like never before. The SOlar Heliospheric Observatory (SOHO) has already followed the Sun through the equivalent of one complete solar cycle— and it has now been joined in space by STEREO A & B, JAXA’s Hinode, ESA’s Proba-2 and NASA’s Solar Dynamics Observatory. NASA’s Interface Region Imaging Spectrograph (IRIS) was also launched earlier this year and has just recently opened for business.
Will there be a second peak following the magnetic polarity reversal of the Sun’s south pole, or is Cycle #24 about to “leave the building?” And will Cycle #25 be absent all together, as some researchers suggest? What role does the solar cycle play in the complex climate change puzzle? These next few years will prove to be exciting ones for solar science, as the predictive significance of HCS SD & SL values are put to the test… and that’s what good science is all about!
-Read the abstract with a link to the full paper in The Astrophysical Journal by University of Michigan researchers here.
The magnetic flux of the Sun through the solar cycle (credit: Ian O'Neill)
The Sun’s magnetic field will likely reverse sometime in the next three to four months. No, this is not the next doomsday prediction scenario. It really will happen. But there’s nothing to fear because in reality the Sun’s magnetic field changes regularly, about every 11 years.
The flip-flopping of the Sun’s magnetic field takes place at the peak of each solar activity cycle when the Sun’s internal magnetic dynamo reorients itself. When the field reversal happens, the magnetic field weakens, then dies down to zero before emerging again with a reversed polarity.
While this is not a catastrophic event, the reversal will have effects, said solar physicist Todd Hoeksema, the director of Stanford University’s Wilcox Solar Observatory, who monitors the Sun’s polar magnetic fields. “This change will have ripple effects throughout the Solar System,” he said.
When solar physicists talk about solar field reversals, their conversation often centers on the “current sheet.” The current sheet is a sprawling surface jutting outward from the sun’s equator where the Sun’s slowly-rotating magnetic field induces an electrical current. The current itself is small, only one ten-billionth of an amp per square meter (0.0000000001 amps/m2), but there’s a lot of it: the amperage flows through a region 10,000 km thick and billions of kilometers wide. Electrically speaking, the entire heliosphere is organized around this enormous sheet.
During field reversals, the current sheet becomes very wavy, and as Earth orbits the Sun, we dip in and out of the current sheet. This means we can see an uptick in space weather, with any solar storms affecting Earth more. So, there may be more auroras in our near future.
Cosmic rays are also affected. These are high-energy particles accelerated to nearly light speed by supernova explosions and other violent events in the galaxy. Cosmic rays are a danger to astronauts and space probes, and some researchers say they might affect the cloudiness and climate of Earth. The current sheet acts as a barrier to cosmic rays, deflecting them as they attempt to penetrate the inner solar system. The good news is that a wavy sheet acts as a better shield against these energetic particles from deep space.
Scientists say the Sun’s north pole is already quite far along losing its polarity, with the south pole coming along behind.
“The sun’s north pole has already changed sign, while the south pole is racing to catch up,” said Phil Scherrer, another solar physicst at Standford. “Soon, however, both poles will be reversed, and the second half of Solar Max will be underway.”
An idea that really captures my imagination is what kinds of future civilizations there might be. And I’m not the only one. In 1964, the Soviet astronomer Nikolai Kardashev defined the future of civilizations based on the amount of energy they might consume.
A Type I civilization would use the power of their entire planet. Type II, a star system, and a Type III would harness the energy of an entire galaxy. It boggles the mind to think about the engineering required to rearrange the stars of an entire galaxy.
Is it possible to move a star? Could we move the Sun?
This idea was first proposed by physicist Dr. Leonid Shkadov in his 1987 paper, “Possibility of controlling solar system motion in the galaxy”.
Here’s how it works.
A future alien civilization would construct a gigantic reflective structure on one side of their star. Light from the star would strike this structure and bounce off, pushing it away.
If this reflective structure had enough mass, it would also attract the star with its gravity.
The star would be trying to push the structure away, but the structure would be pulling the star along with it.
If a future civilization could get this in perfect balance, it would be able to “pull” the star around in the galaxy, using its own starlight as thrust. At first, you wouldn’t get a lot of speed. But by directing half the energy of a star, you could get it moving through the galaxy.
Over the course of a million years, you would have changed its velocity by about 20 meters/second. The star would have traveled about 0.3 light years, less than 10% of the way to Alpha Centauri. Keep it up for a billion years and you would be moving a thousand times faster. Allowing you to travel 34,000 light years, a significant portion of the galaxy.
Imagine a future civilization using this technique to move their stars to better locations, or even rearranging huge portions of a galaxy for their own energy purposes.
This may sound theoretical, but Duncan Forgan, from the University of Edinburgh suggests a practical way to search for aliens moving their stars. According to him, you could use planet-hunting telescopes like Kepler to detect the bizarre light signatures we’d see from a Shkadov Thruster. There’s nothing in the laws of physics that says it can’t happen.
It’s fun to think about, and gives us another way that we could search for alien civilizations out there across the galaxy.
Projected vs observed sunspot numbers for solar cycles #23 & #24. (Credit: Hathaway/NASA/MSFC).
Our nearest star has exhibited some schizophrenic behavior thus far for 2013.
By all rights, we should be in the throes of a solar maximum, an 11-year peak where the Sun is at its most active and dappled with sunspots.
Thus far though, Solar Cycle #24 has been off to a sputtering start, and researchers that attended the meeting of the American Astronomical Society’s Solar Physics Division earlier this month are divided as to why.“Not only is this the smallest cycle we’ve seen in the space age, it’s the smallest cycle in 100 years,” NASA/Marshall Space Flight Center research scientist David Hathaway said during a recent press teleconference conducted by the Marshall Space Flight Center.
Cycle #23 gave way to a profound minimum that saw a spotless Sol on 260 out of 365 days (71%!) in 2009. Then, #Cycle 24 got off to a late start, about a full year overdue — we should have seen a solar maximum in 2012, and now that’s on track for the late 2013 to early 2014 time frame. For solar observers, both amateur, professional and automated, it seems as if the Sun exhibits a “split-personality” this year, displaying its active Cycle #24-self one week, only to sink back into a blank despondency the next.
This new cycle has also been asymmetrical as well. One hallmark heralding the start of a new cycle is the appearance of sunspots at higher solar latitudes on the disk of the Sun. These move progressively toward the Sun’s equatorial regions as the cycle progresses, and can be mapped out in what’s known as a Spörer’s Law.
The sunspot number “butterfly” graph, illustrating Spörer’s Law that susnpots gradually migrate towards the equator of the Sun as the solar cycle progresses. (Credit: NASA/MSFC).
But the northern hemisphere of the Sun has been much more active since 2006, with the southern hemisphere experiencing a lag in activity. “Usually this asymmetry lasts a year or so, and then the hemispheres synchronize,” said Giuliana de Toma of the High Altitude Observatory.
So far, several theories have been put forth as to why our tempestuous star seems to be straying from its usual self. Along with the standard 11-year cycle, it’s thought that there may be a longer, 100 year trend of activity and subsidence known as the Gleissberg Cycle.
The Sun is a giant ball of gas, rotating faster (25 days) at the equator than at the poles, which rotate once every 34.5 days. This dissonance sets up a massive amount of torsion, causing the magnetic field lines to stretch and snap, releasing massive amounts of energy. The Sun also changes polarity with every sunspot cycle, another indication that a new cycle is underway.
But predictions have run the gamut for Cycle #24. Recently, solar scientists have projected a twin peaked solar maximum for later this year, and thus far, Sol seems to be following this modified trend. Initial predictions by scientists at the start of Cycle #24 was for the sunspot number to have reached 90 by August 2013; but here it is the end of July, and we’re sitting at 68, and it seems that we’ll round out the northern hemisphere Summer at a sunspot number of 70 or so.
Some researchers predict that the following sunspot Cycle #25 may even be absent all together.
“If this trend continues, there will be almost no spots in Cycle 25,” Noted Matthew Penn of the National Solar Observatory, hinting that we may be on the edge of another Maunder Minimum.
Looking back over solar cycles for the past 500 years. (Credit: D. Hathaway/NASA/MSFC).
The Maunder Minimum was a period from 1645 to 1715 where almost no sunspots were seen. This span of time corresponded to a medieval period known as the Little Ice Age. During this era, the Thames River in London froze, making Christmas “Frost Fairs” possible on the ice covered river. Several villages in the Swiss Alps were also consumed by encroaching glaciers, and the Viking colony established in Greenland perished. The name for the period comes from Edward Maunder, who first noted the minimum in papers published in the 1890s. The term came into modern vogue after John Eddy published a paper on the subject in the journal of Science in 1976. Keep in mind, the data from the period covered by the Maunder Minimum is far from complete— Galileo had only started sketching sunspots via projection only a few decades prior to the start of the Maunder Minimum. But tellingly, there was a span of time in the early 18th century when many researchers supposed that sunspots were a myth! They were really THAT infrequent…
Just what role a pause in the solar cycle might play in the climate change debate remains to be seen. Perhaps, humanity is getting a brief (and lucky) reprieve, a chance to get serious about controlling our own destiny and doing something about anthropogenic climate-forcing. On a more ominous note, however, an extended cooling phase may give us reason to stall on preparing for the inevitable while giving ammunition to deniers, who like to cite natural trends exclusively.
Down but not out? Sol looking more like its solar max-self earlier this month on July 8th. (Photo by author).
Whatever occurs, we now have an unprecedented fleet of solar monitoring spacecraft on hand to watch the solar drama unfold. STEREO A & B afford us a 360 degree view of the Sun. SOHO has now monitored the Sun for the equivalent of more than one solar cycle, and NASA’s Solar Dynamics Observatory has joined it in its scrutiny. NASA’s Interface Region Imaging Spectrograph (IRIS) just launched earlier this year, and has already begun returning views of the solar atmosphere in unprecedented detail. Even spacecraft such as MESSENGER orbiting Mercury can give us vital data from other vantage points in the solar system.
Cycle #24 may be a lackluster performer, but I’ll bet the Sun has a few surprises in store. You can always get a freak cloud burst, even in the middle of a drought. Plus, we’re headed towards northern hemisphere Fall, a time when aurora activity traditionally picks up.
Be sure to keep a (safely filtered) eye on ol’ Sol— it may be the case over these next few years that “no news is big news!”
The Sun is hot, really hot. How hot hot really is, depends on which part you’re talking about:
The sun has a core, a middle, a surface, and an atmosphere.
Starting from the inside out…
There’s the core, where the pressure and temperature are so great that atoms of hydrogen are fused into helium. Every second, 600 million tons of material go through this conversion, releasing vast amounts of gamma radiation. This is the hottest natural place in the Solar System, reaching temperatures of 15 million degrees Celsius. Photons generated at the core of the Sun are emitted and absorbed countless times over thousands of years on their journey to reach the surface.
Outside the core is the radiative zone. Here, temperatures dip down to where fusion reactions can no longer occur, ranging from 7 million down to 2 million degrees Celsius.
Next on our journey outwards from the centre of the Sun, is the convective zone, where bubbles of plasma carry the heat to the surface like a giant lava lamp. Temperatures at the bottom of the convective zone are 2 million degrees.
Finally, the surface, the part of the star that we can see. This is where the temperature is a relatively cool 5,500 degrees Celsius.
Here’s the strange part, as you move further away from the Sun into its atmosphere, the temperature rises again. Above the surface is the chromosphere, where temperatures rise back up to 20,000 degrees Celsius.
Then there is the corona, the Sun’s outer atmosphere. The corona as a wispy halo around the Sun, visible during eclipses, that stretches millions of kilometres out into space. In the corona, the gases from the Sun are superheated to more than a million degrees – some parts of can even rise to 10 million degrees Celsius.
How can the atmosphere of the Sun get hotter than regions inside it? Astronomers aren’t really sure, but there are two competing theories. It’s possible that waves of energy are released from the surface of the Sun, sending their energy high into the solar atmosphere. Or perhaps the Sun’s magnetic field releases energy into the corona as currents collapse and reconnect.
Stars can get much hotter or colder than our Sun. From the coldest, dimmest red dwarf stars to the hottest blue giants; it’s an amazing Universe out there.
This image shows the tiny lunar crescent at the precise moment of the New Moon, in full daylight at 7h14min UTC on July 8 2013. Credit and copyright: Thierry Legault.
It’s always striking to see a tiny sliver of the New Moon. But you’ve probably never seen a sliver this tiny or a Moon this “new” before. This brand new image by astrophotographer extraordinaire Thierry Legault was taken this morning and is the youngest possible lunar crescent, with the “age” of the Moon at this instant being exactly zero — at the precise moment of the New Moon. The image was taken in full daylight at 07:14 UTC on July 8, 2013.
Normally it is just about impossible (and dangerous) to see this, as when the Moon is this “new,” the Moon is between the Earth and the Sun and it is so close to the Sun in our sky that it can’t be seen because of the Sun’s glare. Plus, the New Moon appears as an extremely thin crescent which is barely brighter than the blue sky. But Thierry has designed a special sunshade to prevent sunlight from entering the telescope (see it below).
Thierry says the irregularities and discontinuities seen in the edge of the crescent are caused by the relief at the edge of the lunar disk; i.e. mountains and craters on the Moon. Very cool!
The “New Moon” is defined as the instant when the Moon is at the same ecliptic longitude as the Sun. When we refer to the “age” of the Moon, it is the number of hours (or days) since New Moon.
From Thierry’s shooting site in Elancourt, France (a suburb of Paris), the angular separation between the Moon and the Sun was only 4.4° (nine solar diameters).
“At this very small separation, the crescent is extremely thin (a few arc seconds at maximum) and, above all, it is drowned in the solar glare, the blue sky being about 400 times brighter than the crescent itself in infrared (and probably more than 1000 times in visible light),” Thierry writes on his website. “In order to reduce the glare, the images have been taken in close infrared and a pierced screen, placed just in front of the telescope, prevents the sunlight from entering directly in the telescope.”
Thierry Legault with his special telescope filter for blocking the Sun’s rays. Image courtesy Thierry Legault.
Thierry cautions anyone trying to see this with the naked eye. Basically, don’t try it.
“The very thin crescent of the New Moon cannot be observed visually whatever the instrument (naked eye, binoculars, telescope, etc),” he said. “Moreover, pointing a celestial object that close to the Sun is dangerous for the observer and his equipment if it is not performed under the control of an experienced astronomer and with the proper equipment.”
If you want to keep track of what the Moon will look like each night (or day!), Universe Today has a great app for that, our Phases of the Moon app, available for iOS or Android.
Billions of aspen seeds float by the sun on tiny hairs creating a multicolored corona around the sun yesterday. To see and photograph the rings, I used a power pole to block the sun. Credit: Bob King
For the past two weeks puffy clumps of seeds have been riding the air in my town. You can’t avoid them. Open a door and they’ll breeze right in. Take a deep breath and you’d better be careful you don’t take a few down the windpipe.
Every June the many aspen trees that call northern Minnesota home release their booty of tiny seeds that parachute through the air on tiny clusters of hairs. And while they all have no particular place to go, their combined and unintentional effect is to create a series of beautiful colored rings about the Sun called a corona.
A single aspen seed (left) only about 1 mm across embedded in a cottony fluff of tiny hairs. At right is a spider web. Both show colors caused by bending and interference of light, a phenomenon called diffraction. Credit: Bob King (left) and Andrew Kirk
Reach your hand up to block the Sun and if your eyes can stand the glare of blue-white sky, you’ll see bazillions of tiny flecks a-flying. If you were to capture one and study it up close, you’d see it diffractlight in tiny glimmers of chrome green and purple.
When light from the sun or moon strikes a tiny water droplet, speck of pollen or aspen seed hairs, it’s scattered in different directions. Some of the scattered waves reinforce each other to make a bright ring of light in the sky while other waves cancel each other out to create a dimmer ring. A series of alternating rings around the sun is called a diffraction pattern or corona. Credit and copyright: Les Cowley www.atoptics.co.uk
Light is always getting messed with by tiny things. When it comes to aspen seeds, as rays of light – made of every color of the rainbow – bend around the hairy obstacles they interfere with one another like overlapping, expanding wave circles in a pond. Some of the waves reinforce each another and others cancel out. Our eyes see a series of colored fringes that flash about the tiny hairs.
Most halos are circular but pollen halos like this one around the moon often have unusual shapes like this oval with bulging sides and top. Credit: Bob King
The exact same thing happens when light has to step around minute water droplets, pollen grains and our hairy aspen fluffs when they’re drift through the air overhead. Overlapping wavelets of light “interfere” with one another to form a series of colorful concentric circles called a solar corona. While the same in name, this corona is an earthly one unrelated to the huge, hot coronal atmosphere that surrounds our star.
Oil-coated water droplets also show beautiful diffraction colors for a similar reason as clouds and pollen do . Light reflecting from the bottom surface of the oil film interferes with light reflecting off the top of the layer to create shifting patterns of color. Credit: Bob King
The ones created by seed hairs and pollen require clear skies and a safe way to block the Sun’s overwhelming light. My filter of choice is the power pole mostly because they’re handy. Sunglasses help to reduce the glare and eye-watering wincing.
While I can’t be 100% certain the chromatic bullseye was painted by poplar hair deflections – there’s always a chance pollen played a part – I’ve seen similar displays when the seeds have passed this way before.
Iridescent clouds are another form of a corona formed by minute water droplets diffracting light. Credit: Bob King
Coronas created by water droplets in mid-level clouds are much more common, and the familiar “ring around the sun” or solar halo is an entirely different creature. Here, light is bent or refracted through billions of microscopic six-sided ice crystals.
I figure that if the night is cloudy, the play of light and clouds in the daytime sky often makes for an enjoyable substitute.
IRIS will take a closer look at the lower parts of the sun's atmosphere, which is producing the spectacular flare shown in this image. Credit: NASA&JAXA/Hinode
How does the sun’s energy flow? Despite the fact that we live relatively close (93 million miles, or eight light-minutes) to this star, and that we have several spacecraft peering at it, we still know little about how energy transfers through the solar atmosphere.
NASA’s next solar mission will launch Wednesday, June 26 (if all goes to plan) to try to learn a little bit more. It’s called the Interface Region Imaging Spectrograph (IRIS), and it will zero in on a spot in the sun’s lower atmosphere known as the “interface region.” The zone only has a thickness of 3,000 to 6,000 miles and is seen as a key transfer point to the sun’s incredibly hot corona (that you can see during total solar eclipses.)
“IRIS will extend our observations of the sun to a region that has historically been difficult to study,” stated Joe Davila, IRIS project scientist at NASA’s Goddard Space Flight Center. “Understanding the interface region better improves our understanding of the whole corona and, in turn, how it affects the solar system.”
Figuring out more about the interface region, NASA stated, will teach us a lot more about the “space weather” that affects Earth.
Some of the energy in the interface region leaks out and powers the solar wind, which is a sort of rain of particles that leave the star. Some of them hit the Earth’s magnetic field and can produce auroras. Most of the sun’s ultraviolet radiation also flows from the interface region.
IRIS’ images will be able to zero in on about 1 percent of the sun in a single go, with resolution of features of as small as 150 miles. The 400-pound satellite will orbit Earth in an orbit perpetually keeping it above the sunrise line, a spot that lets the satellite look at the sun continuously for eight months without the sun being obscured by Earth.
It’ll also form part of a larger network of sun-staring satellites.
Technicians work on NASA’s Interface Region Imaging Spectrograph (IRIS) in a “clean room”, a specially designed facility intended to minimize contaminants on spacecraft before launch. Credit: Lockheed Martin
NASA highlighted its Solar Dynamics Observatory and a joint mission it has with Japan, called Hinode, which both take images of the sun in high-definition. These other two observatories, however, look at different solar layers (specifically, the surface and the outer atmosphere).
With IRIS joining the fleet and looking at the interface region, it will provide a more complete picture.
“Relating observations from IRIS to other solar observatories will open the door for crucial research into basic, unanswered questions about the corona,” stated Davila.
Solar transit of the Chinese space station Tiangong-1 with the Shenzhou-10 module docked, taken from Southern France on June 16, 2013 at 12:14:50 UTC; using a white light filter. Credit and copyright: Thierry Legault.
As soon as you see these images, you’ll probably guess who the photographer is … yes, Thierry Legault. He had less than half a second to capture these incredible shots of the Shenzhou-10 module docked to Tiangong-1 Chinese station transiting across the Sun, and it he did it not only once, but twice, on two consecutive days. Can you see the tiny spacecraft among the sunspots? And keep in mind, there are three taikonauts in these images as well, as the Shenzou has been docked to the Chinese space station module since June 11!
The Tiangong-1 space station is just 10.4 meters (34.1 ft) in length, while the Shenzou 10 is 9.25 meters (30.35 ft) long. This top image is a crop of a full-face view of the Sun, (see the full-face view on Thierry’s website) taken with white light filters by Thierry from southern France on June 16, just after noon UTC. The transit duration was just 0.46 seconds, and Thierry calculated the distance of the spacecraft to observer was 365 km away, and the spacecraft was traveling at 7.4km/s (26,500 km/h or 16,500 mph).
He used a Takahashi TOA-150 refractor, Baader Herschel prism and Canon 6D (1/4000s, 100 ISO).
Below is another solar transit of the two Chinese spacecraft, also taken from Southern France, but the next day, June 17, 2013 at 12:34:24 UTC. This one, in Hydrogen-alpha shows the Shenzhou-10/Tiangong-1 complex in multiple shots over the 0.46 second transit.
Hydrogen-alpha solar transit of Shenzhou-10 module docked to Tiangong-1, taken from Southern France on June 17, 2013 at 12:34:24 UT. Credit and copyright: Thierry Legault.
For this image, Thierry used his Takahashi FSQ-106, Coronado SM90 double stack, camera IDS CMOSIS 4Mp sensor at 38 fps.
This isn’t the first time Thierry has trained his cameras on the Tiangong-1 – in May of 2012 he captured the tiny space station alone transiting the Sun, and it was dwarfed by a huge sunspot sported by the Sun at the time.
For transits I have to calculate the place, and considering the width of the visibility path is usually between 5-10 kilometers, but I have to be close to the center of this path,” Legault explained, “because if I am at the edge, it is just like a solar eclipse where the transit is shorter and shorter. And the edge of visibility line of the transit lasts very short. So the precision of where I have to be is within one kilometer.”
Legault studies maps, and has a radio synchronized watch to know very accurately when the transit event will happen.
“My camera has a continuous shuttering for 4 seconds, so I begin the sequence 2 seconds before the calculated time,” he said. “I don’t look through the camera – I never see the space station when it appears, I am just looking at my watch!”
He uses CalSky to make his calculations and figure out the timing.
Congrats to Thierry and our thanks to him for sharing his amazing images and skills with Universe Today!
Diagram of Shenzhou-10 (right) docked with Tiangong-1 (left). Via Wikimedia Commons.
