This is an image of a unique eclipse as viewed by NASA's Solar Dynamics Observatory, with a model of the moon from NASA's Lunar Reconnaissance Orbiter replacing the lunar shadow. Credit: NASA/SDO/LRO/GSFC
You’ve probably never before seen an image like the one above. That’s because it is the first time something like this has ever been created, and it is only possible thanks to two fairly recent NASA missions, the Solar Dynamics Observatory and the Lunar Reconnaissance Orbiter. We’ve shared previously how two or three times a year, SDO goes through “eclipse season” where it observes the Moon traveling across the Sun, blocking its view.
Now, Scott Wiessinger and Ernie Wright from Goddard Space Flight Center’s Scientific Visualization Studio used SDO and LRO data to create a model of the Moon that exactly matches SDO’s perspective of a lunar transit from October 7, 2010. They had to precisely match up data from the correct time and viewpoint for the two separate spacecraft, and the end result is this breathtaking image of the Sun and the Moon.
“The results look pretty neat,” Wiessinger said via email, “and it’s a great example of everything working: SDO image header data, which contains the spacecraft’s position; our information about lunar libration, elevation maps of the lunar surface, etc. It all lines up very nicely.”
‘Nicely’ is an understatement. How about “freaking awesome!”
And of course, they didn’t just stop there.
his is an up close shot of two NASA images: An image rendered from a model of the moon from the Lunar Reconnaissance Orbiter overlaid onto an image of the sun from the Solar Dynamics Observatory, during a lunar transit as seen by SDO on Oct. 7, 2010. The various features of the moon’s horizon are labeled. Credit: NASA/SDO/LRO/GSFC
Since the data from both spacecraft are at such high resolution, if you zoom in to the LRO image, features of the Moon’s topography are visible, such as mountains and craters. This annotated image shows what all is visible on the Moon. And then there’s the wonderful and completely unique view in the background of SDO’s data of the Sun.
So while the imagery is awesome, this exercise also means that both missions are able to accurately provide images of what’s happening at any given moment in time.
The image on the left is a view of the sun captured by NASA’s Solar Dynamics Observatory on Oct. 7, 2010, while partially obscured by the moon. Looking closely at the crisp horizon of the moon against the sun shows the outline of lunar mountains. A model of the moon from NASA’s Lunar Reconnaissance Orbiter has been inserted into a picture on the right, showing how perfectly the moon’s true topography fits into the shadow observed by SDO. Credit: NASA/SDO/LRO/GSFC
In this image, the Solar Dynamics Observatory (SDO) captured an X1.2 class solar flare, peaking on May 15, 2013. Credit: NASA/SDO
What’s more fun than something that misbehaves? When it comes to solar dynamics, we know a lot, but there are many things we don’t yet understand. For example, when a particle filled solar flare lashes out from the Sun, its magnetic field lines can do some pretty unexpected things – like split apart and then rapidly reconnect. According to the flux-freezing theorem, these magnetic lines should simply “flow away in lock-step” with the particles. They should stay intact, but they don’t. It’s not just a simple rule they break… it’s a law of physics.
What can explain it? In a paper published in the May 23 issue of “Nature”, an interdisciplinary research team led by a Johns Hopkins mathematical physicist may just have found a plausible explanation. According to the group, the underlying factor is turbulence – the “same sort of violent disorder that can jostle a passenger jet when it occurs in the atmosphere” – or the one your brother leaves behind after he’s eaten baked beans. By employing a well-organized and logically constructed computer modeling technique, the researchers were able to simulate what happens when magnetic field lines meet up with turbulence in a solar flare. Armed with this information, they were then able to state their case.
“The flux-freezing theorem often explains things beautifully,” said Gregory Eyink, a Department of Applied Mathematics and Statistics professor who was lead author of the “Nature” study. “But in other instances, it fails miserably. We wanted to figure out why this failure occurs.”
Just what is the flux-freezing theorem? Maybe you’ve heard of Hannes Alfvén. He was a Swedish electrical engineer, plasma physicist and winner of the 1970 Nobel Prize in Physics for his work on magnetohydrodynamics (MHD). He’s the man responsible for explaining what we now know as Alfvén waves – a low-frequency travelling oscillation of the ions and the magnetic field in plasma. Well, some 70 years ago, he came up with the thought that magnetic lines of force sail along a locomotive fluid similar to snippets of thread flowing along a stream. It should be impossible for them to break and then join again. However, solar physicists have discovered this just isn’t the case when it comes to activity within a particularly violent solar flare. In their observations, they have determined that the magnetic field lines within these flares can stretch to the breaking point and then reconnect in a surprisingly quick amount of time – as little as 15 minutes. When this happens, it expels a copious amount of energy which, in turn, powers the flare.
“But the flux-freezing principle of modern plasma physics implies that this process in the solar corona should take a million years!” Eyink animatedly states. “A big problem in astrophysics is that no one could explain why flux-freezing works in some cases but not others.”
Of course, there has always been speculation that turbulence may have been the root source of the enigmatic behavior. Time for investigation? You bet. Eyink then joined forces – and minds – with other experts in astrophysics, mechanical engineering, data management and computer science, based at Johns Hopkins and other institutions. “By necessity, this was a highly collaborative effort,” Eyink said. “Everyone was contributing their expertise. No one person could have accomplished this.”
Gregory Eyink, professor of applied mathematics and statistics at Johns Hopkins. Photo by Nat Creamer.The next step was to create a computer simulation – a simulation which could duplicate the plasma state of solar flare activity and all the nuances the charged particles undergo during different conditions. “Our answer was very surprising,” stated Eyink. “Magnetic flux-freezing no longer holds true when the plasma becomes turbulent. Most physicists expected that flux-freezing would play an even larger role as the plasma became more highly conducting and more turbulent, but, as a matter of fact, it breaks down completely. In an even greater surprise, we found that the motion of the magnetic field lines becomes completely random. I do not mean ‘chaotic,’ but instead as unpredictable as quantum mechanics. Rather than flowing in an orderly, deterministic fashion, the magnetic field lines instead spread out like a roiling plume of smoke.”
Of course, other solar experts feel there may be alternative answers for this rule-breaking activity within solar flares, but as Eyink says, “I think we made a pretty compelling case that turbulence alone can account for field-line breaking.”
What is most exciting is the collaborative effort of the team members from such widely varied disciplines. It was a group effort which aided Eyink to come up with this new theory on the solar flare riddle. “We used ground-breaking new database methods, like those employed in the Sloan Digital Sky Survey, combined with high-performance computing techniques and original mathematical developments,” he said. “The work required a perfect marriage of physics, mathematics and computer science to develop a fundamentally new approach to performing research with very large datasets.”
In conclusion, Eyink noted this type of research work may very well give us a better understanding of solar flares and coronal mass ejections. As we know, this type of dangerous “space weather” can be harmful to astronauts, disrupt communications satellites, and even be responsible for the shut-down of electrical power grids on Earth. And you know what that means… no satellite TV and no power to watch it by. But, that’s O.K.
“I don’t stay out late. Don’t care to go. I’m home about eight… Just me and my radio. Ain’t misbehavin’.. Savin’ my love for you.”
An X3.2-class flare observed by SDO's AIA instrument at 0114 UT on May 14 (NASA/SDO/AIA)
Last night, as Commander Hadfield and the Expedition 35 crew were returning to Earth in their Soyuz spacecraft, the Sun unleashed yet another X-class flare from active region 1748, the third and most powerful eruption yet from the sunspot region in the past 24 hours — in fact, at a level of X3.2, it was the most intense flare observed all year.
And with this dynamic sunspot region just now coming around the Sun’s limb and into view, we can likely expect much more of this sort of activity… along with a steadily increasing chance of an Earth-directed CME.
According to SpaceWeather.com AR1748 has produced “the strongest flares of the year so far, and they signal a significant increase in solar activity. NOAA forecasters estimate a 40% chance of more X-flares during the next 24 hours.”
(Find out more about the classification of solar flares here.)
The sunspot region just became fully visible to Earth during the early hours of May 13 (UT).
Most recent SDO image of AR1748 (NASA/SDO/AIA)
Sunspots are regions where the Sun’s internal magnetic fields rise up through its surface layers, preventing convection from taking place and creating cooler, optically darker areas. They often occur in pairs or clusters, with individual spots corresponding to the opposite polar ends of magnetic lines.
Sunspots may appear dark because they are relatively cooler than the surrounding area on the Sun’s photosphere, but in ultraviolet and x-ray wavelengths they are brilliantly white-hot. And although sunspots look small compared to the Sun, they are often many times larger than Earth.
According to SDO project scientists Dean Pesnell on the SDO is Go! blog, AR1748 is not only rapidly unleashing flares but also changing shape.
“The movies show that the sunspot is changing, the two small groups on the right merging and the elongated spot on the lower left expanding out to join them,” Pesnell wrote earlier today.
Of course, as a solar scientist Pesnell is likely much more excited about the chance to observe further high-intensity activity than he is concerned about any dramatically negative impacts of a solar storm here on Earth, which, although possible, are still statistically unlikely.
“Great times ahead for this active region!” he added enthusiastically.
For updated information on AR1748’s activity visit SpaceWeather.com and NASA’s SDO site, and also check out TheSunToday.org run by solar physicist C. Alex Young, Ph.D.
Images courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.
A close-up of an an X1.7-class solar flare on May 12, 2013 as seen by NASA's Solar Dynamics Observatory. Credit: NASA/SDO/AIA. Click for larger version.
The Sun gets active! On May 12, 2013, the Sun emitted what NASA called a “significant” solar flare, classified as an X1.7, making it the first X-class flare of 2013. Then earlier today, May 13, 2013, the Sun let loose with an even stronger flare, an X2.8-class. Both flares took place just beyond the limb of the Sun, and were also associated with another solar phenomenon, a coronal mass ejection (CME) which sent solar material out into space.
Neither CME was Earth-directed, and according to SpaceWeather.com, no planets were in the line of fire. However, the CMEs appear to be on course to hit NASA’s Epoxi, STEREO-B and Spitzer spacecraft on May 15-16. NASA said their mission operators have been notified, and if warranted, operators can put spacecraft into safe mode to protect the instruments. Experimental NASA research models show that the CMEs were traveling at about 1,930 km/second (1,200 miles per second) when they left the Sun.
The sunspot associated with these flares is just coming into view, and the next 24 to 48 hours should reveal much about the sunspot, including its size, magnetic complexity, and potential for future flares.
See more images and video below:
Both the X1.7 and the X2.8-class solar flare, plus a prominence eruption, all in one video:
SDO image of an X2.8-class flare on May 13, 2013. Credit: NASA/SDO
NASA’s Solar Dynamics Observatory (SDO) captured this X1 flare (largest of the year so far) in extreme UV light:
Imagery from SDO, SOHO and LASCO of the May 1, 2013 coronal mass ejection. Credit: NASA/ESA.
Just in time for May Day, the Sun blasted out a coronal mass ejection (CME) from just around the limb earlier today, May 1, 2013. In a gigantic rolling wave, this CME shot out about a billion tons of particles into space, traveling at over a million miles per hour. This CME is not headed toward Earth. The video, taken in extreme ultraviolet light by NASA’s Solar Dynamics Observatory (SDO), covers about two and a half hours of elapsed time.
Camilla, the rubber chicken mascot for the SDO, said via YouTube that getting this side view shows the power and force behind these solar flares and coronal mass ejections.
This image shows three views of the CME from three different instruments. Left is the SDO image, taken at 02:40 UT. Center is from the SOHO spacecraft, looking through their coronograph instrument. The “mushroom” cloud of plasma leaving the Sun is visible. On the right is the LASCO C2 (red) and C3 (blue) instruments on SOHO, which use a disk to block out the Sun. Visible are the solid occulter disk, used to create a false eclipse; the “pylon”, which is an arm that holds the occulter disk in place; a representation of the Sun in the form of a white disk drawn on the occulter during our image processing and then you can see background stars and the cloud of plasma leaving the Sun.
A coronal mass ejection from the Sun on May 1, 2013. Credit: NASA/SDO
A long, magnetic filament burst out from the Sun after a C-cladd flare on(Aug. 31, 2012 (NASA/SDO/AIA)
We live on a planet dominated by weather. But not just the kind that comes in the form of wind, rain, and snow — we are also under the influence of space weather, generated by the incredible power of our home star a “mere” 93 million miles away. As we orbit the Sun our planet is, in effect, inside its outer atmosphere, and as such is subject to the constantly-flowing wind of charged particles and occasional outbursts of radiation and material that it releases. Although it may sound like something from science fiction, space weather is very real… and the more we rely on sensitive electronics and satellites in orbit, the more we’ll need to have accurate weather reports.
Fortunately, the reality of space weather has not gone unnoticed by the U.S. Federal Government.
An X1.6 flare eruption on Jan. 27, 2012 (NASA/SDO/AIA)
Today the White House Office of Science and Technology Policy released a new report, Space Weather Observing Systems: Current Capabilities and Requirements for the Next Decade, which is an assessment of the United States government’s capacity to monitor and forecast potentially harmful space weather and how to possibly mitigate the damage from any exceptionally powerful solar storms in the future.
The report was made by a Joint Action Group (JAG) formed by the National Space Weather Program Council (NSWPC).
The impacts of space weather can have serious economic consequences. For example, geomagnetic storms during the 1990’s knocked out several telecommunications satellites, which had to be replaced at a cost of about $200 million each. If another “once in a century” severe geomagnetic storm occurs (such as the 1859 “super storm”), the cost on the satellite industry alone could be approximately $50 – $100 billion. The potential consequences on the Nation’s power grid are even higher, with potential costs of $1 – 2 trillion that could take up to a decade to completely repair.
– Report on Space Weather Observing Systems: Current Capabilities and Requirements for the Next Decade (April 2013)
“In other words,” according to the report, “the Nation is at risk of losing critical capabilities that have significant economic and security impacts should these key space weather observing systems fail to be maintained and replaced.”
The National Space Weather Program is a Federal interagency initiative with the mission of advancing the improvement of space weather services and supporting research in order to prepare the country for the technological, economic, security, and health impacts that may arise from extreme space weather events.
the Solar Heliospheric Observatory (SOHO) captured this series of four images of a coronal mass ejection (CME) escaping the sun on the morning of April 25, 2013. The images show the CME from 5:24 a.m. to 6:48 a.m. EDT. This was the second of two CMEs in the space of 12 hours. Both are headed away from Earth toward Mercury. Credit: ESA&NASA/SOHO.
Over the past 24 hours, the Sun has erupted with two coronal mass ejections (CMEs), sending billions of tons of solar particles into space. While these CMEs are not directed at Earth, they are heading towards Mercury and may affect the Messenger spacecraft, as well as the Sun-watching STEREO-A satellites. One CME may send a glancing blow of particles to Mars, possibly affecting spacecraft at the Red Planet.
This solar radiation can affect electronic systems on spacecraft, and the various missions have been put on alert. When warranted, NASA operators can put spacecraft into safe mode to protect the instruments from the solar material.
The first CME began at 01:30 UTC on April 25 (9:30 p.m. EDT on April 24), and the second erupted at 09:24 UTC (5:24 a.m. EDT) on April 25. Both left the sun traveling at about 800 kilometers (500 miles per second).
See this animation from the STEREO-B spacecraft:
Animations of CMEs on April 25, 2013 from the STEREO-B spacecraft. Credit: NASA/Goddard Space Flight Center.
This image is a composite of 25 separate images spanning the period of April 16, 2012, to April 15, 2013. It uses the SDO AIA wavelength of 171 angstroms and reveals the zones on the sun where active regions are most common during this part of the solar cycle.
Credit: NASA/SDO/AIA/S. Wiessinger
Since the Solar Dynamics Observatory opened its multi-spectral eyes in space about three years ago, we’ve posted numerous videos and images from the mission, showing incredible views of our dynamic Sun. Scott Wiessinger from Goddard Space Flight Center’s Space Visualization Studio has put together great timelapse compilation of images from the past three years, as well as a one composite still image to “try to encapsulate a timelapse into one static graphic,” he told us via email. “I blended 25 stills from over the last year, and it’s interesting to see the bright bands of active regions.” Scott said he was fascinated by seeing the views of the Sun over a long range of time.
Within the video, (below) there are some great Easter egg hunts – things to see like partial eclipses, flares, comet Lovejoy, and the transit of Venus.
How many can you find?
SDO’s Atmospheric Imaging Assembly (AIA) captures a shot of the sun every 12 seconds in 10 different wavelengths, but the images shown here are based on a wavelength of 171 Angstroms, which is in the extreme ultraviolet range. It shows solar material at around 600,000 Kelvin. In this wavelength it is easy to see the Sun’s 25-day rotation as well as how solar activity has increased over three years as the Sun’s solar cycle has ramped up towards the peak of activity in its 11-year cycle.
You’ll also notice that during the course of the video, the Sun subtly increases and decreases in apparent size. This is because the distance between the SDO spacecraft and the Sun varies over time. The image is, however, remarkably consistent and stable despite the fact that SDO orbits the Earth at 6,876 miles per hour and the Earth orbits the sun at 67,062 miles per hour.
An artist's illustration of a planetary nebula engulfing its orbiting planets (image credit: Regulus36/deviantart, adjusted by DM to mitigate compression effects).
Textbooks often cite that planetary nebulae (PNe, plural) represent an endstate for lower-mass single stars. But conversely, recent research suggests that most PNe stem from binary systems. The lowest mass star theorized to form the typical PN is near 1 solar mass, and thus without a companion the Sun may not surpass the mass limit required to generate the hot glowing (ionized) nebula typically tied to PNe. New research continues to question our original understanding of how the Sun’s life may end.
A new study spearheaded by G. Jacoby aimed in part to test that binary hypothesis by searching for PNe in star clusters occupying M31. The team remarked that, “while the binary interaction model explains some of the anomalies associated with the observed planetary nebula population, this theory awaits final confirmation.”
“The traditional theory states that the progenitors of PNe are low- to intermediate-mass single stars … However, this theory does not provide a natural explanation for the non-spherical morphologies observed for the great majority of PNe, nor their low rate of formation. For these and other inconsistencies, a new paradigm has been developed, wherein most PNe are shaped via the interaction … with a binary companion,” said Jacoby et al. 2013. Continue reading “Astronomers Hint that our Sun won’t Terminate as the Typical Planetary Nebula”
Here’s a question… how long does it take sunlight to reach Earth? This sounds like a strange question, but think about it. Sunlight travels at the speed of light. Photons emitted from the surface of the Sun need to travel across the vacuum of space to reach our eyes.
The short answer is that it takes sunlight an average of 8 minutes and 20 seconds to travel from the Sun to the Earth.
If the Sun suddenly disappeared from the Universe (not that this could actually happen, don’t panic), it would take a little more than 8 minutes before you realized it was time to put on a sweater.
Here’s the math. We orbit the Sun at a distance of about 150 million km. Light moves at 300,000 kilometers/second. Divide these and you get 500 seconds, or 8 minutes and 20 seconds.
This is an average number. Remember, the Earth follows an elliptical orbit around the Sun, ranging from 147 million to 152 million km. At its closest point, sunlight only takes 490 seconds to reach Earth. And then at the most distant point, it takes 507 seconds for sunlight to make the journey.
But the story of light gets even more interesting, when you think about the journey light needs to make inside the Sun.
You probably know that photons are created by fusion reactions inside the Sun’s core. They start off as gamma radiation and then are emitted and absorbed countless times in the Sun’s radiative zone, wandering around inside the massive star before they finally reach the surface.
What you probably don’t know, is that these photons striking your eyeballs were ACTUALLY created tens of thousands of years ago and it took that long for them to be emitted by the sun.
Once they escaped the surface, it was only a short 8 minutes for those photons to cross the vast distance from the Sun to the Earth
As you look outward into space, you’re actually looking backwards in time.
The light you see from your computer is nanoseconds old. The light reflected from the surface of the Moon takes only a second to reach Earth. The Sun is more than 8 light-minutes away. And so, if the light from the nearest star (Alpha Centauri) takes more than 4 years to reach us, we’re seeing that star 4 years in the past.
There are galaxies millions of light-years away, which means the light we’re seeing left the surface of those stars millions of years ago. For example, the galaxy M109 is located about 83.5 million light-years away.
If aliens lived in those galaxies, and had strong enough telescopes, they would see the Earth as it looked in the past. They might even see dinosaurs walking on the surface.
