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The 2016 Mercury transit occurred on May 9th, between about 7:12 a.m. and 2:42 p.m. EDT.
The images in this video are from NASA's Solar Dynamics Observatory, or SDO.
Transits provide a great opportunity to study the way planets and stars move in space– information that has been used throughout the ages to better understand the solar system and which still helps scientists today calibrate their instruments.
Though SDO sees dozens of Earth eclipses and several lunar transits each year, this is the first time ever that the two have coincided.
SDO’s orbit usually gives us unobstructed views of the sun, but Earth’s revolution around the sun means that SDO’s orbit passes behind Earth twice each year, for two to three weeks at a time. During these phases, Earth blocks SDO’s view of the sun for anywhere from a few minutes to over an hour once each day.
Earth’s outline looks fuzzy, while the moon’s is crystal-clear. This is because—while the planet itself completely blocks the sun's light—Earth’s atmosphere is an incomplete barrier, blocking different amounts of light at different altitudes. However, the moon has no atmosphere, so during the transit we can see the crisp edges of the moon's horizon.
This flare is classified as an X1.2-class flare. X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc.
Note in the pictures how crisp the horizon is on the moon, a reflection of the fact that the moon has no atmosphere around it to distort the light from the sun.
The sun emitted a mid-level solar flare, peaking at 11:11 a.m. EST on Jan. 30, 2014. Images of the flare were captured by NASA's Solar Dynamics Observatory, or SDO, shortly after the observatory witnessed a lunar transit. The black disk of the moon can be seen in the lower right of the images.
This flare is classified as an X4.9-class flare. X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc.
Scientists track sunspots that are part of active regions, which often produce large explosions on the sun such as solar flares and coronal mass ejections, or CMEs. Each time an active region appears it is assigned a number. Active regions that have survived their trip around the back of the sun and reappear are assigned a new number – a convention left over from when we had no telescopes observing the far side of the sun and so could not be sure that the new sunspot was indeed the same as the old one. This active region is currently labeled AR11990. Last time around it was labeled AR11967and its first time it was AR11944.
During its three trips thus far, this region has produced two significant solar flares, labeled as the strongest kind of flare, an X-class. It has also produced numerous mid-level and smaller flares. While many sunspots do not last more than a couple of weeks, there have been sunspots known to be stable for many months at a time.
Studying what causes active regions to appear and disappear over time, as well as how long they remain stable, is key to understanding the origins of space weather that can impact Earth’s technological infrastructure.
All Video and Image Credit: NASA/SDO
Not to be confused with a solar flare, a CME is a solar phenomenon that can send solar particles into space and reach Earth one to three days later.
Earth-directed CMEs can cause a space weather phenomenon called a geomagnetic storm, which occurs when they connect with the outside of the Earth's magnetic envelope, the magnetosphere, for an extended period of time. In the past, CME's such as this have caused auroras near the poles but didn't disrupt electrical systems on Earth or interfere with GPS or satellite-based communications systems.
Not to be confused with a solar flare, a CME is a solar phenomenon that can send solar particles into space and reach Earth one to three days later.
Earth-directed CMEs can cause a space weather phenomenon called a geomagnetic storm, which occurs when they connect with the outside of the Earth's magnetic envelope, the magnetosphere, for an extended period of time. In the past, CMEs at this strength have had little effect. They may cause auroras near the poles but are unlikely to disrupt electrical systems on Earth or interfere with GPS or satellite-based communications systems.
The spot quickly evolved into what's called a delta region, in which the lighter areas around the sunspot, the penumbra, exhibit magnetic fields that point in the opposite direction of those fields in the center, dark area. This is a fairly unstable configuration that scientists know can lead to eruptions of radiation on the sun called solar flares.
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel. This disrupts the radio signals for as long as the flare is ongoing, anywhere from minutes to hours.
This flare is classified as an M6.5 flare, some ten times less powerful than the strongest flares, which are labeled X-class flares. M-class flares are the weakest flares that can still cause some space weather effects near Earth. This flare produced a radio blackout that has since subsided. The blackout was categorized as an R2 on a scale between R1 and R5 on NOAA's space weather scales.
This is the strongest flare seen so far in 2013. Increased numbers of flares are quite common at the moment, since the sun's normal 11-year activity cycle is ramping up toward solar maximum, which is expected in late 2013. Humans have tracked this solar cycle continuously since it was discovered, and it is normal for there to be many flares a day during the sun's peak activity.
This flare is classified as an M5.7-class flare. M-class flares are the weakest flares that can still cause some space weather effects near Earth. Increased numbers of flares are quite common at the moment, as the sun's normal 11-year activity cycle is ramping up toward solar maximum, which is expected in late 2013.
Such eruptions soon leave SDO's field of view, but other satellites in NASA's Heliophysics fleet can pick them up, tracking such space weather to determine if they are headed toward Earth or spacecraft near other planets. With advance warning, many space assets can be put into safe mode and protect themselves from the effects of such particle radiation.
In addition to the images captured by SDO, the May 1, 2013 CME was also observed by the ESA/NASA Solar and Heliospheric Observatory (SOHO). SOHO houses two overlapping coronagraphs—telescopes where the bright sun is blocked by a disk so it doesn't overpower the fainter solar atmosphere—and they both saw the CME continue outward. The LASCO C2 coronagraph shows the region out to about 2.5 million miles. The LASCO C3 coronagraph expands even farther out to around 13.5 million miles. Both of these instruments show the CME as it expands and becomes fainter on its trip away from the sun.
NASA's Solar Terrestrial Relations Observatory (STEREO) Ahead satellite saw the eruption from a very different angle. It, along with its twin STEREO Behind, is orbiting at a similar distance as Earth. STEREO-A orbits slightly faster than Earth and STEREO-B orbits slightly slower. Currently, STEREO-A is more than two-thirds of the way to being directly behind the sun, and has a view of the far side of the sun. From this perspective, the CME came off the right side of the sun. STEREO has an extreme ultraviolet camera similar to SDO's, but it also has coronagraphs like SOHO. As a result, using its two inner coronagraphs, it was able to track the CME from the solar surface out to 6.3 million miles.
Working together, such missions provide excellent coverage of a wide variety of solar events, a wealth of scientific data—and lots of beautiful imagery.
Watch this video on YouTube.
On May 12, 2013, the sun emitted a significant solar flare, peaking at 10 p.m. EDT. This flare is classified as an X1.7, making it the first X-class flare of 2013. The flare was also associated with another solar phenomenon, called a coronal mass ejection (CME) that can send solar material out into space. This CME was not Earth-directed.
The May 12 flare was also associated with a coronal mass ejection, another solar phenomenon that can send billions of tons of solar particles into space, which can affect electronic systems in satellites and on the ground. Experimental NASA research models show that the CME left the sun at 745 miles per second and is not Earth-directed, however its flank may pass by the STEREO-B and Spitzer spacecraft, and their mission operators have been notified. If warranted, operators can put spacecraft into safe mode to protect the instruments from solar material. There is some particle radiation associated with this event, which is what can concern operators of interplanetary spacecraft since the particles can trip computer electronics on board.
Experimental NASA research models, based on observations from NASA's Solar Terrestrial Relations Observatory and ESA/NASA's Solar and Heliospheric Observatory show that the CME left the sun at speeds of around 1350 miles per second, which is a fast speed for CMEs.
Earth-directed CMEs can cause a space weather phenomenon called a geomagnetic storm, which occurs when they funnel energy into Earth's magnetic envelope, the magnetosphere, for an extended period of time. The CME's magnetic fields peel back the outermost layers of Earth's fields changing their very shape. Magnetic storms can degrade communication signals and cause unexpected electrical surges in power grids. They also can cause aurora. Storms are rare during solar minimum, but as the sun's activity ramps up every 11 years toward solar maximum—currently expected in late 2013—large storms occur several times per year.
In the past, geomagnetic storms caused by CMEs of this strength and direction have usually been mild.
In addition, the CME may pass by additional spacecraft: Messenger, STEREO B, Spitzer, and their mission operators have been notified. If warranted, operators can put spacecraft into safe mode to protect the instruments from the solar material.
In reality, the sun is not made of fire, but of something called plasma: particles so hot that their electrons have boiled off, creating a charged gas that is interwoven with magnetic fields.
These images were captured on Sept. 29-30, 2013, by NASA's Solar Dynamics Observatory, or SDO, which constantly observes the sun in a variety of wavelengths.
Different wavelengths help capture different aspect of events in the corona. The red images shown in the movie help highlight plasma at temperatures of 90,000° F and are good for observing filaments as they form and erupt. The yellow images, showing temperatures at 1,000,000° F, are useful for observing material coursing along the sun's magnetic field lines, seen in the movie as an arcade of loops across the area of the eruption. The browner images at the beginning of the movie show material at temperatures of 1,800,000° F, and it is here where the canyon of fire imagery is most obvious. By comparing this with the other colors, one sees that the two swirling ribbons moving farther away from each other are, in fact, the footprints of the giant magnetic field loops, which are growing and expanding as the filament pulls them upward.
This flare is classified as an X1.7 class flare. "X-class" denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc. In the past, X-class flares of this intensity have caused degradation or blackouts of radio communications for about an hour.
Increased numbers of flares are quite common at the moment, since the sun's normal 11-year activity cycle is currently near solar maximum conditions. Humans have tracked this solar cycle continuously since it was discovered in 1843, and it is normal for there to be many flares a day during the sun's peak activity. The first X-class flare of the current solar cycle occurred on February 15, 2011. The largest X-class flare in this cycle was an X6.9 on August 9, 2011.
Then, on Nov. 5, 2013, The sun emitted a significant solar flare, peaking at 5:12 p.m. EST. This flare was classified as an X3.3 flare.
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel.
One of the larger flares was classified as an X1.0 flare, which peaked at 10:03 p.m. EDT on Oct. 27. "X-class" denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc. In the past, X-class flares of this intensity have caused degradation or blackouts of radio communications for about an hour.
Another large flare was classified as an M5.1 flare, which peaked at 12: 41 a.m. EDT on Oct. 28. Between Oct. 23, and the morning of Oct 28, there were three X-class flares and more than 15 additional M-class flares.
Increased numbers of flares are quite common at the moment, since the sun is headed toward solar maximum conditions as part of its normal 11-year activity cycle. Humans have tracked this solar cycle continuously since it was discovered in 1843, and it is normal for there to be many flares a day during the sun's peak activity.
The recent solar flare activity has also been accompanied by several coronal mass ejections or CMEs, another solar phenomenon that can send billions of tons of particles into space that can reach Earth one to three days later. These particles cannot travel through the atmosphere to harm humans on Earth, but they can affect electronic systems in satellites and on the ground.
The M class flare on March 4 flare also came with what's called a Type IV radio burst that lasted for about 46 minutes. Sending out broadband radio waves, these bursts can occur towards the end of a solar flare and are believed to be created by moving electrons trapped in great, looping magnetic fields left over from the initial flare. The bursts can interfere with radio communications on Earth.
About an hour later, at 8:14 PM ET, March 6, the same region let loose an X1.3 class flare. ?An X1 is 5 times smaller than an X5 flare.
These X-class flares erupted from an active region named AR 1429 that rotated into view on March 2. ?Prior to this, the region had already produced numerous M-class and one X-class flare. ?The region continues to rotate across the front of the sun, so the March 6 flare was more Earthward facing than the previous ones. ?It triggered a temporary radio blackout on the sunlit side of Earth that interfered with radio navigation and short wave radio.
In association with these flares, the sun also expelled two significant coronal mass ejections (CMEs), which are traveling faster than 600 miles a second and may arrive at Earth in the next few days. ?In the meantime, the CME associated with the X-class flare from March 4 has dumped solar particles and magnetic fields into Earth's atmosphere and distorted Earth's magnetic fields, causing a moderate geomagnetic storm, rated a G2 on a scale from G1 to G5. ?Such storms happen when the magnetic fields around Earth rapidly change strength and shape. ?A moderate storm usually causes aurora and may interfere with high frequency radio transmission near the poles. ?This storm is already dwindling, but the Earth may experience another enhancement if the most recent CMEs are directed toward and impact Earth.
In addition, last night's flares have sent solar particles into Earth's atmosphere, producing a moderate solar energetic particle event, also called a solar radiation storm. These particles have been detected by NASA's SOHO and STEREO spacecraft, and NOAA's GOES spacecraft. ?At the time of writing, this storm is rated an S3 on a scale that goes up to S5. ?Such storms can interfere with high frequency radio communication.
Besides the August 2011 X-class flare, the last time the sun sent out flares of this magnitude was in 2006. ?There was an X6.5 on December 6, 2006 and an X9.0 on December 5, 2006. Like the most recent events, those two flares erupted from the same region on the sun, which is a common occurrence.
For full 4k frames of the April 15 small eruption and April 16 large eruption go here.
On June 5 2012, SDO collected images of the rarest predictable solar event—the transit of Venus across the face of the sun. This event lasted approximately 6 hours and happens in pairs eight years apart, which are separated from each other by 105 or 121 years. The last transit was in 2004 and the next will not happen until 2117.
The videos and images displayed here are constructed from several wavelengths of extreme ultraviolet light and a portion of the visible spectrum. The red colored sun is the 304 angstrom ultraviolet, the golden colored sun is 171 angstrom, the magenta sun is 1700 angstrom, and the orange sun is filtered visible light. 304 and 171 show the atmosphere of the sun, which does not appear in the visible part of the spectrum.
These are the basic images, collected from the telemetry. To see the insets composited, see Venus Transit 2012 Composited Visuals.
From a different spot, but on that same day, the sun unleashed a coronal mass ejection (CME) that began at 4:36 AM EDT. Models from the NASA's Space Weather Center at Goddard Space Flight Center in Greenbelt, Md, describe the CME at traveling at nearly 700 miles per second, but do not show it heading toward Earth.
Earth's magnetosphere also underwent a minor geomagnetic storm on the evening of July 6 in response to relatively slow coronal mass ejections (CMEs) that have erupted from other regions on the sun since July 4.
The flare is classified as an M7.7 flare. This means it is weaker than the largest flares, which are classified as X-class. M-class flares can cause brief radio communications blackouts at the poles.
Increased numbers of flares are currently quite common, since the sun's standard 11-year activity cycle is ramping up toward solar maximum, which is expected in 2013. It is quite normal for there to be many flares a day during the sun's peak activity.
"X-class" denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, and on. An X-class flare of this intensity can cause degradation or blackouts of radio communications for about an hour.
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel. This can disrupt radio signals for anywhere from minutes to hours.
The National Oceanic and Atmospheric Association, which is the United States government's official source for space weather forecasts and alerts, categorized the radio blackout associated with this flare as an R3, on a scale from R1 to R5. It has since subsided.
Increased numbers of flares are quite common at the moment, since the sun's normal 11-year activity cycle is ramping up toward solar maximum, which is expected in 2013. Humans have tracked this solar cycle continuously since it was discovered in 1843, and it is normal for there to be many flares a day during the sun's peak activity. The first X-class flare of the current solar cycle occurred on Feb. 15, 2011 and there have been 15 X-class flares total in this cycle, including this one. The largest X-class flare in this cycle was an X6.9 on Aug. 9, 2011. This is the 7th X-class flare in 2012 with the largest being an X5.4 flare on March 7.
This flare did not have an associated Earth-directed coronal mass ejection (CME), another solar phenomenon that can send solar particles into space and affect electronic systems in satellites and on Earth.
Watch this video on YouTube.
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel. This disrupts the radio signals for as long as the flare is ongoing, anywhere from minutes to hours.
This flare is classified as an M6 flare. M-class flares are the weakest flares that can still cause some space weather effects near Earth. They can cause brief radio blackouts at the poles. This M-class flare caused a radio blackout categorized according to the National Oceanic and Atmospheric Association's Space Weather Scales as R2 — or "moderate" — on a scale of R1 to R5. It has since subsided.
Increased numbers of flares are quite common at the moment, since the sun's normal 11-year activity cycle is ramping up toward solar maximum, which is expected in 2013. Humans have tracked this solar cycle continuously since it was discovered in 1843, and it is normal for there to be many flares a day during the sun's peak activity.
The flare was not associated with a coronal mass ejection (CME), another solar phenomenon that can send solar particles into space and can reach Earth one to three days later. When Earth-directed, CMEs can affect electronic systems in satellites and on Earth.
As of March 2014, this flare is the largest of solar cycle 24.
Comet Lovejoy survived its encounter with the sun. The second clip shows the comet exiting from behind the right side of the sun, after an hour of travel through its closest approach to the sun. By tracking how the comet interacts with the sun's atmosphere, the corona, and how material from the tail moves along the sun's magnetic field lines, solar scientists hope to learn more about the corona. This movie was filmed by the Solar Dynamics Observatory in 171 angstrom wavelength, which is typically shown in yellow.
Credit: NASA/SDO
SDO observed the flare's peak at 1:41 AM ET. SDO recorded these images in extreme ultraviolet light that show a very large eruption of cool gas. It is somewhat unique because at many places in the eruption there seems to be even cooler material — at temperatures less than 80,000 K.
This video uses the full-resolution 4096 x 4096 pixel images at a one minute time cadence to provide the highest quality, finest detail version possible.
It is interesting to compare the event in different wavelengths because they each see different temperatures of plasma. See the transcript for more notes on this.
Frames for each wavelength are available on these separate pages: 304, 171, 211, and1700.