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A Year on the Sun Through Our Satellite’s Eyes

Did you know we’re watching the Sun 24/7 from space?

We use a whole fleet of satellites to monitor the Sun and its influences on the solar system. One of those is the Solar Dynamics Observatory. It’s been in space for eight years, keeping an eye on the Sun almost every moment of every day. Launched on Feb. 11, 2010, this satellite (also known as SDO) was originally designed for a two-year mission, but it’s still collecting data to this day — and one of our best ways to keep an eye on our star.

To celebrate another year of SDO, we’re sharing some of our favorite solar views that the spacecraft sent back to Earth in 2017.

 March: A long spotless stretch

For 15 days starting on March 7, SDO saw the yolk-like spotless Sun in visible light.

The Sun goes through a natural 11-year cycle of activity marked by two extremes: solar maximum and solar minimum. Sunspots are dark regions of complex magnetic activity on the Sun’s surface, and the number of sunspots at any given time is used as an index of solar activity.

Solar maximum = intense solar activity and more sunspots

Solar minimum = less solar activity and fewer sunspots

This March 2017 period was the longest stretch of spotlessness since the last solar minimum in April 2010 – a sure sign that the solar cycle is marching on toward the next minimum, which scientists expect in 2019-2020. For comparison, the images on the left are from Feb. 2014 – during the last solar maximum –  and show a much spottier Sun.

June: Energized active regions

 A pair of relatively small but frenetic active regions – areas of intense and complex magnetic fields – rotated into SDO’s view May 31 – June 2, while spouting off numerous small flares and sweeping loops of plasma. The dynamic regions were easily the most remarkable areas on the Sun during this 42-hour period.

July: Two weeks in the life of a sunspot

On July 5, SDO watched an active region rotate into view on the Sun. The satellite continued to track the region as it grew and eventually rotated across the Sun and out of view on July 17.  

With their complex magnetic fields, sunspots are often the source of interesting solar activity: During its 13-day trip across the face of the Sun, the active region — dubbed AR12665 — put on a show for our Sun-watching satellites, producing several solar flares, a coronal mass ejection and a solar energetic particle event. 

August: An eclipse in space

While millions of people in North America experienced a total solar eclipse on Aug. 21, SDO saw a partial eclipse from space. SDO actually sees several lunar transits a year from its perspective – but an eclipse on the ground doesn’t necessarily mean that SDO will see anything out of the ordinary. Even on Aug. 21, SDO saw only 14 percent of the Sun blocked by the Moon, while most US residents saw 60 percent blockage or more.

September: A spate of solar activity

In September 2017, SDO saw a spate of solar activity, with the Sun emitting 31 notable flares and releasing several powerful coronal mass ejections between Sept. 6-10. Solar flares are powerful bursts of radiation, while coronal mass ejections are massive clouds of solar material and magnetic fields that erupt from the Sun at incredible speeds.

One of the flares imaged by SDO on Sept. 6 was classified as X9.3 – clocking in at the most powerful flare of the current solar cycle. The current cycle began in December 2008 and is now decreasing in intensity, heading toward solar minimum. During solar minimum, such eruptions on the Sun are increasingly rare, but history has shown that they can nonetheless be intense.

September: A trio of tempests

Three distinct solar active regions with towering arches rotated into SDO’s view over a three-day period from Sept. 24-26. Charged particles spinning along the ever-changing magnetic field lines above the active regions trace out the magnetic field in extreme ultraviolet light, a type of light that is typically invisible to our eyes, but is colorized here in gold. To give some sense of scale, the largest arches are many times the size of Earth.

December: A curling prominence

SDO saw a small prominence arch up and send streams of solar material curling back into the Sun over a 30-hour period on Dec. 13-14. Prominences are relatively cool strands of solar material tethered above the Sun’s surface by magnetic fields.

 December: Solar question mark

An elongated coronal hole — the darker area near the center of the Sun’s disk — looked something like a question mark when seen in extreme ultraviolet light by SDO on Dec. 21-22. Coronal holes are magnetically open areas on the Sun that allow high-speed solar wind to gush out into space. They appear as dark areas when seen in certain wavelengths of extreme ultraviolet light.

For all the latest on the Solar Dynamics Observatory, visit nasa.gov/sdo. Keep up with the latest on the Sun on Twitter @NASASun or at facebook.com/NASASunScience.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com 

September 2017 Was 🔥 on the Sun

The Sun started September 2017 with flair, emitting 31 sizable solar flares and releasing several powerful coronal mass ejections, or CMEs, between Sept. 6-10.

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. 

CMEs are massive clouds of solar material and magnetic fields that erupt from the Sun at incredible speeds. Depending on the direction they’re traveling in, CMEs can spark powerful geomagnetic storms in Earth’s magnetic field.

As always, we and our partners had many missions observing the Sun from both Earth and space, enabling scientists to study these events from multiple perspectives. With this integrated picture of solar activity, scientists can better track the evolution of solar eruptions and work toward improving our understanding of space weather.

The National Oceanic and Atmospheric Administration (NOAA)’s Geostationary Operational Environmental Satellite-16, or GOES-16, watches the Sun’s upper atmosphere — called the corona — at six different wavelengths, allowing it to observe a wide range of solar phenomena. GOES-16 caught this footage of an X9.3 flare on Sept. 6, 2017. 

This was the most intense flare recorded during the current 11-year solar cycle. 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 so on. GOES also detected solar energetic particles associated with this activity.

Our Solar Dynamics Observatory captured these images of X2.2 and X9.3 flares on Sept. 6, 2017, in a wavelength of extreme ultraviolet light that shows solar material heated to over one million degrees Fahrenheit.

JAXA/NASA’s Hinode caught this video of an X8.2 flare on Sept. 10, 2017, the second largest flare of this solar cycle, with its X-ray Telescope. The instrument captures X-ray images of the corona to help scientists link changes in the Sun’s magnetic field to explosive solar events like this flare.

Key instruments aboard our Solar and Terrestrial Relations Observatory, or STEREO, include a pair of coronagraphs — instruments that use a metal disk called an occulting disk to study the corona. The occulting disk blocks the Sun’s bright light, making it possible to discern the detailed features of the Sun’s outer atmosphere and track coronal mass ejections as they erupt from the Sun.

On Sept. 9, 2017, STEREO watched a CME erupt from the Sun. The next day, STEREO observed an even bigger CME. The Sept. 10 CME traveled away from the Sun at calculated speeds as high as 7 million mph, and was one of the fastest CMEs ever recorded. The CME was not Earth-directed: It side-swiped Earth’s magnetic field, and therefore did not cause significant geomagnetic activity. Mercury is in view as the bright white dot moving leftwards in the frame.

Like STEREO, ESA/NASA’s Solar and Heliospheric Observatory, or SOHO, uses a coronagraph to track solar storms. SOHO also observed the CMEs that occurred during Sept. 9-10, 2017; multiple views provide more information for space weather models. As the CME expands beyond SOHO’s field of view, a flurry of what looks like snow floods the frame. These are high-energy particles flung out ahead of the CME at near-light speeds that struck SOHO’s imager.

Our Interface Region Imaging Spectrometer, or IRIS, captured this video on Sept. 10, 2017, showing jets of solar material swimming down toward the Sun’s surface. These structures are sometimes observed in the corona during solar flares, and this particular set was associated with the X8.2 flare of the same day.  

Our Solar Radiation and Climate Experiment, or SORCE, collected the above data on total solar irradiance, the total amount of the Sun’s radiant energy, throughout Sept. 2017. While the Sun produced high levels of extreme ultraviolet light, SORCE actually detected a dip in total irradiance during the month’s intense solar activity. 

A possible explanation for this observation is that over the active regions — where solar flares originate — the darkening effect of sunspots is greater than the brightening effect of the flare’s extreme ultraviolet emissions. As a result, the total solar irradiance suddenly dropped during the flare events. 

Scientists gather long-term solar irradiance data in order to understand not only our dynamic star, but also its relationship to Earth’s environment and climate. We are ready to launch the Total Spectral solar Irradiance Sensor-1, or TSIS-1, this December to continue making total solar irradiance measurements.

The intense solar activity also sparked global aurora on Mars more than 25 times brighter than any previously seen by NASA’s Mars Atmosphere and Volatile Evolution, or MAVEN, mission. MAVEN studies the Martian atmosphere’s interaction with the solar wind, the constant flow of charged particles from the Sun. These images from MAVEN’s Imaging Ultraviolet Spectrograph show the appearance of bright aurora on Mars during the September solar storm. The purple-white colors show the intensity of ultraviolet light on Mars’ night side before (left) and during (right) the event.

For all the latest on solar and space weather research, follow us on Twitter @NASASun or Facebook.

GOES images are courtesy of NOAA. Hinode images are courtesy of JAXA and NASA. SOHO images are courtesy of ESA and NASA. 

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

The Sun Just Released the Most Powerful Flare of this Solar Cycle

The Sun released two significant solar flares on Sept. 6, including one that clocked in as the most powerful flare of the current solar cycle.

The solar cycle is the approximately 11-year-cycle during which the Sun’s activity waxes and wanes. The current solar cycle began in December 2008 and is now decreasing in intensity and heading toward solar minimum, expected in 2019-2020. Solar minimum is a phase when solar eruptions are increasingly rare, but history has shown that they can nonetheless be intense.

Footage of the Sept. 6 X2.2 and X9.3 solar flares captured by the Solar Dynamics Observatory in extreme ultraviolet light (131 angstrom wavelength)

Our Solar Dynamics Observatory satellite, which watches the Sun constantly, captured images of both X-class flares on Sept. 6.

Solar flares are classified according to their strength. X-class denotes the most intense flares, followed by M-class, while the smallest flares are labeled as A-class (near background levels) with two more levels in between. Similar to the Richter scale for earthquakes, each of the five levels of letters represents a 10-fold increase in energy output. 

The first flare peaked at 5:10 a.m. EDT, while the second, larger flare, peaked at 8:02 a.m. EDT.

Footage of the Sept. 6 X2.2 and X9.3 solar flares captured by the Solar Dynamics Observatory in extreme ultraviolet light (171 angstrom wavelength) with Earth for scale

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 Earth’s atmosphere in the layer where GPS and communications signals travel.

Both Sept. 6 flares erupted from an active region labeled AR 2673. This area also produced a mid-level solar flare on Sept. 4, 2017. This flare peaked at 4:33 p.m. EDT, and was about a tenth the strength of X-class flares like those measured on Sept. 6.

Footage of the Sept. 4 M5.5 solar flare captured by the Solar Dynamics Observatory in extreme ultraviolet light (131 angstrom wavelength)

This active region continues to produce significant solar flares. There were two flares on the morning of Sept. 7 as well. 

For the latest updates and to see how these events may affect Earth, please visit NOAA’s Space Weather Prediction Center at http://spaceweather.gov, the U.S. government’s official source for space weather forecasts, alerts, watches and warnings.

Follow @NASASun on Twitter and NASA Sun Science on Facebook to keep up with all the latest in space weather research.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.