http://sdo.gsfc.nasa.gov SDO is designed to help us understand the Sun's influence on Earth and Near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously. Kevin.M.Addison@nasa.gov (Kevin M. Addison) Kevin.M.Addison@nasa.gov (Kevin M. Addison) en 200 Wed, 20 Mar 2019 03:45:11 +0000 http://sdo.gsfc.nasa.gov/assets/img/site/SDO_logo_glassy.jpg http://sdo.gsfc.nasa.gov http://sdo.gsfc.nasa.gov/gallery/potw/item/954 On Mar. 6, 2019, SDO observed a long lunar transit - with a twist. The shadow of the Moon in SDO's images first touched the limb of the Sun at 2200 UTC (5pm EST) on Mar. 6, making its way across and finally left the solar disk at 0209 UTC on Mar. 7 (9:09 pm EST, Mar. 6). The moon's apparent reversal is caused by SDO first overtaking the moon in its orbit, then the moon catching up as SDO swings around Earth's dusk side. During the transit the Sun moves in the frame as the telescopes cool and flex in the lunar shadow.ÊNote that the edge of the Moon is very sharp because it has no atmosphere. Credit: Solar Dynamics Observatory, NASA. This is the last Picture of the Week produced by Steele Hill. We would like to thank Steele for 9 years of SDO POTWs! He also selects POTWs for SoHO and STEREO. With 23 and 13 years on-orbit, that means Steele has picked over 2000 POTWs! Thanks for looking at all those beautiful images and finding a favorite almost every week! http://sdo.gsfc.nasa.gov/gallery/potw/item/954 Fri, 08 Mar 2019 14:58:00 +0000 aia, tansit, eclipse, 171 Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/952 For the first time in a long time the Sun has gone an entire month without any sunspots (Feb. 1-28, 2019). To put this in context, for five years (2011-2015) surrounding the latest solar maximum in March 2014 - the period when the Sun's magnetic activity is the most intense - there were only three days without any sunspots[MH1]. What a difference! The change in the level of activity during the Sun's average 11-year solar cycle is quite dramatic. We are probably not quite at the minimum level of activity yet, but are certainly getting close. The images were taken in filtered white (visible) light. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/952 Mon, 04 Mar 2019 11:03:52 +0000 hmi, intensitygram, sunspot Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/950 The SDO spacecraft is in another eclipse season as of Feb. 6, 2019. This begins a several week period when the Earth briefly blocks SDO’s view of the Sun each day. In fact, because SDO orbits above the Mountain Time zone, the Earth passes between SDO and the Sun at about 7:20 UT (12:20 am MT) each orbit. Eclipses are due to SDO’s circular geosynchronous orbit some 22,000 miles above Earth. At the speed we are showing the frames, the eclipse is only a flicker. The still image shows that the edge of Earth, here about halfway across the Sun, looks quite rough due to the absorption of the 304 Å EUV light by our atmosphere. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/950 Wed, 13 Feb 2019 12:33:44 +0000 aia, 304, transit Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/948 The sun sported four smallish prominences along its edge at about the same time (Dec. 12-14, 2018). They were at the positions of 2 o'clock, 5 o'clock, 7 o'clock, and 10 o'clock. The largest and most active of the prominences was at the 7 o'clock point. Prominences are clouds of charged particles suspended above the sun by magnetic forces. These were observed in a wavelength of extreme ultraviolet light. The video clip covers almost two days' of activity: it consists of 335 frames being shown at 20 frames per second. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/948 Mon, 17 Dec 2018 14:47:14 +0000 aia, 304, prominence Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/946 The only active region observed this week appeared on Dec. 5, 2018 and grew into an average size display of dynamic activity (Dec. 6-7, 2018). As viewed in a wavelength of extreme ultraviolet light, the region presented numerous magnetic loops of charged particles, rapidly changing their shapes and directions. As the sun is approaching its minimum level of activity in its 11 year solar cycle, we expect to see fewer and fewer active regions for quite a while. However, this active region is in the southern hemisphere of the Sun and has the North magnetic pole in the lead, so it is a sunspot of Solar Cycle 24. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/946 Fri, 07 Dec 2018 14:37:52 +0000 aia, 171, active region, magnetic loops Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/944 A long-lasting coronal hole has again rotated around to face the Earth (Nov. 28-30, 2018). This persistent hole - the elongated dark region seen in the still image - first appeared in July and has been observed each rotation of the Sun since. Coronal holes are the source of high-speed solar wind; when this one faced Earth, it sparked outbursts of aurora some of which were observed in our northern tier states. Coronal holes are magnetically open regions on the Sun that can last from days to months, although this one has lasted longer than most. The time-lapse video, taken in a wavelength of extreme ultraviolet light, covers about two days of activity. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/944 Tue, 04 Dec 2018 13:56:03 +0000 aia, 193, coronal hole Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/942 Two solar prominences, directly at opposite sides of the Sun, rose up, twisted around, and fell apart at roughly the same time over a 26-hour period (Nov. 12-13, 2018). Prominences are cooler clouds of plasma suspended above the Sun by powerful magnetic forces. Although prominences are fairly common, it is uncommon to see two of them, about the same size, diametrically opposed to each other and lasting just about the same time. The images were taken in a wavelength of extreme ultraviolet light. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/942 Mon, 19 Nov 2018 12:09:39 +0000 aia, 304, prominence Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/940 On Nov. 7 for just under an hour, SDO viewed a lunar transit, when the Moon partially blocked SDO's view of the Sun. At its peak about 44% of the Sun was covered. In this view, the Sun was observed in extreme ultraviolet light and, as is customary, been given false color. These lunar transits provide scientific value as well: The sharp edge of the lunar limb helps researchers measure how light diffracts around the telescope's optics and filter support grids, allowing scientists to better calibrate the instruments for even sharper images. Lunar transits happen less often than the daily eclipses when the Earth passes in front of its view of the Sun during two three-week eclipse periods each year. http://sdo.gsfc.nasa.gov/gallery/potw/item/940 Tue, 13 Nov 2018 11:48:46 +0000 aia, 171, lunar transit Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/938 The most distinctive feature on the Sun this week was a good-sized coronal hole at a slanted angle nearly centered on the face of the sun (Oct. 31-Nov.2, 2018). Coronal holes are magnetically open areas from which solar wind particles speed into space. They appear darker in this wavelength of extreme ultraviolet light. If these particles impact Earth's magnetosphere, they will likely generate aurora near the Earth's poles regions. The video clip covers about two days of activity. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/938 Mon, 05 Nov 2018 12:16:10 +0000 aia, coronal hole, 193 Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/936 On Oct. 24 - 25, 2018 a solar prominence rose up above the Sun's surface, twisted and spun around, then became elongated and broke away. Prominences are unstable clouds of cooler plasma suspended above the Sun by strong magnetic forces. They often fall apart after a few days. Although tiny on the scale of the Sun, this prominence stretched out about ten times the diameter of Earth (see inset). Images were taken in a wavelength of extreme ultraviolet light. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/936 Mon, 29 Oct 2018 10:52:27 +0000 aia, 304, prominence Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/934 The Sun's rotation brought a new active region into view, revealing the dynamic arches and twisting streams of its magnetic field (Oct. 10-11, 2018). A new active region is becoming more of a rare sight, as the Sun is currently approaching solar minimum--the point of the 11-year solar cycle when activity is most reduced. The video clip, showing images taken in a wavelength of extreme ultraviolet light covers 33 hours and consists of over 500 frames (i.e., one frame selected every 4 minutes). Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/934 Wed, 17 Oct 2018 11:34:08 +0000 aia, 171, active region Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/932 SDO observes the Sun in ten different wavelengths because each wavelength reveals different solar features. Here, we have selected two images taken at the virtually the same time but in different wavelengths of extreme ultraviolet light. The red tinted image, which captures material not far above the Sun's surface, is especially good for revealing details along the edge of the Sun, like the small prominence at the ten o'clock position. The brown tinted image clearly shows two large coronal holes (darker areas) as well as some faint magnetic field lines and hints of solar activity (lighter areas), neither of which are apparent in the red image. This activity is occurring somewhat higher in the Sun's corona. In a way it is like peeling away the layers of an onion, a little at a time. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/932 Mon, 24 Sep 2018 11:15:27 +0000 AIA, 304, 193 Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/930 In just about seven hours, the SDO spacecraft saw the moon transit the Sun two times (Sept. 9-10, 2018). Transits occur when an object passes between a larger body and the viewer.ÊThe first transit lasted about an hour and covered 92 percent of the Sun at its peak.ÊThe second transit lasted about 50 minutes and covered just 34 percent of the Sun at its peak. The Moon appears to go in one direction in the first transit and the opposite direction in the second. This is because the SDO spacecraft orbits around Earth, moving in the same direction as the Moon but faster. On the first transit it catches up with and passes the Moon. As SDO swings back around the far side of Earth, it encounters the Moon again from the far side of Earth, where it appears to travel in the opposite direction. The images were taken in a wavelength of extreme ultraviolet light. None of this was visible from Earth. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/930 Wed, 19 Sep 2018 09:35:33 +0000 aia, 304, lunar transit Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/928 The Sun already featured one good-sized coronal hole, when another larger coronal hole began to emerge and intensify (Sept. 4-6, 2018). Coronal holes appear dark in extreme ultraviolet light, as is shown here. They are magnetically open areas from which solar wind streams out into space, and can last from days to months. The brighter area between the two coronal holes is an active region where the level of magnetic activity is strong. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/928 Mon, 17 Sep 2018 11:00:12 +0000 aia, 193, coronal hole Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/926 Over the course of just one day a tiny active region grew to became almost as large as its many-days-old neighbor (Aug. 23-24, 2018). Active regions, which are areas of intense magnetism, appear brighter in wavelengths of extreme ultraviolet light and are often the source of solar storms. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/926 Tue, 04 Sep 2018 10:01:32 +0000 aia, 193, active regions Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/924 This close-up of the Sun from a two-hour period on Aug 13, 2018 shows a minor eruption of charged particles rising up and twisting about before falling back into the Sun. Imaged in extreme ultraviolet light, these kinds of events are difficult to see except when they occur along the sun's edge, also known as the limb. At its peak the plasma rises several times the diameter of Earth. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/924 Wed, 22 Aug 2018 13:54:25 +0000 aia, 304, prominence Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/922 Every day scientists use their computer models to generate a view of the sun's magnetic field (Aug. 10, 2018). We took the opportunity to compare an extreme ultraviolet view of the sun with the same image showing the superimposed field lines. The bright active region right at the central area of the sun clearly shows a concentration of field lines, as well as the small active region at the sun's right edge, but to a lesser extent. Magnetism drives the dynamic activity near the sun's surface. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/922 Mon, 13 Aug 2018 13:28:55 +0000 aia, 193, magnetic field, field lines Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/920 Two relatively small prominences above the Sun's surface twisted and streamed charged particles over a 20-hour period (July 30-31, 2018), shown here in a wavelength of extreme ultraviolet light. Prominences are large, bright features anchored to the Sun's photosphere but extending outward into its hot outer atmosphere, called the corona. Scientists are still researching how and why prominences are formed. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/920 Thu, 09 Aug 2018 14:32:07 +0000 aia, 304, prominences Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/918 Over a three-week period (July 3-24, 2018), the Sun produced just one small, short-lived sunspot - but it tells a big story. Up until July 22, the Sun had no sunspots for 23 consecutive days, the first time that has happened in nine years. The Sun is rapidly approaching solar minimum, a period of very low solar activity in its 11-year cycle - and doing so more rapidly than many scientists predicted. Credit: Solar Dynamics Observatory, NASA. http://sdo.gsfc.nasa.gov/gallery/potw/item/918 Tue, 31 Jul 2018 11:55:44 +0000 hmi, intensitygram, sunspot Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams. http://sdo.gsfc.nasa.gov/gallery/potw/item/916 We zoomed in to watch close-up the dynamics of this single active region on the sun over a two-day period (July 14-16, 2018). The loops we are observing in extreme ultraviolet light are illuminated by charged particles spinning along the magnetic field lines above an active region. Active regions are magnetically intense areas that are pushed up to the surface of the sun from below. These regions are often the sources of large eruptions that cause solar storms, though no large eruptions seem to have occurred during this period. To give a sense of scale, these loops are rising up many times the diameter of Earth. Credit: Solar Dynamics Observatory. http://sdo.gsfc.nasa.gov/gallery/potw/item/916 Wed, 25 Jul 2018 13:14:00 +0000 aia, 171, eruptions, active region, loops Courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.