SOHO, or the Solar and Heliospheric Observatory, just celebrated 20 years in space with a main goal of learning more about the sun's activity. The spacecraft has seen some neat things, including comets, planets and unexpected solar activity. Here,based on a video recently produced by NASA
, are some of the more unusual things SOHO has witnessed.PHOTOS: The Psychedelic Anatomy of a Solar Flare
SOHO/LASCO (ESA & NASA)
Because the planets periodically pass nearby the sun from SOHO's perspective, the spacecraft can see them in its viewfinder. They look a little overexposed because they are so bright (compared with the wispy clouds of plasma in the solar wind), but they still provide a unique view of our neighbors in space. This congregation pictured here took place in 2000 and includes Venus, Mercury, Jupiter and Saturn -- as well as a famous star cluster called the Pleiades.NEWS: Ace Solar Observatory to Make 3,000th Comet Discovery
"Such congregations of planets are rare events, and they cannot be seen from the ground when close in the sky to the dazzling sun. But the LASCO C3 instrument on SOHO uses a mask to blot out direct sunlight, and it has a wide enough field of view (15 degrees) to take in the four planets in the same picture," the SOHO website wrote at the time.
Is that a snowstorm in space? No, it's actually energetic particles hitting the viewfinder of SOHO. These are caused by fast-moving protons coming from the sun, and you can see the view can get rather ... intense at times. This particular image happened in January 2012 during one of the strongest radiation storms since 2005. These storms are more frequent when the sun reaches its maximum, which last happened in roughly 2013-14.RELATED: Bye Bye Snowball - A Comet's Hellish Death Dive
NASA is interested in these storms not only because they are awesome to watch, but also to monitor their effects on Earth. Solar storms can cause blackouts in radio communications, satellites and power lines if they are strong enough. Part of SOHO's role is to provide better predictions of the sun's activity and how Earth's environment will react to it.
SOHO was not designed to look for comets, but the sun happens to be a great place to look for them. The massive gravitational attraction of the star periodically pulls comets very close to its vicinity. Most of these so-called "sungrazers" do not survive their closest approach, called perihelion, but at least we can see their remains in pictures. Comet count so far? More than 3,000.ANALYSIS: Ace Solar Observatory to Make 3,000th Comet Discovery
This is a particularly spectacular example from 2003, when Comet NEAT made a close approach while the sun was quite active. "The LASCO pictures and movies of this comet are quite out of the ordinary, with a sizeable tail and a very bright (saturated) comet nucleus," the SOHO website wrote at the time. "We even got a nice coronal mass ejection (CME) off the west limb close to perihelion time, putting the icing on the cake!"
The sun has a fairly routine cycle of activity that lasts roughly 11 years between maximum and maximum. But it's not always a clear shot as to when you're going to see a big flare. In 2003, the sun became extremely active long after its expected peak in 2001, which shows us how much more scientists have to learn.PHOTOS: Ten Mind-Blowing Solar Views from the SDO
"Some of the most intense activity that we saw was in the fall of 2003," said Joe Gurman, the U.S. project scientist for SOHO, in a NASA video posted on Twitter. "This was bit of a surprise as it was a couple of years after the maximum of the 11 year cycle."
Image: A spectacular coronal mass ejection erupts off the sun in 2003. At left is a planet.
This was a surprise discovery for SOHO. The spacecraft's observations reveal a sort of pulse that takes place during coronal mass ejections -- those particle-laden explosions from the sun. It's a neat find because it shows us more about how the inner workings of the sun create the activity that you can see in pictures of CMEs.RELATED: The Sun Rumbles With Bright Magnetic Activity
"Think of an underwater explosion: you will get water forced upwards as a great spray, but you will also get a wave on the surface of the water that travels outwards from the explosion site," SOHO wrote on an educational website. "The waves on the sun are similar, although in this case the explosion occurs just above the surface rather than below it."
Image: A 2008 solar explosion caught up close by the TRACE spacecraft after first being spotted by SOHO.
The skies went dark over parts of Indonesia and the Pacific Ocean region Tuesday evening (March 8) as the only total solar eclipse of 2016 took hold.
The moon briefly blotted out the sun for observers in a 90-mile-wide (145 kilometers) strip of land and sea — the “path of totality” — that stretched east across Sumatra, Borneo, Sulawesi and other islands, all the way to an empty patch of the Pacific northeast of Hawaii. You can see photos of the total solar eclipse of 2016 here from Space.com readers and live webcasts.
“We’ve got totality here!” Paul Cox said Tuesday evening from Sulawesi, where he had traveled to host a live eclipse webcast for the Slooh Community Observatory. [Video: NASA Explains the Total Solar Eclipse of 2016]
“I can now see prominences — they are beautiful. Wow!” Cox added. His excitement then ratcheted up even more as he witnessed the “diamond ring effect,” in which the sun-moon pair resembles a piece of gigantic sky bling. “That is the most beautiful thing I’ve ever seen.”
Indeed, the next solar eclipse — which will be visible from parts of Africa on Sept. 1 — will be the annular type.
North American skywatchers may feel left out by Tuesday’s event and the upcoming African eclipse, but their time is coming. On Aug. 21, 2017, a total solar eclipse will be visible from a swath of the north-central United States stretching from Oregon to South Carolina. And most of North America will be able to catch a partial version of this “Great American Eclipse.”