The Solar and Heliospheric Observatory referred to as SOHO, having just celebrated 20 years in space with the main goal of learning more about solar activity. The spacecraft saw several remarkable things, such as comets, planets and the manifestation of unexpected solar activity. Here, from the video data recently obtained by NASA, we can say SOHO has witnessed several of the most unusual phenomena.
Since the planets periodically pass near the Sun, from the SOHO position, the spacecraft can see them in its video detectors. They look a bit overexposed because they are so bright (compared to the thin plasma clouds of the solar wind), but they still provide a unique view of our neighbors in space. This congregation, depicted here, was captured in 2000 and includes Venus, Mercury, Jupiter and Saturn - as well as the famous Pleiades star cluster.
“Such assemblies of planets are rare events and cannot be seen from Earth because the sky covers the dazzling Sun. But the LASCO C3 on SOHO uses a mask that smoothes out direct sunlight and, having a fairly wide field of view (15 degrees), takes the same picture in four planets, "wrote the SOHO website at the time.
"Snow" from energetic particles
A blizzard in space? No, in fact, these are energetic particles trapped in the SOHO viewfinder. This phenomenon is caused by the rapid movement of protons coming from the Sun, and you can see the view more intensely at times. This image was captured in January 2012 during one of the strongest radiation storms that began in 2005. These storms occur more often when the Sun reaches its maximum, in the past occurred around 2013-14. NASA is interested in these storms, not only because they are astounding when viewed, but also to determine their impact on the Earth. Solar storms can cause blackouts, satellites and power lines, if they are strong enough. Part of the role of SOHO is to provide improved predictions about solar activity and how the Earth’s environment will respond to it.
SOHO was not designed to search for comets, but there are excellent places on the Sun where you can see them. The massive gravitational attraction of a star periodically pulls comets very close to its surroundings. Most of them are so-called "sangrazers" do not withstand a close approximation, but at least we can see their remains in pictures. How many of them? More than 3000.
Especially a vivid example from 2003, when the comet NEAT was with a close approach, while the sun was quite active. "The LASCO photos and films of this comet are very unusual, with a significant tail and a very bright (saturated) comet core," wrote the SOHO website at that time. "We even got a good ejection of the coronal mass (CME) of the western part close to the time of perihelion by putting icing on the cake!"
Unintended solar activity
The sun has a fairly ordinary cycle of activity that lasts about 11 years between the maximum and the next maximum. However, it is not always clear when there will be a big flash. In 2003, the Sun became extremely active, later than its expected peak in 2001. “The most intense activity that we saw was in the fall of 2003,” said Joe Gourmand, a US SOHO project scientist, in a NASA video posted on Twitter. "It was a bit unexpected since it happened after the high of the 11-year cycle."
This discovery was a surprise for SOHO. Observations of the spacecraft revealed that the impulse passes during coronal mass ejections — these particles are charged explosions from the Sun. This is a great find because it shows more about how the inner workings of the Sun create energy, which you can see in the CME photo.
“Think of the underwater explosion: you get the water pointing upwards like a big spray, but you also get a wave on the surface of the water that moves outward from the explosion,” it is written on the educational site SOHO. "The waves on the Sun are similar, although in this case an explosion occurs just above the surface, and not beneath it."