Today, @ESA & @NASA’s SOHO solar observatory marks 25 years in space! Over the past quarter century, SOHO has revolutionized the way we understand the Sun, illuminating everything from its inner workings to the storms that explode from its atmosphere. https://go.nasa.gov/3mDcSLO 

SOHO’s coronagraph — one of 12 instruments — was a gamechanger. Coronagraphs use a disk to block out the Sun’s bright face and reveal the faint outer atmosphere, the corona, to see how it changes and track giant eruptions of solar material called coronal mass ejections.

Coronal mass ejections can impact robotic spacecraft in their path, or — when intense and aimed at Earth — threaten astronauts on spacewalks and even disrupt power grids on the ground. Today, SOHO’s coronagraph images are the backbone of space weather models.

Beyond day-to-day monitoring, SOHO has also provided insight into our Sun over a full magnetic cycle, when the Sun’s magnetic poles flip from north to south and back again, a process that takes 22 years.

SOHO’s trove of data has led to revolutions in solar science: from revelations about the behavior of the solar core to new insight into space weather events that explode from the Sun and travel throughout the solar system.

Listen to some of SOHO’s sonified data.

The legacy of SOHO’s instruments — such as the extreme ultraviolet imager, the first of its kind to fly in orbit — also paved the way for the next generation of NASA solar satellites, like the Solar Dynamics Observatory and STEREO.

SOHO has also become the greatest comet finder of all time, thanks to its coronagraph instrument. The mission’s data has revealed more than 4,000 comets to date, many of which were found by citizen scientists. https://go.nasa.gov/33x53Qb 

“25 years should just be the start. From a scientific point of view, we need to keep going, we can’t take our eyes off the Sun.” - Jack Ireland, SOHO project scientist at @NASAGoddard https://go.nasa.gov/3mDcSLO