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This news came as a surprise to me: SOHO launched into space on December 2, 1995, so Tuesday marked its 30^th year in space! It’s a surprise because geez, that’s a long time ago, but also geez, I remember when it launched.

The NASA/ESA Solar and Heliophysics Observatory was an ambitious mission, designed to stare at the Sun continuously, day in and day out, measuring it with a fleet of scientific instruments, including LASCO, the Large Angle and Spectrometric Coronagraph, which took wide-angle shots of the Sun. It had a wedge of metal in it that blocked the Sun’s direct light, allowing the fainter parts of the Sun like its corona to become visible.

Sometimes, when the Sun was feisty, blowing out a big flare (a highly local but extremely powerful magnetically induced explosion) or a coronal mass ejection (larger and fainter but still flinging out a billion tons of hydrogen gas at disturbingly high velocity) — I explain more about these in BAN #582 — the LASCO image would get covered in cosmic ray hits, subatomic particles slamming into it and creating thousands of bright pixels all over it. That always gave me the creeps; those particles play havoc with electronics, and in sufficient quantity don’t play well with human cells, either. Our atmosphere protects us, but astronauts have to take cover in a protected area of the space station to make sure they don’t get too big a radiation dose.

Speaking of which, I remember the immense solar storms of the early 2000s, like the Bastille Day event in July 2000 and the Halloween storms of 2003. That latter one was truly terrifying; one flare was estimated to be an X45 on the scale, which made it one of the most powerful ever seen. Smaller flares can cause blackouts and such, and this one did play havoc with communications and it interacted with Earth’s atmosphere. The SOHO observations of these events were crucial in understanding the underlying physics.

As for the launch date… I had just defended my PhD in 1994 and gotten a job at a contractor for NASA’s Goddard Space Flight Center when SOHO launched. Later, when I got another job at Goddard, I would sometimes walk the halls and talk to other scientists (I had a difficult time focusing on work for eight hours straight every day), and many of them worked on solar astronomy. Many are also still friends today, and it’s interesting and a bit nostalgic to think back to those times when SOHO was the most sophisticated observatory to watch the Sun. And it’s still up there, between Earth and the Sun at the L1 point, sending back important information to help us study our nearest star. Literally our technological civilization depends on this, so I’m glad the old observatory is still ticking away.

Congrats to the thousands of people involved with this mission, and may it continue to keep an eye on Sol for a long time to come.

You can read more about this 30^th celebration at the ESA and NASA websites.

I am not an expert in either of these fields, so take this with a grain of salt, but a team of scientists claims they have found a link between climate and seismic activity. The catch is, it’s occurring in a single specific place. Still, if this pans out, it’s pretty cool.

The spot is Lake Turkana in Kenya, which is on the East African Rift Valley, a long crack in the ground where two continental plates are moving apart. As climate patterns in the area change, the lake has water levels that fluctuate dramatically; thousands of years ago, for example, the water level was 100 meters higher than it is now.

The team sampled the subsurface volume under the huge lake at many locations, and after analyzing them found a curious pattern: the fault lines moved and magma under the surface increased when the lake was dry, and decreased when the lake was more full. They posit the pressure of the water when the lake is fuller affects the seismic conditions under the lake.

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