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The auroras are one of earth's most dazzling displays, but thanks to Joan Feynman we know that they're so much more.

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[ intro ].

If you’ve ever been lucky enough to look up and see bright lights  dancing across the night sky, you’re familiar with one of the planet’s  most dazzling natural displays: the auroras. And for a long time, these light  shows were pretty mysterious.

But the late physicist Joan Feynman helped us  understand the origin of these light shows. She also figured out that they  can reveal clues about the Sun, as well as about the surprising connections  between our planet and the star we orbit. Joan Feynman was born in 1927 in Queens, New York.

You may already recognize her last  name and associate it with science, and that’s no coincidence. Her brother was Richard Feynman, one of the  most famous physicists of the 20th century. But before he was a famous  physicist, he was a brother.

And he would often talk with his  younger sister about science. He was the one to take her out to a  golf course near their house in Queens to see her first aurora when she was five or six. What neither one of them knew at  the time was that this experience would later inspire her career: in particular the decades she would spend  working on the physics underlying auroras.

After graduating with a PhD in solid state  physics from Syracuse University in 1958,. Joan Feynman got to work, trying to understand  what drives these polar light shows. For about 100 years,  astronomers had suspected a link between the Sun’s activity and auroras.

In 1859, they spotted a huge solar flare, and then two days later telegraph  wires started heating up and bright auroras extended as far  south as the Carribean and Hawaiʻi. But it wasn’t until we started sending  scientific instruments to space on satellites in the 1960s that we could really  figure out what was going on. And Feynman and her collaborators  were the first to do so.

In 1977, they used 14 years’  worth of satellite data to show that there was a close link between  the intensity of geomagnetic activity,   such as auroras, and the speed of the charged  particles streaming from the Sun, known as the solar wind. The most activity, and the most dazzling auroras, always happened during the most  tumultuous times on the Sun. So there was no longer any question  that auroras were caused by the Sun.

And armed with that insight, Feynman was able to   gain a greater understanding of  the Sun’s long-term patterns. See, previous researchers had  noticed that the Sun goes through an 11-year cycle of high and low activity caused by a switching of the Sun’s north and south poles. But there also seemed to be a longer, 88-year cycle running underneath the shorter one.

For about half of that cycle, the peaks and troughs in solar activity seemed to rise; then for the next half of that cycle,  all the peaks and troughs seemed to fall. But we didn’t exactly have solar data  going back for hundreds of years, so it was a little hard to verify. Instead, in the late 1970s and early 80s,.

Feynman and other researchers used  historical observations of auroras to figure out what the Sun’s activity  was like at different points in time. They knew that when the Sun is more active, it makes more, brighter auroras  happen further from the poles. So they could infer when it was most active  based on recorded observations of auroras.

And through this method, they were able to  confirm that the 88-year cycle really exists. Aside from being generally interesting, that’s also helpful to know  because the Sun’s activity   can have a big impact on us here on Earth. A rush of charged particles can disrupt our  telecommunications and electrical systems.

Like, during a peak of solar activity in 1989, a burst of hot plasma from the Sun caused  a 12-hour blackout for all of Quebec. So, understanding those patterns  can help us be better prepared. But Feynman’s later research suggests there are even more ways the Sun’s  activity affects us here on Earth.

In 2006, Feynman’s knack for finding patterns led   her to discover a connection between solar  activity and the water level of the Nile. It just so happens that the  people living by the Nile kept   very close track of this river for many centuries. Because of this, there are good records  of its water levels for almost 1000 years, between 622 and 1470 C.

E. And when Feynman and her collaborators matched that up with historical aurora  records for the same time period,   they found a surprising correlation. Both the patterns of the  auroras and the water levels in the Nile aligned with an 88-year cycle.

When the Sun was active and  there were lots of auroras, the water levels were low. When it was  less active, the water levels were higher. It may sound far-fetched, but there is a  good physical reason to believe it’s real.

In the 1990s, other researchers  used modern climate models to show how variations in UV light could mess with  the balance of ozone in Earth’s upper atmosphere. That, in turn, could affect temperature patterns and cause ripple effects that could  influence the overall climate. And Feynman and her collaborators  found that increased solar activity could affect a certain climate pattern  called the Northern Annular Mode, leading to decreased rainfall in Africa.

So not only did Feynman help us understand the colorful light shows in  northern and southern skies; she also made great leaps in  understanding the star we live beside   and its connection to our lives. Joan Feynman died in July of 2020, but thanks to her decades of  work and endless curiosity, she left us with a new appreciation and  understanding of our place in the natural world. Thanks for watching this episode of SciShow Space!

And a special thanks to everyone who supports us— whether it’s by joining our patron community or by   staying curious about the world.  We’re here because of all of you. And if you’d like to learn about  how you can support SciShow, you can find out more at [ outro ].