Do not miss this! Tyler Nordgren and solar eclipses

Tyler Nordgren wants to make sure that what happened to him as a nine-year-old astronomy nut doesn’t happen to you this summer.

Tyler Nordgren reads an excerpt from his book Sun Moon
Earth during a presentation January 14, 2017 at Town
Hall Seattle. Photo: Greg Scheiderer.

Nordgren, a professor of physics at the University of Redlands and author of Sun Moon Earth: The History of Solar Eclipses From Omens of Doom to Einstein and Exoplanets (Basic Books, 2016), talked at Town Hall Seattle earlier this month about the book and his work to educate the public about the total solar eclipse that will cross the United States on August 21, 2017.

As a kid Nordgren was passionate about astronomy and already knew he wanted to be an astronaut. He was living in Portland, Oregon in 1979 when a total solar eclipse passed right over his house.

“Because of the news warning us about looking at the Sun, I was sure that if I accidentally looked at the Sun during the eclipse, there were these special rays that would come out and burn my eyes,” he recalled. “So I hid in the house with the curtains drawn and I watched it on TV.”

He could tell the eclipse was happening because the house got really dark, but that was his one and only take-away from the event.

“One of the things that has driven me to work on this and to help promote this eclipse that is coming up this year is I don’t want to see another nine-year-old child out there having the experience that I did!” Nordgren said.

Good things come to those who wait

“It took me twenty years to eventually, finally see (a total solar eclipse) for myself,” Nordgren noted. He described what it’s like, the things that happen approaching and during totality, but said that he had an unexpected reaction to that first totality.

“As an astronomer, I know the mechanics of the celestial alignment, yet in this moment of totality, I fully understand the difference between knowledge and feeling,” he said. “When I finally, after 20 years, got a chance to see this for myself as a professional astronomer south of Budapest in Hungary in 1999, I swear the hair stood up on the back of my neck. It still remains the most amazing thing I have ever seen in the sky.”

“I could understand why generations of human beings would cower in fear at this,” he added, “and wonder, ‘When is the life-giving Sun going to come back?’”

Eclipse science

Nordgren described some of the stories different cultures cooked up to explain eclipses, and also discussed some of the science done during eclipses, including the determination, from spectra, that the Sun was largely made of hydrogen and contained some iron. Helium was discovered on the Sun 25 years before it was found on Earth. Perhaps the most famous science made possible by an eclipse was the determination that mass can indeed bend light waves, as predicted by Einstein’s theory of general relativity and measured during a solar eclipse in 1919. The media coverage turned Einstein from an obscure physicist into an icon.

“This is what made Einstein Einstein in the popular culture,” Nordgren said.

Do not miss this!

This August’s total solar eclipse will be the first to cross the United States from coast to coast since 1918. Nordgren, also an artist, has designed travel posters for many of the spots along the path of totality, and shared them as he talked about the path the eclipse will take. You can see, and buy, them on his website.

He pointed out that virtually everyone in the country will be able to see some degree of partial solar eclipse, but he urged us all not to settle and stay home just because there might be traffic.
“Do not miss this!” Nordgren urged.

“The difference between being inside and outside that path of totality is literally the difference between night and day,” he noted. “Inside totality, the sky goes black, the Sun turns dark, the stars come out, the corona is visible. Outside totality, yeah, it kinda gets sorta dark. Yeah, use your glasses. Yeah, there’s a bite taken out of the Sun. But it will pale in comparison to what you experience—not just what you see, but what you feel inside that path of totality.”

Nordgren said a good solar eclipse may be just the thing that we need.

“In difficult times, when, heaven knows, there have been lots of things that do not unite us, here is going to be a moment in which we are all united under the shadow of the Moon, and we will all be seeing this together,” he said. “This will become the most photographed, the most Tweeted, the most Instagrammed, the most shared group moment in the history of the world.”
“That’s what we have to look forward to this summer,” he concluded.

Grinspoon: Earth in human hands

David Grinspoon himself wonders how an astrobiologist wound up writing a book about the human impact on Earth. Grinspoon, author of Earth in Human Hands: Shaping Our Planet’s Future (Grand Central Publishing, 2016), answered the question during a Science in the City lecture recently at Pacific Science Center.

Astrobiologist and author David
Grinspoon talked about his new book,
Earth in Human Hands, January 10 at
the Pacific Science Center.
Photo: Greg Scheiderer.

“I am struck by the unique strangeness of the present moment,” Grinspoon said, noting that we are at the controls, if not actually in control, as we enter a new epoch in human history. Some find the proposed name of Anthropocene—the age of humanity—a touch self-centered or self-aggrandizing, but Grinspoon feels it is a fitting moniker.

“It represents a recognizable turning point in geological history brought about by one species: anthropos,” he said. “Our growing acknowledgement of this inflection point can be a turning point in our ability to respond to the changes we’ve set in motion.”

In fact, Grinspoon finds it promising that there’s some recognition that we the people are a major factor in what is happening.

“We need to learn all that we can about how planets work so we can make the transition from inadvertently messing with Earth to thoughtfully, artfully, and constructively engaging with its great systems,” he said.

A long history of planetary change

Grinspoon noted that it’s always fruitful to take a close look at the long-term history of Earth.
“We are not the first species to come along and radically change the planet and cause problems for the rest of the biosphere,” he said. In fact, the first one was not nearly so clever as we are. About 2.5 billion years ago the humble cyanobacteria caused a terrible calamity.

“They transformed the planet, the most radical chemical transformation that our planet has ever experienced,” Grinspoon explained. “They flooded the atmosphere with a poison gas that spelled certain doom for most of the other species that were living on the planet at that time.”
What they learned to do was photosynthesis, and the poison gas they spewed was oxygen. The oxygen also destroyed much of the warming methane in the atmosphere of the time, which led to a global glaciation that turned Earth into a giant snowball, a condition that lasted until volcanoes pumped out enough carbon dioxide to warm the planet up again.

“Cyanobacteria presumably never discussed that fact that they were starting to ruin the world,” Grinspoon quipped.

Four types of change

Grinspoon identifies four broad types of planetary change:

• Random
• Biological
• Inadvertent
• Intentional

The classic example of the random is an asteroid strike, something that just happens that there’s little control over. The cyanobacteria fall under the biological change. We’re in the midst of great inadvertent change right now, with automobiles, population growth and other factors driving a spike in carbon dioxide levels that began in the 1950s.

We’ve barely dipped our toes into the intentional. Grinspoon explained that our first stab at intentional change came with regard to fixing the hole in Earth’s ozone layer. The solution came from scientists studying Venus and trying to explain the planet’s lack of oxygen. They realized that chlorine destroys oxygen and ozone. Other scientists connected the dots and concluded that chlorofluorocarbons in refrigerants, propellants, and other products on Earth were eating away at our planet’s ozone layer.

Fixing the ozone

Interestingly, Grinspoon noted that this created an argument that may sound familiar. Some called the notion a hoax, there were attempts to discredit it, opposing “science” was created, and there was lengthy debate.

“The truth won out,” Grinspoon said. A global agreement was reached: the Montreal Protocol. Alternate chemicals were developed that didn’t deplete the ozone. Grinspoon said it’s working.

“It’s still going to be another fifty years or so because it takes time for the ozone layer to come back,” he said. “The natural chemical reactions that re-create ozone take fifty to one hundred years.”

“Assuming we stay on track, this is actually a success story, and it’s an existence proof that this kind of global change is possible,” Grinspoon added. “Not that it’s easy, and there are some ways in which fixing global warming will be inherently harder than this, but it shows that we are capable of a different approach.”

Thinking long term

While global warming is an important challenge, Grinspoon said it is a relatively short-term one, and that we need to think even further down the road. He said such random events as asteroid strikes don’t have to happen.

“We have a space program; the dinosaurs didn’t, and look what happened to them!” he quipped. We know how to identify possible threats and have a pretty good idea about what to do when they occur.
Further, Grinspoon said that we have an illusion that climate is always more-or-less fine, only because we’ve been lucky enough to live in a time of relative stability. We need to think about the next ice age, which he said will eventually occur.

“If we get over the near-term climate harm that we’re doing, we will have the knowledge that will allow us, when the need arises—we’re talking 10,000 or maybe even as much as 50,000 years in the future—we’ll have the ability to interrupt that cycle of ice ages and preserve the relatively benign climate, not just for ourselves but for other species as well,” Grinspoon said.

Who is out there?

All of this allowed Grinspoon to put on his astrobiologist hat and talk a little about the search for extra-terrestrial intelligence (SETI).

“When you do the math of SETI what you realize is that the question of is there anybody out there to talk to comes down to the question of longevity,” he said. “You can show this mathematically, that if civilizations last for a long time—that is, if this problem is soluble of how to create a stable technological civilization and use technology in the service of survival rather than self destruction—if that’s possible to do and if it happens on other planets, then there ought to be other civilizations out there that we could discover and maybe even communicate with.”

Thus the Anthropocene epoch represents something of a turning point. There are those who regard it as doom and gloom, as something we can’t beat, but Grinspoon doesn’t see it that way.

“The true Anthropocene is something that should be welcomed,” he said. “Though it is yet only in its infancy, it can be glimpsed. Don’t fear it; learn to shape it.”

“It is the awareness of ourselves as geological change agents that, once propagated and integrated, will provide us with the capacity to avoid doom and take our future into our own hands,” Grinspoon concluded.

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Books by David Grinspoon:

Total solar eclipse 2017 in Music City

You can’t blame people in Nashville for being excited about the total solar eclipse that will darken the city on August 21, 2017.

“The last time the path of totality crossed through town Nashville wasn’t even a thing!” laughed Derrick Rohl, manager of the Sudekum Planetarium at the Adventure Science Center in Nashville. Indeed, the last total solar eclipse there happened on July 29, 1478.

“It’s a big deal for us,” Rohl said.

Rohl’s big role in the planetarium’s preparation for the eclipse has been the creation of an exciting new show about eclipses. Titled Eclipse: The Sun Revealed, it has been in the works for more than a year. It starts off with a look at the ways people have responded to total solar eclipses over time.

“It gives people a great look at different cultural histories, ways that different cultures have interpreted eclipses and just how they would react,” Rohl said. Eclipse lore is filled with serpents and dragons and other scary creatures eating the Sun. The show also explores the geometry of eclipses so viewers will better understand what’s happening, and takes a look back at the interesting science that has been accomplished during total solar eclipses.

Of course, it also has the obligatory lessons about how to safely view the eclipse, and Rohl says they stress that during totality, it’s OK to look up without eye protection.

“It’s one of the greatest views that nature has for us and we would hate to have anyone miss that,” Rohl said.

The show closes out with a story about someone seeing a recent eclipse, “so that people can get an idea of just what a profound, impactful experience it will be,” Rohl said.

Eclipse: The Sun Revealed will premiere next weekend, January 21, exactly seven months before the total solar eclipse will hit town. Rohl said they’ve also sold it to planetariums in four other states and others are expressing interest.

Speaking of eye safety, that’s been a big investment for the Adventure Science Center, which ordered some 300,000 pairs of eclipse glasses.

“We have pallets and pallets of eclipse glasses sitting out on a loading dock now,” Rohl laughed. The glasses are earmarked for the city’s school kids, science center visitors, hotels, the convention and visitors bureau, and others. Center staff are helping teachers with lesson plans about eclipses, and are helping everyone from city officials to park rangers and bus drivers learn about the eclipse. That’s for good reason; Rohl says they’ve heard estimates that as many as two million visitors may hit Nashville for the eclipse.

Bracing for visitors

“We’re trying to prepare as many people around town as we can to be experts,” he said. “We’re trying to connect as many people as we can just to make sure that this a smooth experience for the huge amount of people that will be here to share it with us.”

In addition to the planetarium show, they’re planning an eclipse festival for the weekend before August 21. While many of the events remain tentative at this date, the festival will likely include lots of information about the eclipse, and Rohl expects it will also touch on virtual reality, robotics, and other cool topics.

“We’re not just limiting it to astronomy; we’re really expanding it to all the different science that we’d like to have people exploring and understanding and appreciating,” he said.

Other attractions of Nashville

One of the reasons that visitor estimates are so high in Nashville is that Music City is already a great tourist draw.

“Nashville is such a tourist friendly city even without an eclipse happening,” Rohl said. “While there are many other cities within the path, Nashville is a very very enticing place for people to choose.”

He expects folks from as far away as Chicago might rise in the wee hours and make the trip to Nashville for the eclipse, noting that practically everyone in the U.S. is within a day’s drive of the path of totality. While it’s a tourist town, Rohl says many Music City hotels have been booked for a long time. He’s got a spare room in his house, but it’s still up in the air who gets it.

“I think a lot of people who live in Nashville might be having long-lost relatives coming out of the woodwork,” Rohl laughed.

There are a couple of other space and astronomy attractions in the region besides the eclipse and the Adventure Science Center. Rohl suggested a visit to the Dyer Observatory, operated by Vanderbilt University in Brentwood, Tennessee, just a bit south of Nashville; and the U.S. Space and Rocket Center in Huntsville, Alabama, which is just a couple of hours drive to the south.

Total eclipse mania

Rohl noted that the buzz is certainly building about the eclipse. He fields several calls each day already, and expects it will only increase. Social media is helping to spread the word, something we didn’t have the last time a total solar eclipse crossed our entire country, back in 1918.

“The hype around this one really makes it so that everyone is expecting it to be the biggest astronomical event ever to happen in the United States,” Rohl said. “It’s something really exciting to look forward to, and of course Nashville is a mighty convenient place to live with that coming.”

Trailer for the planetarium show Eclipse: The Sun Revealed:

LIGO and the era of multimessenger astronomy

Multimessenger astronomy is a fairly new buzz word in the science. Dr. Joey Key, an assistant professor of physics at the University of Washington Bothell and a member of the LIGO Scientific Collaboration, talked about the concept at last month’s meeting of the Seattle Astronomical Society.

Dr. Joey Key of the UW Bothell gave a talk about LIGO and
the era of multimessenger astronomy at the Dec. 21 meeting
of the Seattle Astronomical Society. Key made the same
presentation to the Everett Astronomical Society Jan. 7.
Photo: Greg Scheiderer.

As you probably know LIGO—the Laser Interferometer Gravitational-wave Observatory—made the first detection of gravitational waves, as predicted by Einstein’s theory of general relativity, back in December 2015 and announced the findings last February. So now what?

“The next big goal for LIGO is to have a gravitational wave detection where we also get an electromagnetic signal from the same source,” Key explained. She noted that various wavelengths of light, from gamma ray to radio, require different types of tools to detect and reveal different things about objects observed. Key said gravitational-wave astronomers refer to such science as “electromagnetic astronomy.” The big hope, then, is to learn even more if there can be an electromagnetic observation as well as a gravitational wave observation of the same event.

“That’s what we would call a multimessgenger source,” Key said.

A difficult search

Einstein never thought gravitational waves could be detected because he figured they would be too small. It took a century of technological advances to prove him right—again. Finding a multimessenger source may be an even more elusive needle in the cosmic haystack.

Key explained that, right now, it’s hard for LIGO to detect with precision from whence a source signal originates. When they detect a source they send an alert to about 60 electromagnetic astronomy partners and give them a general direction in which to look. In addition to the challenge of pinpointing the source, they also don’t really know what to look for. Key said their models aren’t very good, not yet anyway. Light from a source may have already passed, but there could be x-rays, gamma rays, afterglow, or shock waves under certain conditions.

Fortunately, LIGO is getting better. The addition of more Earth-based observatories will help better locate sources and discover collisions of neutron stars or stellar-mass black holes. Project LISA, scheduled to launch in 2029, will look for supermassive black hole collisions and “extreme mass ratio in-spirals” which occur when a little star or black hole falls into a big black hole. Pulsar timing arrays could detect when supermassive black holes collide in galaxy mergers. There’s even study of the cosmic microwave background to try to detect gravitational waves from early universe.

“Just like electromagnetic astronomy, different sources are detected by these different kinds of experiments,” Key said. “We need all these different kinds of gravitational-wave experiments to be able to study the gravitational-wave sky.”

The LIGO Scientific Collaboration includes more than a thousand scientists from 15 countries and 90 institutions. Four of the institutions are in Washington: The University of Washington, UW Bothell, Whitman College, and Bellevue College.

Unknown discoveries ahead

Key said it is an interesting time to be involved in the field as LIGO is just into its second observing run.

“We’re really going to be able to map out and explore the population of black holes in our universe,” Key said.

“We don’t know what we’ll discover, and that is always the story of a new astronomy,” she added. ”We do not know very much about black holes in general, and so this is a new way to study the universe and study what is out there. It will be very exciting!”

LIGO could discover new kinds of sources like cosmic strings, study supernovae, and maybe even lead to the detection of dark matter and dark energy.

“We are lucky we live in the era of gravitational-wave astronomy, and we hope soon that it will be the era of multimessenger astronomy,” Key concluded.

Dava Sobel and the ladies of the Harvard Observatory

If you don’t know the names Williamena Fleming, Antonia Maury, Henrietta Leavitt, Cecilia Payne, and Annie Jump Cannon, you’re not alone. Many people working in astronomy don’t recognize these women who have made enormous contributions to the field.

Dava Sobel talked about her new book The Glass Universe
Dec. 15 at Town Hall Seattle. Photo: Greg Scheiderer.

“They’re making a splash now,” laughed Dava Sobel, author of the new book The Glass Universe: How the Ladies of the Harvard Observatory Took the Measure of the Stars (Viking, 2016). Sobel talked about the book Thursday night at Town Hall Seattle.

There is an impression that the women who worked at the observatory were trivialized or marginalized, Sobel said that really wasn’t the case.

“They really were well treated, they were given this tremendous responsibility, they made valuable discoveries, and they were well regarded—and some of them even world famous—in their own lifetimes,” Sobel said. She pointed out that Cannon, for example, held a number of honorary degrees, was a member and officer of the American Astronomical Society, and also was an honorary foreign member of the Royal Astronomical Society.
Interestingly enough, even Sobel, whose bailiwick is science history, hadn’t heard of Leavitt until her name came up during an interview for a magazine article she was writing 20 years ago. Her curiosity was piqued, and the seed for The Glass Universe was planted.

Cheap labor

Sobel noted that when Edward Pickering took over as director of the observatory in 1877 there were already a half a dozen women working there, many of them relatives of the resident astronomers. He liked working with the women. They did good work, and they were inexpensive.

“Women cost less,” Sobel said. “This is an old story about women earning less than men for doing the same work.”

But she added that it wasn’t just dollars and cents for Pickering.

“He was very open minded, broad minded, and felt that higher education for women was a good thing even at a time when this was questioned,” Sobel said. “There were people who really thought that college was bad for girls and could affect their ability to have children.”

Pickering recruited alumnae of women’s colleges who studied astronomy, asking them to make observations and contribute their data to the work of the observatory.

“That would be a way to prove to the world that women could make a contribution to science and that their education wasn’t wasted,” Sobel said.

Financial support from women

The observatory was a separate entity and didn’t receive any money from Harvard. Much of the work at the observatory was possible due to significant financial support from women.

Heiress Anna Palmer Draper and her husband, Dr. Henry Draper, had done some of the earliest work on photographing the spectra of stars. Henry Draper was a medical doctor, but he was, according to Sobel, a passionately engaged and inventive amateur astronomer. They built their own observatory and Henry created many of his own instruments for the work on spectra. Unfortunately, Henry got sick and died at the age of 45. Anna eventually donated much of their gear, and a lot of money, to the observatory to continue the work on stellar spectra.

Philanthropist Catherine Wolfe Bruce donated $50,000 to help the observatory set up a telescope in Peru for observing the skies of the southern hemisphere. Data from this instrument informed Leavitt’s work on variable stars.

Major achievements

The contributions by the computers were significant. A few examples noted by Sobel:
Leavitt studied variable stars and discovered that the brightest ones took longer to cycle through their changes, and that the length of the cycle correlated to the true brightness of the star. Knowing this, one can calculate how far away a variable star is based on how bright it appears from Earth.

“This work was fundamental to distance measurements all over the sky,” Sobel said. The discovery, most often called the period-luminosity relation, is more often these days being referred to as “Leavitt’s Law.”

Cannon, a renowned observer, came up with the star classification system still in use today. Fleming first came to the observatory as a maid, but later found astronomical success, too.

“She was the first woman to get a university title at Harvard,” Sobel said. “She was the curator of astronomical photographs.” Her analysis of some ten thousand stars were critical to the publication of the first Henry Draper Catalogue.

Maury, Draper’s niece, studied at Vassar, graduated with honors in astronomy and physics, and went to work at the observatory, where she came up with a system of identifying stars.

Payne was Harvard’s first Ph.D. in astronomy. It was no surprise that a woman earned the top degree first; all of the early graduate students in astronomy were women because the only money the observatory had for the graduate program came through fellowships established for women to study there. Payne studied spectra of stars and found that hydrogen was far more prevalent in stars than any other element. She wrote about her findings in her dissertation, but it was so counterintuitive that it was downplayed. Within a few years, however, her findings were confirmed.

Given the stature of the accomplishments, it seems astounding that these women are not more well known.

“A lot of history gets buried just because there are so many people, so many characters, so much time goes by,” Sobel noted, adding that the women didn’t feel marginalized at the time. “They really loved what they did and were credited for it, but over time I think it has been downplayed.”

They’re making a splash now

There’s been a lot more attention for the women astronomers in recent years. A decade ago George Johnson penned the biography Miss Leavitt’s Stars (W.W. Norton and Company, 2006). A couple of plays have been written about them, including Silent Sky by Laruen Gunderson, which was produced earlier this year in Seattle by Taproot Theatre. You can go back to read our coverage of the play. The 2014 reboot of the television series Cosmos with Neil deGrasse Tyson featured a segment about the computers.

“This got the attention of a lot of young women,” Sobel said. The Harvard women are also featured in the web series Insignificant.

“It’s great fun to see their story being remembered in so many ways. There are even Lego figures,” of Cannon, Leavitt, and Payne, Sobel said. “You know you’ve made it!”

Several other recent books have highlighted the work of women in space and astronomy. Sobel singled out The Rise of the Rocket Girls (Little, Brown and Company, 2016) by Nathalia Holt, a story about the women who made contributions to space science at the NASA Jet Propulsion Lab; and Hidden Figures (William Morrow, 2016) by Margot Lee Shetterly, a look at the African-American women who worked at Langley in the 1940s and ‘50s. Hidden Figures has been made into a feature film that is scheduled to open in theaters in January.

An important story for our times

Sobel said she enjoyed getting to know the personalities of the ladies of the Harvard College Observatory and feels that their story is an important one in the era of fake news and anti-science attitudes.

“All of us need to be telling true stories about science,” Sobel said. “I feel especially good about this one not only because it’s true, but because I hope it will be inspirational to young women to have models like these ladies and to show that women have always been interested in science.”

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More books by Dava Sobel:

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