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Pi Day, Mars Madness, and more this week

Pi Day, Mars Madness, planetarium shows galore, and astro club events fill a busy calendar this week.

Pi Day

Celebrate Pi Day at 5 p.m. Tuesday, March 14 at the Pierce College Science Dome. This free celebration will include hands-on math and science activities, a pi recitation typing contest, and Chaos and Order: A Mathematical Symphony. Please reserve seats in advance for the symphony, which will run at 5 p.m., 6 p.m., and 7 p.m. in the dome. Reservations are not needed for the other activities.

MOF Mars Madness

Phoenix landerMars Madness continues at the Museum of Flight at 2 p.m. Saturday, March 18. This week’s presentation will feature the museum’s Carla Bitter, former education and public outreach manager of NASA’s Phoenix Mars Lander mission, who will give a family friendly, fast paced Mars 101: Know Your Missions presentation, complete with Red Planet prizes. Mars Madness is happening every Saturday in March, and is free with museum admission.

Club meetings

The Olympic Astronomical Society will hold its monthly meeting at 7:30 p.m. Monday, March 13 in room Engineering 117 at Olympic College in Bremerton. A guest speaker will talk about the Moon. Mysteriously, the club website doesn’t list who the speaker will be. Is it a major Moon celebrity?

The Seattle Astronomical Society plans its monthly meeting for 7:30 p.m. on the Ides of March—Wednesday, March 15—in room A102 of the Physics/Astronomy building on the University of Washington campus in Seattle. Guest speaker Dan Dixon, creator of the Universe Sandbox simulation game, will talk about how he and his team of programmers, a planetary scientist, and a climate scientist collaborated to create an app that can model galactic collisions and solar system dynamics.

Planetarium shows

Check out The Secret Lives of Stars, a free show at the Bellevue College Planetarium that will play at 6 p.m. and repeat at 7 p.m. on Saturday, March 18. Reservations are recommended; information about reservations, parking, and location is online.

The Willard Smith Planetarium at the Pacific Science Center offers a variety of programs every day. Check their complete lineup on our calendar page.

Futures file

You can scout out future astronomy events on our calendar. We’ve recently added:

Up in the sky

Jupiter, Spica, and the Moon will form a nice triangle in the evening on Tuesday. The Sky This Week from Astronomy magazine and This Week’s Sky at a Glance from Sky & Telescope offer more observing highlights for the week.

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The expanding universe: discovery, controversies, and hope

We’ve known that there is a universe outside the Milky Way, and that it is expanding, for less than a century.

“Throughout the entire history of the universe, of knowing it’s expanding, there have been a tremendous number of controversies over it, and there’s still one that persists today,” said astrophysicist and author Ethan Siegel. Siegel, author of Beyond the Galaxy: How Humanity Looked Beyond Our Milky Way and Discovered the Entire Universe (World Scientific Publishing, 2015), spoke at last week’s meeting of the Rose City Astronomers in Portland, Oregon.

The controversy actually goes back to before the expansion was observed, to Albert Einstein. His equations describing general relativity suggested that gravity would collapse the universe onto itself, and as he believed the universe was static, he threw in a “cosmological constant” to push back against gravity. Einstein later called that his biggest blunder, though some wanted to let him off the hook for it when dark energy was proposed to do the exact same thing.

“I am here to tell you that this was Einstein’s reasoning and throwing this in there when he did was a super big blunder because the universe isn’t static,” Siegel said. Einstein should have trusted his theory, he said, and taken it to the next step.

The universe is expanding

By the 1920s Edwin Hubble observed a Cepheid variable star in the Andromeda “nebula” that indicated that it was far outside the Milky Way and a galaxy in its own right. Astronomers were also studying redshift as an indication for the speeds at which galaxies were receding from us. Siegel explained that through this, Hubble determined that the universe was expanding at a rate of 600km/sec/Mpc (kilometers per second per megaparsec.) This became the Hubble constant. But it wasn’t so constant.

Siegel noted that, knowing the size and expansion rate of the universe, you can figure its age by running the numbers in reverse and going back to the beginning, to the Big Bang. The resulting calculation determined that the universe was about two billion years old. Geologists at the time had already pegged the age of the Earth as at least four billion years.

“This was a problem for Hubble, because the universe isn’t allowed to be half the age of the Earth,” Siegel noted. “Either this expansion rate is wrong and this age for the universe is wrong, or the age of the Earth is wrong.”

It turns out that Hubble’s main mistake was in figuring that all variable stars are alike. Siegel said Walter Baade came along in the 1940s and discovered that they are not. Finding that most of the Cepheids Hubble had looked at were non-classical, they re-ran the numbers from Hubble’s data.

“As you accumulate more knowledge, as you accumulate a better understanding of what you’re actually loooking at, you can go back and get more useful science out of this data,” Siegel said. This second look doubled the distance to these stars and reduced the value for the Hubble constant to 270km/sec/Mpc. This in turn put the age of the universe at five billion years.

“That’s better,” Siegel noted. “The universe is older than Earth. That’s one problem solved.”

Narrowing it down

Siegel

Dr. Ethan Siegel, creator of the “Starts With a Bang” blog, gave a talk about the age and size of the universe to the Rose City Astronomers February 20. Photo: Greg Scheiderer.

As time went on astronomers developed the “distance ladder” for determining the vast distances in the universe. You first measured the distance to Cepheid variables within the Milky Way, then gauged the distances to other galaxies using Cepheids spotted there. Type 1a supernovae could be spotted really far out. As we learned more about the stars we got a little better at figuring distances.

Things got really interesting in the 1960s, according to Siegel. We discovered that we could determine the ages of stars by measuring their color and brightness. The Hertzsprung–Russell diagram told us that the oldest stars were between 14 billion and 16 billion years old, significantly older than the age of the universe determined by Baade. Astronomer Allan Sandage, who as a graduate student was an assistant to Hubble, came along and said you needed two things to make the universe that old: it had to be low enough in density to make a vast expansion, and the expansion rate had to be low.

Dueling Hubble constants

This, Siegel said, was where the controversy came in. Sandage said the expansion rate would have to be between 50-60km/sec/Mps. Rival astronomer Gérard de Vaucouleurs of France put it at around 100km/sec/Mpc. The race was on to make observations to see which group was right. Amazingly enough, each group’s observations matched up with what they thought the answer would be.

“This just goes to show that you cannot have the same people making the same measurements and trust them,” Siegel said. “This is why you need independent confirmation.”

It turns out Sandage and de Vaucouleurs were both wrong. There’s still no agreement on the right answer, but the disagreements are getting closer together. Sigel said the Hubble Space Telescope’s improvements in measuring the size of the universe return a value of 74±2km/sec/Mpc. The Planck mission’s observations of the cosmic microwave background radiation suggest 67±1km/sec/Mpc.

“There is a fight over the results like there always seems to be, because we are scientists and we cannot agree on anything,” Siegel said. “That is good, because questioning is what keeps us moving forward and what keeps us learning more.”

“The way we’re going to get there is with more and better data,” he added.

Better data

The better data will come from missions such as the European Space Agency’s Gaia, the James Webb Space Telescope, WFIRST, and the Large Synoptic Survey Telescope, which combined might improve our parallax measurements of cosmic distances by a factor of ten. We might also weed out faulty assumptions in the earlier work or get more accurate insights into the balance between matter and dark energy in the universe.

“If we can wait until the next decade, we might see that 74 number come down, we might also see the 67 number come up,” Siegel said. “The point is uncertainties are going to be reduced by more and better data.”

Siegel said that right now it’s pretty much agreed that the universe is about 13.8 billion years old and consists of about 30 percent matter and 70 percent dark energy. But the miniscule pluses or minuses can lead to huge fights.

“When that data comes in at last we will know exactly how fast our universe is expanding, how old it is, and what it all means for both our cosmic origins and our cosmic fate,” Siegel concluded. “That’s pretty good stuff.”


In the podcast linked below Siegel covers much of the topic matter of this article and his talk. His new book, Treknology: The Science of Star Trek from Tricorders to Warp Drive (Voyageur Press, 2017), is scheduled for release in October.

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Search for meaning continues

There is a great menu of interesting talks on this week’s calendar, including three with astronomy themes at a weekend event at Seattle University.

Search for Meaning FestivalSeattle University’s annual Search for Meaning Festival will be held on the university campus all day Saturday, February 25. The festival is a community event dedicated to topics surrounding the human quest for meaning and the characteristics of an ethical and well-lived life. It draws more than 50 authors and artists who will give interactive presentations. Three of these sessions are on astronomy-related topics.

At 9 a.m. Father George Coyne, SJ, former director of the Vatican Observatory and author of Wayfarers in the Cosmos: The Human Quest for Meaning (Crossroad 2002), will discuss the history of the evolution of life in the cosmos. Coyne’s thesis is that this history may lead us to a deeper understanding of what many secular physicists say themselves about the cosmos: that a loving creator stands behind it.

At 10:45 a.m. Margot Lee Shetterly, author of the book Hidden Figures: The American Dream and the Untold Story of the Black Women Mathematicians Who Helped Win the Space Race (William Morrow, 2016), on which the current hit film is based, will give one of the keynote addresses at the festival. Shetterly will talk about race, gender, science, the history of technology, and much else. Reservations for Shetterly’s talk are sold out.

At 12:45 p.m. Marie Benedict, author of The Other Einstein (Sourcebooks Landmark, 2016), will explore the life of Mileva Maric, who was Albert Einstein’s first wife and a physicist herself, and the manner in which personal tragedy inspired Mileva’s possible role in the creation of Einstein’s “miracle year” theories.

Check our post from December previewing the festival, and look at the trailer video below. Tickets to the festival are $12.50 and are available online.

Siegel at Rose City

Author and astrophysicist Ethan Siegel will be the guest speaker at the monthly meeting of the Rose City Astronomers in Portland at 7:30 p.m. Monday, February 20. Siegel will talk about his book Beyond the Galaxy: How Humanity Looked Beyond Our Milky Way and Discovered the Entire Universe (World Scientific Publishing, 2015). He’ll examine the history of the expanding universe and detail, up until the present day, how cutting-edge science looks to determine, once and for all, exactly how the universe has been expanding for the entire history of the cosmos. Siegel is an informative and engaging speaker; check our recap of his talk from last year about gravitational wave astronomy.

AoT Seattle and an app for simulating the universe

AoT FebruaryAstronomy on Tap Seattle’s monthly get-together is set for 7 p.m. Wednesday, February 22 at Peddler Brewing Company in Ballard. Two guest speakers are planned. Dan Dixon, creator of Universe Sandbox² will give an introduction to the app, an accessible space simulator that allows you to ask fantastical what-if questions and see accurate and realistic results in real-time. It merges real-time gravity, climate, collision, and physical interactions to reveal the beauty of our universe and the fragility of our planet. University of Washington professor in astronomy and astrobiology Rory Barnes will talk about “Habitability of Planets in Complicated Systems.” It’s free, except for the beer.

TAS public night

Tacoma Astronomical SocietyThe Tacoma Astronomical Society plans one of its public nights for 7:30 p.m. Saturday, February 25 at the Fort Steilacoom campus of Pierce College. The indoor presentation will be about the zodiac. If the skies are clear they’ll set up the telescopes and take a look at what’s up.

Futures file

You can scout out future astronomy events on our calendar. We’ve recently added several events scheduled at the Museum of Flight, including:

Up in the sky

There will be an annular solar eclipse on Sunday, February 26, but you’ll have to be in South America or Africa to see it. This Week’s Sky at a Glance from Sky & Telescope magazine and The Sky This Week from Astronomy offer more observing highlights for the week.

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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

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.


Further reading: Also check out our review of Sun Moon Earth, posted in December, and our article about Nordgren’s keynote address at the Seattle Astronomical Society annual banquet in 2014.

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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.

David Grinspoon

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.


Books by David Grinspoon:

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SU Search for Meaning Fest includes three talks with astronomy themes

If you’re looking for meaning you may be able to get some clues in February at Seattle University. The university’s annual Search for Meaning Festival is set for February 25, 2017, and will bring more than 50 authors and artists to campus to tackle topics surrounding the human quest for meaning and the characteristics of an ethical and well-lived life. Three of these talks may be of particular interest to astronomy enthusiasts.

ShetterlyMargot Lee Shetterly, author of Hidden Figures: The American Dream and the Untold Story of the Black Women Mathematicians Who Helped Win the Space Race (William Morrow, 2016) will give a keynote talk at the festival about race, gender, science, the history of technology, and much else. She will show us the surprising ways that women and people of color have contributed to American innovation while pursuing the American Dream. Hidden Figures has been made into a feature film that opens in theaters in January.

Marie BenedictMarie Benedict, author of The Other Einstein (Sourcebooks Landmark, 2016) will talk about her novel and explore the life of Mileva Maric, who was Albert Einstein’s first wife and a physicist herself, and about the manner in which personal tragedy inspired Mileva’s possible role in the creation of Einstein’s “miracle year” theories. She’ll also discuss how Mileva’s story is, in many ways, the story of many intelligent, educated women whose own aspirations and contributions were marginalized, or even hidden, in favor of those of their spouses.

CoyneRev. George V. Coyne, SJ, former director of the Vatican Observatory and currently the endowed McDevitt Chair in Physics at Le Moyne College in Syracuse, New York, is author of Wayfarers in the Cosmos: The Human Quest for Meaning (Crossroad, 2002). Father Coyne will talk about the history of the evolution of life in the cosmos—a history which may lead us to a deeper understanding of what many secular physicists say themselves about the cosmos: that a loving creator stands behind it.

The full schedule for the daylong event is available online. General admission tickets are $12.50 and are also available online.

Get the books in advance:


Purchases made through links on Seattle Astronomy help our efforts to bring you interesting space and astronomy stories. We thank you for your support.

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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

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.

Harvard women 1918

Some suggest this 1918 photo of Harvard College Observatory women in “paper doll” pose marginalizes them, but Sobel says they were regarded and treated well in their time. Photo: Harvard University Archives.

“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.”


More books by Dava Sobel:


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