Category Archives: Astronomy

An Artistic Search for Pluto

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How do you illustrate a non-fiction book for kids based on the former ninth planet? Some people still have some pretty strong feelings about Pluto’s demotion: protest signs, student protest speeches, public demonstrations. Cries of unfairness could be heard when news of poor Pluto’s removal from the planetary ranks occurred. It is the intention of this new children’s book to set the story straight or at least attempt to share “Pluto’s side of the story.”

I‘ve worked in the children’s book market as a freelance illustrator for several years in addition to my full-time job with the Museum’s Early Childhood program. My latest book assignment from Abrams Books for Young Readers, Pluto’s Secret: an Icy World’s Tale of Discovery, connected my job as an artist and an educator.

Pluto's Secreet

Pluto’s Secret, An Icy World’s Tale of Discovery, by Margaret A. Weitekamp and David DeVorkin. Illustrated by Diane Kidd.

In publishing, typically the illustrator and the author never meet or exchange ideas. In some cases the author might live across the state or in another country. The approved manuscript is sent to the artist from the publisher. It is then up to the artist to find the visual voice of the text. Fortunately, for this project the authors Margaret Weitekamp and David DeVorkin were my Museum colleagues. In my first sketch, for example, I used my daughter’s old high school algebra homework, which was my interpretation of a possible equation mathematician Percival Lowell might have calculated. David knew right away it was not correct and gave me a copy of an actual Lowell equation which is now in the book. I also needed to re-work my idea of a telescope, which originally looked like one from Dr. Seuss, to one that looked more like Lowell’s telescope.

Telescope

Original draft of the telescope from Pluto’s Secret.

telescope

Revised draft of the telescope, based on David DeVorkin’s comments.

When I work, I use water jars, brushes, water color pads, and tissue paper. I need good lighting and scads of paper towel, and music really helps the flow. Next I usually consider color and composition. In this case, “What color should I make Pluto? Hmmm… Purple? Blue? Meatball brown? Red is taken by Mars.” There is also a lot of activity in space. Things crash into each other, explosions and collisions happen, surfaces have been impacted by objects bumping into them.  Maybe Pluto might have a somewhat bumpy surface with a few craters. What does dirty methane gas look like? An icy world might have a few patches of surface ice. What might life in a Kuiper belt be like? No one really knows exactly, so imagination holds the paint brush.

Pluto

Color sample for Pluto’s Secret, by Diane Kidd

First I sketched out my ideas then sent them to the editor for review and critique, and to Margaret and David for review. Later the publisher sent corrections back marked in red.  The corrected sketches were re-drawn and then re-submitted  to the publisher. Once all the corrected sketches were approved, I worked on re-drawing and painting each image by hand on watercolor paper.

In the past, the procedure of mailing sketches back and forth between the publisher and artist often took weeks to complete. Today sketches can be scanned and sent out and corrections returned within a few days. Once the designer receives the corrected art, he/she can lay out the text copy with finished art work and get a pretty good idea of what the final product will look like. No more mailing tubes or runs to the copy shop in the middle of the night, or trips to the local post office trying to make a deadline.

Nevertheless, I still waited with baited breath for comments from the art editor/publisher/authors as they reviewed the final art work. Did they like it? Did I get the right look? Did they notice that smudge? For me, this is one of the hardest parts of the process, the waiting. Finally, a thumbs up. Everything was approved. It’s a go.

My hope is that young readers and adults alike will have as much fun as I did learning why Pluto is no longer considered a planet and how “he” really feels about it. And I hope you like the book as much as I liked creating the art!

Diane Kidd is manager of the National Air and Space Museum’s Early Childhood Program.

Join us this Friday, March 15, at the Museum in Washington, DC to learn more about Pluto with the authors of Pluto’s Secret. Children can participate in educational activities, and purchase a signed copy of the book.

Vulcan? But that’s not logical…

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The news that “Vulcan” topped the poll results taken by the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California as a possible name for one of the two tiny moons newly discovered to be orbiting Pluto has gotten quite a bit of press this week. In 2012, Mark Showalter of SETI, working with scientists on the New Horizons mission sending a probe to Pluto, found a tiny fifth moon orbiting the icy world. Showalter was also the lead author of the discovery of a fourth moon in 2011 using observations from the Hubble Space Telescope.

Pluto

This image, taken by NASA’s Hubble Space Telescope, shows five moons orbiting the distant, icy dwarf planet Pluto.

As SETI contemplated what names to propose for these two newly-discovered moons, they opened the question to the public in an on-line poll.  Inspired by a tweet from William Shatner, the actor who became famous playing Capt. James T. Kirk in the original Star Trek television program (1966-69), Vulcan, Pluto’s mythological nephew and the name of a fictional world in Star Trek’s imagined universe, became the top vote getter.  Leonard Nimoy, who played Spock, the most famous Star Trek Vulcan, reportedly tweeted that naming one of the two moons “Vulcan” would be the “logical choice.”

shatner

nimoy

But did you know that there already was a Vulcan?  Or, actually, there wasn’t.  But astronomers thought that there was.

Since the 18th century, astronomers worried that the orbit of the innermost planet in the solar system, Mercury, did not behave the way that they expected.  By the mid-nineteenth century they knew that perturbations in the orbit of Uranus had just (in 1846) resulted in the discovery of Neptune, the first planet to be predicted mathematically before it was confirmed through observation.  Could that also apply to Mercury? Was there another planet orbiting between Mercury and the Sun that could explain Mercury’s orbit?  Urbain Jean Joseph Leverrier, whose calculations had been used to discover Neptune, thought so.  By 1859, amateur and professional astronomers started searching.

And they found some things.  Some scientists reported seeing a bright, star-like object orbiting near the Sun.  And others saw circular shapes transiting (or crossing) the face of the Sun. It must be Vulcan, they thought!  Some textbooks printed in the 1860s and 1870s even listed Vulcan as a planet. (For, indeed, Pluto is not the first body to have been considered a planet and then reclassified. Ceres, the spherical body in the asteroid belt, was also called a planet when it was discovered in 1801 but then reconsidered when the many other bodies discovered in that same region of space became known as the asteroid belt.)  But the observations of Vulcan did not compute.  They were not consistent.  According to Newton, and to vast experience, planets, above all, were predictable in their orbits. Any deviation was not acceptable.  That’s how Kepler decided that planets did not travel in circular orbits. So when scientists looked for Vulcan where it was predicted to be visible and they could not find it, they started to doubt that Vulcan existed.

When something does not move as predicted, astronomers start looking for a perturbing mass.  That is in fact how dark matter was detected, and after almost 50 years, finally accepted as a major factor in controlling the motions of things like stars and galaxies in the universe.  In the early 20th century, astronomers thought that the existence of a faint disk of material around the sun, called the Zodiacal Light, might be massive enough to make Mercury’s orbit shift in the way it appeared to do.  But in the end, Einstein solved the problem (literally) and Vulcan was no more.  In 1915, Einstein’s General Theory of Relativity explained the shifts in Mercury’s orbit without the presence of another world orbiting nearer to the Sun.  Vulcan, which had never existed, entered the history books.  But astronomers still use the name: NASA’s project to detect new planets has been called “Project Vulcan.”

The names of Pluto’s moons have still not been decided.  The International Astronomical Union, the worldwide professional organization of astronomers, will make the final choice.  They may choose “Vulcan.” Or they may decide that there was already a Vulcan. Except that there wasn’t.

Margaret Weitekamp and David DeVorkin are curators in the Space History Department of the National Air and Space Museum.

Reflections on “Explore the Universe” 2001-2012

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One of the jokes I inherited from my student years is the final exam question “Describe the Universe” which was followed by “and give two examples.” In the 1960s, this could be funny of course, at least to astronomers. Today, however, the answer might be, “Only two?”  Since the Explore the Universe gallery opened in September 2001, the appreciation that more than our universe may well exist has strengthened  If we were to revamp the gallery today, there would be some discussion of where the evidence might someday actually come from.  What we will probably do instead is utilize one of the various updatable features already in the gallery, when the time really comes.

Indeed, as the Museum contemplated a new astronomy gallery in the 1990s, we knew that we were dealing with a subject that is constantly changing.  We had formed a core group of scientists, historians, educators, and designers to craft a vision for the new presentation.  What emerged, after three Museum directors and many other staff changes, was a simple and hardly radical statement: “New Tools, New Universes.”  Of course, it was the same universe each time, but seen and understood more completely, and, typically, was found to be very unlike the conception that went before.  This single statement embodied others, like “New Universes tend to be larger and less homocentric” or “There are no final answers, only better informed questions.”

One of the most interesting themes, or threads, that we decided to incorporate, however, was how “Women have played significant roles in changing our view of the nature of the Universe.”  This last one, like the others, helped to guide the choices we made as to what instruments played a role in giving us new views, where did those instruments come from, and who were the people who either used those instruments or analyzed the data coming from them?

During the course of developing the gallery we well knew that astronomy has long been a male-dominated enterprise.  This is, happily, no longer the case. But even in past times, it is not difficult to point to women who played critical roles in revolutionizing our view of the nature of the Universe.

We therefore set about to portray some of these women in Explore the Universe, within the contexts in which they worked, and the roles they played making the new discoveries.  As you walk through the gallery located on the east end of the first floor of the Museum, here are some of the stories  you will encounter:

The First Room

The first universe you will encounter is human or earth-centered, “homocentric” in other words.  It was the view we constructed based upon observations by eye alone, aided only by pointing devices to determine positions of things in the sky, and over time, their motions.  The geometric earth centered view of the Greeks is depicted, together with the instruments that refined it, ending in a replica of Tycho Brahe’s great 16th Century equatorial armillary sphere being used by one of his assistants.  No women are depicted here.

Armillary Sphere

A view of the Tycho Armillary Sphere reproduction on display in “Explore the Universe.” The Sphere was built by Danish astronomer Tycho Brahe in the late 1500s to study the sky and to teach about the celestial coordinate system.

The Second Room

The second universe, brought by the advent of the telescope, led to the confirmation of a model suggested prior to Tycho: that the universe was centered on the Sun and not the earth.  Tycho’s tables and observations had given strong evidence of this, but in and of themselves were not sufficient to overthrow the Aristotelian universe.  Observations with Galileo’s telescope were sensational enough to bring about this revolution, enabled by his ability to dramatically portray his evidence (the Jovian satellites, the Venusian phases, the Sun’s spots, etc.) through visual representation.

Walking through this second room is a walk through telescopic history in a universe composed of stars, all contained within what we call the Milky Way.  Ever bigger and more powerful telescopes were built through the 18th and 19th centuries to probe this universe. Featured in the gallery is the grand 20-foot reflector of William Herschel in a diorama showing him at work gauging the heavens, with his sister Caroline both directing and recording his observing routine from an open window.  Caroline’s contribution to William’s legacy, producing the first observational map of the structure of the known universe, was in fact as more than his assistant.  It was she, according to recent scholarship, who made William’s work systematic, and it was she who also encouraged him to carefully catalog those fuzzy faint apparitions they were recording night after night, year by year.  These so-called nebular forms could be unresolved clusters of stars, or some ethereal shining fluid out of which stars someday would form.  But were they among the stars? Or beyond the stars?  Were they other universes, the Herschels asked?  The distribution of the nebulae was oddly different than the distribution of stars, or the shape of the universe as they found it.

Carolyn Herschel

Carolyn Herschel was an astronomer and researcher who became the first woman, and the only woman for well over a century, to be awarded the Gold Medal of the Royal Astronomical Society of London. Her work was formally recognized in 1828.

Caroline, of course, worked in astronomy by virtue of her brother’s interests, and they both were supported by a king’s pension, provided by George III  after William had discovered the planet Uranus in 1781.

The Third Room

The question the Herschels posed (“what was the nature of the nebulae?”) was answered in the early 20th century when photography was applied to increase the power of the telescope.  The eye is a very sensitive detector of light energy, but it accumulates that energy for only a very small fraction of a second, depending upon the light level.  Photographic emulsions can collect and accumulate light energy for many hours, providing a vast increase in sensitivity.  This is why, once photographic emulsions came available, they were quickly adapted to telescope cameras to replace the eye.  Now, also, information could be stored on these photographic plates and be available permanently, housed in protected chambers astronomers called vaults, and brought out for examination day and night.

By 1900, photographic astronomy had shown that most of the faint nebulae Herschel had glimpsed were in fact spiral in structure, reminiscent of whirlpools.  And there were many many thousands of them.  Meanwhile, women working at Harvard College Observatory, like Henrietta Swan Leavitt, were making some very valuable observations and coming to powerful conclusions examining many photographs over time of  nearby star clusters like the Clouds of Magellan, visible only from the southern hemisphere.

Henrietta Swan Leavitt

Henrietta Swan Leavitt examined photographs of both the Small and the Large Magellanic Clouds taken over many weeks and months and found over 2,500 stars that varied in brightness in the two clouds, now known as companion galaxies to the Milky Way. She was the first to show that the variations in brightness were a measure of the intrinsic brightnesses of these stars, thus providing a powerful new distance indicator for astronomy.

There were many stars in these clusters that did not radiate constantly, but varied in brightness over great ranges.  Leavitt’s contribution, between 1908 and 1912, was to realize that for a certain class of these light-varying (or variable) stars, the period of their variation was in proportion to their mean brightnesses.  The brighter ones had longer periods (a matter of days) than the fainter ones.  Since all the stars were in the same cluster, and therefore at the same distance, she had discovered an intrinsic property of these stars.  Without even knowing why these stars varied in brightness, she showed that they constituted a new and valuable means for determining the distances to stars, if their intrinsic brightnesses could be ascertained.  Her conclusion was quickly picked up by a astronomers both in Europe and the United States.  The Mount Wilson astronomer Harlow Shapley calibrated this class of variables and found bunches of them in globular clusters. By 1920, he had determined their distribution and from it deduced the size of the Milky Way Galaxy, finding it so vast he felt nothing could be outside of it.

Soon after Shapley’s work, Edwin Hubble, also working at Mount Wilson with the new 100-inch reflecting telescope, used Leavitt’s variables and Shapley’s calibrations, modified by others, to determine the distance to the Andromeda nebulae, one of the largest and brightest spirals in the sky. He found that its distance was at least 10 times greater than Shapley’s estimate for the size of the Milky Way. In others words, it lay outside the Milky Way and hence was an island universe.  Thus Leavitt, employed as an assistant at the Harvard College Observatory (not included through an accident of family as Caroline Herschel had been) produced a distance-determining tool that once again revolutionized the universe.  We live in a universe of galaxies, not stars.

Magellanic Clouds

Magellanic Clouds. Credit: AURA/NOAO/NSF.

Neither Leavitt or Caroline Herschel worked as independent astronomers, setting their own course of investigation. Although Leavitt was given a certain degree of freedom to search out anything that might be interesting, she was directed to this work by others.  As you continue to walk through the gallery, you will encounter other women, in more recent times, who designed their own research programs and carried them out. These include Vera Rubin in the fifth room, who found in the 1970s that dark matter dominates galaxies like Andromeda, and Margaret Geller, who found in the 1980s that the universe is not uniform, but clumpy on a huge scale that may well outline the distribution of dark matter in the universe.

So if and when we find evidence that, indeed, universes other than our own exist, and have left their marks on our own universe in deep time, what role will women play in that realization?  Only time, and larger telescopes on the ground and in space, will tell.

David DeVorkin is a curator in the Space History Division at the National Air and Space Museum.

Minor Planet 4262 DeVorkin

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David DeVorkin

David DeVorkin is a curator in the Space History Department of the National Air and Space Museum.

On  6 April 2012, the following notice appeared in the Minor Planet Circular, under the category “Names of New Minor Planets”:

(4262) DeVorkin = 1989 CO
Discovered 1989 Feb. 5 by M. Arai and H. Mori at Yorii.
David H. DeVorkin (b. 1944) Chair of the Historical Astronomy Division of the American Astronomical Society (1997-1999), wrote the definitive biography of astronomer Henry Norris Russell. DeVorkin has been Curator at the Smithsonian National Air and Space Museum since 1981.

How did a “minor planet”—colloquially and better known as an asteroid—come to be named after our own David DeVorkin? The story goes back to the retirement party at NASA Headquarters of Steven J. Dick, then Chief Historian of NASA, and before that, the historian of the Naval Observatory in Washington, D.C., for many years. At the party the honoree was delighted by the announcement of a new asteroid name, 6544 Stevendick. I was happy for him, and thought that it would be great if we could the same thing some day for David, who had made so many contributions to the Museum and to the history of astronomy. The idea sat in the back of my mind for a couple of years, as I really wasn’t sure how to go about it. I decided to postpone it until Steve arrived as the Charles A. Lindbergh Chair in Aerospace History in mid-2011 (a one-year fellowship for senior scholars with distinguished publication records).

After he arrived, Steve and I talked about whether we could time a naming for some event, such as a birthday, but the timing could not be reliably controlled. That indeed turned out to be the case, as the first time we submitted a nomination, someone lost Steve’s e-mail and we had to do it all over again in early 2012. The naming process is to submit a short nomination paragraph  (often a capsule biography) to the International Astronomical Union’s Committee for Small-Body Nomenclature via the Minor Planet Center, a body of the IAU run by the Smithsonian Astrophysical Observatory in Cambridge, Mass.

We fashioned the biography above to fit the strict criteria for brevity and included details that might appeal to the astronomers on the committee. Then we waited for something to happen, such as an e-mail. Of course we couldn’t take it for granted that the nomination would be accepted, although it appeared likely. Steve was also concerned that the news would leak after the name came out, based on David’s close contacts with the astronomical community. But nothing happened. Last April Steve finally suggested that we check the Minor Planet Circular, which is the official publication of record and comes out each month around full Moon, and there it was. At least we managed to surprise David.

Comets are named after their first discoverers, a convention that arose in the early twentieth century, but that rule applies to almost nothing else in the sky. When astronomers found the first four asteroids, Ceres, Pallas, Vesta and Juno, at the beginning of the nineteenth century, they treated them as planets, naming them for Roman gods to continue the tradition. As Caltech astronomer Mike Brown notes in his eminently readable memoir How I Killed Pluto, And Why It Had It Coming  (2010), for some time there were 11 or 12 planets, including  those four and in 1846, the newly discovered Neptune. But the proliferation of asteroid discoveries in the late nineteenth century, combined with their small size, resulted in their demotion to minor planethood—sending the number of major planets back to eight, then nine when Clyde Tombaugh discovered  Pluto in 1930, and back to eight when the IAU demoted it to “dwarf planet” in 2006. (Brown discovered the erstwhile tenth planet, Eris, in 2005, but actually favored the reduction to eight, based on the fact that Pluto turned out to only one of a number of rather small “Kuiper Belt objects.”)

As the number of asteroid names grew, a Greco-Roman naming convention became less and less feasible and was eventually dropped for Main Belt objects between Mars and Jupiter—570,355 on the day I write this, and growing by the day, although many have not been assigned formal numbers yet. As the rules in the above link reveal, there are several special classes of minor planets that do retain classical or mythological naming conventions, many of them in special orbits like the Earth-crossers we are increasingly worried about. But Main Belt asteroids can be named almost anything credible by their discoverers for ten years after the object receives an official number—but as the rules say, not for one’s dog, or for political figure who hasn’t been dead for a century. After the decade is up, unnamed asteroids are left to the discretion of the IAU Committee. Rightly or wrongly, Steve and I take the assignment of the relatively low number of 4262 to David DeVorkin as a sign of the appreciation of the committee for the importance of his work (only one with a lower number was named in the 6 April Circular).

What do we know about 4262 DeVorkin? Not very much. Discovered by two Japanese astronomers, it is a small rock, only a few kilometers across, orbiting in the Main Belt. The only pictures of it that have been taken show just a moving pinpoint of light. But perhaps in this or some future century, one of our spacecraft, crewed or robotic, might pass by and take some pictures. Someone will ask: who was DeVorkin anyway? The official description on some future version of the web will be one way he or she could find out.

Michael J. Neufeld is a curator in the Space History Department of the National Air and Space Museum. He is the author of  Von Braun: Dreamer of Space, Engineer of War (2007).

Going Three Billion Miles at the Public Observatory

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At our evening observing sessions at the Public Observatory, we’ve shared views of Mars, Jupiter, Saturn, the Moon, and other astronomical objects with thousands of visitors. But Neptune, the most distant planet in the Solar System, is one that I’ve not yet looked at with the main 16” telescope.

Public Observatory

Visitors gather to use telescopes at the Public Observatory. Photo credit: National Air and Space Museum, Eric Long.

The spectacular sights of the closer planets will be below the horizon for our next stargazing session, this Saturday night from 6:30 – 8:30 PM.  As the last remnants of Hurricane Sandy dissipate, we anticipate clear skies. We will point our 45-year-old telescope further afield, at the gas giant Neptune, almost 3 billion miles away.

Neptune

Hubble Space Telescope image of Neptune and some of its moons. Our view will not be nearly this detailed, but if the weather is good, we will see Neptune’s color.

Visitors will use an assortment of telescopes to observe the sky. Because the Observatory is located in Washington, DC, where the light-polluted skies never get very dark, some objects are not visible no matter how large a telescope we use.

The Andromeda Galaxy is by far the biggest object visible to the naked eye, but only from a very dark location. It is hard to appreciate its glory from the city. Through our telescope, it shows up as a dim, slightly fuzzy dot. Galaxies, nebulae, and globular clusters of stars look best from locations under a truly dark sky, such as our monthly star parties at Sky Meadows State Park in Northern Virginia. The next star party is on November 10th, and it’s the last one until next April.

Instead, during evening programs at the Public Observatory in DC, we usually observe bright objects like the planets, stars, and star clusters.  This Saturday, while the 16” offers views of Neptune, one of our telescopes will point at the binary star Almach.  The telescope will “split” the star into two, one gold and one blue. The blue one is actually three hot blue stars in close orbit. We look forward to discussing with our visitors how most of the stars we see in the sky are actually multiple-star systems.

We hope to see you there!

Geneviève de Messieres and Katie Nagy are Astronomy educators at the National Air and Space Museum.