International Astronomical Union

Williams College and MIT Astronomers Observe Pluto and its Moons

WILLIAMSTOWN, Mass. — A Williams College team of astronomers, headed by Bryce Babcock and Jay Pasachoff, have been in Hawaii, near Honolulu, to observe a rare double-double event about Pluto. On June 23, they observed an occultation, a hiding, when Pluto's largest moon, Charon, only 755 miles across, went in front of (occulted) a star, revealing its size accurately as well as the absence of any atmosphere. About 11 minutes later, Pluto went in front of the same star, though the astronomers and their students have to analyze their observations to see if they detected that second event. On June 27, Pluto, which is about 1750 miles across, had a second double occultation. It went in front of another star, occulting it. About 33 minutes later, its tiny moon Hydra, perhaps only 50 miles wide, was scheduled to go in front of the star, casting a shadow exactly its same size on Earth, perhaps only 40 to 100 miles across. The Williams team is allied with an MIT group that provided the continually updated calculations and that itself sent out astronomers with special cameras. Indeed, one MIT astronomer carried such a camera to Yunnan, China, to a telescope with access arranged by Pasachoff. The Williams College team includes Babcock, Pasachoff, and students Shubpanga Pandey, a junior from Nepal, as well as Wesleyan exchange student David Amrhein, a senior, part of the National Science Foundation sponsored Keck Northeast Astronomy Consortium. The MIT team, founded by the late Jim Elliot, is now headed by Michael Person and Amanda Bosh in collaboration with Amanda Gulbis, who is also at the South African Astronomical Observatory in Cape Town. They also work with Stephen Levine, who works at the Lowell Observatory in flagstaff, who has been providing up-to-the-day positions of Pluto and of the stars. The  consortium has the cooperation of David Tholen of the University of Hawaii's  Institute for Astronomy, who provided late corrections to the position of Hydra based on Hubble Space Telescope observations, with the tiny motions of the stars across the sky over the last few years providing the limit in accuracy. Contrary to popular belief, the International Astronomical Union's actions in Prague in 2006 promoted Pluto to its current state of "dwarf planet," making it the first and a major object in its class instead of a diminutive member of a class of much larger "planets.

How I Killed Pluto and Why It Had It Coming by Mike Brown « The YA ...

Nearly five years ago, on August 25, 2006, as a result of a vote at the meeting of the International Astronomical Union, Pluto lost its status as a planet.

Sure, people had recognized the oddity of Pluto since its discovery by Clyde Tombaugh, but while “it looked and behaved like no other planet known, there was not other way to classify it, so it became accepted as the ninth planet.” So how did we get to the point at which Pluto’s planetary status was questioned?

In 1999, Mike Brown was a young astronomer with a hunch that, despite accepted astronomical wisdom, there was another planet beyond Pluto. He and fellow astronomer made a friendly bet about whether or not a new planet would be found by the end of 2004, with the loser paying up in the form of five bottles of champagne. The only potential snag Brown thought of at the time was, how exactly do you define what a planet is?

Beginning with this bet, How I Killed Pluto and Why It Had It Coming details how Brown went on to discover several new, um, planets. At least, they were considered planets when their discovery was first announced, despite Brown’s belief that they, and Pluto, were not actually planets. It didn’t matter that one of them was slightly bigger than Pluto; he was adamant that it wasn’t a planet and neither was Pluto. Despite Brown’s strong feelings on the matter, the choice of terminology wasn’t up to him. Instead, it was up to the members of the International Astronomical Union to define what planet is a surprisingly entertaining and humorous read.* (Although the book does not include a bibliography or further reading section, much to my dismay.) Brown writes in an accessible, conversational style that makes his passion for astronomy obvious. His expertise in his field is clear, but he shares his knowledge simply and lucidly for a lay audience. The book was published for an adult audience and some teens will not be as interested in the details of Brown’s family life, but may find inspiration in how his childhood interest in planets led to a career as an (depending on your point of view, planet-killing or planet-redefining) astronomer. I found a couple of moments in the chronology a bit confusing, but overall, How I Killed Pluto… is a stimulating look at our solar system and how Brown deliberately undertook his search for new planets.

Book source: public library.

* It also garnered my favorite author blurb of the year thus far, courtesy of Neil deGrasse Tyson on the back cover, which begins: “Finally I have someone to whom I can forward the hate mail I get from schoolchildren. After all these years, the real destroyer of Pluto has confessed.