Lecture: Mike Brown, "How I Killed Pluto and Why It Had It Coming"

[mabfan]

Last night, thanks to the Boston Skeptics organization, Nomi and I got to meet Mike Brown, the man who discovered Eris and indirectly led to the demotion of Pluto's status as a planet.

Nomi S. Burstein, Mike Brown, Michael A. Burstein Photo ©2011 D. Moskowitz. All rights reserved.

The Boston Skeptics had arranged for Mike Brown to give a talk last night at Tommy Doyle's in Cambridge. We had only found out about the talk on Tuesday morning, but thanks to a good friend who volunteered to put our kids to bed, we managed to clear our schedule to attend. But when the National Weather Service predicted a significant snowfall starting yesterday afternoon, we weren't sure if we were going to make it to the lecture.

The roads turned out to be clear, and we made it to the pub just as things were getting started at 7 pm. Brown was already there, and willing to sign books even before his talk began. We brought our copy of his book over to him and introduced ourselves. It turned out he had already heard of us and was as delighted to meet us as we were to meet him. He was very gracious and personable, and his talk demonstrated quite clearly why he had won a teaching award.

The space was somewhat small and crowded, and not designed very well for his talk, I'm afraid. The screen for his presentation slides didn't face the main body of the room, so it was hard for us to see. Having arrived just at 7 pm, Nomi and I had difficulty finding seating, but a nice scientist named Jason allowed us to sit at the table with him and his two friends.

Brown discussed his research in the outer solar system. He had a graphic that showed just how big in comparison all the planets are to each other and to the objects in the Kuiper Belt, making it clear why Pluto is such an outlier. He talked about the telescopes at Palomar Observatory that they use to photograph the sky, and how they look for those tiny objects that are so far away. Back when Clyde Tombaugh found Pluto, Tombaugh used a blink comparator, a device that allowed him to compare two photos of the same portion of sky from two different nights to see if any points of light had moved. Brown relied on something similar, except in his case a computer went through a slew of photos and would present him with likely candidates in his morning email. I wonder what Tombaugh would have thought of that.

Brown seemed very respectful of those of us who still feel that Pluto should be considered a planet. He understands where the impulse comes from, and in a way, if Pluto were still a planet it would be better for him. After all, he'd be able to go down in history as the discoverer of the tenth planet (and eleventh, and twelfth, and thirteenth, etc.) Instead, he's going to be the discoverer of a lot of astronomical bodies that he himself points out are rather insignificant to the solar system.

Although he feels that Pluto should not be a planet, it turns out we do have a few points of agreement. He and we both feel that the term "dwarf planet" is a bad one, and he also has issues with the way the term "planet" is currently being defined by the IAU.

Brown also spun a brief tale of alternate history that, as a science fiction writer, I found fascinating. He pointed out that the discovery of bodies like Pluto, Eris, and Sedna relies a lot on the good luck of looking in the right place at the right time. He suggested that had Eris's orbit been different, and had it been discovered only a few years after Pluto, that perhaps we wouldn't have this controversy over Pluto's status today. After all, when Ceres was discovered in 1801 it was thought to be a planet, but as soon as many other small bodies were discovered nearby it got demoted as well and became known as the largest asteroid instead. Had Tombaugh or others managed to find other Pluto-like objects in the outer solar system in the early twentieth century, then perhaps we wouldn't have this debate today. But, Brown acknowledges, he does prefer what really did happen, as otherwise he wouldn't have been the discoverer of Eris.

All in all, a lovely evening, and it was wonderful to have the chance to meet him.

Mike Brown's Message to Supporters of Pluto Photo ©2011 M. Burstein. All rights reserved.

Comments

[mabfan.livejournal.com]

As in ours.

[laurele.livejournal.com]

Pluto IS still a planet in a lot more than just people's hearts. Only four percent of the IAU voted on the controversial demotion, and most are not planetary scientists. Hundreds of professional astronomers led by New Horizons Principal Investigator Dr. Alan Stern signed a formal petition rejecting the IAU definition and the demotion. The New Horizons mission continues to refer to Pluto as a planet. This is an ongoing debate with two equally legitimate views. Brown's is the dynamical planet definition. The alternative is a geophysical planet definition, in which a planet is any non-self luminous spheroidal body orbiting a star. In other words, if the object is large enough to be rounded by its own gravity, a state known as hydrostatic equilibrium, and it orbits a star, it's a planet. By this definition, Ceres is a planet, as are Pluto, Haumea, Makemake, Eris, and any other dwarf planet large enough to be spherical. Dwarf planets are simply a third class of planets in addition to terrestrials and jovians--objects orbiting a star and large enough to be spherical but not large enough to gravitationally dominate their orbits.