‘Pluto really did have it coming,’ Caltech professor Mike Brown explained last night

Along with his many awards including the Urey Prize for best young planetary scientist, a Presidential Early Career Award and the Richard P. Feynman Award for Outstanding Teaching at Caltech, Mike Brown said the one award that is always left out is his nomination as one of Wired Online’s Top Ten Sexiest Geeks in 2006.

Brown, a professor of planetary astronomy at the California Institute of Technology, spoke to more than 700 people at the Kent State Stark Campus last night about how he killed Pluto and why it had it coming.

“I hope that by the time of my lecture is over, most of you will be convinced that Pluto really did have it coming, and I think it did,” Brown said.

Brown is best known for discovering Eris, the largest object found in the solar system in 150 years, and the object that led to the debate and eventual demotion of Pluto from a real planet to a dwarf planet.

In 1930 when Pluto was discovered by Clyde Tombaugh, the process of finding new objects in the sky was very meticulous. Brown said Tombaugh had to attach a large glass plate to his telescope and then expose it to the sky. The plate then had to be developed by hand. After that another plate was exposed to the same spot, and the two pictures were compared to see if anything had moved.

Using slides of the sky, Brown showed how hard it was to see movement of objects from picture to picture by showing two photos in a row and asking the audience to spot the difference. The moving object wasn’t recognizable until he pointed it out with a large arrow.

When Tombaugh found Pluto, astronomers expected it to be much larger than it actually was. Brown said astronomers hypothesized that Pluto appeared small in the picture because it had a uranium core surrounded by a liquid oxygen ocean that appeared transparent in the picture.

“There is actually a much more interesting reason why Pluto appears so small,” Brown said. “Anyone want to take a guess? Oh yeah, that’s because it is small.”

At the time of Pluto’s discovery, it was larger than any other unmoving object and so it gained planet status. About 65 years down the road, in 1992, another object was discovered by astronomers in Hawaii, and the craze for searching for moving objects in the sky began. More than 200 new moving objects were discovered; however, astronomers were only focused on looking along the Kuiper belt.

“In 2002 while studying the region of the Kuiper belt, it occurred to me that one of the reasons Pluto was still the largest object known could very well be that no one had ever looked very hard for things bigger than Pluto,” Brown said. “It seems a strange thing to say, right? Clyde Tombaugh looked really hard; in fact Tombaugh looked over the whole sky, and he didn’t find anything else.”

No one had gone back and looked at the whole sky as Clyde Tombaugh had done. This was mostly because astronomers were technologically limited. Brown said with the invention of the digital camera, it made photographing the sky much easier.

Brown eventually was able to take pictures with a 180-megapixel digital camera. “You’re impressed today, but next year you’ll be able to buy it at Best Buy for $300,” Brown said. “But at the time it was the biggest astronomical camera in the world.”

Brown systematically photographed the sky and looked for moving objects outside of the Kuiper belt. After five years of looking at pictures of the sky every day, Brown’s work finally paid off.

When Brown first spotted what would come to be known as Eris, he said he almost fell out of his seat for three reasons.

“The first reason is because I really slouch, but there are two other reasons,” Brown said. “The object was moving really slow and was very bright.”

Brown said the combination of slow moving and bright meant the object was very large, much larger than Pluto. This new object, Eris, would also gain planetary status. After much debate, astronomers demoted both planets to dwarf planets in 2006.

At a press conference earlier in the day, Brown said, “In some ways it was sad to see Pluto and Eris go, except it was the right thing to do.”

Brown said he never thought Pluto would be demoted because he didn’t think astronomers had the guts to do it. It took a lot of guts to tell everyone that Pluto wasn’t a planet.

“I occasionally get hate mail, mostly from two groups, either elementary school kids who are just learning about how evil I am or professional astronomers who were involved with the mission to Pluto,” Brown said.

Even though he is known as the guy who killed Pluto, Brown said he is OK with it.

“I am happy being the guy who correctly put the solar system in order by killing Pluto,” Brown said.

Brown said he wonders if there is something much further out in the sky that is truly big, even bigger than Pluto and Eris, that could be discovered in the future.

“It’s not impossible that something that size is still out there, and it should be fun to see what it’s like at these distances, to see what’s really going on at the far reaches of the solar system,” Brown said. “We might actually find them in the next couple of years, and that would be fun because then I’ll have to keep thinking. I’ll have to come up with something else.”

Contact regional campuses reporter Mary Jo Spletzer at [email protected].