When Jupiter got socked by comet fragments this week, Heidi B. Hammel had one of Earth's best ringside seats for watching the interplanetary pugilism.
And the 34-year-old astronomer, who led the team using the Hubble Space Telescope to take close-ups of the aftermath of these impacts, was knocked out by what she saw.
"In my heart of hearts, before it all happened, I really didn't think it would be the show that it has been," said Dr. Hammel, in an interview at the Space Telescope Science Institute in Baltimore. "But when . . . the first images came in -- and we saw plumes, and we saw spots, and explosions -- we were just blown away."
Dr. Hammel, a research scientist at MIT, was chosen by a panel of her peers to lead the team taking snapshots of the smashup using the Hubble's wide-field camera -- the first time earthlings have witnessed any large object collide with another planet.
Hubble's location in space,above the Earth's blur-causing atmosphere, meant that it had a sharper view of Jupiter than any ground-based telescope. There was a lot to see. A fragment that hit Monday yielded a 6 million-megaton fireball, a punch many times more powerful than what all of Earth's nuclear arsenals combined can produce.
Dr. Hammel recalled when colleagues at the Massachusetts Institute of Technology first talked about the comet P/Shoemaker-Levy 9's expected collision with Jupiter. "My initial reaction was, pffft, who cares?" she said, rolling her eyes in theatrical disdain. "It's a teeny, tiny little comet. It's a big planet. It's not going to do a thing! It's crazy. Why even bother thinking about it?"
But she did think about it, studied computer models and submitted a proposal for using Hubble to one of the National Aeronautics and Space Administration committees that parcels out precious time on the telescope. The panel not only accepted her proposal, it asked her to lead the team.
In recent days, Dr. Hammel has become a minor media celebrity. She has appeared at televised NASA news conferences and granted interviews. Her research has been featured in television broadcasts, magazines and newspapers worldwide.
Meanwhile, Dr. Hammel and her team -- Reta F. Beebe of New Mexico State University and Andrew P. Ingersoll of the California Institute of Technology -- have been busy processing a stream of images coming from Hubble.
Even after several days with little sleep, Dr. Hammel seemed full of energy, peppering her sentences with "gosh" and "gee." When she earned her doctorate in planetary science from the University of Hawaii in 1988, she said, she was chided for speaking "with exclamation marks."
Fellow astronomers say she is enthusiastic, but not starry-eyed, and known for speaking her mind. "She's very well organized, knows what she's after and knows how to get it," said James L. Elliot, director of the planetary sciences at MIT.
Some astronomers say she is too quick to disagree with her fellow scientists, both in televised news conferences and private meetings. But Dr. Elliot said Dr. Hammel does not look for fights.
Born near Sacramento, Calif., Dr. Hammel and her family moved to Pennsylvania when she was a child. In high school in Clarks Summit, Pa., near Scranton, Dr. Hammel excelled in mathematics and science.
She vividly recalls how, when she told her chemistry teacher that she had been accepted at MIT, he replied: "It's only because you're a woman. They have quotas to fill." That, she said, was a pivotal moment. She decided she wanted to "show this guy, look, it's not just because I'm a woman. It's not because they have quotas to fill. I can do it on my own."
Like many undergraduates, she found MIT a tough place to survive academically. "I barely, barely got through," she said. But she earned her degree in planetary science and headed to graduate school in Hawaii.
There, she studied Neptune with an 84-inch-diameter telescope near the 14,000-foot summit of the Mauna Kea volcano, focusing on the planet's huge storm system known as the Great Dark Spot. Her work "has been incredibly important to all other astronomical investigations of the planet," said Richard P. Binzel, an MIT colleague.
Capturing Jupiter's pummeling was another demanding task. Months in advance, Dr. Hammel's team had to calculate when the the fragments would hit and where Hubble would be in Earth orbit when they collided. Then they had to make an educated guess as to the best moment to snap their pictures and tell Hubble's handlers when to schedule the exposures.
Now, Dr. Hammel's team must pay for its success.
"For several days, we were still in shock about the whole thing," she said. " . . . Now we're at the point where it's sinking in, and we're starting to realize what an enormous amount of work is ahead of us just to try to understand it."