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Sharing a Love of Science
Who are NASA's Earth and Space Science Explorers?

The middle school students who track weather to study its effect on bursting tree buds. And the scientist studying black holes in distant galaxies. But also the teacher whose class shares Earth science data with students around the world. And the engineer who designs robotic instruments to probe hard-to-reach planets. All of these people are Earth Explorers, Space Science Explorers or both. The Earth Explorers and Space Science Explorers series features NASA explorers, young and old, with many backgrounds and interests.

Charles Keeton

Charles Keeton is an astrophysicist who uses the Hubble Telescope to study dark matter. Image Credit: Charles Keeton

The years surrounding 1980 were exciting ones in space exploration. The Voyager probes were returning the first pictures from Jupiter and Saturn; the space shuttle program was beginning. The events amazed Charles Keeton, who is now a NASA-funded astrophysicist at Rutgers University.

From that time on, Keeton had a clear career path. "I think all along I knew I wanted to study space," Keeton says, "and here I am 30 years later doing it." During middle school and high school, he prepared for a career in science by taking advanced mathematics courses. In college, Keeton planned to study astronomy, but the university he chose to attend did not have a specific astronomy major. He majored in physics instead. "Physics was the right path to pursue along the way. I looked for opportunities to take astronomy classes and work on astronomy research as I was going."

When Keeton began considering research topics, dark matter caught his attention. Dark matter cannot be seen with visual telescopes. Scientists can detect it only indirectly in the X-ray part of the electromagnetic spectrum. However, there is enough evidence that dark matter does exist. "It's a huge puzzle. To learn that 80 percent of the mass in the universe is something we've never studied in physics (directly) is a little humbling but also pretty compelling. It means there's a great opportunity to learn more about what’s out there." Keeton decided to seize that opportunity.

Working with NASA's Hubble Telescope, Keeton uses gravitational lensing to study dark matter. Gravitational lensing is the effect of light from a distant galaxy being bent by the gravitational pull of the mass of another galaxy in front of it, as the light from the distant galaxy passes through it. Scientists can use this light-bending in research. "It can be used to study many different problems in astrophysics. It also lets me work with a wide range of research methods and research styles. I do some computer simulations. I do some analytical mathematical calculations. I do some telescope observations as well. Being able to mix it up like that is very appealing to me."

The first goal for Keeton and other scientists studying dark matter is to measure the amount of dark matter and its distribution. "We think that every galaxy is embedded in a large massive halo of dark matter. By now we have a pretty good set of hypotheses for how that dark matter is distributed around galaxies." Though they are working on investigating that distribution in even more detail, Keeton and others are looking ahead.

A colorful composite image of galaxy cluster 1E 0657-66

This composite of images was taken by the Hubble Space Telescope and the Chandra X-ray Observatory. The bluish cloud is dark matter detected by gravitational lensing. Image Credit: NASA

"The next step that I've been working on is to understand how dark matter is distributed on small scales," Keeton says. "The theory of dark matter predicts that not only should galaxies be embedded in dark matter halos but those halos should be full of hundreds or thousands of dwarf galaxies, clumps of dark matter that we may or may not see as visible galaxies." Currently, scientists have observed only a few dozen dwarf galaxies orbiting our own, far fewer than what is predicted.

In addition to doing his own research, Keeton is the Faculty Director for the Aresty Research Center for Undergraduates at Rutgers University, a position he is passionate about. He thinks it is vital to encourage students to engage science outside the classroom as well as for professors to bring current research into the classroom. In his current class, he tries to talk every day about some new discovery. "There's so much going on in planetary science, which is the focus of the course. It's a great opportunity for me to tell the students what's going on right now. It gives them a sense that science is a living endeavor ... and that we're still learning a lot. We use that then to talk about the process of science, about how scientists think about the world."

Keeton sees great value in astronomy. "A couple of years ago, I heard a prominent cosmologist asked why we as a society should spend money on astronomy when there are so many other pressing problems. This cosmologist said that the value of cosmology comes down to three words: 'we do wow.' That really sums it up for me. Astronomy inspires people. We live in an increasingly technological society, a society where a lot of the challenges we face demand scientific literacy, quantitative reasoning and critical thinking skills. We can use astronomy to get people excited and say this is what science is about, this is how scientists think about the world, this is why it's valuable to learn about science even if you're not going to become a scientist. I think if we can inspire people, get them excited, and get them comfortable with science, then that will pay dividends down the road."

Indeed, Keeton's enthusiasm for science is contagious. Like most scientists, Keeton enjoys his research, but he is also active in outreach. He loves to talk about his new discoveries or just learn about colleagues' projects. Besides his public outreach, he also visits his son's elementary school class on a regular basis to share the wonders of cosmology. He hopes the students will develop an early love for science, whether they become scientists or not.

Keeton has been lucky enough to follow his dreams, and he encourages others to do the same. "I think if you can find something you're interested in -- whether it's space or science or not science -- if you can find something that really excites you and put a lot of energy and passion into it, that will serve you well."

Related Resources:
› Space Science Explorers Series
› NASA Career Resources

Brandi Bernoskie/Institute for Global Environmental Strategies