Who are NASA's Space Science Explorers?

The scientist studying black holes in distant galaxies. And the engineer designing robotic instruments for probing hard-to-reach planets. But also the teacher explaining the mysteries of the cosmos. And the elementary schooler wondering if life exists anywhere besides Earth. All of these people are Space Science Explorers -- they are all connected by their quest to explore and understand our solar system and universe. This series will introduce you to NASA Space Science Explorers, young and old, with a variety of backgrounds and interests.
 

He's one of the greatest space science explorers of all time. Yet the bulk of his discoveries came more than 50 years before the first satellite was launched into space, more than 60 years before humans walked on the moon and more than 70 years before liftoff of the first space shuttle.

Image to right: A century ago, Albert Einstein began creating his theory of relativity -- the ideas we use to understand space, time and gravity. Credit: NASA

The year 1905 will forever be regarded as Albert Einstein's "miracle year," the year a 26-year-old changed the way we view space, time, matter, energy and the universe. Einstein’s theories about the speed of light, the relative motion of objects, the effects of gravity and the relationship between energy and mass eventually led to the big-bang theory of how the universe began, and to concepts such as black holes and dark energy.

NASA and other organizations are marking the 100th anniversary of Einstein's revolutionary research, although some of his most important work did not come until 1915. This yearlong celebration is known as the Einstein Centennial; the impact of his findings on science and society will surely last for centuries to come.

Much of the cutting-edge space science underway today is an extension of Einstein’s work. Scientists in NASA's "Beyond Einstein" research program, for example, are using their minds and NASA instruments to search for answers to three important questions: What could have powered the big bang? What is dark energy? What happens at the edge of a black hole?

There are different theories for how the universe began. Einstein himself did not conceive the big-bang theory, which proposes that the universe began with the explosion of a tiny but dense mass of energy, and has been expanding ever since. But it was his mathematical equations describing how mass, energy, gravity and other aspects of the universe interact that scientists later manipulated to support such an explanation.
 

Image to left: This "baby picture" of the universe shows small changes in temperature from more than 13 billion years ago. That's not long after the big bang would have taken place. Scientists captured this image using NASA's Wilkinson Microwave Anisotropy Probe (WMAP) during a sweeping 12-month observation of the entire sky. Credit: NASA

Johns Hopkins University professor Charles Bennett is lead scientist for NASA's Wilkinson Microwave Anisotropy Probe mission. With the help of powerful space-based telescopes, the mission produced a "baby picture" of the universe as it was more than 13 billion years ago, less than a billion years after the big bang would have occurred. He says that today's researchers must continue to ask questions and think outside the box -- much like Einstein did -- if they are to figure out what could have triggered the big bang.

"Einstein was a big believer in experiments and observations, both to guide and test theories," said Bennett, who is now focused on determining how the universe might have evolved from an explosive beginning to the state shown in the baby picture. "He always kept a keen eye on things that didn't quite add up. He asked himself how he could resolve these problems with creative new ideas."

New ideas are what University of Chicago professor Sean Carroll is all about. His job is to think up ways in which a mysterious, yet-to-be-seen force known as dark energy could be causing the universe to expand at an increasing rate. And if that sounds challenging, imagine anticipating this force before knowing the universe is expanding. That's what Einstein did.

Einstein's equations that model the universe required that it either be expanding or contracting. At the time, though, he and others believed the universe was doing neither. So Einstein added to his equations what he called a "cosmological constant," a term that accounted for whatever force was supposedly keeping the universe static. He promptly dropped the term, however, when it was later demonstrated that the universe is indeed expanding. Einstein called the whole idea his "greatest blunder."

But now it looks as if Einstein was on to something after all. Scientists have recently found that the universe is not only expanding, but that its expansion is accelerating, and one way to explain this acceleration is the existence of a force similar to the one represented by Einstein's original cosmological constant. As Carroll contemplates what dark energy is and where it comes from, he emulates what he regards as Einstein's greatest qualities.

"He learned as much as he could about what was already understood," said Carroll, who develops new theories and suggests how they can be tested. "At the same time, he kept an open mind about new ways of doing things."

It certainly took an open mind to imagine the existence of black holes, which Einstein himself did not believe in, even though they were predicted by his theories.

Mitch Begelman, a professor at the University of Colorado, studies the formation of black holes -- areas in space where gravity is so strong that light is unable to escape -- and how they affect galaxies. He says he's looking forward to the launches of two NASA missions around a decade from now. The Laser Interferometer Space Antenna spacecraft will employ laser technology to help scientists better understand how medium-size black holes merge together to form larger ones, while Constellation-X, a group of four satellites carrying X-ray telescopes, will measure radiation emitted by matter just before it is sucked into a black hole.

Whether studying black holes or other weird phenomena, Begelman approaches his research with a strategy reflective of Einstein's work ethic.

"He was able to take a hypothesis ... and follow it to its logical conclusion, no matter how counterintuitive that proved to be," Begelman said. "I try to remember this when I am thinking about a bizarre astrophysical object, where commonplace ideas can only take you so far."