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Einstein and Beyond
Who Are NASA's Space Science Explorers?

Who are NASA's Space Science Explorers? The scientist studying black holes in space. The teacher talking about the secrets of the cosmos. And the student asking if there is life away from Earth. All of these people are Space Science Explorers. They are all curious about our solar system and space. This is a story about a NASA Space Science Explorer.

A picture of Albert Einstein with a background of stars
He's one of the greatest space science explorers of all time. And yet most of his discoveries came more than 50 years before the first satellite was launched into space. They came more than 60 years before humans would walk on the moon. And they came 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." It was the year a 26-year-old changed the way we view the universe. Einstein's theories about light, motion, gravity, mass and energy began a new era of science. They led to the big-bang theory of how the universe was born. And they led to concepts such as black holes and dark energy.

One hundred years later, NASA and others are honoring Einstein. This yearlong celebration is known as the Einstein Centennial. The impact of his findings will surely last for centuries to come.

Many current space science projects build on Einstein's famous work. NASA's "Beyond Einstein" research program is a good example. Scientists are using their minds and NASA instruments to answer three important questions:
  • What could have powered the big bang?
  • What is dark energy?
  • What happens at the edge of a black hole?
What Could Have Powered the Big Bang?

Scientists think that the universe is almost 14 billion years old. There are different theories for how the universe began. The big-bang theory says that it began when a tiny but dense mass of energy exploded. And it says that the universe has been expanding ever since. Einstein himself did not come up with the theory. But his ideas led scientists to propose it.

Charles Bennett leads a NASA mission that has made a "baby picture" of the universe. This was done with the help of powerful telescopes in space. The picture shows what the universe looked like less than a billion years after the big bang would have taken place. Bennett and others are trying to figure out what could have caused the big bang. He says that today's researchers must think creatively, like Einstein did.

This map of the sky uses color to show the oldest light in the universe with red showing the warmer spots and blue showing the cooler spots
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 during a sweeping 12-month observation of the entire sky. Credit: NASA

"Einstein was a big believer in experiments and observations, both to guide and test theories," Bennett said. "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."

What Is Dark Energy?

New ideas are what Sean Carroll is all about. Carroll is a theorist. He dreams up ways that an unseen force could be causing the universe to expand faster and faster. That sounds like a challenging job. But imagine being able to predict this force without knowing the universe is expanding. That's what Einstein did.

Einstein came up with mathematical formulas to describe the universe. The formulas only worked if the universe were growing or shrinking. At the time, though, he and others believed the universe was doing neither. So he added an extra term to the formulas. He called it a "cosmological constant." With that the formulas described a universe that did not change.

Einstein soon dropped the term, however, when he found out later that the universe is expanding. He called the whole idea his "greatest blunder."

Einstein's idea may not have been a blunder after all. Scientists have found that the universe isn't just expanding. It is expanding faster and faster, they say. So what is causing this? One way to explain this is "dark energy." This hidden force may be Einstein's cosmological constant.

Carroll is trying to figure out what dark energy is and where it comes from. In doing so, he takes after Einstein.

"[Einstein] learned as much as he could about what was already understood," Carroll said. "At the same time, he kept an open mind about new ways of doing things."

What Happens at the Edge of a Black Hole?

It certainly took an open mind for anyone to imagine black holes. Einstein himself did not believe in such things, even though they were predicted by his theories. Mitch Begelman studies how black holes form. He also studies how they affect galaxies. Black holes are areas in space where gravity is so strong that light is unable to escape.

Begelman says he's looking forward to when NASA will launch two missions to study black holes. This will be in about 10 years. One mission will use lasers to help scientists learn how two black holes join into one large black hole. The other will measure radiation given off by matter just before it gets sucked into a black hole.

Whether exploring black holes or other weird wonders, Begelman takes the same approach. His strategy is similar to Einstein's.

"[Einstein] was able to take a hypothesis … and follow it to its logical conclusion. No matter how [strange] that proved to be," Begelman said.

Begelman and other scientists mimic Einstein in other ways, too. They treat Einstein's theories the way he treated those that came before his. The scientists use the ideas to explain as much about our universe as possible. But they also know that they can change the theories as needed. Or they may invent completely new ones.

Who knows? Maybe someday someone will come up with a new set of theories that even Einstein never thought of. It could even be you.

See previous Space Science Explorers articles:
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Related Resources:
Inside Einstein's Universe
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Beyond Einstein
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Laser Interferometer Space Antenna
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Dan Stillman, Institute for Global Environmental Strategies