America's space agency has unveiled an ambitious plan to learn more about what happened just seconds after the Big Bang.
Paul Hertz, theme scientist for NASA's Structure & Evolution of the Universe Road Map team, recently laid out the agency's latest 10-year plan for scientific research projects, called Beyond Einstein.
The space agency completes a similar decade-long plan every three years. The latest plan aims to answer lingering questions about the origins and structure of the universe.
"The Beyond Einstein program asks three of the most fundamental questions in physics today," said Lynn Cominsky, a physics and astronomy professor at Sonoma State University in Northern California. "These questions actually come at a place where cosmology, particle physics and astronomy all meet. The three questions all come from Einstein's theory of general relativity. They are things that Einstein's theory predicted, but he never lived to experience the observations that showed that the theories were correct."
Cominsky said the three questions are: What powered the Big Bang? What happens at the edge of a black hole? And what is the nature of the dark energy that seems to be pulling the universe apart?
It is believed that light did not appear until about 300,000 years after the Big Bang. Hertz said NASA has planned a number of missions over the next 15 years whose goal is to home in on what happened in the first 10 to 34 seconds after the Big Bang by examining "gravity waves" -- ripples in the fabric of the space-time continuum that Einstein predicted would result from cataclysmic events, like the collision of two massive black holes.
One of the big-ticket items on NASA's equipment wish list is the Laser Interferometer Space Antenna, nicknamed LISA, a set of three satellites parked in a triangle about 3.25 million miles apart and connected by laser beams. Each of the three spacecraft will hold free-floating "proof masses" protected from everything except the effects of gravity. By combining the laser beams, scientists hope to measure the infinitesimal motion of the masses caused by gravity waves.
A second large-scale project Hertz described is the Constellation-X mission -- four X-ray telescopes held in a precise formation that will focus on the same point in the sky to produce X-ray observations 100 times more sensitive than the current Chandra X-ray space telescope. He said Constellation-X will look "at the behavior of atoms as they orbit and fall into black holes."
In what Hertz described as "part two" of the road map, NASA has three smaller space probes still in the concept stage. Hertz said the agency will request ideas from astrophysicists and astronomers about how the probes should work. The ultimate goal is to use all five spacecraft to measure different aspects of dark energy, which astrophysicists now believe makes up 70 percent of the cosmos.
The idea of dark energy came from Einstein's "Cosmological Constant," Cominsky said.
"Einstein personally believed that the universe should be static," she said. But the equations in the theory of relativity suggested it was actually expanding, as is now widely believed.
"He put that constant in to try to make the universe hold still. Now, the Cosmological Constant that we find has the opposite sign, because not only is the universe expanding from the Big Bang, but there's actually something that's accelerating that expansion."
Hertz said NASA is hoping to start on the projects as soon as funding is approved. He estimated that LISA and Constellation-X would run about $1 billion each, and the three smaller missions would cost between $350 million and $500 million per project.
