Tuesday, November 21, 2006

The Beyond Einstein Project

A description of the project can be found at the blog Science and Reason which I found by way of Galactic Interactions

From the NASA page - Beyond Einstein

The questions ->

What powered the Big Bang?

...NASA's Cosmic Background Explorer (COBE) satellite discovered the fluctuations and, most recently, NASA's Wilkinson Microwave Anisotropy Probe (WMAP) has refined the measurement. We see how gravity has pulled these wrinkles into stars and planets. We can even determine the ratio the ratio of matter to energy, the era of first starlight, and the age of the Universe, 13.8 billion years.

What we don't know is the most basic fact: What started it all? Modern theoretical ideas that try to answer this question predict that the wrinkles COBE discovered arose from two kinds of primordial particles: from the energy field that powered the Big Bang; and gravitons, which are fundamental particles of space and time.

Clues to the nature of these particles exist in the Big Bang afterglow. Measurements from Beyond Einstein missions will coax information from this ancient light, which has held its secrets for so long. This would enable us to piece together the story of how time, space, and energy worked together to power the Big Bang.


What happens at the edge of a black hole?

...One key mission will create movies from the X-ray light emitted from multimillion-degree gas as it approaches a black hole's border, called the event horizon. Another mission will listen for gravitational waves, which are ripples in spacetime predicted by Einstein. These waves are created by black hole mergers; they move undisturbed across the "sea" of space at light speed, and offer an unobstructed view of these powerful collisions.

Einstein himself never dreamed that it would be possible to detect gravitational waves, which only distort the distance between objects as far apart as the Earth and Moon by less than the width of an atom. Yet the technology now exists to do so.

Data from X-ray satellites, such as NASA's Chandra X-ray Observatory and ESA's XMM-Newton, show signs of gas whizzing about black holes at close to the speed of light and hint that time is slowing as the gas plunges into the zone from which escape is impossible. Beyond Einstein missions will take a census of black holes in the Universe and give detailed pictures of what happens to space and time at the edges of these gravitational chasms.


What is dark energy?

...Because Einstein originally thought the Universe was static, he conjectured that even the emptiest possible space, devoid of matter and radiation, might still have an energy countering gravity, which he called a "Cosmological Constant." When Edwin Hubble discovered the expansion of the Universe, Einstein rejected his own idea, calling it his greatest blunder.

But the Universe isn't just expanding; the expansion rate, which appears to have slowed several billion years ago, is revving up. We live in a runaway Universe, in which the most distant galaxies visible today will soon fly off forever beyond the horizon. This acceleration could be due to the concept that "empty space" isn't empty. Richard Feynman and others who developed the quantum theory of matter realized that empty space is filled with "virtual" particles continually forming and destroying themselves. These particles create a negative pressure that pulls space outward. No one, however, could predict this energy's magnitude.

Independent measurements reveal that dark energy comprises about 70% of the total mass-energy budget of the Universe. We still do not know whether or how the highly accelerated expansion in the early Universe, called inflation, and the current accelerated expansion, due to dark energy, are related. A Beyond Einstein mission will measure the expansion accurately enough to learn whether this energy is a constant property of empty space, as Einstein conjectured, or whether its strength varies over time, a property predicted by modern theories of the forces of nature.

1 comment:

Anonymous said...

Einstein's mistake was a mathematical oversite. He knew that with no cosmological constant it was impossible to have a static universe. What he did not realize was that we could have a static universe even with the cosmological constant term (DeSitter rectified the error a few years later). Though Einstein did not know it, his biggest mistake was actually in deleting the cosmological constant. He was right to begin with.

For more about current attempts to detect gravitational waves, check out the LIGO experiment. In a few years a similar experiment will take place in space. Unfortunately, LIGO has not seen any waves yet.