Author: Falishia Sloan
Institution: Eastern Virginia Medical School
Date: December 2007
An international research team is currently working to test Einstein's long-ago dismissed theory of a cosmological constant, noted by Einstein himself as being his "biggest blunder." In the project ESSENCE, this group of scientists is studying supernovae to see whether the accelerating force of the universe, known as "dark energy," is related to Einstein's postulation.
"Eighty years later, it turns out that Einstein may have been right [about a cosmological constant].So he was smarter than he gave himself credit for," stated Kevin Krisciunas, a Texas A&M scientist that participated in the project.
Einstein originally created this theory of a force to oppose the gravitational attraction of matter in the universe. According to Einstein, this force acts to prevent the universe from collapsing, as he described in his famous Theory of General Relativity, in which he formulated many of the fundamental ideals of space, matter, and time used in modern physics today. He later denounced this theory of a force to prevent the collapse of the universe when Edwin Hubble discovered that the universe is not static and is actually expanding.
In 1998, however, a group of scientists discovered that the universe is not only expanding, but this expansion is also accelerating. The fact that the universe's expansion was accelerating was proof that there exists some force to create this acceleration.
Nicholas Suntzeff, ESSENCE project scientist and one of the scientists who made the discovery in 1998, deduced, "So there had to be some other force that had overcome the force of gravity and is driving the universe into an exponential acceleration."
The force Suntzeff spoke of is now known as "dark energy," and is believed to make up about 74% of the universe.
Now, the team of scientists involved with the ESSENCE project plan to observe the brightness of the supernovae that they've found, and compare this brightness with the actual known brightness to determine how far away a given supernova is. To discover the acceleration of the universe's expansion due to the force of dark energy, they plan to look at the supernova's redshift, which is how fast the supernova is receding from Earth. This value of acceleration will then by used to calculate the density of dark energy, which in turn can be used to calculate the w-parameter. The value of the w-parameter must be -1 in order for Einstein's theory on the cosmological constant to be correct, and so far the results of the project have been confirmed to be very close to -1.
"The magic value is -1 exactly," Krisciunas said. "If the number turns out to be precisely -1, then this dark energy is a relatively simple thing it is Einstein's cosmological constant."
Written by Falishia Sloan
Reviewed by Brittany Raffa
Published by Pooja Ghatalia