Washington: University of Michigan scientists have argued a long-held assumption that the universe has mirror symmetry, like a basketball.
They have suggested that the shape of the Big Bang might be more complicated than previously thought, and that the early universe spun about an axis.
To test for the assumed mirror symmetry, physics professor Michael Longo and a team of five undergraduates catalogued the rotation direction of tens of thousands of spiral galaxies photographed in the Sloan Digital Sky Survey.
The researchers found evidence that galaxies tend to rotate in a preferred direction.
They uncovered an excess of left-handed, or counter-clockwise rotating, spirals in the part of the sky toward the north pole of the Milky Way.
The effect extended beyond 600 million light-years away.
“The excess is small, about 7 percent, but the chance that it could be a cosmic accident is something like one in a million,” Longo said.
“These results are extremely important because they appear to contradict the almost universally accepted notion that on sufficiently large scales the universe is isotropic, with no special direction,” he added.
The study provides new insights about the shape of the Big Bang.
A symmetric and isotropic universe would have begun with a spherically symmetric explosion shaped like a basketball.
If the universe was born rotating, like a spinning basketball, Longo said, it would have a preferred axis, and galaxies would have retained that initial motion.
Asked if the universe is still spinning, Longo stated, “It could be. I think this result suggests that it is.”