Dark energy is a mysterious force that cosmologists use to fill gaps in our model of why our universe continues its ever-faster expansion. But now two mathematicians have found a way to explain those baffling observations of the universe without the dark energy question mark hanging overhead.
Cosmologists first proposed dark energy to explain why astronomers saw supernovae receding into the distance at an accelerating pace. That suggested a massive amount of energy must exist somewhere to counter the gravity that would otherwise slow down such universal expansion. Such dark energy must make up roughly 70 percent of the universe, in addition to 20 percent constituting dark matter. A measly 4 percent belongs to humans, planets and stardust.
Mathematicians Blake Temple and Joel Smoller developed a new theory: Earth sits near the center of an expanding wave that began after the Big Bang. That accelerating expansion could have led to the spread of galaxies as astronomers see them today, but would not itself represent a constant accelerating force. The duo from the University of California-Davis and the University of Michigan talked with other mathematicians and astrophysicists to flesh out their calculations.
Such an alternative vision of our universe has the attraction of only relying on Einstein's equations of general relativity, Seed Magazine explains. The theory also helps explain another cosmological idea known as the "bubble of underdensity," or the idea that Earth inhabits a low-mass density area of the universe.
But cosmologists say that the new expansion theory has problems. First, observations of the Big Bang's afterglow also indicate the existence of dark energy. Simulations also fit rather well with the observed universe expansion when dark energy becomes a factor. And then there's the counterargument based on the Copernican principle that Earth does not have a unique place in the universe.
Only time may tell if the elegance of mathematics triumphs over the black sheep of cosmology. For now, the mathematician duo hopes to work out a testable prediction that can truly pit theory against observation.
[via Seed Magazine]
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