© 2016 Peter Free
Citation — to press release
HubbleSite, NASA’s Hubble Finds Universe Is Expanding Faster Than Expected, NASA (02 June 2016)
Theoretically unaccounted for zoom
From the press release:
Astronomers using NASA’s Hubble Space Telescope have discovered that the universe is expanding 5 percent to 9 percent faster than expected.
“This surprising finding may be an important clue to understanding those mysterious parts of the universe that make up 95 percent of everything and don’t emit light, such as dark energy, dark matter, and dark radiation,” said study leader and Nobel Laureate Adam Riess of the Space Telescope Science Institute and The Johns Hopkins University . . . .
The results will appear in an upcoming issue of The Astrophysical Journal.
There are a few possible explanations for the universe’s excessive speed. One possibility is that dark energy, already known to be accelerating the universe, may be shoving galaxies away from each other with even greater — or growing — strength.
Another idea is that the cosmos contained a new subatomic particle in its early history that traveled close to the speed of light. Such speedy particles are collectively referred to as “dark radiation” and include previously known particles like neutrinos. More energy from additional dark radiation could be throwing off the best efforts to predict today’s expansion rate from its post-big bang trajectory.
The boost in acceleration could also mean that dark matter possesses some weird, unknown characteristics. Dark matter is the backbone of the universe upon which galaxies built themselves up into the large-scale structures seen today.
And finally, the speedier universe may be telling astronomers that Einstein’s theory of gravity is incomplete.
HubbleSite, NASA’s Hubble Finds Universe Is Expanding Faster Than Expected, NASA (02 June 2016) (extracts)
The moral? — Fun for mind and measurement
Grappling with what we apparently do not know sharpens what we do.