Much important but unpublished data are already collected, SPACE.com has learned, and by the end of this year the history of the universe's expansion could become a bit clearer, further illuminating the path toward understanding dark energy.
Change of pace
Our universe has always been expanding, with practically all galaxies receding from each other, except for those bound in clusters.
The expansion was decelerating until about 6.3 billion years ago, however. Then an important switch to acceleration occurred. Something caused the universe to step on the gas, driving a growth that now speeds up each day. It is like a rocket whose speed increases 100 mph in the first mile, then by the same amount the next half-mile, then in a quarter-mile, and so on.
Scientists admit they've made almost zero progress in understanding dark energy. They have no idea what it is or how it works.
Various researchers describe the phenomenon as a repulsive force, as vacuum energy, as anti-gravity, and as possibly no more than a different manifestation of gravity over large distances. Some say the repulsion could be a response to dark matter, unseen stuff that is known to make up nearly a quarter of the universe, but such a link has never been established.
All that's clear is that dark energy comprises 73 percent of the mass-energy budget of the universe, and that it is no longer an arguable point for theorists but instead is a viable quarry for astronomers. |
