We know that the universe is expanding, and that it’s doing so faster and faster. But we don’t know why the rate of expansion is increasing. Astronomers have dubbed the unknown cause “dark energy,” which is a pretty cool name for something we know absolutely nothing about. To shine some light on the mystery, scientists devised a the most powerful digital camera in the world: the Dark Energy Camera, capable of seeing 8 billion light years into space. And after eight years of development, last week the camera captured its first images.
The Big Bang was not the beginning, Roger Penrose believes.
The eminent Oxford physicist has long advocated the wild idea of “conformal cyclic cosmology,” a cyclical universe without beginning or end in which the Big Bang 13.75 billion years ago was simply one of many. This month, Penrose pushed his idea further: His team says it has detected a pattern in the cosmic microwave background—radiation left over from just after the Big Bang—that represents the echo of events that occurred before the Big Bang itself.
Penrose examined the data from the Wilkinson Microwave Anisotropy Probe (WMAP), the mission that just completed nine years of surveying the cosmic microwave background across the sky. His study points to concentric circular patterns in the WMAP data where he says he found something surprising:
The circular features are regions where tiny temperature variations in the otherwise uniform microwave background are smaller than average. Those features, Penrose said, cannot be explained by the highly successful inflation theory, which posits that the infant cosmos underwent an enormous growth spurt, ballooning from something on the scale of an atom to the size of a grapefruit during the universe’s first tiny fraction of a second. Inflation would either erase such patterns or could not easily generate them. [Science News]
“We have an amazingly simple picture of the universe,” says Princeton University astrophysicist Michael Strauss. “Of course, we don’t understand that picture—we don’t know what dark energy is, and we don’t know what dark matter is.” [Scientific American]
To get a better handle on these “dark” forces, which we can’t detect with our puny human equipment, researchers Christian Marinoni and graduate student Adeline Buzzi from the University of Provence used an approach that’s actually been around longer than the idea of dark energy–a 1979 theory from Charles Alcock.