“It is undeniable that we are profoundly puzzled, especially when it comes to the first fraction of a second that followed the Big Bang,” wrote theoretical physicist Dan Hooper, author of The Edge of Time in an email to The Daily Galaxy–Great Discoveries Channel. “I have no doubt that these earliest moments hold incredible secrets, but our universe holds its secrets closely. It is up to us to coax those secrets from its grip, transforming them from mystery into discovery.”
Welcome to this week’s fix of news of space and science –a random journey from Planet Earth through the Cosmos– that has the capacity to provide clues to our existence and add a much needed cosmic perspective in our current epoch.
One early result of the ongoing Dark Energy Survey is the previously untold story revealed by old, giant RR Lyrae pulsating stars, which tell scientists about the region of space beyond the edge of our Milky Way. In this area nearly devoid of stars–the motion of the RR Lyrae stars hints at the presence of an enormous halo of invisible dark matter, which may provide clues to how our galaxy evolved over the last 12 billion years.
Following the inflationary epoch after the singularity of the Big Bang, the universe continued to expand, but at a slower rate. The acceleration of the expansion due to dark energy began after the universe was already over nine billion years old (four billion years ago). The weakest of the Standard Model forces, gravity, may provide the solution to this unsolved enigma –the cosmic elephant in the room–in astronomy.
“There is probably no way to tell whether the mysteries faced by cosmologists today are the signs of a coming scientific revolution or merely the last few loose ends of an incredibly successful scientific endeavor. There is no question that we have made incredible progress in understanding our universe, its history, and its origin,” says Dan Hooper, a senior scientist at the Fermi National Accelerator Laboratory about 40 miles west of Chicago and a professor of astronomy and astrophysics at the University of Chicago.
Physicists have found that for the last 7 billion years or so — the anticipated halfway point of the lifetime of the cosmos – galactic expansion has been accelerating. Some unknown force is pushing the galaxies, adding energy to them. A force physicist have named “dark energy”.