What is Cosmic Microwave Background Radiation?
CMBR is a relic of the birth of our Universe, when the entire cosmos was filled with hot plasma. The plasma emitted strong electromagnetic radiation, but as the Universe grew, this radiation lost energy as it traveled through the expanding void. Like a rubber sheet being stretched, the fabric of space-time expanded, stretching the radiation itself.
Over billions of years, this primordial radiation was red-shifted so much by universal growth that it's become nothing more than a background echo of microwave noise. But it's there, everywhere, and it can be measured.
The CMBR provides strong evidence of a Big Bang (i.e., everything came from a compressed, hot state) and universal inflation (i.e., the rapid expansion of the Universe immediately after the Big Bang).
Although instruments such as NASA's Wilkinson Microwave Anisotropy Probe (WMAP) have measured slight temperature variations in the CMBR - known as anisotropies (pictured below) - revealing startling clues as to the structure, age and history of the Universe, this new controversial discovery suggests the CMBR contains something else.
In an unpublished paper submitted to the arXiv preprint service, world-renowned Oxford University physicist Roger Penrose and co-author Vahe Gurzadyan from the Yerevan Physics Institute in Armenia have announced a pattern in the CMBR that could reveal events that occurred before the Big Bang.
If Penrose and Gurzadyan suggested that evidence of a pre-Big Bang Universe survived into our Universe without any physical proof, it would be highly speculative at best; the kind of discussion you'd only have in an advanced theoretical physics class. But this study has used data from WMAP and the balloon-borne BOOMERang experiment, adding some ‘meat' to this hypothesis.
The problem is that it is generally accepted that the Big Bang, end ensuing inflation, destroyed any hint of what came before. We cannot "see" what happened before the Big Bang because, as far as we're concerned, it didn't. But Penrose and Gurzadyan have decided to put their hypothesis out there and, unsurprisingly, it's causing one hell of a stir.
A Cyclical Universe?
According to the pair of physicists, there is a circular pattern embedded in the CMBR like ripples (pictured top). These ripples show slight decreases in average temperature in a cyclical manner. The reason? This could be evidence for repeated birth and death of the Universe, or universes, that came before our current 13.75 billion year-old Universe.
Rather than one Big Bang, there have been many Big Bangs. This finding supports Penrose's preferred "conformal cyclic cosmology" (CCC), a cyclical universe theory where there's a Big Bang followed by another Big Bang and so on, but the laws of nature may evolve with time.
But there's a problem. If this theory holds true, and the fingerprints of a pre-Big Bang universe can be seen in our Universe, the inflationary mechanism that is theorized to have occurred immediately after the Big Bang didn't happen.
Cosmic inflation - the rapid, exponential increase in universal volume between 10-36 to 10-32 seconds after the Big Bang - would have erased any trace of these pre-Big Bang cycles. If we can "see" previous universes, this suggests inflation might not be entirely correct, despite all the evidence to the contrary.
So what is causing these circular ripples in the CMBR?
Crashing Black Holes, Gravitational Waves and Dark Matter
From calculations made by Penrose, he believes that as each universe evolved, the catastrophic collisions between supermassive black holes (the black hole behemoths living in the centers of galaxies) would have generated gravitational waves within that universe's lifetime. When the next universe exploded into being, these gravitational waves were converted into energy, ensuring their "fingerprint" bled through to the next universe.
The pulse of energy caused by the transfer of gravitational waves from one universe to the next would have caused a kick to the distribution of dark matter, creating uniform, spherical patterns in the current universe.
"The dark matter material along the burst therefore has this uniform character," Penrose told Science News. "This is what is seen as a circle in our cosmic microwave background sky, and it should look like a fairly uniform circle."
So are these apparent rings in the CMBR the remnants of universes past? Are they a cosmic ticker-tape keeping count of the number of universes that have come before?
Needless to say, there's a huge number of reasons to believe this CMBR pattern could be something entirely different, but it is certainly intriguing considering the physicists used two different instruments (WMAP and BOOMERANG) and found a similar pattern in both.
Another mission, the European Planck space telescope, is currently mapping the microwave background too, so it will be interesting to see whether a similar pattern emerges.
Sci-Fi Does Sci-Fact
So what's my reference to SGU got to do with this mindboggling research? In the sci-fi plot line, our human explorers aboard the Ancients' spaceship Destiny are currently on a whirlwind tour of interstellar and intergalactic space where each episode is punctuated with crew problems, alien encounters, stargates and wormholes. The Ancients, as the name suggests, is an extinct (we assume) ancient hi-tech alien race.
In "The Greater Good," an episode that ran a couple of weeks ago, physicist Nicolas Rush (played by the superb Robert Carlyle) announced that he knows what the Ancients were studying (thereby revealing the main story arc of the whole season): a pattern discovered in the cosmic background radiation.
The thing is, in this sci-fi universe, the CMBR pattern isn't natural, it has an artificial structure.
Needless to say, when I first read about this research, SGU came to mind. Although I don't think for a second that some kind of intelligence created our universe (and the ringed pattern in the CMBR is some kind of signature of the technology that did it), it is a wonderful sci-fi plot that has stumbled into science fact.
As Robert Carlyle says in the following Stargate interview, "That's pretty epic."
I couldn't agree more.
Via: Science News
Publication: Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity, Gurzadyan & Penrose, arXiv:1011.3706v1 [astro-ph.CO]