“Planck could still wield the key to understanding more about our infant cosmos”
We’re reminded of the defunct satellite that could tell us even more about the early Universe
And then there was light. That’s pretty much how our Universe sprang into existence – as a point that contained everything and continued to expand through to today, building the first stars and galaxies and stretching light years of distance between them. According to findings released today, South Pole telescope BICEP2 has provided the strongest evidence yet – in the form of gravitational waves – of cosmic inflation theories that state that this expansion caused the cosmos to race apart by 100 trillion trillion times in less than the blink of an eye.
Despite its name, the Big Bang wasn’t some kind of explosion that spat out matter, energy, time and space it is imagined almost like a balloon that continues to stretch, originally holding a incredibly hot and dense primordial soup that cooled and thinned out.
As ever, such an event has opened up a whole deluge of questions. And the only way to attempt to look back in time is to lift missions off the ground to seek answers; providing us with the holy grail that is the snapshot of our newborn Universe. Several missions have stepped up to the challenge, most notably the recently switched off Planck mission – which communicated its final signal of what it knew about the ancient Universe in October this year – under the joint efforts of ESA and NASA. Planck built upon and improved observations returned by its complementary mission, NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) which, after a good nine years of service rests in its heliocentric graveyard orbit.
Planck’s main aim was to measure the Cosmic Microwave Background (CMB) – the afterglow of the Big Bang, that’s encoded with how the Universe appeared some 400,000 years after the event. And to get the best measurements possible, the mission had to be kept to freezing temperatures.
“[Planck had] a passive cooling and three refrigerators taking it to -273.05 degrees Celsius which made it the coolest place in the Universe,” says the University of Manchester’s Richard Davis, who led the UK’s involvement in one of the instruments onboard the craft. “It also had the lowest noise detectors ever made and are lower than anything detected before.” An important feature of the CMB is that it is, by no means, smooth – it is a mess of different temperatures and it was from soaking up this relic radiation from its orbit around the Sun that Planck was able to pick out even the most subtle blips in temperature. This is something, Davis admits, that the mission did incredibly well. “The fluctuations go down to as low as 2 micro Kelvin,” he tells All About Space. “Planck surpassed its expectations and in some cases even exceeded its goals so it has been stunning.”
Indeed, a couple of the many achievements that the space mission has in its arsenal is an all-sky survey that has provided us with our best view of the oldest light in our Universe to now as well as a better measurement of the age of the cosmos, dated at 13.8 billion years old – 100 million years more than previously thought. And even though the mission has since been commanded to deactivate, Davis assures us that Planck could still wield the key to understanding more about our infant cosmos. “We will go on analysing the data for at least the next ten years so there is much to come,” he says. “We will release the data in the next few years.”
You can read more about the Birth of the Universe in issue 21 of All About Space
Image Credit: ESA