A space telescope that spent over a year mapping the birth of the universe has revealed the cosmos is older than originally thought, but began with a single 'Big Bang' explosion that caused the universe to burst from subatomic size to a sprawling expanse in less than a second.
The European Space Agency's US$900 million Planck space telescope, launched in 2009, spent more than 15 months mapping the ancient light still radiating from the Big Bang, with the help of NASA scientists.
- Scroll down to view an animation of how light has travelled since the Big Bang
The result, released Thursday, is a detailed map of the universe's "cosmic microwave background" (CMB) which serves as a sort-of time machine for astronomers, allowing them to peer deep into the universe's past, right to the nanosecond after the Big Bang occurred.
The map shows tiny CMB heat fluctuations from across the entire sky "that correspond to regions of slightly different densities at very early times, representing the seeds of all future structure: the stars and galaxies of today," according to a statement from the European Space Agency.
The points of light that populate the map, now invisible to the human eye, "started out as a white hot glow," NASA's director of astrophysics Paul Hertz said at a news conference Thursday.
"Had there been any eyes to see it, it would have been blindingly bright, but during 13.8 billion years the universe has expanded by 1,100 times and that white hot glow has cooled by the same factor to a very cool glow that our eyes can't see. Planck, however, was built to see it and to measure it better than ever before."
Astronomers believe the fluctuations measured by Planck emerged after the Big Bang, expanding almost instantaneously through a process known as inflation. But the new map provides the first glimpse of what that may have actually looked like.
The Big Bang afterglow is believed to have been imprinted on the sky when it was 380,000 years old -- just a newborn, by space standards.
Most of the revelations from the Planck telescope confirm already-held theories with "unprecedented accuracy." But there are also some stunning new findings, said Charles Lawrence, a NASA scientist working on the Planck project.
"Compared to the previous best measurements, the universe is a little older -- 13.8 billion years -- it's expanding a little more slowly, there's more matter -- both the kind we're made of that we can see and the dark kind we can't see but that has gravity to pull things around. There's less dark energy, the mysterious stuff that's pushing the universe apart," he said at the news conference.
Before Planck:
- Dark matter: 22.7 per cent
- Ordinary matter: 4.5 per cent
- Dark energy: 72.8 per cent
After Planck:
- Dark matter: 26.8 per cent
- Ordinary matter: 4.9 per cent
- Dark energy: 68.3 per cent
Dark matter is matter which cannot be detected by telescope but which exerts a gravitational pull on objects around it. Ordinary matter can be detected by telescope and appears to absorb light and exert a gravitational pull. Dark energy is a hypothetical form of energy that is believed to permeate all of space, and plays a role in the expansion of the universe.
But it also revealed some major black holes in the body of knowledge on how the universe was formed.
"The extraordinary quality of Planck's portrait of the infant universe allows us to peel back its layers to the very foundations, revealing that our blueprint of the cosmos is far from complete," ESA Director General Jean-Jacques Dordain said in a statement.
The Planck space telescope is expected to keep transmitting data until it runs out of cooling fluid, expected later this year.
Planck's on-board instruments filter out newer light and measure temperature fluctuations of ancient radiation to within a few millionths of a degree -- making it what the ESA describes as "the most sophisticated time machine ever."
