WMAP made EZ
The Universe >
What if I said that astronomers now have a pretty good idea about how the universe has shaped up over the last 13.7 billion years, since the first trillionth of a trillionth of a trillionth of a second until now? Sounds rather pompous, doesn't it?
But discoveries in the last decade and especially the last couple months have raised sky high our confidence level in our understanding of how this universe has changed over time. Here are some highlights
In the early 1900's both Edwin Hubble and Albert Einstein independently had their own pioneering insights that led us to believe our universe is expanding. Astronomers have been forced to conclude since then that this universe - all matter, space, energy, and even time - had a beginning many long years ago.
You can imagine why they'd think that. If we ran the film of our expanding universe backwards that there must have been a point, how ever many years ago, when it all started. This moment was sarcastically labeled "big bang" from the skeptical astronomer Fred Hoyle back in the '50's.
Moreover if the universe is cooling off now, then it must have been hot - real hot - back then. So, it was hypothesized, it must have been a "hot big bang."
On top of all this some astronomers had to try to explain some mystifying characteristics of the cosmos by invoking a sudden expansion of the universe when it was a mere fraction of a fraction of a second old, an expansion several times the speed of light, lasting less than the twinkling of an eye, in a period understatedly called "inflation." That would now make it an "inflationary hot big bang."
So how does one go about proving this?
Well, it was thought that if it was a hot big bang, then there should be some heat left over from the earliest times of the creation, sort of like heat left over in a kitchen long after the oven has been turned off. This was hypothesized many years ago and the leftover heat was called the cosmic background radiation. And it was first vaguely detected back in the 1960's.
But in the early 1990's, when technology finally caught up with theory, a satellite called COBE, with very sensitive equipment, was able to see this background radiation all around us at exactly the cooled down temperature it was predicted to be - the "afterglow" of a hot big bang. And there was much rejoicing.
Then it was time to send up a new, much more sensitive satellite that could see the background radiation in much greater detail. Could it see traces of the proposed great inflation, too?
The Wilkinson Microwave Anisotropy Probe - WMAP as its also known, thank goodness - gave us in 2003 an amazing view of the universe that showed the details COBE could not.
And all this seemingly dull cosmic background radiation picked up from WMAP was actually a treasure trove of complicated information that answered some of the great hidden mysteries of the cosmos. Among other things astronomers could now determine were the age of the universe (13.74 billion years), and its composition (4% atoms, 22% dark matter, 74% dark energy).
It was a watershed moment for cosmology. And there was much rejoicing.
Yet with all this new info, there still was not enough data to see remnants of the proposed inflation period.
Now the newest WMAP data is being published and they show not only more details about age and composition and geometry and expansion, but they reveal the first evidences of that elusive inflationary period, that hyperexpansion during the first trillionths of a second after the Creation Event.
It's looking more and more like we have ourselves an inflationary hot big bang after all! And, again, there is much rejoicing.
Yes, it sounds arrogant to say that we think we know pretty well how the universe came into existence. But that came with decades of hard work, and there are still plenty of details to be worked out, to be sure.
I have oversimplified it here, and we'll go into deeper aspects in future columns, but what cosmologists are showing us today is a universe that is nothing less than a grand work of stupendously complex art, a hyperfine-tuned magnum opus, from the earliest moments of creation to now.
Even more sensitive satellites are being sent up soon. Stay tuned. It just keeps getting better.
Mark Ritter teaches astronomy in Temecula, and free podcasts of The Skies Above column can be found online at the iTunes Music Store.
Posted by Mark Ritter at 2006.04. 2 11:38 AM | Comments (0)
