AGE OF UNIVERSE NARROWED DOWN (2-2003)

Just how old is our universe anyway? 

That question has been asked by astronomers for decades. 
And the answer has always been given in billions of years. 
But the margin of error was pretty large in the early days 
of astronomy.

Back in my high school days, it was pretty much known that 
the earth was well over 4 billion years old, but the age of 
the universe was given as being somewhere between 9 and 20 
billion years old. That’s a pretty large margin.

But this week astronomers have narrowed it down 
considerably. The age of the universe is now reported to be 
precisely 13.7 billion years old. That’s 13,700 million 
years.

That degree of precision was obtained thanks to one of 
NASA’s unmanned space probes that is now about a million 
miles from earth. The Wilkinson Microwave Anisotopy Probe, 
or WMAP, is capable of looking back to a time that was just 
380,000 years after the Big Bang, the theoretical explosion 
that gave birth to the universe.

That’s just about like taking a picture of a middle-aged 
man and somehow being able to see him exactly as he 
appeared as an infant, just 12 hours old. It’s possible in 
space because as one looks farther away in distance, he is 
also looking further back in time. That’s because the 
radiation (such as light, radio waves, and x-rays) that we 
are observing is traveling at a certain speed – the speed 
of light. It takes time for the light from distant objects 
to reach us.

An object at the edge of the known universe looks to us as 
it would have appeared 13.7 billion years ago, because it 
took the light that long to reach us. But that long ago 
there were no objects, only slight temperature differences. 
And it is these differences in temperature that the WMAP 
spacecraft plotted.

The graphic produced looks like a speckled oval, 
representing the entire sky. It is much higher in 
resolution than a similar picture produced in 1992 by an 
earlier probe. The definition is so clear that astronomers 
were able to use it to pin down the exact age of the 
universe as well as the time when the first stars were 
born, just 200,000 years later. That would put the age of 
the oldest stars in the universe at about 13.5 billion 
years old. Our sun, by comparison, is only 4.6 billion 
years old.

So what relevance does this latest astronomical discovery 
have for our everyday lives? It probably doesn’t have any 
relevance at all. But it does represent cutting-edge 
science, which is not only fascinating in itself, but has 
always eventually led to more practical applications. 

When Michael Faraday demonstrated that electricity moving 
through a wire could make a compass needle move, his 
spectators were mesmerized by the magic of it, but one of 
them still asked him, “Of what practical importance is it?” 
Faraday replied, “Of what practical importance is a newborn 
baby?”

This week, scientists have observed another newborn baby – 
the baby universe. And now they know exactly how old that 
infant really is. It’s only a matter of time until the 
technology associated with that discovery matures into 
something useful for all of us. 

In the mean time, we can all delight in the discovery that 
science has once again confirmed one of its most 
fundamental theories – the Big Bang.