Commentary

Measuring the age of the Universe

April 1, 2014

Personally, I've never believed the Big Bang theory--it seems to me that always having a beginning and an ending is a human construct.

Gail Overton

As summarized by NASA, the Big Bang cosmology theory dates the origin of our Universe to around 14 billion years ago, when ultradense matter was only a few millimeters across, exploded into space in a "Big Bang", and is now cooling and racing outwards. Personally, I've never believed the Big Bang theory--it seems to me that always having a beginning and an ending is a human construct; perhaps, the Universe is indeed infinite and never-ending and has witnessed millions of Big Bang events ... but that is the subject of a more philosophical argument well beyond the scope of measuring the age of the Universe (as if that weren't a daunting enough task). Actual cosmological measurements of the cosmic microwave background form the basis of modern Universe aging theories. Just recently, for example, measurements from the 10 meter South Pole Telescope and the BICEP (Background Imaging of Cosmic Extragalactic Polarization) telescope (see image below; image credit: Keith Vanderlinde, National Science Foundation) confirmed the presence of gravitational waves in the cosmic microwave background, supporting the inflation or "Big Bang" theory of how the Universe began.

So how do you measure the age of the Universe (or as I like to say, the Age of the Universe since our local Big Bang)? It turns out that the Hubble Telescope was principally justified by its ability to measure the size and age of the Universe by analyzing the most distant stars and galaxies. The Hubble website explains, "One of Hubble's initial 'core' purposes was to determine the rate of expansion of the Universe, known to astronomers as the 'Hubble Constant'. Today we know the age of the Universe to a much higher precision than before Hubble: around 13.7 billion years." In under three minutes, this video from Roger Linsell from fizzics.org gives a brief description of the Hubble constant measurement:

A more sophisticated video explains the measurement in a nearly hour-long lecture from professor Carolin Crawford from Gresham University (London, England):

The University of California, Davis is active in Universe measurement theory. Back in 2010, they described how dark matter and gravitational lensing could be used to measure the age of the Universe. Essentially, a gravitational lens created by a galaxy surrounded by dark matter, as an example, exerts its gravitational pull on light and objects behind the lens are distorted. The researchers say, "It works something like this. Two photons of light leave the background galaxy at the same time and travel around the lens, their paths distorted in different ways by the gravitational field so that they arrive on Earth at slightly different times. Based on that time delay, it is possible to calculate the distance of the entire route, and then infer the Hubble constant."

If you can measure it, is it true? Maybe. But what about the time period before the Big Bang--isn't our Universe in theory much older and the Big Bang is just one event on an endless time horizon? I personally favor the Multiverse theory of the Universe (see http://en.wikipedia.org/wiki/Multiverse). And now, as other editorial deadlines await, I'll have to wait for the next Sunday episode of "Cosmos" (http://www.cosmosontv.com/) to get my cosmological theorizing fix for the week.

About the Author

Gail Overton | Senior Editor (2004-2020)

Gail has more than 30 years of engineering, marketing, product management, and editorial experience in the photonics and optical communications industry. Before joining the staff at Laser Focus World in 2004, she held many product management and product marketing roles in the fiber-optics industry, most notably at Hughes (El Segundo, CA), GTE Labs (Waltham, MA), Corning (Corning, NY), Photon Kinetics (Beaverton, OR), and Newport Corporation (Irvine, CA). During her marketing career, Gail published articles in WDM Solutions and Sensors magazine and traveled internationally to conduct product and sales training. Gail received her BS degree in physics, with an emphasis in optics, from San Diego State University in San Diego, CA in May 1986.