Scientifically Speaking - How Old is the Universe? - KNOE 8 News; KNOE-TV; KNOE.com |

Scientifically Speaking - How Old is the Universe?

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MONROE, La. (KNOE 8 News) If you look at the night sky without any light pollution, it is possible to see upwards of 8,000 stars on any given clear night. You can even see one of the Milky Way's four arms stretching across the horizon. 

Our own cozy galactic home is tiny compared to what lies beyond. Deep field images from the Earth-orbiting Hubble Space Telescope have revealed stunning images of hundreds of galaxies suspended millions and billions of light years away. Recently, they have even spied the oldest galaxies in the known universe, coming in at the ripe age of 13.2 billion years old. 

STARTING AT THE BEGINNING

The most commonly accepted scientific theory for how the universe began is the Big Bang theory. While not proven fact, scientists have been able to use the physics of general relativity (which describes gravity in modern physics) to work back through time to a moment where the only thing in existence was an infinitely dense and hot point: a singularity.

As the hot, dense gas began to rapidly expand (we're talking really fast and really hot...temperatures were over 1 billion giga Kelvin), it rocketed outward and began to cool and become less dense according to the laws of thermodynamics. Particles formed, were destroyed, and re-formed. Eventually elements (think: periodic table) were synthesized. The cosmos as we know them developed over many millions and billions of years and continue to evolve to this day.

HOW LONG AGO WAS THE BEGINNING?

 

 


The tremendous energy associated with the early universe is believed to have left a thermal imprint known as Cosmic Microwave Background Radiation (CMBR) which originated around 380,000 years after the Big Bang itself. Scientists are able to detect this with very powerful radio telescopes and it represents the oldest light in the universe. CMBR gives us the ability to see a "snapshot" of the universe at the point it cooled enough to form hydrogen atoms. 

As the universe expanded and continues to expand even today, the CMBR cools. We know the mathematical expression to describe this cooling and can work backwards through the math to the earliest moments in the universe using the rate of cooling (which is similar to how we determined how long a potato had been out of the oven based on the cooling rate). 

With that information, we can estimate the age of the universe itself, which is roughly 13.8 billion years old. There is, of course, some uncertainty in the measurement. The actual age could be as much as 37 million years more or less than that. In any case, Hubble finding galaxies that are around 13.2 billion years old shows us that we are fairly close with our current age...scientifically speaking.

 

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