If you have ever had the fortune of looking up on a clear night sky where the moon and stars can shine without obstruction from cloud cover or light pollution, you may have pondered the question of how old the universe happens to be. “What are we really looking up at?””How old is our reality?” These are the sort of questions that astronomers and astrophysicists have long sought the answers to.
Before we can reach an answer or card the universe, let us consider what we used to know. In the beginning, we knew nothing. As time progressed, we started understanding more of the universe; initially placing ourselves at the center of everything. During the era of geocentrism, we believed all things revolved around Earth, hence why the sun and moon traveled-we also believed that the earth was flat. The first wrinkle in this belief would come in 1514; Nicolaus Copernicus penned “The Little Commentary,” a text claiming that heliocentrism, a state where the sun was the center of our universe and our perception of the sun and moon moving was due to Earth’s rotation.
Despite being introduced in the early 1500s, it would not be until the 17th Century that heliocentrism would be commonly accepted.
So how old is the universe? Just a few million years?
As scientific progress continued, humanity would continue to ask big questions of cosmic significance, pondering how the universe came to be or if it had always been. The 18th Century featured two leading theories.
- The universe was millions of years old.
- Sigur of Brabant’s “The Eternity of the World”, a text from the 13th Century, claimed the universe to be an eternal constant with neither a start nor stop.
Come the 19th Century, ideas regarding the universe’s age underwent another shift. Thermodynamics was a nice science coming into theory, followed by the theory of entropy. The latter theory claimed that if the universe were infinite, all matter would have the same temperature; as the universe is full of temperature differentials, this poked many holes in the idea of an eternal universe.
By the 20th Century, men like Albert Einstein and Alexander Friedman theorized that the universe must either be continually growing or shrinking. This still left the question of the universe’s origin point, its age, in question. Advances in telescopes helped humanity gain a better understanding of the universe. Notably, Edwin Hubble, the man whose name belongs to one of the most iconic of telescopes, discovered stars in other galaxies. Hubble and Georges Lemaître, a Belgian scientist, proved their theory that the universe was continually expanding and clearing away some of the mystery behind our universe’s age. Hubble believed that the universe had been growing from a single point over 2 billion years.
How many billions now?
While we now know that Hubble’s math was a bit off, his claims helped lay the ground for other scientists to narrow down the variables and pin down the universe’s age. Hubble actually inspired the Hubble Constant, a law of physics that helped to measure universal expansion. Hubble’s law was also useful to calculate the ages of various celestial bodies. It should be noted that because the calculations used in Hubble’s math were a bit off, his predicted ages for various galaxies were lower than we now understand them to be.
Thanks to various enterprises into travel out into the stars, including various probes, we have been able to collect data like background radiation traced to the Big Bang. In 2012, NASA landed at the universal age being 13.772 billion years; a year later, the European Space Agency (ESA) claimed it to be 13.82 billion years old.
So there you have it. While we do not know the exact age of the universe we live in, we do know that it is nearly 14 billion years old.