The Universe is Approximately 13.8 Billion Years Old, But How Do We Know This?
Scattered throughout the vacuum of space are stars, galaxies, remnants of stars, and other objects that are billions of years old. Currently, the universe is estimated to be around 13.8 billion years old. But how do we arrive at this figure?
Scientists say that the age of the universe can be determined by analyzing light and other types of radiation traveling from distant regions of space. However, they often do not agree on the universe’s exact age and continue to seek more precise answers as telescopes improve.
By analyzing light, we can determine the age of the universe. (Image: NASA).
In the 1920s, astronomer Edwin Hubble discovered a method to determine the relationship between an object’s distance, based on the time it takes light to travel from that object to Earth, and the speed at which that light is moving away from Earth, based on how much light from distant locations has redshifted. (Redshift is the phenomenon where light emitted from objects moving away from the observer appears redder).
This figure is now referred to as the Hubble constant, which describes the expansion of the universe at various locations. According to NASA, the Hubble constant is higher for objects that are farther away and vice versa. This implies that the expansion of the universe is accelerating, which complicates the calculation of its age.
Currently, many scientists believe the universe is 13.8 billion years old. They arrived at this number based on calculations made in 2020 after reassessing data from the European Space Agency’s Planck spacecraft and analyzing data collected from the Atacama Observatory in Chile.
Using this method, the universe is estimated to be about 100 million years older than previous calculations based on data from the Planck spacecraft provided in 2013. Both the Planck spacecraft and the Atacama Observatory have mapped the cosmic microwave background (CMB), which is the residual light from the Big Bang.
By combining this data with existing models of the emergence of various types of matter and celestial bodies after the universe began, scientists can estimate the time of the explosion that gave birth to the universe.
According to scientists, the light from the CMB appeared about 400,000 years after the Big Bang. The universe began in a plasma state, where photons, or light, were bound to electrons.
Eventually, the universe cooled enough for the photons to separate from the electrons, leaving the plasma state and scattering throughout space, forming the CMB. Thus, by measuring how far these scattered lights are, scientists can estimate the age of the universe.
The figure of 13.8 billion years was proposed by a group of scientists at the Flatiron Institute’s Center for Computational Astrophysics in New York City in 2020. The research team re-examined the CMB using telescopes at the Atacama Observatory.
Lead researcher Dr. Simone Aiola stated that although the Atacama maps cover a smaller area compared to those from the Planck spacecraft, the higher resolution allows for more accurate measurements.
Dr. Aiola and his colleagues made a breakthrough by observing the CMB at the smallest scale ever. This enabled them to see many details and anomalies that indicate what occurred in the early universe and when. By comparing these high-precision maps with predictions about the age of the universe, the research team calculated the universe’s age to be 13.8 billion years.
Could the universe be even “older” than that? It’s possible! As telescopes continue to improve and evolve, they may look further back into the past than we can currently imagine and uncover something that changes everything we thought we knew.
