The cosmos has long captivated humanity with its vastness and mystery. One of the most profound questions that both astronomers and curious minds have asked is: “How big is the universe?”
Despite significant advances in technology and astrophysics, it remains difficult to give a definitive answer to this question.
The observable universe (the part we can see from Earth) has been estimated to be about 93 billion light years in diameter. This astonishing figure is based on the distance that light, traveling at 300,000 kilometers per second, could travel in the 13.8 billion years since the Big Bang.
However, this does not take into account the continuous expansion of the universe over time, which complicates the measurement.
Astronomers use several methods to measure cosmic distances. They use baryon acoustic oscillations to study the waves of the early universe within the cosmic microwave background.
In addition, standard candles, such as type 1A supernovae, serve as reference points for measuring large distances. The Hubble Space Telescope has observed Cepheid variables, which are used as stepping stones to determine the scale of the universe through its relationship to supernovae.
Despite these techniques, the true size of the universe remains uncertain. It may be infinite, and parts of it are too distant for the light emitted from the Big Bang to have reached Earth or our instruments, putting them outside the observable universe.
The European Space Agency’s Planck space mission has provided detailed maps of the oldest light in the universe, but even this only scratches the surface of its entire extent.
Inflation theory suggests that the visible universe is only a fraction of the total, potentially infinite cosmos. The shape of the universe also influences its size, with possibilities ranging from a closed sphere to an infinite, flat expanse.
Scientists led by Mihran Vardanyan from the University of Oxford attempted to statistically analyze all measurement results to estimate the size of the universe.
Their findings suggest that the universe is at least 250 times larger than the observable universe, or at least 7 billion light years in diameter.
The challenge of understanding the scale of the universe is not only scientific but also philosophical. The distances between celestial bodies are so enormous that they defy the scales of human understanding.
As we continue to explore and map the cosmos, the vastness of the universe serves as a humbling reminder of our place within it. While we may be getting closer to more precise measurements, the true size of the universe could remain one of the great mysteries of science.