The universe and space are still concepts that the human mind does not fully understand, basically because there is so much mystery yet to be understood and discovered that it is hard to even believe it. Although science is full of certainties, it also holds surprises, and one of the most shocking comes from some data obtained by James Webb and its predecessor, the Hubble. Because what was believed to be a small error in the speed at which our universe expands has become a crisis in cosmology. Could it be that the Universe expands at different speeds depending on the method with which it is measured?
What are the James Webb and the Hubble?
The James Webb and the Hubble are two space telescopes that have allowed us to explore the universe like never before, each in its own way and with different technologies. The Hubble, launched in 1990, revolutionized astronomy with iconic images of galaxies, nebulae and planets that had never been seen before. It is in low Earth orbit and captures visible and near-infrared light.
On the other hand, the James Webb, operational since 2021, is its improved successor, designed to see further in time and space thanks to its advanced infrared technology. Located 1.5 million kilometres from Earth, it allows us to study the birth of galaxies and search for signs of life on exoplanets. It is as if through a telescope we could observe the past of the stars, so far back in time that there are even some stars from when our planet was created! A true wonder for the astrophysical world that has the entire community wanting to know more.
What is the “Hubble tension”?
Let’s start by explaining this effect that astronomers have been trying to explain for years at what speed our universe is expanding. This is called the “Hubble constant” and there are two ways to measure it.
- The first is through the cosmic microwave background radiation, a remnant of the Big Bang.
- And the second is by measuring the distance of variable stars known as Cepheids and supernovae, which allow us to calculate how fast nearby galaxies are moving away.
But the main problem is that both methods give different results: one indicates that the expansion is 67 km/s/Mpc and the other suggests a higher value of 74 km/s/Mpc. Who is right?
James Webb confirmed it
That’s right, in case there was any doubt, scientists have considered that the technology used by the James Webb is much more precise than that of the Hubble, so the difference between the two measurements is real, suggesting that there could be a flaw in our understanding of the universe.
Adam Riess, Nobel Prize winner in Physics and leader of the study, pointed out that, if there are no measurement errors, “what remains is the exciting possibility that we have misinterpreted the universe” leaving behind a big question: what happened?
What does this mean for the Big Bang theory?
As you may know, our understanding of our universe stems from the Big Bang theory, a huge explosion that gave rise to the sun and different planets, on one of which, after millions and millions of years, life arose and that is how we ended up existing today.
Some scientists have not been able to resist making their own theories about this new discovery, some focus on the fact that the error may be due to the fact that there is a new physics that we do not yet understand (such as the existence of an unknown particle or force that causes the universe to expand like this), and others believe that there have been errors in the interpretation of the cosmic background.
James Webb will have to continue making measurements and collecting data on other galaxies to be able to answer the questions that continue to arise around this “Hubble tension” but, if our calculations are correct, then all that remains is to understand that we do not yet know all the secrets of the universe. What will be the next mystery?