The theory goes that, as the years go by, scientists They have more technology at their disposal with which to make better advances and studies. Therefore, we should be solving puzzles of the universe more easily now than in the past. The problem is that this technological improvement also opens up new unknowns and complicates investigations. That is what is happening with the expansion of the universe.
Two competing theories
The challenge for experts has always been to try to provide an answer to the Hubble constant. To do this, two methods have been used that have given two different results, which has become a headache for those who are studying this issue. What they want to know is the exact speed at which it is being produced the expansion of the universe. Because, as we told you, we already know that it is expanding, but at what rate is it doing so?
One of the two ways to calculate the expansion speed has been by taking the brightness of certain stars as a reference, such as Cepheid variable stars. The results of the analysis of these stars are combined with those of type Ia supernovae. The study of both types of stars provides the necessary data to be able to calculate the Hubble constant, which was determined to be 72 kilometers per second per megaparsec. But, as we indicated, this is only one of the two proposals.
The debate continues
The first of the theories uses distance as a way to arrive at a result of the Hubble constant. For this, we resorted to use of the most powerful telescopes that is on Earth. First, the Hubble Space Telescope was used, but scientists agreed that they were limited and that possibly more could be achieved with more advanced machinery.
The work continued, therefore, with the James Webb telescope, which is breaking down many barriers in the exploration of the universe and of which several documentaries have already been filmed. The idea of taking advantage of it was attractive, since with this telescope you could use greater power and thus be able to observe the stars and make much more precise calculations. What they found was that the James Webb’s superior spatial resolution made analyzes easier without having to make as many manual adjustments. In practice, this It meant having more precise data that allowed calculations to be made. The curious thing was that, after using the James Webb and benefiting from the different tools it provides, the result that the scientists reached was the same as with the Hubble. Therefore, his data on the expansion rate of the universe must have been correct.
But, at the same time, as we told you, there was a second theory. In this case, the scientists who have investigated to discover this speed have done so by analyzing the microwave background radiation. And what they found was that the expansion speed of the universe was 67 kilometers per second per megaparsec. The difference may seem small, from 67 to 72, but in practice in the space environment, This is a huge number. The problem is that these radiation data, obtained by analyzing the energy left by the Big Bang, have also been polished and improved over the years.
With only a 1% margin of error, scientists have ended up determining that the expansion speed of the universe through the second system is 67.4 km/s/Mpc. So how can it be that both figures are correct but at the same time, they are different?
Many of the scientists involved in this type of research mention that both theories are undoubtedly correct and that what happens is that there is something we don’t know about the universe. That is to say, we are being passed on some type of concept that is crucial and that would be the necessary piece for all this data to fit together. The hope that astronomers and specialists have is that clearer answers can be obtained when we have more precise and efficient technology. There is talk, in particular, of the construction of new gravitational wave detectors that will take place within a few decades. With this technology we could better understand the universe, but, today, the Hubble constant is something that continues to frustrate experts. And, at the same time, it is an aspect that shows us that there is still much we do not know about our universe.