The James Webb Space Telescope has given scientists the opportunity to see the light of two supernovae that exploded several billion years ago in distant galaxies. They hope that with their help, they will be able to resolve a long-standing dispute known as the “Hubble tension.”
Hubble tension
Recently, scientists working on the VENUS project published research on two very distant supernovae observed by the James Webb Space Telescope. They believe that their research will eventually help resolve the so-called “Hubble tension.”
It owes its name to American astronomer Edwin Hubble, although scientists only learned of its existence after his death. The fact is that Hubble formulated a law back in the 1920s, according to which our Universe is expanding proportionally to a certain value known as the “Hubble constant.”
The only problem is that Hubble has become impossible to derive from anywhere. It can only be determined on the basis of observations. And if you measure it by observing supernovae, you get 67 km/s per Mpc, and if you measure it by observing background microwave radiation, you get 73 km/s per Mpc. This is called the Hubble tension.
Two supernovae
And this is where the scientists working on the VENUS project got lucky. The project is essentially a study of various interesting point sources in the early Universe. Therefore, scientists used the James Webb Space Telescope to carefully examine the galaxy cluster.
The fact is that, thanks to their enormous mass, they can act as gravitational lenses. Simply put, they distort the light from objects behind them and sometimes focus it. This allows us to see large arcs from objects that we would otherwise not be able to see even as dots.
And now scientists have managed to see something interesting in the galaxy clusters MJ0308 and MJ0417 almost simultaneously. Among the arcs generated by each of them, they discovered traces of supernovae, named Ares and Athena. Although the light from them reached us simultaneously, the first one ignited 4 billion years ago, and the second one 6.5 billion years ago.
But that’s not the main point. The fact is that the gravity of galactic clusters not only distorts the flow of photons, but can also split it, sending it in different directions. That is why we can see light from the same event several times at different times.
In the case of Athena, it will reach us again in 2-3 years, and in the case of Ares, in 60 years. It is precisely this difference that scientists want to use to overcome Hubble tension. Based on the exact delay in both cases, they want to establish the precise value of stable Hubble.
According to phys.org
