It should be noted right away that we are currently only talking about candidates for the oldest galaxies. Despite the loud headlines that are starting to appear on the net, astronomers still need to do additional research. Specifically, for example, do a spectroscopic analysis of detected “red” objects and verify that a given redshift value does indeed correspond to distance/time and is not due to other factors or even obstructions.

Last week’s most distant galaxy candidates, GLASS-z11 and GLASS-z13, have redshifts of z11 and z13, respectively. This means that the light from them went to us for about 13.5 billion years.

How do scientists determine the age of distant objects and galaxies?

Like other elementary particles, photons have a wavy structure. Therefore, the movement of photons is not linear, but wave-like, extending their path. The farther the object is from us, the greater the “extra” path the photons have to traverse.

In addition, dust and gas in intergalactic space absorb shorter wavelengths of emitted light, and photons, mainly of the red and infrared regions of the spectrum, can reach us from the depths of the universe.

Thanks to this radiation, scientists receive information to more or less accurately determine the age of observed objects.

A new candidate for the oldest galaxies

Macy’s Galaxy or CEERSJ141946.35+525632.8 has a redshift of z14.3, which can be defined as 286 million years after the Big Bang. The discovery of this object was assisted by research in the infrared range by the James Webb NIRCam instrument on June 21, 2022, as part of the CEERS (Cosmic Evolution Early Release Science Survey) program. Hubble telescope images were also used to clarify the data.

Below are three combined images from Hubble on the left and an ultraviolet range image from James Webb on the right.

Galaxy CEERSJ141946.35+525632.8 “Macy” / Photo by University of Texas at Austin

How does “James Webb” allow us to look back?

According to the theory of the evolution of the universe presented by astrophysicists and supported largely by space observations, galaxies began to form in the Reionization era, roughly corresponding to the z15 crane shift, or about 550 million years after the Big Bang. .

“James Webb” allows you to get a better look at objects from this era and even look deeper using effects like gravity lensing. The preliminary results of the observations show that galaxies may form denser and more frequently than theory suggests. This means that science imagines many things a little differently, and that needs to be fixed.