The first image made by the James Webb Space Telescope (JWST), the largest and most powerful space telescope ever made, was unveiled this evening by the President of the United States, Joe Biden. It shows, with levels of detail never reached before for this type of images, a cluster of galaxies 5 billion light years away from us with other galaxies even more distant behind them.
The presentation took place shortly after 6pm on Monday in Washington, DC (in Italy it was just Tuesday), as an anticipation in view of the press conference scheduled for Tuesday 12 July in which NASA – together with the European Space Agency (ESA) and the Canadian one (CSA) – will show the other images providing more scientific information on the celestial bodies observed and on the conditions of the telescope.
The new image has been called “Webb’s First Deep Field” and can be considered an evolution, especially in terms of resolution, compared to similar images made in the past by the Hubble Space Telescope, of which the JWST is a sort of heir. The long exposure image, to collect as much light as possible, was made in about a day of telescope activity, capturing light sources up to 100 times less bright than Hubble’s capacity. The cluster of galaxies (SMACS 0723) appears in the image as it did about 4.6 billion years ago, when the light from its stars and that reflected from other celestial bodies began their journey to Earth.
Characteristics and structures of the galaxies of the cluster are visible which until now had not been possible to observe with this degree of detail in infrared, the electromagnetic radiation with a frequency lower than that of visible light which cannot be detected by our eyes, but which allows to observe bright objects at a very great distance.
Launched on December 25, 2021, the JWST in recent months has traveled millions of kilometers to reach a point, at a safe distance from Earth, from which to make observations of the cosmos as it had never been possible to do before. For weeks, NASA has been working to calibrate the telescope’s instruments and make sure they are performing as expected, gathering various types of data and taking measurements.
In the next few years, the JWST will allow us to observe very distant galaxies, allowing us to travel in time, showing us celestial bodies billions of light years away from us, so distant that they were among the first to occur during the turbulent phase of formation of the ‘Universe about 13.8 billion years ago.