How Webb’s NIRSpec tool uncovers the mysteries of the universe

(ORDO NEWS) — Astronomy asks questions about how the first stars and galaxies began to form, and what ultimately led to our existence.

The answers are hidden in a distant universe, so far away that light has traveled billions of years to reach us, carrying images of the first galaxies forming.

This early period was beyond the reach of previous telescopes, but that all changed with the advent of the James Webb Space Telescope.

However, even the largest space telescope is only as good as its instruments, and this is where the NIRSpec spectrograph comes into play.

Its task is to divide the infrared light collected by Webb into its component wavelengths and form a spectrum.

By measuring how the brightness of an object in space changes at different wavelengths, astronomers can extract a wealth of information about its physical characteristics and chemical composition.

NIRSpec can record spectra of up to 200 observed objects simultaneously. To achieve this result, the spectrograph uses a microshutter array made by the Goddard Space Flight Center.

It consists of about a quarter of a million tiny autonomous blinds. The size of each of them is only 80×180 microns. They can be controlled individually, opening or closing them as needed.

NIRSpec can divide larger objects such as galaxies and nebulae into 30 fragments and observe the spectrum for each fragment in just one image.

For near-infrared observations, the NIRSpec must operate at -233°C, which is maintained by the Webb sunshield. This presents a big problem in the creation of precise scientific instruments.

Different materials shrink at different rates when cooled, and this results in slight distortions in the instrument that affect its accuracy.

For this reason, Airbus has manufactured most of the spectrograph elements, including the mirrors, from silicon carbide.

The first NIRSpec images and data are coming back to Earth.

Once the painstaking analysis is completed, we will have new answers to questions so important to understanding our own existence: how the first galaxies and stars formed in our universe, and how often planets orbiting other stars create the conditions that would allow life to exist. as we know it.

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