Giovanna Giardino he is Esa scientist of James Webb’s Nirspec instrument, a spectrograph, among the instruments that Europe, through ESA, has provided to the new super space telescope. Nirspec is a product of the highest technology, it does not take pictures but can see the essence: it recognizes from the light the signature of the chemical elements that make up the stars and galaxies at the borders of the known Universe or the atmospheres of the exoplanets. According to the scientist, the observations of the James Webb will open new horizons, will allow us to see the first lights that came on at the end of the dark era after the Big Bang and to find new answers on the evolution of the Universe and, who knows, also to find out if there is life on some distant world.
What kind of work do you do on the James Webb team?
“For many years I have been working on one of the instruments on board, Nirspec (Near infrared spectrograph), one of the European contributions. It is a very advanced high-tech spectrograph, with the ESA team following the development and tests on the ground. ‘integration of the instrument on the telescope. Our role in the last six months, since the James Webb has been in flight, has been to prepare it for scientific observations, we turned it on and checked how it worked, verified the alignment with respect to the telescope and the calibration ” .
How did you feel as you saw the composing of pieces of the universe never seen before?
“The important thing, from the scientist’s point of view, is to see the power of this instrumentation, the sensitivity and quality. It opens up new horizons.”
What is one of the observations that you, like ricAre you waiting with more expectation?
“I am involved in the Deep field program, to point Webb for substantial times in the same direction, reach the faintest objects and primordial galaxies”.
We always talk about the power of JW compared to the Hubble Space Telescope, what do we expect to see? How much farther?
“Surely we will be able to reach greater distances in the universe. James Webb captures light in the near and mid-infrared. It is fundamental because the radiation we receive from very distant objects, even that which starts as visible light, undergoes a shift towards the infrared, the” redshift. “Hubble does not operate in the ideal band to see these objects (the Hubble Space Telescope captures visible light and in the near infrared ed). With Webb we will be able to see galaxies so far away that the light took 13.5 billion years to reach us, that Hubble doesn’t have the tools to observe. “
We are talking about just 300 million years after the Big Bang, what do we expect to see so soon?
“Protogalaxies, the first galaxies still under development. It is very important for us to understand the processes, how they formed in the initial moments. After the initial phases of the Big Bang there was a phase in which there were still no stars , we call it “dark age”. The matter then began to thicken, the first nuclear reactions took place and the first stars were lit, but there is an area of uncertainty as to the times yet to be investigated “.
Even the first stars?
“It is one of the questions we ask ourselves. We will see perhaps the so-called ‘population three’, the first stars that should be metal-free, composed only of hydrogen and helium. A piece of the evolution of the Universe”.
However, infrared is not just for looking into the distance.
“Infrared light better penetrates interstellar dust, it is very important for studying star formation or the last stages of a star’s life. And it is useful for observing the area where there is more contrast between the star’s emission and an exoplanet than Webb, in particular with the Nirspec instrument, which we have nicknamed “Webb’s Swiss Army Knife” will certainly make very important contributions to study the composition of the planets orbiting other stars, impossible with Hubble “.
Do you think we will be able to observe rocky planets like Earth to see if they have an atmosphere similar to ours?
“I think so, especially rocky planets around small stars, red dwarfs. Surely we will be able to understand the elements that make up the atmosphere: if there is water, oxygen, methane, a way to enrich our understanding of the types of planets that exist. and with what atmospheres “.
Could the presence of methane mean biological activity, hence life?
“Methane along with other tracers such as ozone, points in that direction, although there are natural mechanisms to create methane through volcanism for example. This depends on the relative compositions.”
We always talk about distant objects, stars and exoplanets. What will James Webb tell us about our solar system?
“It will throw a very interesting look at the moons of Jupiter and Saturn, some show clear indications of the presence of liquid water, on Enceladus for example. Or the Medici Moons (Io, Europa, Ganymede and Callisto that orbit Jupiter ed), even there it will be interesting to be able to do spectroscopy, to better understand the composition and physics of these objects “.