Major Projects of Astronomy – 04/04/2024 – Basic Sciences

In late 2021, the James Webb Space Telescope was launched into space. With the ability to observe objects 100 times lighter than its predecessor, Hubble, the new instrument has revolutionized astronomy, investigating the formation of the universe's first stars and examining the properties of planetary systems in our neighborhood.

One of the new telescope's most recent discoveries, for example, announced on March 6, was of a galaxy that was already dead when the universe was only 5% of its current age. However, sometimes you get the impression that James Webb does everything on his own. That he would be much better than everyone before him, and that he would ignore his peers. This is partly due to the excellent marketing campaign organized by space agencies in North America and Europe, but it is important to understand the importance of diversity of resources.

First, even Hubble itself is not obsolete. Although smaller and less sensitive, the original space telescope, launched in 1990, remains of paramount importance to astronomy, complementing its smaller sibling. By observing ultraviolet and visible wavelengths, which James Webb cannot reach, he is able to detect types of radiation that are not visible to state-of-the-art instruments, and investigate other physical processes in objects in space.

Moreover, space telescopes do not solve all our problems. It is true that they have great advantages, because their images are not subject to interference from the Earth's atmosphere. On the other hand, it is severely limited by the ability to send instruments into space – especially in cases like James Webb, which is more than a million kilometers away, and is inaccessible for any possibility of repair.

Thus, the possibility of building giant telescopes, with a collection area equivalent to four tennis courts, becomes promising. Each camera, connected to the main telescope via side mirrors, takes up the space of a small house. They are extremely powerful instruments, of unimaginable proportions to be carried on a rocket, and in many respects more powerful than James Webb himself.

For example, with this new generation of giant telescopes, we will be able to examine the chemical composition of galaxies tens of billions of light-years away, and study the birth of stars with a precision unheard of by even the most powerful space telescopes.

But the ambitions do not stop there. We also have a group of telescopes of more modest dimensions, but with an important feature: enormous cameras, capable of scanning the sky in an instant (in astronomical terms, of course). Two of them (Euclid and Nancy Roman) are designed to be launched into space, while Vera Rubin, which is being built in Chile, will be a ground-based telescope equipped with a huge 3.2 gigapixel camera.

Using this new detector, every three or four nights Vera Rubin will be able to photograph the entire sky visible from its location, producing not only a large-scale image of the sky, but also a night-time video, greatly increasing our ability to detect transient events such as, for example, Supernovae.

I am proud to say that many of these projects are receiving important Brazilian contributions. The country is a member of the International Federation for the Construction of Vera Rubin, and has the direct participation of more than a hundred scientists who will be able to benefit from the first data produced by the telescope when it begins operating in early 2025.

Moreover, of the three giant telescopes under construction in the next decade, we have directly contributed to two of them: The State of São Paulo funds, through FAPESP, the participation of astronomers from São Paulo in the GMT, with a diameter of 24 metres, and a large Brazilian team is participating In building a giant camera for ELT, 39 meters in diameter, both also in Chile.

But I like to think we can contribute more. We certainly do not lack intellectual capacity, our country has many brilliant scientists. Perhaps what we lack is investment, so that we can achieve the necessary and deserved leading position in the most important international scientific unions.

Note that I am not just referring to money here. Rather, the resources exist, although sparse, and allow Brazilian scientists to participate as collaborators. As for leaders and prominent positions, it is very difficult to rely on continuous funding for science in the country, at the mercy of temporary support from one government or another.

Cutting-edge science isn't done that way. James Webb has been in planning for over 30 years, with continued investment. In the United States, all the nation's astronomers meet every decade to set scientific priorities and plan research investments for the coming decades.

In Brazil, this scenario remains a dream, given the fragility of science in the political landscape and possible sudden cuts. For the country to emerge as an international scientific leader, we must ensure that science is a long-term country plan, not just a government plan for a short period of four years.

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Thiago Gonçalves is an astronomer, director of the Valongo Observatory at the Federal University of Rio de Janeiro, and science promoter.

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