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New horizons

on 20 January 2022

The James Webb Space Telescope (JWST) is on its way to the Earth-Sun Lagrange point L2, from where it will prepare to broaden our horizons, literally. The telescope was folded at launch, and is now fully dismantled, with the command centre team aligning and calibrating the on-board equipment in the next period.

Webb

Image credit: NASA/Chris Gunn

Once this process is completed, the space telescope will show us how the first stars and galaxies formed, observing the farthest horizons of the known Universe, in a way that no other telescope has done so far. This is because, unlike the legendary Hubble, James Webb is designed to observe in the infrared, meaning he will capture those photons that have longer wavelengths than photons in the visible spectrum and can thus ”bypass” cosmic dust particles from primordial planetary nebulae, in which stars and planets were born. This is also the reason why James Webb was sent away from Earth, away from the Sun, away from any heat source, because these observations must be made at -223 ° C. At the same time, he will study the composition of the atmosphere of exoplanets - planets orbiting other stars -, lost planets in the Universe that are invisible to our eye but visible in the infrared due to the heat that their hot core emits, or perhaps new planets, larger or smaller, located at the cold edges of our Solar System.

This kind of project, the largest, most complex, and most expensive space telescope in history - 10 billion dollars, an amount almost equivalent to the annual gross domestic product of the Republic of Moldova, couldn’t be achieved using the efforts of a single state, both human resources as well as the know-how. So, this telescope represents a good example, especially nowadays, of how more nations can work together in order to build a set of scientific tools that will change the way we look at the Universe.

JWST is an international collaborative project between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA). ESA provided the Ariane 5 launcher, a huge continuous explosion of liquid hydrogen, combined with oxygen, so well controlled that it launched the highly accurate space telescope on its trajectory allowing it to conserve fuel reserves from board, to extend its life beyond the 10 years originally planned. ESA is also responsible for two key scientific tools which are essential to the smooth running of the mission: the Near InfraRed Spectrograph — NIRSpec and the Mid-InfraRed Instrument — MIRI. It will be almost 6 months before James Webb gives us the first images of the early Universe. During this time instruments onboard are cooled, aligned and calibrated.

Due to the fact that Romania is an ESA Member State, Romanian astronomers will be able to send proposals for observation times after the telescope begins its scientific mission. To prepare these proposals, almost two years ago, the Institute of Space Sciences (ISS) organised a workshop for specialists to become familiar with the protocols and software used to interact with James Webb.

But Hubble and James Webb are not the only space telescopes, and Romania had an essential contribution to some of them.

James Webb is not the first telescope to take advantage of the excellent conditions offered by the Lagrange Sun-Earth L2 point and will not be the last: between 2009 and 2013 the Planck Space Telescope was active, built by the European Space Agency, and also launched with an Ariane 5 rocket. For four years, Planck provided us with data that helped us better understand the fundamentals of the Universe: when the Big Bang took place and what happened immediately after that moment, how homogeneously is distributed the matter in the known Universe, as well as the dark matter, all these being essential aspects for a more solid fundamental knowledge of astrophysics. For this, Planck made observations mainly in the microwaves field, that means longer wavelengths than those in the infrared, quite similar to those used in the kitchen to reheat our food. Planck helped us understand the shape of the Universe: it was confirmed that it is a flat, ever-expanding Universe, and the data obtained by the Planck Observatory are used today to refine the theories we have about the age of the Universe, the neutrino mass, fundamental gravitational waves and the mysterious dark energy — which we know exists, but no other details. Romania participated in the Planck mission as part of a pre-accession program to the European Space Agency and contributed to the processing of scientific data provided by Planck.

Artist s impression of the Planck spacecraft

Image credit: ESA - C. Carreau

And if JWST is looking towards the beginning of the Universe, the future European space telescope Euclid will look the other way, to the near universe and help us understand how the Universe will end, capturing light from the visible and infrared spectrum to better characterize dark matter, one of the mysteries of contemporary physics: no one knows, just assumes, what kind of exotic particles is his dark matter made of. Researchers know that this dark matter exists because we see and measure its gravitational effects, but because it does not interact with other known particles or in a way which is familiar to us, we don’t know the nature of this dark matter. In a certain way, Euclid will continue Planck’s job, but he will do it using other complementary methods, through which he will try to clarify some inaccuracies of the Theory of General Relativity or at least to clarify certain aspects of it. The Euclid Space Telescope will be launched in 2023 by a Russian Soyuz-STB rocket, operated by the European company Arianespace. For at least six years, data sent by Euclid will be analyzed at the Institute of Space Sciences (ISS) in Romania, where a computer center was built for this mission, Romania being one of the 15 states actively participating in the Euclid mission.

Euclid

Image credit: ESA/ATG-medialab

So far, we only talked about telescopes that use electromagnetic radiation (photons) to deliver information back to us, one way or another. But to discover even more intimate things about the structure of the Universe, we have to use other methods as well: gravitational wave detection. Here, on Earth, LIGO observatory was the first to detect gravitational waves formed by the collision of two black holes in 2016, which confirmed Albert Einstein's Theory of General Relativity. But LIGO has a problem: he is only four kilometers long and for more accurate measurements we need a longer interferometer. Much longer. So long that the Earth can’t reach us, the reason why we call on space again: the LISA mission involves three space probes, which will fly in formation, keeping a constant distance between them: 2.5 million kilometers, forming a huge interferometer, the first of its kind ever built. And in Romania, some of the data sent by LISA will be processed and also here a sensor will be made for the alignment and calibration of the three components of the mission. Moreover, Romania has representatives on board the mission and thus decides how the interferometer will be designed, built and subsequently used. LISA is currently in the early stages of design and if all goes well, the launch of the three satellites will take place in 2035.

Romania's membership in the European Space Agency, obtained by the Romanian Space Agency (ROSA) after several decades of strategic coordination, allows Romanian specialists to use the most complex space telescopes ever built, to record and process the data taken by these sensors that are spread throughout the Universe and take part in future space missions that will polish the current models of physics, astrophysics or astronomy in the coming decades.