Telescopio spaziale Euclid per far luce sull'universo oscuro

Di University College London2 agosto 2023

La missione Euclid dell'ESA è un progetto molto ambizioso intrapreso dall'Agenzia spaziale europea (ESA) per indagare e comprendere la natura di due componenti enigmatiche del nostro Universo: la materia oscura e l'energia oscura. Lanciata il 1 luglio 2023, la navicella spaziale osserverà miliardi di galassie fino a 10 miliardi di anni luce di distanza per costruire la mappa 3D dell'Universo più accurata mai realizzata. Credito: ESA

Euclid, a space mission led by the European Space AgencyThe European Space Agency (ESA) is an intergovernmental organization dedicated to the exploration and study of space. ESA was established in 1975 and has 22 member states, with its headquarters located in Paris, France. ESA is responsible for the development and coordination of Europe's space activities, including the design, construction, and launch of spacecraft and satellites for scientific research and Earth observation. Some of ESA's flagship missions have included the Rosetta mission to study a comet, the Gaia mission to create a 3D map of the Milky Way, and the ExoMars mission to search for evidence of past or present life on Mars." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]">L'Agenzia spaziale europea (ESA), che include un'enorme telecamera ottica progettata e costruita dai ricercatori dell'University College di Londra (UCL), mapperà le strutture su larga scala dell'universo per comprendere meglio due componenti misteriosi: la materia oscura e l'energia oscura.

Tutto ciò che possiamo vedere e rilevare nel mondo che ci circonda – le stelle, le galassie, i fiori, i nostri corpi, gli atomi – rappresenta solo il 5% dell’universo. Il resto, secondo le teorie attuali, è formato da due componenti: materia oscura ed energia oscura. La loro esistenza è dedotta indirettamente. La materia oscura tiene insieme le galassie; l’energia oscura sta accelerando l’espansione dell’universo. Ma cosa siano non è noto. Ora, un telescopio è stato lanciato nello spazio per aiutare a svelare questo mistero.

Il professor Tom Kitching, del Mullard Space Science Laboratory dell'UCL, è uno dei quattro coordinatori scientifici della missione Euclid guidata dall'Agenzia spaziale europea. Dice che i dati che riporta hanno il potenziale per determinare se l’energia oscura è o meno “energia del vuoto” – l’energia delle particelle virtuali che entrano ed escono dall’esistenza nello spazio vuoto. Se così fosse, le teorie fondamentali della fisica delle particelle dovranno essere riviste, poiché questa energia del vuoto dovrebbe essere molto più forte di quanto previsto dalle teorie attuali. In caso contrario, è la teoria della gravità di Einstein che potrebbe essere sbagliata. "In ogni caso sarebbe una rivoluzione nella fisica", dice.

Una replica della navicella spaziale Euclid presso la sede di Thales Alenia Space a Cannes, in Francia, nel 2019. Credit: Stephane Corvaja/ESA

La missione è un enorme progetto collaborativo: il consorzio che l’ha proposto da solo è composto da 2.000 scienziati e ingegneri in 15 paesi. Il telescopio ha due strumenti. Uno, lo spettrometro e fotometro del vicino infrarosso (NISP), catturerà la luce dallo spettro invisibile del vicino infrarosso. L'altro, chiamato VIS, catturerà la luce visibile. Il professor Mark Cropper (UCL Mullard Space Science Laboratory) (nella foto sotto) ha guidato la progettazione e lo sviluppo della fotocamera ottica VIS per oltre 16 anni, lavorando con team dell'UCL, della Open University e in tutta Europa.

Professor Mark Cropper, Laboratorio di scienze spaziali dell'UCL Mullard. Credito: UCL

La fotocamera, una delle più grandi mai inviate nello spazio, scatterà immagini panoramiche ad alta risoluzione di un'ampia fascia dell'universo, risalendo a 10 miliardi di anni fa e coprendo un terzo del cielo notturno. Utilizzando questi dati, gli astronomi misureranno le forme di due miliardi di galassie e utilizzeranno una tecnica chiamata lente gravitazionale debole – osservando come la luce proveniente da galassie lontane è stata piegata dalla gravità della materia nel suo percorso verso il telescopio – per dedurre l’effetto su larga scala. distribuzione della materia visibile e oscura in modo più preciso di quanto fosse possibile prima.

VIS’s wide field of view means that, while it will take images nearly as sharp as the Hubble Space TelescopeThe Hubble Space Telescope (often referred to as Hubble or HST) is one of NASA's Great Observatories and was launched into low Earth orbit in 1990. It is one of the largest and most versatile space telescopes in use and features a 2.4-meter mirror and four main instruments that observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. It was named after astronomer Edwin Hubble." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"Hubble Space Telescope, it will cover a much larger area of the sky – covering the same area in one day as Hubble covered over 25 years. Each image would require 300 high-definition TV screens to display. Over six years it will allow the shape of more than 1.5 billion galaxies to be measured. “These are huge, unprecedented images,” says Professor Cropper./p>

The laboratory, located in a Victorian mansion in the Surrey Hills, is staffed by 60 engineers and 140 scientists. It has supported 300 space missions. Instruments designed and built at MSSL have reached many corners of the solar system, from MarsMars is the second smallest planet in our solar system and the fourth planet from the sun. It is a dusty, cold, desert world with a very thin atmosphere. Iron oxide is prevalent in Mars' surface resulting in its reddish color and its nickname "The Red Planet." Mars' name comes from the Roman god of war." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]">Mars to SaturnSaturn is the sixth planet from the sun and has the second-largest mass in the Solar System. It has a much lower density than Earth but has a much greater volume. Saturn's name comes from the Roman god of wealth and agriculture." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"Saturn to close to the Sun, and have helped illuminate the most distant galaxies. A model of Britain’s first rocket, the Skylark, sits at the bottom of a staircase./p>

When I visit shortly before the Euclid launch, engineers in a clean room (pictured above) are testing a plasmaPlasma is one of the four fundamental states of matter, along with solid, liquid, and gas. It is an ionized gas consisting of positive ions and free electrons. It was first described by chemist Irving Langmuir in the 1920s." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"plasma analyzer for a space weather satellite, Vigil (due to launch in the mid-2020s), by firing ions at it. Nitrogen is piped in through tubes to keep instruments cold, mimicking the environment in space./p>

This process — part of the ground segment, or ground-based element of the mission — is painstaking but crucial. “Every step of the ground segment has to be perfectly done,” says Professor Joachimi. “Any tiny mistake can mess up the science that comes out at the end. Some of the accuracyHow close the measured value conforms to the correct value." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"accuracy requirements can be measured as parts per million.” Euclid’s sharp view of galaxies – its increased resolution compared to previous surveys of the universe – “ups the ante on how accurately we have to process that information.”/p>

On July 1, 2023, Euclid successfully launched aboard a SpaceXCommonly known as SpaceX, Space Exploration Technologies Corp. is a private American aerospace manufacturer and space transport services company that was founded by Elon Musk in 2002. Headquartered in Hawthorne, California, the company designs, manufactures, and launches advanced rockets and spacecraft. SpaceX's ultimate goal is to reduce space transportation costs and enable the colonization of Mars." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]">SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station in Florida, USA. Its instruments were turned on 11 days later. The spacecraft has now reached the second Lagrangian Point, a stable hovering spot about 1.5 million kilometers (1 million miles) from Earth, joining the NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is "To discover and expand knowledge for the benefit of humanity." Its core values are "safety, integrity, teamwork, excellence, and inclusion." NASA conducts research, develops technology and launches missions to explore and study Earth, the solar system, and the universe beyond. It also works to advance the state of knowledge in a wide range of scientific fields, including Earth and space science, planetary science, astrophysics, and heliophysics, and it collaborates with private companies and international partners to achieve its goals." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]">NASA-led James Webb Space TelescopeThe James Webb Space Telescope (JWST or Webb) is an orbiting infrared observatory that will complement and extend the discoveries of the Hubble Space Telescope. It covers longer wavelengths of light, with greatly improved sensitivity, allowing it to see inside dust clouds where stars and planetary systems are forming today as well as looking further back in time to observe the first galaxies that formed in the early universe." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"James Webb Space Telescope and the ESA Gaia mission: UCL-MSSL provided parts of both of those missions too./p>Euclid, a space mission led by the European Space AgencyThe European Space Agency (ESA) is an intergovernmental organization dedicated to the exploration and study of space. ESA was established in 1975 and has 22 member states, with its headquarters located in Paris, France. ESA is responsible for the development and coordination of Europe's space activities, including the design, construction, and launch of spacecraft and satellites for scientific research and Earth observation. Some of ESA's flagship missions have included the Rosetta mission to study a comet, the Gaia mission to create a 3D map of the Milky Way, and the ExoMars mission to search for evidence of past or present life on Mars." data-gt-translate-attributes="[{"attribute":"data-cmtooltip", "format":"html"}]"European Space Agency (ESA) that includes a massive optical camera designed and built by University College London (UCL) researchers, will map the large-scale structures of the universe to better understand two mysterious components: dark matter and dark energy./strong>