The Euclid spacecraft will change our view of the dark universe

European Space Agency (ESA) Euclid satellite She completed the first part of her long journey into space on May 1, 2023, when she He arrived in Florida by boat from Italy. It is scheduled to lift off on a Falcon 9 rocket, built by SpaceX, from Cape Canaveral in early July.

Euclid is designed to give us a better understanding of our “mysterious” components beingknown as dark matter and dark energy.

Unlike ordinary matter that we experience here on Earth, dark matter It does not reflect or emit light. It binds galaxies together and is believed to make up about 80% of the total mass in the universe. We’ve known about it for a century, but its true nature remains a mystery.

dark energy Equally baffling. Astronomers have shown that the expansion of the universe over the past five billion years has been Acceleration faster than expected. many think This acceleration Driven by an invisible force, which has been dubbed dark energy. This makes up about 70% of the energy in the universe.

Euclid will map this “dark universe”, using a range of scientific tools to shed light on different aspects of dark energy and dark matter.

A light in the dark

After launch, Euclid will make a month-long trip to a region in space called the The second Lagrangian point between the Earth and the SunIt is five times farther from us than the Moon. It is the place where the gravitational pull of the Sun and Earth balances out and provides a fixed vantage point for Euclid to observe the universe. Euclid will join James Webb Space Telescope (JWST) At this point it would be the perfect companion to this amazing space observatory.

My involvement with Euclid began in 2007 when I was invited by the European Space Agency to participate in an independent concept advisory panel evaluating two competing mission proposals called SPACE and DUNE.

Both used different techniques, and therefore different tools, to study the dark universe, and the European Space Agency was struggling with choosing between them. Both were compelling concepts and our team decided they both had merit, especially for providing a vital check between them. So was Euclid Born out of the best of both concepts.

Euclid is designed to study the entire universe, so it needs instruments with wide fields of view. The wider the imager’s field of view, the larger the universe it can observe. To do this, Euclid uses a telescope that is relatively small compared to the JWST. In size, the Euclid is roughly the size of a truck compared to the JWST the size of an airplane. But Euclid also carries some of the largest digital cameras deployed in space with fields of view hundreds of times larger than JWST’s cameras.

Shapes and colors

the Euclid’s VIS tool (or visual)Designed mostly in the UK, it measures the positions and shapes of as many galaxies as possible to look for subtle correlations in this data generated by the gravitational lensing of light as it travels to us through the intervening dark matter. This gravitational lensing effect is weak, only one part in a hundred thousand for most galaxies, and thus requires many galaxies to see the effect at high resolution. Thus VIS will produce Hubble-like image quality on a third of the night sky.

However, VIS cannot measure the colors of objects. This is necessary to measure the distance through redshift effect, as the light from those objects shifts to longer wavelengths or red in a way that relates to their distance from us. Some of this data should come from existing and planned ground-based observatories, but Euclid holds as well NISP (Near Infrared Spectrometer and Photometer) An instrument specifically designed to measure the infrared colors and spectra, and thus the redshifts, of the distant galaxies that Euclid will see.

To measure dark energy, NISP will exploit a relatively new technology called Baryon Acoustic Oscillations (BAO) It provides an accurate measurement of the expansion history of the universe over the last 10 billion years. This history is vital for testing possible models for dark energy, including proposed modifications to Einstein’s general theory of relativity.

treasure

Such an experiment would require an army of scientists and not everyone would work on it alone dark matter And dark energy. Like JWST, it will be Euclid treasure New discoveries in many areas of astronomy. Euclid Union needs hundreds of people to help develop Sophisticated program Necessary to integrate space data with terrestrial data, and to extract the shapes and colors of billions of galaxies with high accuracy.

This program has also been vetted and validated with some of the largest simulations of the universe ever created. After arriving at L2, Euclid will undergo several months of testing, validation, and calibration to ensure that the instruments and telescope work as expected. We are all familiar with such a tense wait after the recent JWST launch.

Once Euclid is ready, he will embark on a five-year survey of 15,000 square degrees of the sky with some 2,000 scientists from around the world collecting results along the way. However, the true power of Euclid will only be realized after all this data is collected together and carefully analyzed. It could take another five years, and it takes us into the next decade before we get our final grim answers. So the launch of SpaceX feels like a halfway point in Euclid’s story.

I’m going to Florida this summer to see the release of Euclid. I will be joined by hundreds of my colleagues who have dedicated their careers to building this amazing telescope and experiment. Seeing the project come together in this way makes me proud to call myself Euclidian.

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