The Euclid spacecraft will transform how we view the ‘dark universe’

The European House Company’s (ESA) Euclid satellite accomplished the primary a part of its lengthy journey into space on Could 1, 2023, when it arrived in Florida on a boat from Italy. It’s scheduled to raise off on a Falcon 9 rocket, constructed by SpaceX, from Cape Canaveral in early July.

Euclid is designed to offer us with a greater understanding of the “mysterious” parts of our universe, generally known as dark matter and darkish power.

In contrast to the traditional matter we expertise right here on Earth, dark matter neither displays nor emits gentle. It binds galaxies collectively and is assumed to make up about 80% of all of the mass within the universe. We have recognized about it for a century, however its true nature stays an enigma.

Dark energy is equally puzzling. Astronomers have proven that the growth of the universe during the last 5 billion years has been accelerating faster than expected. Many consider this acceleration is pushed by an unseen pressure, which has been dubbed darkish power. This makes up about 70% of the power within the universe.

Euclid will map this “darkish universe,” utilizing a collection of scientific devices to make clear totally different facets of darkish power and dark matter.

A lightweight at midnight

After launch, Euclid will undertake a month-long journey to a area in space referred to as the second Earth-Sun Lagrangian point, which is 5 occasions farther from us than the Moon. It is the place the gravitational pull of the Solar and the Earth stability out and supplies a secure vantage level for Euclid to watch the universe. Euclid will be a part of the James Webb Space Telescope (JWST) at this level and would be the excellent companion to that tremendous space observatory.

My involvement in Euclid started in 2007 after I was invited by ESA to take part in an impartial idea advisory staff to evaluate two competing mission proposals referred to as SPACE and DUNE.

Each used totally different strategies, and subsequently totally different devices, to review the darkish universe, and ESA was struggling to determine between them. Each had been compelling ideas and our staff determined that each had benefit, particularly to offer an important cross-check between them. Euclid was thus born from the best of both concepts.

Euclid is designed to review the entire universe so wants devices with large fields of view. The broader the sector of view of the imaging instrument, the extra of the universe it could possibly observe. To do that, Euclid makes use of a comparatively small telescope in comparison with JWST. In dimension, Euclid is roughly the dimensions of a truck in comparison with the aircraft-sized JWST. However Euclid additionally carries a number of the greatest digital cameras deployed in space with fields of view a whole lot of occasions higher than JWST’s.

Shapes and colours

The Euclid VIS (or visible) instrument, constructed largely within the UK, is designed to measure the positions and shapes of as many galaxies as potential to search for delicate correlations on this knowledge brought on by the gravitational lensing of the sunshine, because it travels to us by way of the intervening dark matter. This gravitational lensing impact is weak, just one half in 100 thousand for many galaxies, thus requiring a number of galaxies to see the impact in excessive definition. Thus VIS will produce Hubble telescope-like picture high quality over a 3rd of the evening sky.

VIS, nevertheless, cannot measure the colours of objects. That is wanted to measure their distance by way of the redshift effect, the place gentle from these objects is shifted to longer, or redder, wavelengths in a means that pertains to their distance from us. A few of this knowledge might want to come from present and deliberate ground-based observatories, however Euclid additionally carries the NISP (Near-Infra Spectrometer and Photometer) instrument which is particularly designed to measure the infrared colours and spectra, and subsequently redshifts, for probably the most distant galaxies that Euclid will see.

To measure darkish power, NISP will exploit a relative new approach referred to as Baryon Acoustic Oscillations (BAO) that gives an correct measurement of the growth historical past of the universe over its final 10 billion years. That historical past is significant for testing potential fashions of darkish power together with prompt modifications to Einstien’s Concept of Common Relativity.

Treasure trove

Such an experiment takes a military of scientists and never everyone seems to be solely engaged on dark matter and dark energy. Like JWST, Euclid might be a treasure-trove of recent discoveries in lots of areas of astronomy. The Euclid consortium wants a whole lot of individuals to assist develop the sophisticated software wanted to merge the space knowledge with the ground-based knowledge, and extract, to excessive accuracy, the shapes and colours of billions of galaxies.

This software program has additionally been checked and verified utilizing a number of the largest simulations of the universe which have ever been constructed. After arriving at L2, Euclid will endure a number of months of testing, validation and calibration to make sure the devices and telescope are working as anticipated. We’re all acquainted with such nervous ready after the latest JWST launch.

As soon as prepared, Euclid will embark on a five-year survey of 15,000 sq. levels of the sky with about 2,000 scientists from internationally gathering outcomes alongside the best way. Nevertheless, the true energy of Euclid will solely be realized as soon as we’ve all this knowledge collectively and analyzed fastidiously. That would take one other 5 years, taking us effectively into subsequent decade earlier than we’ve our last darkish solutions. The SpaceX launch subsequently solely feels just like the half-way level within the Euclid story.

I’ll journey to Florida this summer time to see the launch of Euclid. I might be joined by a whole lot of my colleagues who’ve devoted their careers to constructing this wonderful telescope and experiment. Seeing the challenge come collectively on this means makes me proud to name myself a “Euclidian.”

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