On Nov. 12, ESA's Euclid space telescope released its first major data batch, designated DR1-Foundation, built from 13 months of observations.

According to The Guardian, the release covers about 14% of the total area of sky Euclid will map, capturing over 900 million galaxies and more than 60 million quasar candidates — objects powered by feeding supermassive black holes.

space.com reports the release also includes light spectra from 160 million sources and spans an area of sky as big as 9,500 full moons.

ESA's Director of Science, Carole Mundell, called it 'a scientific milestone in our study of the cosmos,' noting it represents the largest space-based survey of its kind.

Euclid launched in July 2023 with the goal of creating the largest-ever 3D map of the universe, covering a third of the sky and more than 10 billion years of cosmic history.

The surprise is the sheer number of strong gravitational lensing candidates: roughly 15,000, compared with about 1,000 cases known before, per The Guardian, with an estimated 170,000 expected by the end of the mission.

Strong lensing occurs when a foreground galaxy's gravity bends light from a background galaxy into bright arcs or rings — an effect Einstein predicted and which is boosted by the presence of dark matter.

Professor Stephen Serjeant of the Open University told The Guardian that lensing reveals how dark matter is clumping, which is diagnostic of its type, saying there is a good chance the next breakthrough on what dark matter actually is could come from strong lensing.

space.com quotes Natalie Lines of the University of Portsmouth saying strong lensing lets scientists 'weigh' individual galaxies, including their invisible dark matter, and explore how the universe is expanding.

Prof. Andy Taylor of the University of Edinburgh, who leads the UK science ground segment, told The Guardian that while there are bigger surveys, none has the detail and information content of Euclid.

Hubble produced images of incredible resolution but over a much smaller sky area; Euclid keeps that high resolution while mapping huge volumes of the universe.

space.com notes ESA's Valeria Pettorino described the change in scale from previous releases of a few days' observations over about 60 square degrees to more than a year of data over a significantly larger area.

Scientists also aim to use weak lensing — subtle distortions of distant objects by foreground dark matter — to map where dark matter lies, and different dark matter or dark energy types would leave slightly different patterns on the sky.

This is only the start. The Guardian says a further data release is expected next summer, including galaxy distribution results and weak lensing data, which Taylor says can be used to make a map of where dark matter is in the universe and compare its statistical properties with different theories.

Pettorino said the release includes enough statistics to uncover even rare objects and that 'so much discovery is yet to come.'

Taylor added the data volume is now beyond human eyes: no human eyeball can look at all of the Euclid data anymore, leaving plenty of never-before-seen objects and research phenomena to explore.