Europe's Euclid telescope maps a billion galaxies and stars in its first big release, and anyone can explore the data online

Europe's Euclid space telescope has released its first big batch of survey data:  images and measurements of more than a billion stars and galaxies across a patch of sky as big as 9,500 full Moons, or about one-eleventh of the sky you can see on a clear night, the European Space Agency announced Nov. 12.  It is the starting point for what ESA calls its best-ever 3D map of the universe, and the data are open for anyone to explore online.

What Euclid is

Euclid is an ESA space telescope built to study dark matter and dark energy, the two unseen ingredients that scientists say make up most of the universe but cannot yet explain.  Dark matter's gravity holds galaxies together; dark energy is speeding up the universe's expansion.  Euclid tackles both by charting where billions of galaxies sit and how that pattern changed over the last 10 billion years.

It launched in July 2023 and works from a point in space about 1.5 million kilometers, or roughly 930,000 miles, from Earth.  Its 1.2-meter, about 4-foot, mirror is smaller than Hubble’s, so it sees less fine detail but covers far more sky.  ESA puts the total cost at about 1.4 billion euros, including launch and six years of operations.  NASA supplied the infrared detectors for one of its two cameras.

What's in the release

The release, called DR1-Foundation, covers about 13 months of observing.  ESA lists around 15,000 candidate gravitational lenses, more than 60 million candidate quasars and light spectra for more than 160 million objects.  The main survey portion covers 1,900 square degrees of sky, about 5% of the whole sky, and totals 1.7 million gigabytes, or roughly what 13,000 128-gigabyte phones would hold.

What does “as big as 9,500 full Moons” mean?  Start with one Moon.  Hold your little finger out at arm’s length:  its fingernail easily covers the full Moon.  Now picture 9,500 Moons laid side by side.  Squeezed into a square, they would make a patch about four fists wide and four fists tall, with your fists held at arm’s length, stretching from the horizon roughly halfway up to straight overhead.  Another way to see it:  think of all the sky above you on a clear night as a pizza cut into 11 slices.  Euclid’s first release covers about one slice.

A gravitational lens forms when a nearby galaxy's gravity bends and magnifies the light of a more distant one behind it, sometimes into a ring.  ESA says only about one galaxy in several thousand acts as a lens, and this catalog is bigger than all earlier ones combined.  The lenses were found with machine learning plus thousands of volunteers on the Zooniverse project Space Warps.  Lenses let astronomers weigh a galaxy, including its invisible dark matter.

Quasars are the blazing centers of galaxies where gas is falling into a giant black hole.  A spectrum splits an object's light into a rainbow; Euclid scientists will use the rainbows to measure how far away each galaxy is, which is what turns a flat picture into a 3D map.

These counts are candidates, not confirmed discoveries.  Many will need follow-up observations to be verified, and ESA describes the release as a foundation for later research rather than a set of findings.

What comes next

This release covers only about 14% of the sky Euclid will eventually survey, which is more than a third of the whole sky.  ESA plans the full first data release in mid-2027, adding weak lensing, the subtle stretching of galaxy shapes used to map dark matter on large scales.  Anyone can browse the data through ESA's Euclid Data Space, and ESA has posted a zoomable video of a 500-gigapixel mosaic from the release.

Source:  European Space Agency, Euclid lays the foundation for its best-ever 3D map of the Universe, Nov. 12, 2026; ESA image pages for the Messier 81 group and Messier 81's disc; ESA fact sheet, FAQ and mission collaboration page.  Mile, light-time, sky-fraction and phone comparisons are the Daily News's own arithmetic.  Drafted by AI for San Jose from ESA material.