Euclid telescope snaps best photo yet of Milky Way’s heart

• The Euclid space telescope captured the largest, most detailed photo of the Milky Way’s crowded heart, revealing 60 million stars.
• This image aids exoplanet research by measuring their masses using microlensing, where a closer star magnifies background light.
• Microlensing has allowed the discovery of nearly 300 exoplanets, and Euclid's data will assist in studying 51 known systems and future finds.

PARIS – The Euclid space telescope has captured the largest and most detailed photo ever taken of our galaxy’s crowded heart, a dazzling image packed with 60 million stars, the European Space Agency (ESA) said on June 24.

The new photo of the Milky Way’s bright centre will help in the search for planets beyond the solar system, the agency added.

At the centre of the spiral galaxy “lies the bulge, a large bubble containing billions of stars”, French astronomer Jean-Charles Cuillandre, who works on the Euclid mission, said.

Euclid launched in 2023 on a mission to chart a third of the sky in the hopes of shedding light on the enduring mysteries of dark matter and dark energy.

“Now, we’ve decided to point Euclid at the brightest area of the sky, and it works superbly. It’s extraordinary,” Cuillandre said.

Euclid, which is hovering 1.5 million km from Earth, captured the image with its visible light camera over 26 hours in March 2025.

The mosaic is composed of nine photographs, each covering an area of the sky larger than the Moon.

The original image was captured in black and white, but colour was added using observations from the Canada-France-Hawaii Telescope located in Hawaii.

However “we didn’t do this just to produce a beautiful image”, Cuillandre emphasised.

‘Cosmic magnifying glass’

In recent decades, scientists have identified thousands of planets outside the solar system, which are known as exoplanets.

New exoplanets are unlikely to be identified within the Euclid image, but it will help scientists measure the mass of planets already spotted, and those that will be discovered in the future.

It can do this via a process called microlensing, which happens when one star crosses over another.

The closer star “acts like a cosmic magnifying glass, bending and brightening the background star’s light”, ESA explained in a statement.

If a planet is orbiting the closer star, its gravity also slightly bends this light. This tiny change in brightness allows scientists to track the planet down.

“During the last 20 years, almost 300 exoplanets have been discovered using this technique, all with ground-based telescopes and all towards the centre of our galaxy,” French astronomer Jean-Philippe Beaulieu said in the statement.

Beaulieu said he, for instance, led the team that discovered an icy planet “a bit like Hoth from Star Wars” 20 years ago.

The new image from Euclid “includes 51 known planetary systems, and it will assist in studying many more that will be found”, he added. AFP