A mind-boggling number of bright galaxies, a nursery of purple and orange stars and a spiral galaxy similar to our own Milky Way: new images from Europa's Euclid Space Telescope were revealed Thursday.
It is the second set of images released by the European Space Agency since Euclid launched last year on the first mission to probe the mysteries of dark matter and dark energy.
Science results were also published for the first time on the six-year mission, which aims to use its wide-ranging vision to map two billion galaxies across a third of the sky.
Euclid project scientist Rene Laureijs told AFP he was “personally most excited” by the image of a massive galaxy cluster called Abell 2390.
The image of the cluster, which is 2.7 billion light-years away from Earth, includes more than 50,000 galaxies.
Just one galaxy, like ours, can be home to hundreds of billions or even trillions of stars.
Abell 2390 alone contains the mass of about 10 trillion suns, Jason Rhodes of NASA's Jet Propulsion Laboratory said in an online news conference.
The image also pointed to traces of dark matter, whose invisible presence can only be detected by observing how its gravity distorts light.
“There is so much dark matter in this cluster that it severely bends the light of some of these background galaxies,” making them appear curved, Rhodes said.
Dark matter and dark energy are thought to make up 95 percent of the universe, but we know almost nothing about it.
Another way the Abell 2390 image hinted at dark matter was by revealing the faint light of “orphan stars” drifting among galaxy clusters.
These stars are ejected from the galaxies, “creating a kind of cloud that surrounds the whole cluster,” French scientist Jean-Charles Cuillandre told AFP.
Astronomers believe that this strange phenomenon indicates the presence of dark matter between galaxies.
– A star is born –
Euclid also captured the deepest image ever of Messier 78, a nursery where stars are born 1,300 light-years from Earth in the constellation Orion.
Stars are still forming in the blue center of the image. After gestating for millions of years, they emerge from the purple and orange clouds at the bottom of the image.
Laureijs emphasized that “only Euclid can show this in one go.”
This is because Euclid has a very wide field of view, in contrast to the James Webb Space Telescope, its neighbor at a stable point 1.5 million kilometers (930,000 miles) from Earth.
Another image, of the huge galaxy cluster Abell 2764, shows a black expanse in which a yellow star stands out.
Cuillandre admitted that it was the result of an error in aiming the telescope. But he said the image demonstrated Euclid's “absolutely unique ability to concentrate light” because it was still able to pick up very faint objects next to the bright star.
Euclid's picture of the young Dorado cluster contained a surprise. Although the cluster was already well studied, Euclid discovered a never-before-seen dwarf galaxy, the scientists said.
“I've never seen anything like it,” Cuillandre said.
In the fifth new image, the spiral galaxy NGC 6744, which bears a striking resemblance to the Milky Way, rises against a backdrop of bright stars.
– In the wake of dark matter –
It's still early days for the mission, and the five new images were captured in just one day.
In the coming years, scientists plan to sift through Euclid's data in hopes of spotting all sorts of celestial bodies, such as “groove” planets, which float freely through the universe unattached to a star.
But researchers have already been analyzing the first batch of Euclid images, which were released in November.
In one of 10 previous studies published Thursday, scientists investigated orphaned stars in the Perseus cluster.
These lost stars “are now trapped in the gravity of dark matter,” Laureijs said.
This remains only “the indirect detection of dark matter,” he stressed, adding that it was too early “to say anything about dark energy.”
The mission has not been entirely smooth sailing.
In March, a delicate operation successfully melted a thin layer of ice that had been slowly clouding the telescope's view by heating one of the telescope's mirrors.
There are signs that the ice is re-accumulating, Laureijs said, adding that the team has time to figure out what to do next.
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