SPACE/COSMOS
Euclid discovers a stunning Einstein ring
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The ring of light surrounding the centre of the galaxy NGC 6505, captured by ESA’s Euclid telescope, is a stunning example of an Einstein ring. NGC 6505 is acting as a gravitational lens, bending light from a galaxy far behind it. The almost perfect alignment of NGC 6505 and the background galaxy has bent and magnified the light from the background galaxy into a spectacular ring. This rare phenomenon was first theorised to exist by Einstein in his general theory of relativity.
This wide field shows the extended stellar halo of NGC 6505 and showcases the Einstein ring, surrounded by colourful foreground stars and background galaxies.
view moreCredit: ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre, T. Li
Euclid blasted off on its six-year mission to explore the dark Universe on 1 July 2023. Before the spacecraft could begin its survey, the team of scientists and engineers on Earth had to make sure everything was working properly. During this early testing phase, in September 2023, Euclid sent some images back to Earth. They were deliberately out of focus, but in one fuzzy image Euclid Archive Scientist Bruno Altieri saw a hint of a very special phenomenon and decided to take a closer look.
“I look at the data from Euclid as it comes in,” explains Bruno. “Even from that first observation, I could see it, but after Euclid made more observations of the area, we could see a perfect Einstein ring. For me, with a lifelong interest in gravitational lensing, that was amazing.”
The Einstein Ring, an extremely rare phenomenon, turned out to be hiding in plain sight in a galaxy not far away. The galaxy, called NGC 6505, is around 590 million light-years from Earth, a stone’s throw away in cosmic terms. But this is the first time that the ring of light surrounding its centre is detected, thanks to Euclid’s high-resolution instruments.
The ring around the foreground galaxy is made up of light from a farther out bright galaxy. This background galaxy is 4.42 billion light-years away, and its light has been distorted by gravity on its way to us. The far-away galaxy hasn’t been observed before and doesn’t yet have a name.
“An Einstein ring is an example of strong gravitational lensing,” explains Conor O’Riordan, of the Max Planck Institute for Astrophysics, Germany, and lead author of the first scientific paper analysing the ring. “All strong lenses are special, because they're so rare, and they're incredibly useful scientifically. This one is particularly special, because it’s so close to Earth and the alignment makes it very beautiful.”
Albert Einstein’s general theory of relativity predicts that light will bend around objects in space, so that they focus the light like a giant lens. This gravitational lensing effect is bigger for more massive objects – galaxies and clusters of galaxies. It means we can sometimes see the light from distant galaxies that would otherwise be hidden.
If the alignment is just right, the light from the distant source galaxy bends to form a spectacular ring around the foreground object. These Einstein rings are a rich laboratory for scientists. Studying their gravitational effects can help us learn about the expansion of the Universe, detect the effects of invisible dark matter and dark energy, and investigate the background source whose light is bent by dark matter in between us and the source.
“I find it very intriguing that this ring was observed within a well-known galaxy, which was first discovered in 1884,” says Valeria Pettorino, ESA Euclid Project Scientist. “The galaxy has been known to astronomers for a very long time. And yet this ring was never observed before. This demonstrates how powerful Euclid is, finding new things even in places we thought we knew well. This discovery is very encouraging for the future of the Euclid mission and demonstrates its fantastic capabilities.”
By exploring how the Universe has expanded and formed over its cosmic history, Euclid will reveal more about the role of gravity and the nature of dark energy and dark matter. The space telescope will map more than a third of the sky, observing billions of galaxies out to 10 billion light-years. It is expected to find around 100 000 strong lenses, but to find one that’s so spectacular – and so close to home – is astonishing. Until now, less than 1000 strong lenses were known, and even fewer were imaged at high resolution.
“Euclid is going to revolutionise the field, with all this data we've never had before,” adds Conor.
Although this Einstein ring is stunning, Euclid’s main job is searching for the more subtle effects of weak gravitational lensing, where background galaxies appear only mildly stretched or displaced. To detect this effect, scientists will need to analyse billions of galaxies. Euclid began its detailed survey of the sky on 14 February 2024 and is gradually creating the most extensive 3D map of the Universe yet. Such an amazing find, so early in its mission, means Euclid is on course to uncover many more hidden secrets.
Close-up of the Einstein ring around galaxy NGC 6505
A close-up view of the centre of the NGC 6505 galaxy, with the bright Einstein ring around its nucleus, captured by ESA’s Euclid space telescope.
The Einstein ring is formed by gravitational lensing, with the mass of galaxy NGC 6505 bending and magnifying the light from a more distant galaxy into a ring. NGC 6505 is a well-known galaxy only around 590 million light-years from Earth, and Euclid’s discovery of a spectacular Einstein ring here was unexpected.
Credit
ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre, T. Li
When we observe a distant galaxy with our telescope, its light may encounter another galaxy on its way to us. The foreground galaxy acts like a magnifying lens, bending the travelling light rays due to its gravity. This is called gravitational lensing. If the background galaxy, the lensing galaxy, and the telescope are perfectly aligned, the image appears as a ring – called an Einstein ring. Einstein rings were first theorised to exist by Einstein in his general theory of relativity.
Credit
ESA
Journal
Astronomy and Astrophysics
Article Title
Euclid: A complete Einstein ring in NGC 6505
Article Publication Date
10-Feb-2025
NASA scientists spot candidate for speediest exoplanet system
NASA/Goddard Space Flight Center
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This artist's concept visualizes a super-Neptune world orbiting a low-mass star near the center of our Milky Way galaxy. Scientists recently discovered such a system that may break the current record for fastest exoplanet system, traveling at least 1.2 million miles per hour, or 540 kilometers per second.
view moreCredit: NASA/JPL-Caltech/R. Hurt (Caltech-IPAC)
Astronomers may have discovered a scrawny star bolting through the middle of our galaxy with a planet in tow. If confirmed, the pair sets a new record for the fastest-moving exoplanet system, nearly double our solar system’s speed through the Milky Way.
The planetary system is thought to move at least 1.2 million miles per hour, or 540 kilometers per second.
“We think this is a so-called super-Neptune world orbiting a low-mass star at a distance that would lie between the orbits of Venus and Earth if it were in our solar system,” said Sean Terry, a postdoctoral researcher at the University of Maryland, College Park and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Since the star is so feeble, that’s well outside its habitable zone. “If so, it will be the first planet ever found orbiting a hypervelocity star.”
A paper describing the results, led by Terry, was published in The Astronomical Journal on February 10.
A Star on the Move
The pair of objects was first spotted indirectly in 2011 thanks to a chance alignment. A team of scientists combed through archived data from MOA (Microlensing Observations in Astrophysics) – a collaborative project focused on a microlensing survey conducted using the University of Canterbury Mount John Observatory in New Zealand — in search of light signals that betray the presence of exoplanets, or planets outside our solar system.
Microlensing occurs because the presence of mass warps the fabric of space-time. Any time an intervening object appears to drift near a background star, light from the star curves as it travels through the warped space-time around the nearer object. If the alignment is especially close, the warping around the object can act like a natural lens, amplifying the background star’s light.
In this case, microlensing signals revealed a pair of celestial bodies. Scientists determined their relative masses (one is about 2,300 times heavier than the other), but their exact masses depend on how far away they are from Earth. It’s sort of like how the magnification changes if you hold a magnifying glass over a page and move it up and down.
“Determining the mass ratio is easy,” said David Bennett, a senior research scientist at the University of Maryland, College Park and NASA Goddard, who co-authored the new paper and led the original study in 2011. “It’s much more difficult to calculate their actual masses.”
The 2011 discovery team suspected the microlensed objects were either a star about 20 percent as massive as our Sun and a planet roughly 29 times heavier than Earth, or a nearer “rogue” planet about four times Jupiter’s mass with a moon smaller than Earth.
To figure out which explanation is more likely, astronomers searched through data from the Keck Observatory in Hawaii and ESA’s (European Space Agency’s) Gaia satellite. If the pair were a rogue planet and moon, they’d be effectively invisible – dark objects lost in the inky void of space. But scientists might be able to identify the star if the alternative explanation were correct (though the orbiting planet would be much too faint to see).
They found a strong suspect located about 24,000 light-years away, putting it within the Milky Way’s galactic bulge — the central hub where stars are more densely packed. By comparing the star’s location in 2011 and 2021, the team calculated its high speed.
But that’s just its 2D motion; if it’s also moving toward or away from us, it must be moving even faster. Its true speed may even be high enough to exceed the galaxy’s escape velocity of just over 1.3 million miles per hour, or about 600 kilometers per second. If so, the planetary system is destined to traverse intergalactic space many millions of years in the future.
“To be certain the newly identified star is part of the system that caused the 2011 signal, we’d like to look again in another year and see if it moves the right amount and in the right direction to confirm it came from the point where we detected the signal,” Bennett said.
“If high-resolution observations show that the star just stays in the same position, then we can tell for sure that it is not part of the system that caused the signal,” said Aparna Bhattacharya, a research scientist at the University of Maryland, College Park and NASA Goddard who co-authored the new paper. “That would mean the rogue planet and exomoon model is favored.”
NASA’s upcoming Nancy Grace Roman Space Telescope will help us find out how common planets are around such speedy stars, and may offer clues to how these systems are accelerated. The mission will conduct a survey of the galactic bulge, pairing a large view of space with crisp resolution.
“In this case we used MOA for its broad field of view and then followed up with Keck and Gaia for their sharper resolution, but thanks to Roman’s powerful view and planned survey strategy, we won’t need to rely on additional telescopes,” Terry said. “Roman will do it all.”
By Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Star Trails
This artist's concept visualizes stars near the center of our Milky Way galaxy. Each has a colorful trail indicating its speed –– the longer and redder the trail, the faster the star is moving. NASA scientists recently discovered a candidate for a particularly speedy star, visualized near the center of this image, with an orbiting planet. If confirmed, the pair sets a record for fastest known exoplanet system.
Credit
NASA/JPL-Caltech/R. Hurt (Caltech-IPAC)
Bow Shock
This Hubble Space Telescope image shows a bow shock around a very young star called LL Ori. Named for the crescent-shaped wave made by a ship as it moves through water, a bow shock can be created in space when two streams of gas collide. Scientists think a similar feature may be present around a newfound star that could be traveling at least 1.2 million miles per hour, or 540 kilometers per second. Traveling at such a high velocity in the galactic bulge (the central part of the galaxy) where gas is denser could generate a bow shock.
Credit
NASA and The Hubble Heritage Team (STScI/AURA); Acknowledgment: C. R. O'Dell (Vanderbilt University)
Journal
The Astronomical Journal
Article Title
A Candidate High-Velocity Exoplanet System in the Galactic Bulge
Article Publication Date
10-Feb-2025
China unveils ground-air dual-mode robot for Mars exploration
A research team from the Harbin Institute of Technology has developed a ground-air dual-mode robot prototype, opening new possibilities for planetary exploration. Weighing just 300 grams — about the same as an average apple — the robot features innovative mobility, capable of rolling on the ground and taking off to overcome obstacles, CCTV News reported.
Designed for extreme environments, the robot comes in multiple configurations, including dual-wheel and spherical designs, allowing it to adapt to diverse terrains. It can also be equipped with robotic arms for specialized tasks. With energy efficiency as a priority, the robot is particularly suited for Mars exploration, where minimal power consumption is crucial.
The research team has developed multiple versions of the dual-mode robot, achieving an endurance time more than six times that of similar-sized devices. By rolling along the ground, the robot conserves energy, significantly extending its operational time. Its modular and lightweight structure allows for customization in tasks such as environmental monitoring, defect detection, and equipment maintenance.
Beyond space exploration, the technology has potential applications in underground environments, such as coal mines and subway systems, where it could aid in construction and exploration of unknown spaces, according to Professor Zhang Lixian from the institute. The prototype has fully achieved these desired features and is ready for broader deployment, Prof Zhang said.
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