Latest news with #AlphaCentauri
Forbes
9 hours ago
- General
- Forbes
Scientists: Webb Telescope May Find Planet Around Closest Bright Star
Alpha Centauri, one of the two "Pointer Stars" that help stargazers find the Southern Cross in the ... More Southern Hemisphere, may have a planet in orbit around it. If it does, the Webb Telescope will find it — as long as it's Jupiter-sized. The closest star to the sun, Proxima Centauri, has a planet. It may even have two planets. Proxima Centauri is located in the constellation Centaurus, visible only from the southern hemisphere, but it's a red dwarf star too small to be seen. That brightest star in Centaurus — and the third brightest in the entire night sky — is Alpha Centauri. It's two stars (Alpha Centauri A and Alpha Centauri B) orbiting each other, with Proxima Centauri orbiting them every 550,000 years, in a weird-sounding (but not rare) three-star solar system. Does Alpha Centauri have planets around it? It's a Holy Grail among planet-hunters, mostly because Alpha Centauri is only 4.37 light-years distant. Since it's so close to the solar system, it's theoretically an ideal target for astrometry (the study of the movements of stars and celestial bodies), as well as for direct infrared imaging using the James Webb Space Telescope, two techniques that can detect planets orbiting distant stars — exoplanets. A new paper published this week in Research Notes of the American Astronomical Society details the use of the Webb telescope to study Alpha Centauri in February 2025. Although it didn't detect any planets, it provides glimpses of what may still be hiding around the star. The Alpha Centauri star system — a triple-star planetary system. According to the paper, the Webb telescope's Mid-InfraRed Instrument would have detected gas giant planets like Jupiter at about twice the Earth-sun distance from Alpha Centauri A if they were roughly similar to Earth's temperature. It's tricky because, in a system with two bright stars, light pollution is always a problem. Although the Webb telescope has a coronagraph disc to block the light from the host star (by creating an artificial eclipse) to help it detect planets in the vicinity, it doesn't have two coronagraphs to use on two separate stars. Despite that — and despite Alpha Centauri Ac being five billion years old, meaning any planets in its orbit would likely be very old, cool and therefore dim — the scientists think the Webb telescope can still be used to find large Jupiter-sized planets in its orbit. The authors call Alpha Centauri "an exceptional but challenging target for exoplanet searches." This early conclusion is based on just one set of observations from February 2025. Webb also observed Alpha Centauri A in August 2024 and April 2025, so more conclusions — and possibly a discovery of a planet — could be imminent. Illustration of the Earth-like exoplanet Proxima Centauri b orbiting the star Proxima Centauri. ... More (Illustration by Tobias Roetsch/Future Publishing via Getty Images) In 2016, astronomers found an exoplanet in Proxima Centauri's habitable zone and named it Proxima Centauri b. This exoplanet orbits its star every 11 days from just 5% of the Earth-sun distance from the star. Proxima Centauri b is thought to orbit the star's 'habitable zone,' which is defined as a distance that allows temperatures to be warm enough for liquid water to pool on the planet's surface. However, it's thought that Proxima Centauri sometimes unleashes a massive stellar flare — an energetic explosion of high energy radiation — that would make life as we know it impossible on any planets in orbit. A paper in 2020 suggested that Proxima Centauri may be orbited by a second "super-Earth" sized planet (bigger than Earth, but smaller than Uranus) about the same distance from its star as Mars is from the sun. If it exists, it orbits Proxima Centauri every 5.2 Earth years. Barnard's star is one of the fastest-moving stars in the night sky because it's just six light-years from the solar system. In October 2024, scientists unveiled a planet around it thought to be about half the size of Venus. Called Barnard's b, it's around 20 times closer than Mercury is to the sun. Wishing you clear skies and wide eyes.
Yahoo
6 days ago
- Science
- Yahoo
Does light lose energy as it crosses the universe? The answer involves time dilation.
When you buy through links on our articles, Future and its syndication partners may earn a commission. My telescope, set up for astrophotography in my light-polluted San Diego backyard, was pointed at a galaxy unfathomably far from Earth. My wife, Cristina, walked up just as the first space photo streamed to my tablet. It sparkled on the screen in front of us. "That's the Pinwheel galaxy," I said. The name is derived from its shape – albeit this pinwheel contains about a trillion stars. The light from the Pinwheel traveled for 25 million years across the universe – about 150 quintillion miles – to get to my telescope. My wife wondered: "Doesn't light get tired during such a long journey?" Her curiosity triggered a thought-provoking conversation about light. Ultimately, why doesn't light wear out and lose energy over time? I am an astrophysicist, and one of the first things I learned in my studies is how light often behaves in ways that defy our intuitions. Light is electromagnetic radiation: basically, an electric wave and a magnetic wave coupled together and traveling through space-time. It has no mass. That point is critical because the mass of an object, whether a speck of dust or a spaceship, limits the top speed it can travel through space. But because light is massless, it's able to reach the maximum speed limit in a vacuum – about 186,000 miles (300,000 kilometers) per second, or almost 6 trillion miles per year (9.6 trillion kilometers). Nothing traveling through space is faster. To put that into perspective: In the time it takes you to blink your eyes, a particle of light travels around the circumference of the Earth more than twice. As incredibly fast as that is, space is incredibly spread out. Light from the Sun, which is 93 million miles (about 150 million kilometers) from Earth, takes just over eight minutes to reach us. In other words, the sunlight you see is eight minutes old. Alpha Centauri, the nearest star to us after the Sun, is 26 trillion miles away (about 41 trillion kilometers). So by the time you see it in the night sky, its light is just over four years old. Or, as astronomers say, it's four light years away. Related: The shape of light: Scientists reveal image of an individual photon for 1st time ever With those enormous distances in mind, consider Cristina's question: How can light travel across the universe and not slowly lose energy? Actually, some light does lose energy. This happens when it bounces off something, such as interstellar dust, and is scattered about. But most light just goes and goes, without colliding with anything. This is almost always the case because space is mostly empty – nothingness. So there's nothing in the way. When light travels unimpeded, it loses no energy. It can maintain that 186,000-mile-per-second speed forever. Here's another concept: Picture yourself as an astronaut on board the International Space Station. You're orbiting at 17,000 miles (about 27,000 kilometers) per hour. Compared with someone on Earth, your wristwatch will tick 0.01 seconds slower over one year. That's an example of time dilation – time moving at different speeds under different conditions. If you're moving really fast, or close to a large gravitational field, your clock will tick more slowly than someone moving slower than you, or who is further from a large gravitational field. To say it succinctly, time is relative. Now consider that light is inextricably connected to time. Picture sitting on a photon, a fundamental particle of light; here, you'd experience maximum time dilation. Everyone on Earth would clock you at the speed of light, but from your reference frame, time would completely stop. That's because the "clocks" measuring time are in two different places going vastly different speeds: the photon moving at the speed of light, and the comparatively slowpoke speed of Earth going around the Sun. What's more, when you're traveling at or close to the speed of light, the distance between where you are and where you're going gets shorter. That is, space itself becomes more compact in the direction of motion – so the faster you can go, the shorter your journey has to be. In other words, for the photon, space gets squished. RELATED STORIES —New theory could finally make 'quantum gravity' a reality — and prove Einstein wrong —Black hole paradox that stumped Stephen Hawking may have a solution, new paper claims —In a first, physicists spot elusive 'free-range' atoms — confirming a century-old theory about quantum mechanics Which brings us back to my picture of the Pinwheel galaxy. From the photon's perspective, a star within the galaxy emitted it, and then a single pixel in my backyard camera absorbed it, at exactly the same time. Because space is squished, to the photon the journey was infinitely fast and infinitely short, a tiny fraction of a second. But from our perspective on Earth, the photon left the galaxy 25 million years ago and traveled 25 million light years across space until it landed on my tablet in my backyard. And there, on a cool spring night, its stunning image inspired a delightful conversation between a nerdy scientist and his curious wife. This edited article is republished from The Conversation under a Creative Commons license. Read the original article.
Yahoo
6 days ago
- Science
- Yahoo
Scientists Intrigued by Strange Behavior of Distant Planet
A team of astronomers observed a confused exoplanet orbiting its two parent stars in a highly unusual way. As New Scientist reports, the planet, which was first discovered in 2004, is located in a system called Nu Octantis 72 light-years away, and is twice the size of Jupiter. After it was spotted, some physicists thought its mere existence was impossible due to its extremely close proximity to its twin stars. But according to a new paper published in the journal Nature, an international team of researchers is proposing a wild new theory to explain how the planet could exist while also having such an extremely tight orbit. They propose that one of the stars and the planet orbit the second star in two opposite directions. In other words, the planet is retrograde, or orbiting the star in reverse. "The existence of this planet has been controversial, because there were no observational precedents and we expect planets to form in prograde orbit if they form at the same time as the stars," coauthor and University of Hong Kong professor Man Hoi Lee told IFLScience. To make matters even more unusual, the researchers propose that the planet's orbit is sandwiched between the two stars, forcing it to thread the needle during each orbit. It's an erratic dance that highlights how much there's still to learn about the complex orbital mechanics of multi-star systems. "It invites scientists to consider a wider range of star and planet scenarios regarding both formation and evolution," University of Texas at Arlington professor Manfred Cuntz, who was not involved in the research, told New Scientist. One of the system's stars is a white dwarf, indicating it's nearing the end of its life cycle and making Nu Octantis an even more exotic outlier. The scientists estimate that the system was formed 2.9 billion years ago. However, the planet came to be much later. The researchers propose that it either used to orbit both stars, and changed to its unusual trajectory after one of the stars turned into a white dwarf, or it accreted its considerable mass from said white dwarf. But more research is needed before they can develop a more accurate picture of how the planet evolved. "Observations of other planets in tight binary systems with late-stage or post-main- sequence stellar components will provide additional clues for us to better understand the formation and dynamical evolution of planetary systems," the team wrote in its paper. The researchers are already excited to get a closer glimpse of a similar binary star system, such as HD 59686, which also hosts an enormous gas giant with six times the mass of Jupiter. More on binary star systems: Alpha Centauri Sending Stream of Objects Into Our Solar System, Scientists Propose
Yahoo
20-05-2025
- Science
- Yahoo
Do photons wear out? An astrophysicist explains light's ability to travel vast cosmic distances without losing energy
My telescope, set up for astrophotography in my light-polluted San Diego backyard, was pointed at a galaxy unfathomably far from Earth. My wife, Cristina, walked up just as the first space photo streamed to my tablet. It sparkled on the screen in front of us. 'That's the Pinwheel galaxy,' I said. The name is derived from its shape – albeit this pinwheel contains about a trillion stars. The light from the Pinwheel traveled for 25 million years across the universe – about 150 quintillion miles – to get to my telescope. My wife wondered: 'Doesn't light get tired during such a long journey?' Her curiosity triggered a thought-provoking conversation about light. Ultimately, why doesn't light wear out and lose energy over time? I am an astrophysicist, and one of the first things I learned in my studies is how light often behaves in ways that defy our intuitions. Light is electromagnetic radiation: basically, an electric wave and a magnetic wave coupled together and traveling through space-time. It has no mass. That point is critical because the mass of an object, whether a speck of dust or a spaceship, limits the top speed it can travel through space. But because light is massless, it's able to reach the maximum speed limit in a vacuum – about 186,000 miles (300,000 kilometers) per second, or almost 6 trillion miles per year (9.6 trillion kilometers). Nothing traveling through space is faster. To put that into perspective: In the time it takes you to blink your eyes, a particle of light travels around the circumference of the Earth more than twice. As incredibly fast as that is, space is incredibly spread out. Light from the Sun, which is 93 million miles (about 150 million kilometers) from Earth, takes just over eight minutes to reach us. In other words, the sunlight you see is eight minutes old. Alpha Centauri, the nearest star to us after the Sun, is 26 trillion miles away (about 41 trillion kilometers). So by the time you see it in the night sky, its light is just over four years old. Or, as astronomers say, it's four light years away. With those enormous distances in mind, consider Cristina's question: How can light travel across the universe and not slowly lose energy? Actually, some light does lose energy. This happens when it bounces off something, such as interstellar dust, and is scattered about. But most light just goes and goes, without colliding with anything. This is almost always the case because space is mostly empty – nothingness. So there's nothing in the way. When light travels unimpeded, it loses no energy. It can maintain that 186,000-mile-per-second speed forever. Here's another concept: Picture yourself as an astronaut on board the International Space Station. You're orbiting at 17,000 miles (about 27,000 kilometers) per hour. Compared with someone on Earth, your wristwatch will tick 0.01 seconds slower over one year. That's an example of time dilation – time moving at different speeds under different conditions. If you're moving really fast, or close to a large gravitational field, your clock will tick more slowly than someone moving slower than you, or who is further from a large gravitational field. To say it succinctly, time is relative. Now consider that light is inextricably connected to time. Picture sitting on a photon, a fundamental particle of light; here, you'd experience maximum time dilation. Everyone on Earth would clock you at the speed of light, but from your reference frame, time would completely stop. That's because the 'clocks' measuring time are in two different places going vastly different speeds: the photon moving at the speed of light, and the comparatively slowpoke speed of Earth going around the Sun. What's more, when you're traveling at or close to the speed of light, the distance between where you are and where you're going gets shorter. That is, space itself becomes more compact in the direction of motion – so the faster you can go, the shorter your journey has to be. In other words, for the photon, space gets squished. Which brings us back to my picture of the Pinwheel galaxy. From the photon's perspective, a star within the galaxy emitted it, and then a single pixel in my backyard camera absorbed it, at exactly the same time. Because space is squished, to the photon the journey was infinitely fast and infinitely short, a tiny fraction of a second. But from our perspective on Earth, the photon left the galaxy 25 million years ago and traveled 25 million light years across space until it landed on my tablet in my backyard. And there, on a cool spring night, its stunning image inspired a delightful conversation between a nerdy scientist and his curious wife. This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Jarred Roberts, University of California, San Diego Read more: Have we made an object that could travel 1% the speed of light? 'Extraordinary claims require extraordinary evidence' − an astronomer explains how much evidence scientists need to claim discoveries like extraterrestrial life Property and sovereignty in space − as countries and companies take to the stars, they could run into disputes Jarred Roberts receives funding from NASA.
Yahoo
20-03-2025
- Science
- Yahoo
4 miniature, Earth-like planets discovered extremely close to our sun
When you buy through links on our articles, Future and its syndication partners may earn a commission. A quartet of Earth-like worlds, each about 20% to 30% the size of our planet, circle one of our closest stellar neighbors, a new study reveals. The rocky alien worlds are close enough that future generations of humans may be able to visit them with futuristic rocket propulsion technology. However, it is unlikely that we will find any life there. Astronomers have long suspected that there was at least one exoplanet orbiting Barnard's Star — a red dwarf with a mass around one-sixth that of the sun. At 5.97 light-years from Earth, it is the fourth-closest star to our solar system, after the three interconnected stars of the Alpha Centauri system. (Five potential planets have also been detected around the stars of Alpha Centauri, though not all of them have been confirmed yet.) In the past, researchers assumed that Barnard's Star was circled by a gas giant exoplanet similar to Jupiter, because the star frequently wobbles closer to and then farther from Earth. This suggests that something is gravitationally tugging on the star, similar to how the moon pulls on our planet and causes Earth's tides. However, proving the existence of such a planet has remained elusive. But in a new study, published March 11 in The Astrophysical Journal Letters, researchers say they have discovered that this wobbling is not caused by the pull of one gas giant but instead by the combined force exerted by four smaller, rocky worlds, each around four times more massive than Mercury. "It's a really exciting find," study lead author Ritvik Basant, a doctoral candidate at the University of Chicago, said in a statement. "Barnard's Star is our cosmic neighbor, and yet we know so little about it." Related: 32 alien planets that really exist The newly detected worlds, which have not been officially named yet, are "so close to their home star that they zip around the entire star in a matter of days," the researchers wrote. "That probably means they are too hot to be habitable." The new findings also likely rule out the possibility that any other exoplanets circle within the habitable zone of Barnard's Star, they added. But that doesn't mean this system will remain uninhabited forever. Although Barnard's Star is currently out of reach for humans using current rocket propulsion technology, future human generations might be able to travel to and colonize these newly discovered planets using new forms of rocket propulsion, such as nuclear fusion engines or light sails. Most exoplanets are discovered when they pass in front of their home star and block out some of the light shining toward Earth. However, in this case, researchers think we are looking at Barnard's Star from above, meaning its planets do not pass in between it and us. As a result, scientists often refer to our stellar neighbor as "great white whale" of planet hunting, researchers wrote. To get around this problem, the study team turned to MAROON-X, an instrument attached to the Gemini North telescope on Hawaii's Mauna Kea volcano. Over 112 nights during a three-year period, the telescope detected subtle shifts in the movement of Barnard's Star in order to "tease apart the number and masses of the planets that must be circling the star to have this effect," the researchers wrote. Initially, MAROON-X identified only three planets. However, in another study, published in October 2024, researchers identified another planet using a similar device, dubbed ESPRESSO, at the Very Large Telescope in Chile. By combining these data with their own, the researchers could see this fourth planet for themselves. Using data from both MAROON-X and ESPRESSO also challenges the idea that the researchers are being misled by anomalies in either data set, making them more confident in their results. RELATED STORIES —'Baby' exoplanet, equivalent to 2-week-old infant, is the youngest alien world ever spotted — and it's orbiting a wonky star —Exoplanet with iron rain has violent winds 'like something out of science fiction' —Nearby exoplanet has grown a tail 44 times longer than Earth — and it's acting like a giant 'stellar windsock' Red dwarfs are the most common star type in the universe, but most are too far from Earth for researchers to easily spot planets around them. However, the new results hint that small, rocky planets could be abundant around these miniature stars. But for the study team, the most exciting thing about the new research was finding worlds that are so close to Earth. "We found something that humanity will hopefully know forever," Jacob Bean, an astronomer at the University of Chicago who specializes in exoplanet systems, said in the statement. "That sense of discovery is incredible."
