In 1776, the year the American Revolution began, the known solar system was a tidy place. Six planets: Mercury, Venus, Earth, Mars, Jupiter, and Saturn. All visible to the naked eye, all known to ancient civilisations, all accounted for. Then, in 1781, an amateur astronomer in England pointed a telescope at what he thought was a comet — and the number six became seven. That was the beginning of more than two centuries of upheaval in how we define and count the worlds orbiting our Sun.&nbsp;From Six To Seven: William Herschel And Uranus&nbsp;William Herschel's discovery of Uranus on March 13, 1781 was the first time in recorded history that a new planet had been found with a telescope. Unlike the five classical planets, Uranus is not visible to the naked eye under ordinary conditions, and Herschel himself initially catalogued it as a comet. When its circular orbit was confirmed, astronomers realised they had found a genuine planet — and the solar system suddenly had seven members. It was a conceptual earthquake: for thousands of years, the planet count had been fixed at six. Now it could change.&nbsp;The Chaotic 1800s: Eleven Planets And Then A Collapse&nbsp;The discovery of Uranus opened the floodgates. In 1801, Italian astronomer Giuseppe Piazzi found Ceres in the gap between Mars and Jupiter — the missing planet that astronomers had predicted must exist based on a mathematical pattern called the Titius-Bode law. The count went to eight. Then came Pallas in 1802, Juno in 1804, and Vesta in 1807 — all discovered in that same region of space. By 1807, the solar system had eleven recognised planets. But the celebration was short-lived. As more and more objects were found in the same region, astronomers began to suspect they had not found planets at all — they had found a new class of smaller body. By the 1850s, Ceres, Pallas, Juno, Vesta and their neighbours were reclassified as asteroids, and the planet count collapsed back to seven.&nbsp;Neptune: Found By Mathematics&nbsp;While the asteroid debate was playing out, mathematicians were noticing something odd about Uranus. Its orbit was not quite following Newton's laws as predicted. Either gravity behaved differently at that distance from the Sun, or something else — something large — was pulling at Uranus from further out. French mathematician Urbain Le Verrier did the calculations to predict exactly where this unseen object should be in the sky. On September 23, 1846, German astronomer Johann Gottfried Galle pointed his telescope at Le Verrier's coordinates and found Neptune within one degree of the predicted position. It was one of science's great triumphs: a planet discovered by pure mathematics before a single observation. The count rose to eight.&nbsp;Pluto's Rise And Fall: Nine Planets For Seventy-Six Years&nbsp;In 1930, American astronomer Clyde Tombaugh discovered Pluto at the Lowell Observatory in Arizona. The solar system had nine planets — a number that would stand for seventy-six years and define the childhood understanding of space for multiple generations. But in the 1990s and 2000s, astronomers began finding dozens of other icy objects in the same distant region as Pluto, culminating in the 2005 discovery of Eris — an object very similar to Pluto in size. The question was unavoidable: if Pluto was a planet, so were Eris and potentially dozens of other Kuiper Belt objects. In 2006, the International Astronomical Union convened a general meeting to vote on a formal definition of the word 'planet' for the first time in history. The initial proposal would have elevated Ceres, Eris, and Pluto's largest moon Charon to planet status, bringing the total to twelve. The final vote went the other way: Pluto was reclassified as a 'dwarf planet,' and the solar system's planet count dropped to eight.&nbsp;Planet Nine: A Mathematical Ghost In The Outer Solar System&nbsp;The story may not be over. In 2016, astronomers Mike Brown and Konstantin Batygin at the California Institute of Technology announced evidence for a ninth planet — not yet observed directly, but inferred from the unusual clustering of trans-Neptunian objects in the Kuiper Belt. Several of these small icy bodies have orbits that appear to have been herded into alignment by the gravity of something large and unseen. Their modelling suggested a planet roughly four to four-and-a-half times the mass of Earth, orbiting the Sun at a distance of around 290 AU — nearly ten times further than Neptune. As of 2025, mass estimates had been refined to approximately 4.4 Earth masses.&nbsp;The Hunt Intensifies — And Gets More Complicated&nbsp;The search for Planet Nine has produced tantalising but contested results. In 2025, a possible detection candidate was identified in the constellation Eridanus using archival data from the IRAS and AKARI infrared satellites — a pair of faint dots consistent with a distant moving object. However, sceptics noted that a single pair of faint detections is far from conclusive. Separately, astronomers hunting for Planet Nine found possible hints of a different, previously unknown planet in the outer solar system — raising the possibility that there may be more than one undiscovered world out there. In June 2026, new research emerged that further complicated the picture, with a discovery appearing to challenge some of the orbital clustering evidence that originally motivated the Planet Nine hypothesis. The debate is very much alive.&nbsp;The Vera Rubin Observatory: The Best Chance Of An Answer&nbsp;The most likely resolution to the Planet Nine question will come from the Vera C. Rubin Observatory in Chile, which is currently conducting an unprecedented decade-long survey of the southern sky. If Planet Nine exists and is anywhere near the predicted position, Rubin's wide-field camera — the largest ever built for astronomy — has a strong chance of detecting it. Brown and Batygin, along with competing teams, expect the search to take up to five more years. If the ninth planet is confirmed, the solar system's count will change for the seventh time in recorded history. If it is not found, the clustering of Kuiper Belt objects that started the whole debate will need a different explanation — and astronomers will return to a solar system of eight, perhaps permanently.

The solar system's planet count has changed seven times in 250 years — from 6 to 11, back down, then up to 9, then 8. Planet Nine could change it again. Full history explained.

In 1776, the year the American Revolution began, the known solar system was a tidy place. Six planets: Mercury, Venus, Earth, Mars, Jupiter, and Saturn. All visible to the naked eye, all known to ancient civilisations, all accounted for. Then, in 1781, an amateur astronomer in England pointed a telescope at what he thought was a comet — and the number six became seven. That was the beginning of more than two centuries of upheaval in how we define and count the worlds orbiting our Sun. From Six To Seven: William Herschel And Uranus William Herschel's discovery of Uranus on March 13, 1781 was the first time in recorded history that a new planet had been found with a telescope. Unlike the five classical planets, Uranus is not visible to the naked eye under ordinary conditions, and Herschel himself initially catalogued it as a comet. When its circular orbit was confirmed, astronomers realised they had found a genuine planet — and the solar system suddenly had seven members. It was a conceptual earthquake: for thousands of years, the planet count had been fixed at six. Now it could change. The Chaotic 1800s: Eleven Planets And Then A Collapse The discovery of Uranus opened the floodgates. In 1801, Italian astronomer Giuseppe Piazzi found Ceres in the gap between Mars and Jupiter — the missing planet that astronomers had predicted must exist based on a mathematical pattern called the Titius-Bode law. The count went to eight. Then came Pallas in 1802, Juno in 1804, and Vesta in 1807 — all discovered in that same region of space. By 1807, the solar system had eleven recognised planets. But the celebration was short-lived. As more and more objects were found in the same region, astronomers began to suspect they had not found planets at all — they had found a new class of smaller body. By the 1850s, Ceres, Pallas, Juno, Vesta and their neighbours were reclassified as asteroids, and the planet count collapsed back to seven. Neptune: Found By Mathematics While the asteroid debate was playing out, mathematicians were noticing something odd about Uranus. Its orbit was not quite following Newton's laws as predicted. Either gravity behaved differently at that distance from the Sun, or something else — something large — was pulling at Uranus from further out. French mathematician Urbain Le Verrier did the calculations to predict exactly where this unseen object should be in the sky. On September 23, 1846, German astronomer Johann Gottfried Galle pointed his telescope at Le Verrier's coordinates and found Neptune within one degree of the predicted position. It was one of science's great triumphs: a planet discovered by pure mathematics before a single observation. The count rose to eight. Pluto's Rise And Fall: Nine Planets For Seventy-Six Years In 1930, American astronomer Clyde Tombaugh discovered Pluto at the Lowell Observatory in Arizona. The solar system had nine planets — a number that would stand for seventy-six years and define the childhood understanding of space for multiple generations. But in the 1990s and 2000s, astronomers began finding dozens of other icy objects in the same distant region as Pluto, culminating in the 2005 discovery of Eris — an object very similar to Pluto in size. The question was unavoidable: if Pluto was a planet, so were Eris and potentially dozens of other Kuiper Belt objects. In 2006, the International Astronomical Union convened a general meeting to vote on a formal definition of the word 'planet' for the first time in history. The initial proposal would have elevated Ceres, Eris, and Pluto's largest moon Charon to planet status, bringing the total to twelve. The final vote went the other way: Pluto was reclassified as a 'dwarf planet,' and the solar system's planet count dropped to eight. Planet Nine: A Mathematical Ghost In The Outer Solar System The story may not be over. In 2016, astronomers Mike Brown and Konstantin Batygin at the California Institute of Technology announced evidence for a ninth planet — not yet observed directly, but inferred from the unusual clustering of trans-Neptunian objects in the Kuiper Belt. Several of these small icy bodies have orbits that appear to have been herded into alignment by the gravity of something large and unseen. Their modelling suggested a planet roughly four to four-and-a-half times the mass of Earth, orbiting the Sun at a distance of around 290 AU — nearly ten times further than Neptune. As of 2025, mass estimates had been refined to approximately 4.4 Earth masses. The Hunt Intensifies — And Gets More Complicated The search for Planet Nine has produced tantalising but contested results. In 2025, a possible detection candidate was identified in the constellation Eridanus using archival data from the IRAS and AKARI infrared satellites — a pair of faint dots consistent with a distant moving object. However, sceptics noted that a single pair of faint detections is far from conclusive. Separately, astronomers hunting for Planet Nine found possible hints of a different, previously unknown planet in the outer solar system — raising the possibility that there may be more than one undiscovered world out there. In June 2026, new research emerged that further complicated the picture, with a discovery appearing to challenge some of the orbital clustering evidence that originally motivated the Planet Nine hypothesis. The debate is very much alive. The Vera Rubin Observatory: The Best Chance Of An Answer The most likely resolution to the Planet Nine question will come from the Vera C. Rubin Observatory in Chile, which is currently conducting an unprecedented decade-long survey of the southern sky. If Planet Nine exists and is anywhere near the predicted position, Rubin's wide-field camera — the largest ever built for astronomy — has a strong chance of detecting it. Brown and Batygin, along with competing teams, expect the search to take up to five more years. If the ninth planet is confirmed, the solar system's count will change for the seventh time in recorded history. If it is not found, the clustering of Kuiper Belt objects that started the whole debate will need a different explanation — and astronomers will return to a solar system of eight, perhaps permanently.

When the American Declaration of Independence was signed in 1776, humanity knew of only six planets. Within decades that number climbed to eleven, then collapsed, then grew again. Today it sits at eight — but a growing body of evidence suggests something large may be lurking at the edge of our solar system, waiting to push that number to nine.

'6 in 1776, 11 in 1800s, 8 today': Why Solar System's count keeps changing and may change again

Scientists have been wondering for years whether there is a ninth planet in our solar system. Now, a study by Japanese scientists seems to bust that belief. They have found an object orbiting the Sun at the very extremes of our star system and have named it Ammonite. Its scientific name is 2023 KQ14, and its discovery has raised a question mark on the existence of Planet Nine. An analysis of its orbit does not align with the calculations done on other cosmic objects roaming in that zone of the solar system. Astronomers in Japan came across “Ammonite” using the Subaru Telescope in Hawaii. They announced its discovery in a paper published on Tuesday (15 July) in Nature Astronomy. Is it a planet or a dwarf planet? Neither. Ammonite is a sednoid, the name given to any cosmic body encircling the Sun beyond Neptune with a highly eccentric orbit. It's only the fourth sednoid ever discovered. 2023 KQ14 comes as close as 66 astronomical units from the sun, and as far away as 252 au. One astronomical unit is equal to the distance between Earth and the Sun. Also Read: <a href="https://www.wionews.com//science/is-there-a-planet-nine-nasas-new-telescope-might-soon-answer-the-question-774356">Is Planet Nine lurking in the solar system? We might know in 2025</a><h2>Planet Nine believed to exist beyond Neptune</h2>What makes Ammonite stand out is its strange orbit, which is different from the other three sednoids. Beyond Neptune, in the Kuiper Belt, several small bodies are orbiting the Sun in highly elongated yet similarly oriented orbits. This includes the dwarf planet Sedna, and 2012 VP113, 2004 VN112, 2010 GB174, 2013 RF98 and 2007 TG422. This unusual clustering triggered the theory that something has pulled them all together there. Astronomers Konstantin Batygin and Mike Brown were the first to discuss it in 2016. This led them to believe that a bigger body is likely exerting gravitational pull on them. The existence of Planet Nine would explain this occurrence, as its gravitational pull could be a reason for their similarly aligned orbits. However, 2023 KQ14, despite having an elliptical orbit, follows a different path than the others. Study authors say this raises serious doubts about Planet Nine. "The fact that 2023 KQ14’s current orbit does not align with those of the other three sednoids lowers the likelihood of the Planet Nine hypothesis," said Dr. Yukun Huang of the National Astronomical Observatory of Japan in a press release. Also Read: <a href="https://www.wionews.com/science-tech/scientists-detect-strongest-hints-of-planet-nine-lurking-way-beyond-pluto-9025324">Planet Nine might exist after all as scientists detect something lurking way beyond Pluto</a>Also Read: <a href="https://www.wionews.com/science/-jumping-jupiter-evicted-a-gas-giant-from-the-solar-system-it-could-be-lurking-at-the-edge-as-planet-nine-1749795964293">One planet is missing from the solar system, blame 'Jumping Jupiter'</a><h2>Where could ninth planet be?&nbsp;</h2>So, what led to these objects gathering in this region of the solar system? Huang says it is possible that there once was a ninth planet whose presence pulled these bodies there, and also gave the other eight planets their current orbits. However, it could have been ejected, or it might still be out there, just even farther than where it was earlier hypothesised to be. "It is possible that a planet once existed in the Solar System but was later ejected, causing the unusual orbits we see today.” The latest study almost bursts the bubble of Planet Nine. Scientists have for years been obsessing over it, pointing to major evidence on its existence. It has always been believed to be just so far away that we have not had a chance to observe it. If Planet Nine does exist, it would be bigger in mass than Neptune, and would lie anywhere between 400 and 800 AU (Astronomical Units) from the Sun. The Vera C. Rubin Observatory in Chile is being touted as the frontrunner in the discovery of this ninth planet. This could happen as soon as the year 2026.&nbsp; &nbsp;

Scientists are almost sure that there is a ninth planet. But a study by Japanese astronomers hints that this might not be true. A new cosmic body called a sednoid has been discovered near the Kuiper Belt, and it almost proves that Planet Nine is a myth.  

Scientists have been wondering for years whether there is a ninth planet in our solar system. Now, a study by Japanese scientists seems to bust that belief. They have found an object orbiting the Sun at the very extremes of our star system and have named it Ammonite. Its scientific name is 2023 KQ14, and its discovery has raised a question mark on the existence of Planet Nine. An analysis of its orbit does not align with the calculations done on other cosmic objects roaming in that zone of the solar system. Astronomers in Japan came across “Ammonite” using the Subaru Telescope in Hawaii. They announced its discovery in a paper published on Tuesday (15 July) in Nature Astronomy. Is it a planet or a dwarf planet? Neither. Ammonite is a sednoid, the name given to any cosmic body encircling the Sun beyond Neptune with a highly eccentric orbit. It's only the fourth sednoid ever discovered. 2023 KQ14 comes as close as 66 astronomical units from the sun, and as far away as 252 au. One astronomical unit is equal to the distance between Earth and the Sun. Also Read: Is Planet Nine lurking in the solar system? We might know in 2025 Planet Nine believed to exist beyond Neptune What makes Ammonite stand out is its strange orbit, which is different from the other three sednoids. Beyond Neptune, in the Kuiper Belt, several small bodies are orbiting the Sun in highly elongated yet similarly oriented orbits. This includes the dwarf planet Sedna, and 2012 VP113, 2004 VN112, 2010 GB174, 2013 RF98 and 2007 TG422. This unusual clustering triggered the theory that something has pulled them all together there. Astronomers Konstantin Batygin and Mike Brown were the first to discuss it in 2016. This led them to believe that a bigger body is likely exerting gravitational pull on them. The existence of Planet Nine would explain this occurrence, as its gravitational pull could be a reason for their similarly aligned orbits. However, 2023 KQ14, despite having an elliptical orbit, follows a different path than the others. Study authors say this raises serious doubts about Planet Nine. "The fact that 2023 KQ14’s current orbit does not align with those of the other three sednoids lowers the likelihood of the Planet Nine hypothesis," said Dr. Yukun Huang of the National Astronomical Observatory of Japan in a press release. Also Read: Planet Nine might exist after all as scientists detect something lurking way beyond Pluto Also Read: One planet is missing from the solar system, blame 'Jumping Jupiter' Where could ninth planet be? So, what led to these objects gathering in this region of the solar system? Huang says it is possible that there once was a ninth planet whose presence pulled these bodies there, and also gave the other eight planets their current orbits. However, it could have been ejected, or it might still be out there, just even farther than where it was earlier hypothesised to be. "It is possible that a planet once existed in the Solar System but was later ejected, causing the unusual orbits we see today.” The latest study almost bursts the bubble of Planet Nine. Scientists have for years been obsessing over it, pointing to major evidence on its existence. It has always been believed to be just so far away that we have not had a chance to observe it. If Planet Nine does exist, it would be bigger in mass than Neptune, and would lie anywhere between 400 and 800 AU (Astronomical Units) from the Sun. The Vera C. Rubin Observatory in Chile is being touted as the frontrunner in the discovery of this ninth planet. This could happen as soon as the year 2026.

Scientists are almost sure that there is a ninth planet. But a study by Japanese astronomers hints that this might not be true. A new cosmic body called a sednoid has been discovered near the Kuiper Belt, and it almost proves that Planet Nine is a myth. &nbsp;

New world Sedna discovered in solar system. What this means for Planet Nine

Scientists have been looking for Planet Nine for quite some time now. For years it has been debated that another planet lives in the solar system. But no one has been able to find it. There have been advocates for it and against it.&nbsp;

But going by data gathered in the past few years, a ninth planet is likely to be lurking somewhere.&nbsp;

Gravitational anomalies along with unusual orbital patterns in the Kuiper Belt have triggered debate over the existence of Planet Nine. NASA is developing a new telescope that can survey the entire night sky. It will be ready by end of 2025 and can determine whether Planet Nine exists or not.

Researchers of a study said a few months back that they had found the strongest evidence yet that a planet is hiding in the solar system and might be the Planet Nine they have been looking for. They say this planet is likely located in the Kuiper Belt.&nbsp;

It is small and only has a mass between 1.5 and 3 times that of Earth. However, they are not sure of its composition and say it can be anything - &nbsp;an icy, rocky Earth, or a super-Pluto.&nbsp;

They believe that its large mass means that it probably has great internal energy and could even sustain subsurface oceans. "Its orbit would be very distant, much beyond Neptune, and much more inclined compared to the known planets," Patryk Sofia Lykawka, associate professor of Planetary Sciences at Kindai University in Japan and co-author of the study, said.

<h2>Past theories about Planet Nine</h2>

The search for Planet Nine has been on since 2014 when Konstantin Batygin and Michael Brown stated that a planet bigger than Earth and one that humans haven't found till now might be roaming somewhere in the solar system.&nbsp;

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The two scientists strongly believe that the planet is altering the paths of distant bodies in the Kuiper Belt. According to them, it is a "super-Earth" and about five to seven times the mass of our planet.&nbsp;

<h2>Strange orbits of objects in Kuiper Belt</h2>

Several other astronomers in the past have also presented the theory that something is affecting the orbits of several known trans-Neptunian objects.

Before Brown and Batygin proposed that a body is affecting objects in the Kuiper Belt, an astronomer named Scott Sheppard and Chadwick Trujillo noticed that several known trans-Neptunian objects have strangely clustered orbits.

"Since Neptune was successfully discovered in 1846, at least 30 astronomers have proposed the existence of various types of trans-Neptunian objects and have always been wrong," Batygin, a professor of Planetary Science at the California Institute of Technology, said.

Meanwhile, there are other who believe that the strange orbits are being caused by a primordial black hole that was created just after the big bang. Our solar system likely captured it as it moved across the galaxy.

Scientists have been looking for Planet Nine for quite some time now. For years it has been debated that another planet lives in the solar system. But no one has been able to find it.

Scientists have been looking for Planet Nine for quite some time now. For years it has been debated that another planet lives in the solar system. But no one has been able to find it. There have been advocates for it and against it. But going by data gathered in the past few years, a ninth planet is likely to be lurking somewhere. Gravitational anomalies along with unusual orbital patterns in the Kuiper Belt have triggered debate over the existence of Planet Nine. NASA is developing a new telescope that can survey the entire night sky. It will be ready by end of 2025 and can determine whether Planet Nine exists or not. Researchers of a study said a few months back that they had found the strongest evidence yet that a planet is hiding in the solar system and might be the Planet Nine they have been looking for. They say this planet is likely located in the Kuiper Belt. It is small and only has a mass between 1.5 and 3 times that of Earth. However, they are not sure of its composition and say it can be anything - an icy, rocky Earth, or a super-Pluto. They believe that its large mass means that it probably has great internal energy and could even sustain subsurface oceans. "Its orbit would be very distant, much beyond Neptune, and much more inclined compared to the known planets," Patryk Sofia Lykawka, associate professor of Planetary Sciences at Kindai University in Japan and co-author of the study, said. Past theories about Planet Nine The search for Planet Nine has been on since 2014 when Konstantin Batygin and Michael Brown stated that a planet bigger than Earth and one that humans haven't found till now might be roaming somewhere in the solar system. Also Read: Hungriest supermassive black hole discovered in early universe by astronomers The two scientists strongly believe that the planet is altering the paths of distant bodies in the Kuiper Belt. According to them, it is a "super-Earth" and about five to seven times the mass of our planet. Strange orbits of objects in Kuiper Belt Several other astronomers in the past have also presented the theory that something is affecting the orbits of several known trans-Neptunian objects. Before Brown and Batygin proposed that a body is affecting objects in the Kuiper Belt, an astronomer named Scott Sheppard and Chadwick Trujillo noticed that several known trans-Neptunian objects have strangely clustered orbits. "Since Neptune was successfully discovered in 1846, at least 30 astronomers have proposed the existence of various types of trans-Neptunian objects and have always been wrong," Batygin, a professor of Planetary Science at the California Institute of Technology, said. Meanwhile, there are other who believe that the strange orbits are being caused by a primordial black hole that was created just after the big bang. Our solar system likely captured it as it moved across the galaxy.

Is Planet Nine lurking in the solar system? We might know in 2025

If astronomers succeed in discovering the elusive Planet Nine, a hypothetical world believed to be lurking in the outer reaches of our solar system, sending a spacecraft to visit this distant world would be an immense challenge.

The journey to Planet Nine, if it exists, would take decades using current technology.

Some experts reportedly estimated that a probe could potentially reach Planet Nine in as little as 20 years using a carefully planned trajectory that involves gravity assists from the outer planets to gain speed.

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"I am confident that in the far future, humans will be able to visit Planet Nine," said Andreas Hein, a space systems engineer at the University of Luxembourg.

But it would not be possible with today's propulsion systems, which are simply not powerful enough to make the journey in a reasonable timeframe.

<h2>Obstacles in reaching Planet Nine&nbsp;</h2>

The main obstacle is the vast distance to Planet Nine.

If it exists, the planet is estimated to orbit the Sun at a distance of 400 to 800 times farther than Earth, or 13 to 26 times beyond the orbit of Neptune. At such extreme distances, even small changes in velocity make a big difference in travel time.

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Sending a spacecraft to Planet Nine would require advances in propulsion technology, such as nuclear thermal rockets or even more exotic concepts like laser sails that use powerful lasers to propel lightweight craft.

A study published in 2022 suggested that a light sail could potentially reach Planet Nine in as little as seven years, but the researchers estimated it would take at least 20 years for this technology to become practical.

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In the meantime, astronomers are racing to confirm the existence of Planet Nine using powerful new telescopes like the Vera C Rubin Observatory in Chile, which is scheduled to begin operations in late 2025.

If Planet Nine is detected, it would likely take at least a decade or more for space agencies to plan and approve a mission to visit it.

(With inputs from agencies)

If astronomers succeed in discovering the elusive Planet Nine, a hypothetical world believed to be lurking in the outer reaches of our solar system, sending a spacecraft to visit this distant world would be an immense challenge.

If astronomers succeed in discovering the elusive Planet Nine, a hypothetical world believed to be lurking in the outer reaches of our solar system, sending a spacecraft to visit this distant world would be an immense challenge. The journey to Planet Nine, if it exists, would take decades using current technology. Some experts reportedly estimated that a probe could potentially reach Planet Nine in as little as 20 years using a carefully planned trajectory that involves gravity assists from the outer planets to gain speed. Also Read | ALMA telescope sheds light on planet formation around binary stars "I am confident that in the far future, humans will be able to visit Planet Nine," said Andreas Hein, a space systems engineer at the University of Luxembourg. But it would not be possible with today's propulsion systems, which are simply not powerful enough to make the journey in a reasonable timeframe. Obstacles in reaching Planet Nine The main obstacle is the vast distance to Planet Nine. If it exists, the planet is estimated to orbit the Sun at a distance of 400 to 800 times farther than Earth, or 13 to 26 times beyond the orbit of Neptune. At such extreme distances, even small changes in velocity make a big difference in travel time. Also Read | China's Chang’e-6 mission returns to Earth with rare sample from Moon's far side Sending a spacecraft to Planet Nine would require advances in propulsion technology, such as nuclear thermal rockets or even more exotic concepts like laser sails that use powerful lasers to propel lightweight craft. A study published in 2022 suggested that a light sail could potentially reach Planet Nine in as little as seven years, but the researchers estimated it would take at least 20 years for this technology to become practical. Watch | Study finds AI can detect Parkinson's seven years before onset × In the meantime, astronomers are racing to confirm the existence of Planet Nine using powerful new telescopes like the Vera C Rubin Observatory in Chile, which is scheduled to begin operations in late 2025. If Planet Nine is detected, it would likely take at least a decade or more for space agencies to plan and approve a mission to visit it. (With inputs from agencies)

Planet Nine: How challenging is the journey to edge of Solar System?

Planet Nine, a hypothetical ninth planet in the outer region of the Solar System, has almost become impossible to trace by scientists and astronomers. Planet Nine is said to be somewhere beyond the orbit of Pluto and lies in a very dark and cold place in the Solar System, which makes it hard to detect.

In the past, scientists have given several reasons for this. One would be that no one has actually seen it yet and it’s only on the paper. Another is the real possibility that it is just not there. Or it might not be a single planet at all, but a swarm of rocks instead. But according to a recent research; it is more than all of that.&nbsp;

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<h2>Mystery of Planet Nine</h2>

New research conducted by physicists Katherine Brown of Hamilton College and Harsh Mathur of Case Western Reserve University deduced that there is something missing from our current model of gravity as described under the general relativity theory.

According to their recent study, the subtle abnormalities in the orbits of various objects some attribute to a hidden planet are also consistent with a different kind of gravitational model – one called Modified Newtonian Dynamics (MOND).

The flaws in Newton's law of universal gravitation were resolved by Einstein's theory of general relativity. MOND is an alternative solution that proposes other gravitational effects take over when Newtonian gravitational acceleration drops below a certain threshold.

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Because MOND can describe the gravitational behaviour of galaxies that don't seem to be tied to normal matter – unexpected rotation curves and lensing effects – it's an attractive alternative to dark matter. But it hasn't really been studied on smaller scales.

"MOND is really good at explaining galactic-scale observations," Mathur says. "I hadn't expected that it would have noticeable effects on the outer Solar System."

Brown and Mathur thought that these clustering observations might not be compatible with MOND. They undertook an investigation, modelling the orbits of outer Solar System Kuiper Belt objects under MOND to observe how they behave.

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Surprisingly, what they ended up with was a bunch of rocks behaving pretty much exactly like the observed clustering. Their calculations suggest under MOND theory, some of the objects in the outer Solar System should be dragged into alignment with the gravitational field of the Milky Way galaxy over time.

It's not enough to confidently assert that MOND is responsible for the strange behaviour of these distant rocks, rather than a planet.&nbsp;

"Regardless of the outcome," Brown says, "this work highlights the potential for the outer solar system to serve as a laboratory for testing gravity and studying fundamental problems of physics."

(With inputs from agencies) 
 
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Planet Nine, a hypothetical ninth planet in the outer region of the Solar System, has almost become impossible to trace by scientists and astronomers. Planet Nine is said to be somewhere beyond the orbit of Pluto and lies in a very dark and cold place in the Solar System, which makes it hard to detect.

Planet Nine, a hypothetical ninth planet in the outer region of the Solar System, has almost become impossible to trace by scientists and astronomers. Planet Nine is said to be somewhere beyond the orbit of Pluto and lies in a very dark and cold place in the Solar System, which makes it hard to detect. In the past, scientists have given several reasons for this. One would be that no one has actually seen it yet and it’s only on the paper. Another is the real possibility that it is just not there. Or it might not be a single planet at all, but a swarm of rocks instead. But according to a recent research; it is more than all of that. Also Read | Hunting was not solely a man's arena in prehistoric times, women did it too, study suggests Mystery of Planet Nine New research conducted by physicists Katherine Brown of Hamilton College and Harsh Mathur of Case Western Reserve University deduced that there is something missing from our current model of gravity as described under the general relativity theory. According to their recent study, the subtle abnormalities in the orbits of various objects some attribute to a hidden planet are also consistent with a different kind of gravitational model – one called Modified Newtonian Dynamics (MOND). The flaws in Newton's law of universal gravitation were resolved by Einstein's theory of general relativity. MOND is an alternative solution that proposes other gravitational effects take over when Newtonian gravitational acceleration drops below a certain threshold. Also Read | Study finds 98 per cent population in world experienced effects of global warming Because MOND can describe the gravitational behaviour of galaxies that don't seem to be tied to normal matter – unexpected rotation curves and lensing effects – it's an attractive alternative to dark matter. But it hasn't really been studied on smaller scales. "MOND is really good at explaining galactic-scale observations," Mathur says. "I hadn't expected that it would have noticeable effects on the outer Solar System." Brown and Mathur thought that these clustering observations might not be compatible with MOND. They undertook an investigation, modelling the orbits of outer Solar System Kuiper Belt objects under MOND to observe how they behave. Also Read | NASA to take 'amusement park' approach to bring Mars samples back to Earth Surprisingly, what they ended up with was a bunch of rocks behaving pretty much exactly like the observed clustering. Their calculations suggest under MOND theory, some of the objects in the outer Solar System should be dragged into alignment with the gravitational field of the Milky Way galaxy over time. It's not enough to confidently assert that MOND is responsible for the strange behaviour of these distant rocks, rather than a planet. "Regardless of the outcome," Brown says, "this work highlights the potential for the outer solar system to serve as a laboratory for testing gravity and studying fundamental problems of physics." (With inputs from agencies) WATCH WION LIVE HERE You can now write for wionews.com and be a part of the community. Share your stories and opinions with us here.

Somewhere beyond Pluto might be a ninth planet. But now astronomers are not sure

Amid the ongoing debate about the existence of a so-called ‘Planet Nine’ which scientists believe has been lurking around in the murky depths of our solar system for years now, two scientists from Japan have a new theory that suggests the existence of a more modestly sized, Earth-like planet closer than the disputed Planet Nine.&nbsp;

<h2>Argument around existence of ‘Planet Nine’</h2>

Scientists have been debating about the presence of the so-called <a href="https://www.wionews.com/science/a-mysterious-planet-may-be-lurking-around-in-our-solar-system-621243">Planet Nine</a>, the supposedly massive terrestrial planet for some time now, after Pluto was unceremoniously stripped of its planetary status and declared a dwarf planet.&nbsp;

So far, the most distant single object ever to be found in our solar system is some 132 astronomical units from the Sun, to put this into perspective, Pluto is at an average distance of about 40 astronomical units from the Sun.

<h2>About the new theory</h2>

Planetary scientists Patryk Sofia Lykawka of Kindai University in Japan and Takashi Ito of the National Astronomical Observatory of Japan, in a recent paper, published in The Astronomical Journal, have put forth an alternative explanation.&nbsp;

They suggest that there might be a more modestly sized, Earth-like planet revolving around the Sun, closer to the debated Planet Nine, on a tilted orbit.

Trans-Neptunian objects (TNOs) found beyond the orbit of Neptune, which scientists have recently taken note of due to their peculiar clustering behaviour have led them to suggest the presence of a hidden world and the idea of a 9th planet lurking beyond our range of visibility.

“We predict the existence of an <a href="https://www.wionews.com/science/scientists-find-earth-like-exoplanet-in-habitable-zone-around-its-star-558568">Earth-like planet</a> and several trans-Neptunian objects on peculiar orbits in the outer solar system, which can serve as observationally testable signatures of the putative planet’s perturbations,” the duo wrote.&nbsp;

This comes as scientists have found a number of TNOs including icy rocks and dwarf planets beyond Neptune which are some 30 astronomical units from the Sun, which extend as far as we can see. This is the Kuiper belt and the objects it contains are called TNOs.

Lykawka and Ito said that they have found the properties of a hypothetical planet that could explain “three fundamental properties of the distant Kuiper Belt: a prominent population of TNOs with orbits beyond Neptune’s gravitational influence, a significant population of high-inclination objects, and the existence of some extreme objects with peculiar orbits.”&nbsp;

The two scientists suggested that the mass of this possible Earth-like planet would be between 1.5 and three times that of Earth. The most distant point from the Sun in this planet’s orbit would be between 250 and 500 astronomical units and an inclination of 30 degrees respective to the plane of the solar system.&nbsp; 
 
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Amid the ongoing debate about the existence of a so-called ‘Planet Nine’ which scientists believe has been lurking around in the murky depths of our solar system for years now, two scientists from Japan have a new theory that suggests the existence of a more modestly sized, Earth-like planet closer than the disputed Planet Nine.

Amid the ongoing debate about the existence of a so-called ‘Planet Nine’ which scientists believe has been lurking around in the murky depths of our solar system for years now, two scientists from Japan have a new theory that suggests the existence of a more modestly sized, Earth-like planet closer than the disputed Planet Nine. Argument around existence of ‘Planet Nine’ Scientists have been debating about the presence of the so-called Planet Nine, the supposedly massive terrestrial planet for some time now, after Pluto was unceremoniously stripped of its planetary status and declared a dwarf planet. So far, the most distant single object ever to be found in our solar system is some 132 astronomical units from the Sun, to put this into perspective, Pluto is at an average distance of about 40 astronomical units from the Sun. About the new theory Planetary scientists Patryk Sofia Lykawka of Kindai University in Japan and Takashi Ito of the National Astronomical Observatory of Japan, in a recent paper, published in The Astronomical Journal, have put forth an alternative explanation. They suggest that there might be a more modestly sized, Earth-like planet revolving around the Sun, closer to the debated Planet Nine, on a tilted orbit. Trans-Neptunian objects (TNOs) found beyond the orbit of Neptune, which scientists have recently taken note of due to their peculiar clustering behaviour have led them to suggest the presence of a hidden world and the idea of a 9th planet lurking beyond our range of visibility. “We predict the existence of an Earth-like planet and several trans-Neptunian objects on peculiar orbits in the outer solar system, which can serve as observationally testable signatures of the putative planet’s perturbations,” the duo wrote. This comes as scientists have found a number of TNOs including icy rocks and dwarf planets beyond Neptune which are some 30 astronomical units from the Sun, which extend as far as we can see. This is the Kuiper belt and the objects it contains are called TNOs. Lykawka and Ito said that they have found the properties of a hypothetical planet that could explain “three fundamental properties of the distant Kuiper Belt: a prominent population of TNOs with orbits beyond Neptune’s gravitational influence, a significant population of high-inclination objects, and the existence of some extreme objects with peculiar orbits.” The two scientists suggested that the mass of this possible Earth-like planet would be between 1.5 and three times that of Earth. The most distant point from the Sun in this planet’s orbit would be between 250 and 500 astronomical units and an inclination of 30 degrees respective to the plane of the solar system. WATCH WION LIVE HERE You can now write for wionews.com and be a part of the community. Share your stories and opinions with us here.

Scientists believe an Earth-like planet might be hiding in our solar system

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