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3 days ago
- Science
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When will the solar system die out?
When you buy through links on our articles, Future and its syndication partners may earn a commission. Our solar system has been around for 4.6 billion years. While that sounds like a long time, it's just a blip in the 13.8 billion-year story of the universe. And one day, the solar system will cease to exist. But when will the solar system end? And how will it die out? The answers to those questions depend on how we define the death of the solar system. The solar system consists of eight planets, several dwarf planets, hundreds of moons, and billions of asteroids, comets and meteoroids. The exact boundaries of the solar system are subject to debate, but there are three main candidates: the Kuiper Belt, a region of icy objects beyond Neptune; the heliopause, where the sun's magnetic field ends; and the Oort cloud, a theoretical icy cloud lying beyond both the Kuiper Belt and the heliosphere. And, of course, at the center of it all, the sun is keeping it all together with its immense gravity. Like all stars, the sun will eventually die. Right now, it creates heat and light by transforming hydrogen into helium in its core through a process called nuclear fusion. The sun will continue to burn hydrogen for approximately another 5 billion years, said Fred Adams, a theoretical astrophysicist at the University of Michigan. But once that hydrogen fuel runs out, the sun will become more and more unstable. Its core will collapse, its surface will expand, and it will transform into a cool, bloated red giant that will engulf Mercury and then Venus. Sign up for our newsletter Sign up for our weekly Life's Little Mysteries newsletter to get the latest mysteries before they appear online. While our planet might be at the border of the red giant's surface, Adams said, chances are, it will get sucked into the red giant, too. By this point, though, humans will have been long gone. Mars will likely survive the red giant, and the outer planets are all safely outside of the red giant's reach. The Oort cloud will also be destabilized, Stern said, and the heliosphere will shrink down. Related: When will the universe die? About a billion years later, the sun will shrink to the size of Earth and transform into a white dwarf — a dim, extremely dense core of its former self. The solar system will become a freezing, desolate place. "From a habitability standpoint, that's kind of the end of the solar system," Alan Stern, a planetary scientist and principal investigator of NASA's New Horizons mission, told Live Science. Although the sun's death marks the end of the solar system as we know it, it doesn't necessarily mean its total demise. "A strict, nerdy answer is that the solar system will never end due to the sun's evolution" or the death of the sun, Stern said. Even when the sun is a burnt out cinder, he said, many objects — including giant planets like Jupiter — will continue to orbit it. Even further into the future, Adams said, the likelihood of rare events increases. Without the sun's gravitational force, the solar system will become increasingly chaotic as the gravitational balance of the solar system shifts. The risk of collisions, passing stars or supernovas coming too close to the solar system and then tearing apart its celestial bodies and space rocks will also be magnified. RELATED MYSTERIES —Did light exist at the beginning of the universe? —Could a black hole devour the universe? —How long can an asteroid 'survive'? "We're not just waiting until the universe is twice as old. We're waiting till it's a billion times older, a trillion times older, and a quadrillion times older," he explained. "If you wait, those enormous time scales and rare events start to add up. It's like, it's rare for you to win the lottery, but if you play a billion times, your chances will go up." Even if the solar system is spared a catastrophic collision, it won't last forever. Some scientists also think the protons that make up our universe will decay. The phenomenon has never been observed, but theoretical experiments have placed the proton's lifetime past 1034 years, and that number might be pushed back even further as experiments into their longevity keep running. Solar system quiz: How well do you know our cosmic neighborhood? Solve the daily Crossword
Yahoo
20-05-2025
- Science
- Yahoo
Jupiter was once twice as large as it is today
One of Jupiter's most recognizable attributes is its sheer size. With a diameter over 88,800 miles, our solar system's largest planet is 11 times as wide as Earth and twice as massive as all its sibling planets combined. But according to recent calculations based on some of the gas giant's tiniest moons, astronomers now believe Jupiter was once more than double its current size, with a magnetic field 50 times as strong. These gargantuan dimensions aren't only impressive—they played a major role in shaping our solar system as it exists today. The new findings are detailed in a study published on May 20 in the journal Nature Astronomy. To better understand Jupiter's primordial stages, researchers turned to the tiniest of the planet's 92 known moons. Almathea and Thebe respectively circle Jupiter at slightly tilted orbits roughly 112,400 and 138,000 miles above the planet's cloudtops. By analyzing the dynamics of these orbital discrepancies along with the planet's conservation of angular momentum, the team could estimate its radius and interior state at about 3.8 million years after the solar system formed its first solids. At that time, the sun was surrounded by a disk of material known as a protoplanetary nebula that was gradually dissipating as it coalesced into the planets we know and love. Based on their calculations, researchers believe early Jupiter was 2 to 2.5 times larger than it is today with a much more powerful magnetic field. 'It's astonishing that even after 4.5 billion years, enough clues remain to let us reconstruct Jupiter's physical state at the dawn of its existence,' said Fred Adams, one of the study's co-authors and a University of Michigan professor of physics and astronomy. By focusing on the directly measurable information from Jupiter's moons and the conservation of its angular momentum, the team was able to sidestep many of the common uncertainties that plague planetary formation models. These often require astronomers to make assumptions about variables like gas opacity, accretion rate, and heavy element core mass. According to the team, their new calculations enhance more than experts' understanding of Jupiter. These factors can be applied to the evolution of other giant planets as they circle stars. They also suggest that gas giants generally form through core accretion–or when a gas rapidly gathers around a core of ice and rock. 'Our ultimate goal is to understand where we come from, and pinning down the early phases of planet formation is essential to solving the puzzle,' said Konstantin Batygin, a Caltech planetary science professor and study co-author. 'This brings us closer to understanding how not only Jupiter but the entire solar system took shape.'
