This distance, called an astronomical unit (AU), is a standard measure of distance for astronomers and astrophysicists. The sun is about 150 million kilometers (93 million miles) from Earth. Other parts of the molecular cloud cooled into a disc around the brand-new sun and became planets, asteroids, comets, and other bodies in our solar system. Eventually, the gases heated up enough to begin nuclear fusion, and became the sun in our solar system. Much of the hydrogen and helium remained in the center of this hot, rotating mass. As one of these regions collapsed, it also began to rotate and heat up from increasing pressure. The molecular cloud began to compress, and some regions of gas collapsed under their own gravitational pull. A nearby supernova emitted a shockwave, which came in contact with the molecular cloud and energized it. About 4.5 billion years ago, the sun began to take shape from a molecular cloud that was mainly composed of hydrogen and helium. Without the sun’s heat and light, life on Earth would not exist. The sun has extremely important influences on our planet: It drives weather, ocean currents, seasons, and climate, and makes plant life possible through photosynthesis. The research has been published in The Astronomical Journal.The sun is an ordinary star, one of about 100 billion in our galaxy, the Milky Way. The likelihood of humanity surviving long enough to see it is slim. So it's by no means engraved in stone.Įven if estimates of the timeline of the Solar System's demise do change, however, it's still many billions of years away. And, the researchers carefully note, it's contingent on current observations of the local galactic environment, and stellar flyby estimates, both of which may change. That's a significantly shorter timeframe than that proposed in 1999. Ultimately, by 100 billion years after the Sun turns into a white dwarf, the Solar System is no more. Eventually, it, too, is knocked loose by the gravitational influence of passing stars. That last, lonely planet sticks around for another 50 billion years, but its fate is sealed. All but one planet escape their orbits, fleeing off into the galaxy as rogue planets. These expanded orbits, as well as characteristics of the planetary resonance, makes the system more susceptible to perturbations by passing stars.Īfter 30 billion years, such stellar perturbations jangle those stable orbits into chaotic ones, resulting in rapid planet loss. Jupiter and Saturn, however, become captured in a stable 5:2 resonance - for every five times Jupiter orbits the Sun, Saturn orbits twice (that eventual resonance has been proposed many times, not least by Isaac Newton himself). These simulations were split into two phases: up to the end of the Sun's mass loss, and the phase that comes after.Īlthough 10 simulations isn't a strong statistical sample, the team found that a similar scenario played out each time.Īfter the Sun completes its evolution into a white dwarf, the outer planets have a larger orbit, but still remain relatively stable. With these additional influences accounted for in their calculations, the team ran 10 N-body simulations for the outer planets (leaving out Mars to save on computation costs, since its influence should be negligible), using the powerful Shared Hoffman2 Cluster. The greater the number of bodies that are involved in a dynamical system, interacting with each other, the more complicated that system grows and the harder it is to predict. "Understanding the long-term dynamical stability of the solar system constitutes one of the oldest pursuits of astrophysics, tracing back to Newton himself, who speculated that mutual interactions between planets would eventually drive the system unstable," wrote astronomers Jon Zink of the University of California, Los Angeles, Konstantin Batygin of Caltech and Fred Adams of the University of Michigan in their new paper.īut that's a lot trickier than it might seem. According to new simulations, it will take just 100 billion years for any remaining planets to skedaddle off across the galaxy, leaving the dying Sun far behind.Īstronomers and physicists have been trying to puzzle out the ultimate fate of the Solar System for at least hundreds of years. But the rest of the Solar System will be long gone by then.
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