Stars are a lot like people–they are born, grow up, grow old, and finally and inevitably die. About 5.4 billion years from now, our own Star, the Sun, will have aged to the tragic point that it will enter what is termed the Red Giant stage of its evolution–this will begin once all of its necessary supply of hydrogen fuel is finally consumed in its seething-hot heart, and the inert helium that it has accumulated becomes unstable and collapses under its own powerful weight. This chain of events will cause our Star’s core to get hotter, and hotter, and hotter–and progressively more and more dense–causing our Sun to swell in size and undergo a hideous sea-change into an enormous, bloated Red Giant Star. But, what will happen to Earth when the inevitable happens, and our Sun grows a hundred times bigger than it is today? Using the most powerful radio telescope currently available, an international team of astronomers embarked on their quest to answer this profound question by watching L2 Puppis, a distant star, that five billion years ago was very similar to the way our Sun is today.
“Five billion years from now, the Sun will have grown into a Red Giant Star, more than a hundred times larger than its current size. It will also experience an intense mass loss through a very strong stellar wind. The end product of its evolution, about 7 billion years from now, will be a tiny white dwarf star. This will be about the size of the Earth, but much heavier: one teaspoon of white dwarf material weighs about 5 tons,” explained Dr. Leen Decin in a December 8, 2016 KU Leuven Press Release. Dr. Decin is at the KU Leuven Institute of Astronomy in Leuven, Belgium.
It has been calculated that the bloated future Sun will balloon to a size large enough to swallow both Mercury and Venus–and, possibly, even our Earth. But even if our planet does manage to survive being consumed by our Star on steroids, its new proximity to our Sun would broil our Earth, and make it absolutely impossible for life to survive on what has become a scorched, hostile ball of hell in orbit around a dying Star. On the brighter side, astronomers are aware that as our Sun expands, the orbit of our Earth is likely going to change as well.
When our Star reaches this advanced stage in its stellar evolution, it will hurl out a large amount of its mass into space through fierce stellar winds. As our Sun swells, it loses mass, and this will cause the planets to spiral outwards. The question is whether the expanding Sun will overtake the planets spiraling outwards, or will Earth (and maybe even Venus) escape the hideous fiery rage of its grasping flames? That is the question!
“The fate of the Earth is still uncertain. We already know that our Sun will be bigger and brighter, so that it will probably destroy any form of life on our planet. But will the Earth’s rocky core survive the Red Giant phase and continue orbiting the white dwarf,” Dr. Decin added in the December 8, 2016 KU Leuven Press Release.
Death Of A Star
Red Giants are elderly, evolved stars that are approaching their inevitable demise. However, they still have a little bit of life left in them. This is because they are still able to fuse their supply of hydrogen fuel into helium within a shell surrounding a degenerate core of helium. The closest Red Giant to Earth is Gamma Crucis, which is almost 90 light-years away.
Elderly and doomed to die, Red Giant stars have radii that are ten to hundreds of times larger than that of our Sun. Yellow-orange to red in color, the outer atmosphere of a Red Giant is not only puffed up and bloated, it also displays a surface temperature of only 5,000 Kelvin–or even lower. This means that Red Giants are cool by star-standards. These gigantic old stars evolved from small, still-“living” Sun-like stars, ranging from about 0.3 solar-masses to around 8 solar-masses, when they were still on the hydrogen-burning main-sequence of the Hertzsprung-Russell Diagram Of Stellar Evolution. The small Sun-like stars ballooned in size after having consumed their necessary supply of hydrogen fuel in their nuclear-fusing cores. 바카라사이트
A baby star is born when an especially dense blob embedded within a dark, giant, molecular cloud collapses under its own weight. Molecular clouds, that float around our Milky Way Galaxy in huge numbers, are enormous, billowing, beautiful, and very, very cold–and they serve as nurseries for sparkling newborn stars (protostars). Molecular clouds are composed mostly of hydrogen and helium–with just a pinch of heavier atomic elements that are termed metals in the jargon of astronomers. For astronomers, a metal is defined as any atomic element that is heavier than helium. These metals are uniformly distributed throughout the forming star. The bouncing baby star finally attains true adult stardom when it reaches the hydrogen-burning main-sequence and its core grows hot enough to commence the process of nuclear fusion at the searing-hot temperature of a few million Kelvin. At this roasting temperature, the young, active star can at last fuse the hydrogen present in its core in order to establish hydrostatic equilibrium. Throughout its entire “life” on the main-sequence, the new star will gradually fuse the hydrogen in its hot heart into helium. The star’s “life” on the main-sequence comes to a sad conclusion when almost all of the hydrogen in its core has been fused into heavier things.
All of the 200 to 400 billion stars inhabiting our Milky Way Galaxy, including our own Sun, were born this way–from the gravitational collapse of an especially dense blob lodged secretively within the swirling, billowing, undulating folds of a cold molecular cloud. Today our Star is still on the hydrogen-burning main-sequence–it is a relatively small roiling, broiling sphere of searing-hot mostly hydrogen gas. Our Sun is currently almost 5 billion years of age, and it is enjoying an active middle-age–and it still has another 5 billion years to go before it goes gentle into that good night. As stars go, our Sun is nothing out of the ordinary–it does not stand out in the crowd of the billions of other stars inhabiting our Galaxy. There are planets, moons, and an assortment of smaller bodies circling our Sun. Our Solar System is situated in the far suburbs of our majestic, large, star-blazing, barred-spiral Galaxy, in one of its pinwheel-like arms.