Stars are conceived, they live, and they kick the bucket. The sun is the same, and when it goes, the Earth runs with it. Yet, our planet won't go unobtrusively into the night.
Or maybe, when the sun ventures into a red monster amid the throes of death, it will vaporize the Earth.
Maybe not the story you were seeking after, but rather there's no compelling reason to begin purchasing star-passing protection yet. The time scale is long — 7 billion or 8 quite a while from now, in any event. People have been around just around 40-thousandth that measure of time; if the age of the Earth were packed into a 24-hour day, people would involve just the latest possible time, at most. On the off chance that thinking about stellar lifetimes does nothing else, it ought to underscore the existential irrelevance of our lives. [What If Earth Were Twice as Big?]
So what happens when the sun goes out? The appropriate response needs to do with how the sun sparkles. Stars start their lives as large agglomerations of gas, for the most part hydrogen with a dash of helium and different components. Gas has mass, so on the off chance that you put a ton of it in one place, it falls in on itself under its own weight. That makes weight on the inside of the proto-star, which warms up the gas until it gets so hot that the electrons get peeled off the particles and the gas winds up plainly charged, or ionized (a state called a plasma). The hydrogen iotas, each containing a solitary proton, intertwine with other hydrogen particles to wind up helium, which has two protons and two neutrons. The combination discharges vitality as light and warmth, which makes outward weight, and prevents the gas from breaking down any further. A star is conceived (with expressions of remorse to Barbra Streisand).
There's sufficient hydrogen to keep this procedure going for billions of years. In any case, in the end, the majority of the hydrogen in the sun's center will have melded into helium. By then, the sun won't have the capacity to create as much vitality, and will begin to crumple under its own particular weight. That weight can't produce enough weight to meld the helium as it did with the hydrogen toward the start of the star's life. Be that as it may, what hydrogen is left on the center's surface wil intertwine, producing a little extra vitality and enabling the sun to continue sparkling.
That helium center, however, will begin to crumple in on itself. When it does, it discharges vitality, however not through combination. Rather it just warms up in light of expanded weight (packing any gas builds its temperature). That arrival of vitality results in more light and warmth, making the sun significantly brighter. On a darker note, in any case, the vitality likewise makes the sun bloat into a red monster. Red mammoths are red in light of the fact that their surface temperatures are lower than stars like the sun. All things being equal, they are substantially greater than their more sultry partners.
Eventually, though, the hydrogen in the sun's outer core will get depleted, and the sun will start to collapse once again, triggering another cycle of fusion. For about 2 billion years the sun will fuse helium into carbon and some oxygen, but there's less energy in those reactions. Once the last bits of helium turn into heavier elements, there's no more radiant energy to keep the sun puffed up against it's own weight. The core will shrink into a white dwarf. The distended sun's outer layers are only weakly bound to the core because they are so far away from it, so when the core collapses it will leave the outer layers of its atmosphere behind. The result is a planetary nebula.
Since white dwarfs are heated by compression rather than fusion, initially they are quite hot — surface temperatures can reach 50,000 degrees Fahrenheit (nearly 28,000 degrees Celsius) — and they illuminate the slowly expanding gas in the nebula. So any alien astronomers billions of years in the future might see something like the Ring Nebula in Lyra where the sun once shone.
No comments:
Post a Comment