All life on Earth owes its existence to the Sun, whose rays have showered the planet with energy for billions of years. But, like all things, the Sun has its days numbered. Every star has a life cycle consisting of formation, main sequence, and ultimately death when it runs out of fuel — the Sun is no exception.
The good news is that before this will happen, our species should have evolved into something entirely different or long become extinct. According to scientists, the sun has enough fuel to keep it running for another 5 billion years. When that happens, the solar system will be transformed forever.
The life cycle of the Sun
The star is classed as a G-type main-sequence star, also known as a yellow dwarf. Like other G-type main-sequence stars, the Sun converts hydrogen to helium in its core through nuclear fusion. Each second, it fuses about 600 million tons of hydrogen to helium. The term yellow dwarf is a misnomer since G stars actually range in color from white to slightly yellow. The Sun is, in fact, white but appears yellow because of Rayleigh scattering caused by the Earth’s atmosphere.
The Sun and its planets have been around for about 4.57 billion years. They were all formed out of the same giant cloud of molecular gas and dust which, at some critical point, collapsed under gravity at the center of the nebula.
Due to a nonuniform distribution of mass, some pockets were denser, consequently attracting more and more matter. At the same time, these clumps of matter that were increasing in mass began to rotate due to the conservation of momentum. The increasing pressure also caused the dense regions of gas and dust to heat up.
Scientists’ models suggest that the initial cloud of dust and gas eventually settled into a huge ball of matter at the center, surrounded by a flat disk of matter. The ‘ball’ would eventually turn into the Sun once the temperature and pressure were high enough to trigger nuclear fusion, while the disk would go on to form the planets.
Scientists estimate that it took the Sun only 100,000 years to gather enough mass in order to begin fusing hydrogen into helium. For roughly a few million years, the Sun shone very brightly as a T Tauri star, before it eventually settled into its current G-type main-sequence configuration.
Like most other stars in the universe, the Sun is currently living through its ‘main sequence’ phase. Every second, 600 million tons of matter are converted into neutrinos and roughly 4 x 1027 Watts of energy.
What happens to Earth after the sun dies
There is only a finite amount of hydrogen in the Sun which means it must eventually run out. Since its formation, scientists estimate the Sun consumed as much hydrogen as about 100 times the mass of the Earth.
As the Sun loses hydrogen, its fuel-holding core shrinks, allowing the outer layers to contract towards the center. This puts more pressure on the core, which responds by increasing the rate at which it fuses hydrogen into helium. Naturally, this means the Sun will get brighter with time.
Scientists estimate that the Sun’s luminosity increases by 1% every 100 million years. Compared to when it turned into a G-type main-sequence star 4.5 billion years ago, the Sun is now 30% more luminous.
All of this means that the Sun will slowly turn the heat up on Earth. About 1.1 billion years from now, the Sun will be 10% brighter, triggering a greenhouse effect on Earth similar to the warming that made Venus into a hellish planet.
The heat transfer with Earth’s atmosphere would be huge by this point in time, causing the oceans to boil and the ice caps to melt. As the atmosphere becomes saturated with water, high energy radiation from the Sun will split apart the molecules, allowing water to escape into space as hydrogen and oxygen until the whole planet becomes a barren wasteland.
Life would stand no chance, permanently sealing Earth’s fate as the next Venus or Mars. Speaking of which, at this point into the future, Mars’ orbit would move into the habitable zone, which might become a second Earth for a short while before it too would become unsalvageable.
Some 3.5 billion years from now, the Sun will be 40% brighter than today.
And, in about 5.4 billion years, the Sun will run out of hydrogen fuel, marking the end of its main sequence phase. What will inevitably happen next is that the built-up helium in the core will become unstable and collapse under its own weight. Since the Sun first started fusing hydrogen, all of the helium it has produced has accumulated in the core with no way to get rid of it.
At this point, the Sun will be ready to enter its “Red Giant” phase, characterized by an enormous swelling in size due to gravitational forces that compress the core and allow the rest of the sun to expand. The Sun will grow so large that it will encompass the orbits of Venus and Mercury, and quite possibly even Earth. Some astronomers estimate it might grow to 100 times its current size.
What this means is that even if life on Earth somehow miraculously survives the tail-end of the Sun’s main sequence, it will most certainly be destroyed by a Red Sun so large it will touch our planet.
Don’t be blue, even stars have to die
The Sun will remain in a Red Giant phase for about 120 million years. At this point, the core of the Sun, when it reaches the right temperature and pressure, will start fusing helium into carbon, then carbon and helium into oxygen, neon and helium into magnesium, and so on all the way up to iron. This reaction is triggered when the last remaining shell of hydrogen that envelops the core is burned.
The Sun will then eventually expel its outer layers and then contract into a white dwarf. Meanwhile, all the Sun’s outer material will dissipate, leaving behind a planetary nebula.
“When a star dies it ejects a mass of gas and dust – known as its envelope – into space. The envelope can be as much as half the star’s mass. This reveals the star’s core, which by this point in the star’s life is running out of fuel, eventually turning off and before finally dying,” explained astrophysicist Albert Zijlstra from the University of Manchester in the UK.
“It is only then the hot core makes the ejected envelope shine brightly for around 10,000 years – a brief period in astronomy. This is what makes the planetary nebula visible. Some are so bright that they can be seen from extremely large distances measuring tens of millions of light years, where the star itself would have been much too faint to see.”
If it were much more massive, the Sun’s final fate would have been much more spectacular exploding into a supernova and perhaps forming a black hole. Due to its relatively small size, however, the Sun will likely live as a white dwarf for trillions of years before finally fading away entirely leaving the solar system in pitch-black darkness. The Sun has now become a black dwarf.
In summary: the sun has about 5-7 billion years left of its main sequence phase — the most stable part of its life. However, life on Earth might become extinct as early as 1 billion years from now due to the Sun becoming hot enough to boil the oceans.
When will the Sun run out of fuel?
The Sun has enough hydrogen fuel to last it another 5 billion years. However, life on Earth might become extinct as early as 1 billion years from now.
by Tibi Puiu
https://www.zmescience.com/feature-post/space-astronomy/solar-system/sun/when-will-sun-die-04233/
All life on Earth owes its existence to the Sun, whose rays have showered the planet with energy for billions of years. But, like all things, the Sun has its days numbered. Every star has a life cycle consisting of formation, main sequence, and ultimately death when it runs out of fuel — the Sun is no exception.
The good news is that before this will happen, our species should have evolved into something entirely different or long become extinct. According to scientists, the sun has enough fuel to keep it running for another 5 billion years. When that happens, the solar system will be transformed forever.
The life cycle of the Sun
The star is classed as a G-type main-sequence star, also known as a yellow dwarf. Like other G-type main-sequence stars, the Sun converts hydrogen to helium in its core through nuclear fusion. Each second, it fuses about 600 million tons of hydrogen to helium. The term yellow dwarf is a misnomer since G stars actually range in color from white to slightly yellow. The Sun is, in fact, white but appears yellow because of Rayleigh scattering caused by the Earth’s atmosphere.
The Sun and its planets have been around for about 4.57 billion years. They were all formed out of the same giant cloud of molecular gas and dust which, at some critical point, collapsed under gravity at the center of the nebula.
Due to a nonuniform distribution of mass, some pockets were denser, consequently attracting more and more matter. At the same time, these clumps of matter that were increasing in mass began to rotate due to the conservation of momentum. The increasing pressure also caused the dense regions of gas and dust to heat up.
Scientists’ models suggest that the initial cloud of dust and gas eventually settled into a huge ball of matter at the center, surrounded by a flat disk of matter. The ‘ball’ would eventually turn into the Sun once the temperature and pressure were high enough to trigger nuclear fusion, while the disk would go on to form the planets.
Scientists estimate that it took the Sun only 100,000 years to gather enough mass in order to begin fusing hydrogen into helium. For roughly a few million years, the Sun shone very brightly as a T Tauri star, before it eventually settled into its current G-type main-sequence configuration.
Like most other stars in the universe, the Sun is currently living through its ‘main sequence’ phase. Every second, 600 million tons of matter are converted into neutrinos and roughly 4 x 1027 Watts of energy.
What happens to Earth after the sun dies
There is only a finite amount of hydrogen in the Sun which means it must eventually run out. Since its formation, scientists estimate the Sun consumed as much hydrogen as about 100 times the mass of the Earth.
As the Sun loses hydrogen, its fuel-holding core shrinks, allowing the outer layers to contract towards the center. This puts more pressure on the core, which responds by increasing the rate at which it fuses hydrogen into helium. Naturally, this means the Sun will get brighter with time.
Scientists estimate that the Sun’s luminosity increases by 1% every 100 million years. Compared to when it turned into a G-type main-sequence star 4.5 billion years ago, the Sun is now 30% more luminous.
All of this means that the Sun will slowly turn the heat up on Earth. About 1.1 billion years from now, the Sun will be 10% brighter, triggering a greenhouse effect on Earth similar to the warming that made Venus into a hellish planet.
The heat transfer with Earth’s atmosphere would be huge by this point in time, causing the oceans to boil and the ice caps to melt. As the atmosphere becomes saturated with water, high energy radiation from the Sun will split apart the molecules, allowing water to escape into space as hydrogen and oxygen until the whole planet becomes a barren wasteland.
Life would stand no chance, permanently sealing Earth’s fate as the next Venus or Mars. Speaking of which, at this point into the future, Mars’ orbit would move into the habitable zone, which might become a second Earth for a short while before it too would become unsalvageable.
Some 3.5 billion years from now, the Sun will be 40% brighter than today.
And, in about 5.4 billion years, the Sun will run out of hydrogen fuel, marking the end of its main sequence phase. What will inevitably happen next is that the built-up helium in the core will become unstable and collapse under its own weight. Since the Sun first started fusing hydrogen, all of the helium it has produced has accumulated in the core with no way to get rid of it.
At this point, the Sun will be ready to enter its “Red Giant” phase, characterized by an enormous swelling in size due to gravitational forces that compress the core and allow the rest of the sun to expand. The Sun will grow so large that it will encompass the orbits of Venus and Mercury, and quite possibly even Earth. Some astronomers estimate it might grow to 100 times its current size.
What this means is that even if life on Earth somehow miraculously survives the tail-end of the Sun’s main sequence, it will most certainly be destroyed by a Red Sun so large it will touch our planet.
Don’t be blue, even stars have to die
The Sun will remain in a Red Giant phase for about 120 million years. At this point, the core of the Sun, when it reaches the right temperature and pressure, will start fusing helium into carbon, then carbon and helium into oxygen, neon and helium into magnesium, and so on all the way up to iron. This reaction is triggered when the last remaining shell of hydrogen that envelops the core is burned.
The Sun will then eventually expel its outer layers and then contract into a white dwarf. Meanwhile, all the Sun’s outer material will dissipate, leaving behind a planetary nebula.
If it were much more massive, the Sun’s final fate would have been much more spectacular exploding into a supernova and perhaps forming a black hole. Due to its relatively small size, however, the Sun will likely live as a white dwarf for trillions of years before finally fading away entirely leaving the solar system in pitch-black darkness. The Sun has now become a black dwarf.
In summary: the sun has about 5-7 billion years left of its main sequence phase — the most stable part of its life. However, life on Earth might become extinct as early as 1 billion years from now due to the Sun becoming hot enough to boil the oceans.
太陽はいつ燃料を使い果たすのでしょうか?
太陽には、あと 50 億年存続できるだけの水素燃料があります。 しかし、早ければ10億年後には地球上の生命が絶滅する可能性があります。
ティビ・プイウ著
https://www.zmescience.com/feature-post/space-astronomy/solar-system/sun/when-will-sun-die-04233/
地球上のすべての生命は太陽のおかげで存在しており、太陽の光は何十億年もの間、地球にエネルギーを降り注いでいます。 しかし、すべてのものと同様に、太陽にも寿命があります。 すべての星には、形成、主系列、そして最終的には燃料が尽きて死ぬというライフサイクルがあります。太陽も例外ではありません。
良いニュースは、これが起こる前に、私たちの種はまったく異なるものに進化するか、長い間絶滅しているはずだということです。 科学者らによると、太陽にはあと50億年間活動し続けるのに十分な燃料があるという。 それが起こると、太陽系は永久に変化するでしょう。
太陽のライフサイクル
この星は G 型主系列星として分類されており、黄色矮星としても知られています。 他の G 型主系列星と同様に、太陽は核融合。 毎秒約6億トンの水素をヘリウムに融合させます。 G 星の実際の色の範囲は白からわずかに黄色であるため、黄色矮星という用語は誤称です。 実際、太陽は白色ですが、地球の大気によって引き起こされるレイリー散乱のため黄色く見えます。
太陽とその惑星が存在してから約 45 億 7,000 万年が経ちます。 これらはすべて、分子ガスと塵の同じ巨大な雲から形成され、ある臨界点で星雲の中心で重力によって崩壊しました。
質量の不均一な分布により、一部のポケットの密度が高まり、その結果、より多くの物質が引き寄せられました。 同時に、質量が増加していたこれらの物質の塊は、運動量保存によって回転し始めました。 圧力の上昇により、ガスと塵の高密度領域も加熱されました。
科学者’ モデルによると、最初の塵とガスの雲は最終的に中心にある巨大な物質の球に落ち着き、その周りを 物質の平らな円盤。 「ボール」 温度と圧力が核融合を引き起こすのに十分に高くなると、最終的には太陽に変わり、一方、円盤は惑星を形成し続けます。
科学者らは、太陽が水素をヘリウムに融合し始めるのに十分な質量を集めるのにわずか 10 万年しかかからなかったと推定しています。 太陽は、最終的に現在の G 型主系列構成に落ち着くまで、およそ数百万年間、おうし座 T 星として非常に明るく輝いていました。
宇宙の他のほとんどの星と同様に、太陽は現在、その「主系列」を生きています。 段階。 毎秒 6 億トンの物質がニュートリノとおよそ 4 x 1027 ワットのエネルギーに変換されます。
太陽が死んだ後、地球はどうなるか
太陽内の水素の量は有限であるため、最終的には水素が枯渇する必要があります。 科学者らは、その形成以来、太陽は地球の質量の約 100 倍に相当する量の水素を消費したと推定しています。
太陽が水素を失うと、燃料を保持する核が収縮し、外層が中心に向かって収縮します。 これにより炉心にさらに圧力がかかり、炉心は水素をヘリウムに融合させる速度を高めることで反応します。 当然のことながら、これは太陽が時間とともに明るくなることを意味します。
科学者らは、太陽の明るさは 1 億年ごとに 1% 増加すると推定しています。 45億年前にG型主系列星になったときと比較して、太陽は現在30％明るくなっている。
これらすべては、太陽が地球の温度をゆっくりと上昇させることを意味します。 今から約 11 億年後、太陽は 10% 明るくなり、金星を地獄のような惑星にした温暖化と同様の温室効果が地球に引き起こされます。
地球の大気との熱伝達はこの時点までに膨大になり、海洋が沸騰し、氷床が溶ける可能性があります。 大気が水で飽和すると、太陽からの高エネルギー放射線が分子を分裂させ、水が水素と酸素として宇宙に逃げ、最終的に地球全体が不毛の荒野となります。
生命にはチャンスはなく、次の金星か火星として地球の運命を永久に封印することになるでしょう。 そういえば、将来のこの時点で、火星の軌道はハビタブルゾーンに移動し、しばらくの間第二の地球となるかもしれないが、その後、それも回収不能になるだろう。
今から約 35 億年後には、太陽は現在より 40% 明るくなるでしょう。
そして、約 54 億年後には太陽の水素燃料が枯渇し、太陽の主系列段階が終わります。 次に必然的に起こるのは、炉心に蓄積されたヘリウムが不安定になり、自重で崩壊することです。 太陽が最初に水素の核融合を始めて以来、太陽が生成したヘリウムはすべて除去する方法がなく、核に蓄積されました。
この時点で、太陽は「赤色巨星」に入る準備が整います。 この相は、核を圧縮して太陽の残りの部分を膨張させる重力によるサイズの巨大な膨張を特徴とします。 太陽は非常に大きくなり、金星と水星、さらには地球の軌道をも包み込むようになるでしょう。 一部の天文学者は、現在の大きさの 100 倍に成長する可能性があると推定しています。
これが意味するのは、たとえ地球上の生命が太陽の主系列の最後尾で何らかの形で奇跡的に生き残ったとしても、地球に触れるほど大きな赤い太陽によってほぼ確実に破壊されるということです。
青くならないでください、星でも死ななければなりません
太陽は約 1 億 2,000 万年間、赤色巨星期に留まります。 この時点で、太陽の中心部は、適切な温度と圧力に達すると、ヘリウムを炭素に融合し始め、次に炭素とヘリウムが酸素に、ネオンとヘリウムがマグネシウムに、というように鉄に至るまで続きます。 この反応は、核を包んでいる最後に残った水素の殻が燃焼するときに引き起こされます。
太陽は最終的に外層を放出し、白色矮星。 一方、太陽の外側の物質はすべて消散し、惑星状星雲が残ります。
もしそれがもっと大質量だったら、太陽の最終的な運命は、超新星爆発を起こし、おそらくブラックホールを形成するという、もっと壮観なものになっていたでしょう。 しかし、その比較的小さいサイズのため、太陽はおそらく白色矮星として何兆年も生き、最終的には太陽系を漆黒の暗闇に残して完全に消滅するでしょう。 太陽は現在、黒色矮星になっています。
要約すると、太陽の主系列相は約 50 ～ 70 億年残っています。 人生の中で最も安定した時期。 しかし、太陽が海を沸騰させるほど熱くなったために、早ければ10億年後には地球上の生命が絶滅する可能性があります。