Will the Earth survive the Sun's Red Giant phase?
Δημοσιεύτηκε στις 8 Ιουν 2014
Red Giant Sun means Habitable Zone beyond Jupiter: http://www.sg1official.com/2015/02/re...
Billions
of years in the future, when our Sun bloats up into a red giant, it
will expand to consume the Earth's orbit. But wait, you say, the Earth
travels the Earth's orbit... what's going to happen to our beloved
planet? Will it be gobbled up like poor Mercury and Venus?
Astronomers
have been puzzling this question for decades. When the sun becomes a
red giant, the simple calculation would put its equator out past Mars.
All of the inner planets would be consumed.
However, as the Sun
reaches this late stage in its stellar evolution, it loses a tremendous
amount of mass through powerful stellar winds. As it grows, it loses
mass, causing the planets to spiral outwards. So the question is, will
the expanding Sun overtake the planets spiraling outwards, or will Earth
(and maybe even Venus) escape its grasp.
K.-P Schroder and
Robert Cannon Smith are two researchers trying to get to the bottom of
this question. They've run the calculations with the most current models
of stellar evolution, and published a research paper entitled, Distant
Future of the Sun and Earth Revisted. It has been accepted for
publication in the Monthly Notices of the Royal Astronomical Society.
According
to Schroder and Smith, when the Sun becomes a red giant star 7.59
billion years, it will start to lose mass quickly. By the time it
reaches its largest radius, 256 times its current size, it will be down
to only 67% of its current mass.
When the Sun does begin to bloat
up, it will go quickly, sweeping through the inner Solar System in just
5 million years. It will then enter its relatively brief (130 million
year) helium-burning phase. It will expand past the orbit of Mercury,
and then Venus. By the time it approaches the Earth, it will be losing
4.9 x 1020 tonnes of mass every year (8% the mass of the Earth).
But
the habitable zone will be gone much sooner. Astronomers estimate that
will expand past the Earth's orbit in just a billion years. The heating
Sun will evaporate the Earth's oceans away, and then solar radiation
will blast away the hydrogen from the water. The Earth will never have
oceans again. It will eventually become molten again.
One
interesting side benefit for the Solar System. Even though the Earth, at
a mere 1.5 astronomical units, will no longer be within the Sun's
habitable zone, much of the Solar System will be. The new habitable zone
will stretch from 49.4 AU to 71.4 AU, well into the Kuiper Belt. The
formerly icy worlds will melt, and liquid water will be present beyond
the orbit of Pluto. Perhaps Eris will be the new homeworld.
Back to the question... will the Earth survive?
According
to Schroder and Smith, the answer is no. Even though the Earth could
expand to an orbit 50% larger than today's orbit, it won't get the
chance. The expanding Sun will engulf the Earth just before it reaches
the tip of the red giant phase. And the Sun would still have another
0.25 AU and 500,000 years to grow.
Once inside the Sun's atmosphere, the Earth will collide with particles of gas. Its orbit will decay, and it will spiral inward.
If
the Earth were just a little further from the Sun, at 1.15 AU, it would
be able to survive the expansion phase. Although it's science fiction,
the authors suggest that future technologies could be used to speed up
the Earth's spiraling outward from the Sun.
I'm not sure why, but
thinking about this far future of the Earth gives an insight into human
psychology. People are genuinely worried about a future billions of
years away. Even though the Earth will be scorched much sooner, its
oceans boiled away, and turned into a molten ball of rock, it's this
early destruction by the Sun that feels so sad.
Subscribe to stay updated and educated. .
Must Watch:
'Pulsars and Quasars' - Learn about the monsters of the universe: https://www.youtube.com/playlist?list...
'Science Fact or Science Fiction?' - Find out what's real and what's made up in science and space: - https://www.youtube.com/playlist?list...
'Top 10 Biggest Blasts' - A countdown of the biggest explosions ever to occur: https://www.youtube.com/playlist?list...
'Time Travel' - Is it possible?: https://www.youtube.com/playlist?list...
'7 Wonders of the Solar System' - Our Solar System isn't as boring as you think - https://www.youtube.com/playlist?list...
'Black Holes' - The end, the infinite, the all consuming: https://www.youtube.com/playlist?list...
Billions
of years in the future, when our Sun bloats up into a red giant, it
will expand to consume the Earth's orbit. But wait, you say, the Earth
travels the Earth's orbit... what's going to happen to our beloved
planet? Will it be gobbled up like poor Mercury and Venus?
Astronomers
have been puzzling this question for decades. When the sun becomes a
red giant, the simple calculation would put its equator out past Mars.
All of the inner planets would be consumed.
However, as the Sun
reaches this late stage in its stellar evolution, it loses a tremendous
amount of mass through powerful stellar winds. As it grows, it loses
mass, causing the planets to spiral outwards. So the question is, will
the expanding Sun overtake the planets spiraling outwards, or will Earth
(and maybe even Venus) escape its grasp.
K.-P Schroder and
Robert Cannon Smith are two researchers trying to get to the bottom of
this question. They've run the calculations with the most current models
of stellar evolution, and published a research paper entitled, Distant
Future of the Sun and Earth Revisted. It has been accepted for
publication in the Monthly Notices of the Royal Astronomical Society.
According
to Schroder and Smith, when the Sun becomes a red giant star 7.59
billion years, it will start to lose mass quickly. By the time it
reaches its largest radius, 256 times its current size, it will be down
to only 67% of its current mass.
When the Sun does begin to bloat
up, it will go quickly, sweeping through the inner Solar System in just
5 million years. It will then enter its relatively brief (130 million
year) helium-burning phase. It will expand past the orbit of Mercury,
and then Venus. By the time it approaches the Earth, it will be losing
4.9 x 1020 tonnes of mass every year (8% the mass of the Earth).
But
the habitable zone will be gone much sooner. Astronomers estimate that
will expand past the Earth's orbit in just a billion years. The heating
Sun will evaporate the Earth's oceans away, and then solar radiation
will blast away the hydrogen from the water. The Earth will never have
oceans again. It will eventually become molten again.
One
interesting side benefit for the Solar System. Even though the Earth, at
a mere 1.5 astronomical units, will no longer be within the Sun's
habitable zone, much of the Solar System will be. The new habitable zone
will stretch from 49.4 AU to 71.4 AU, well into the Kuiper Belt. The
formerly icy worlds will melt, and liquid water will be present beyond
the orbit of Pluto. Perhaps Eris will be the new homeworld.
Back to the question... will the Earth survive?
According
to Schroder and Smith, the answer is no. Even though the Earth could
expand to an orbit 50% larger than today's orbit, it won't get the
chance. The expanding Sun will engulf the Earth just before it reaches
the tip of the red giant phase. And the Sun would still have another
0.25 AU and 500,000 years to grow.
Once inside the Sun's atmosphere, the Earth will collide with particles of gas. Its orbit will decay, and it will spiral inward.
If
the Earth were just a little further from the Sun, at 1.15 AU, it would
be able to survive the expansion phase. Although it's science fiction,
the authors suggest that future technologies could be used to speed up
the Earth's spiraling outward from the Sun.
I'm not sure why, but
thinking about this far future of the Earth gives an insight into human
psychology. People are genuinely worried about a future billions of
years away. Even though the Earth will be scorched much sooner, its
oceans boiled away, and turned into a molten ball of rock, it's this
early destruction by the Sun that feels so sad.
Subscribe to stay updated and educated. .
Must Watch:
'Pulsars and Quasars' - Learn about the monsters of the universe: https://www.youtube.com/playlist?list...
'Science Fact or Science Fiction?' - Find out what's real and what's made up in science and space: - https://www.youtube.com/playlist?list...
'Top 10 Biggest Blasts' - A countdown of the biggest explosions ever to occur: https://www.youtube.com/playlist?list...
'Time Travel' - Is it possible?: https://www.youtube.com/playlist?list...
'7 Wonders of the Solar System' - Our Solar System isn't as boring as you think - https://www.youtube.com/playlist?list...
'Black Holes' - The end, the infinite, the all consuming: https://www.youtube.com/playlist?list...
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