Q: Red giant heating effects on earth-like planets over time

Bruce Sterling Woodcock wrote:

"Eric Chomko" wrote in message
...
Bill Bonde ( ``Soli Deo Gloria'' ) ) wrote:
: Can anyone answer the following query or point me in a direction where I
: might find relevant information?: What are the supposed red giant
: heating effects on earth-like planets over time? I'm specifically
: interested in transition points, times, where a planet might be liveable
: for humans and then not be.

Well as I understand it when the Sun becomes a Red Giant, it will swell in
size to be as big as Mars' orbit. So, terrestial planets will be engulfed.
But don't worry that won't happen for another several billion years.

Actually, this is something of a misperception. When the sun swells up,
it will also be rapidly losing mass. This, in turn, will cause the orbits
of
the planets to be pushed outward. The sun may swell up to the current
orbit of Earth, or perhaps even as far as Mars, but Mars, Earth, and
possibly even Venus may survive being engulfed.

Can anyone put numbers or hints of numbers on the sort of time frame we
are talking about?


--
That's what is at stake. It is us or them. The chips are down. Two

worlds stand against each other. One must die. One must live. One

hundred and seventy years of freedom decrees our answer." -+ Frank

Capra's "Prelude to War"

Bill Bonde ( ``Soli Deo Gloria'' ) ) wrote:


: Bruce Sterling Woodcock wrote:
:
: "Eric Chomko" wrote in message
: ...
: Bill Bonde ( ``Soli Deo Gloria'' ) ) wrote:
: : Can anyone answer the following query or point me in a direction where I
: : might find relevant information?: What are the supposed red giant
: : heating effects on earth-like planets over time? I'm specifically
: : interested in transition points, times, where a planet might be liveable
: : for humans and then not be.
:
: Well as I understand it when the Sun becomes a Red Giant, it will swell in
: size to be as big as Mars' orbit. So, terrestial planets will be engulfed.
: But don't worry that won't happen for another several billion years.
:
: Actually, this is something of a misperception. When the sun swells up,
: it will also be rapidly losing mass. This, in turn, will cause the orbits
: of
: the planets to be pushed outward. The sun may swell up to the current
: orbit of Earth, or perhaps even as far as Mars, but Mars, Earth, and
: possibly even Venus may survive being engulfed.
:
: Can anyone put numbers or hints of numbers on the sort of time frame we
: are talking about?

I think you have to find out the life span of stars along the "Main
Sequence" in the H-R Diagram. That might be a good place to start.

Eric

: --
: That's what is at stake. It is us or them. The chips are down. Two

: worlds stand against each other. One must die. One must live. One

: hundred and seventy years of freedom decrees our answer." -+ Frank

: Capra's "Prelude to War"

In sci.space.policy Eric Chomko wrote:
Bill Bonde ( ``Soli Deo Gloria'' ) ) wrote:
: Can anyone answer the following query or point me in a direction where I
: might find relevant information?: What are the supposed red giant
: heating effects on earth-like planets over time? I'm specifically
: interested in transition points, times, where a planet might be liveable
: for humans and then not be.

Well as I understand it when the Sun becomes a Red Giant, it will swell in
size to be as big as Mars' orbit. So, terrestial planets will be engulfed.
But don't worry that won't happen for another several billion years.

I think you would need to start with far more stellar mass than the
Sun has to swell quite that large.



Eric

--
Sander

+++ Out of cheese error +++

"Bruce Sterling Woodcock" wrote:
"Eric Chomko" wrote:
Bill Bonde ( ``Soli Deo Gloria'' ) ) wrote:
: Can anyone answer the following query or point me in a direction where I
: might find relevant information?: What are the supposed red giant
: heating effects on earth-like planets over time? I'm specifically
: interested in transition points, times, where a planet might be liveable
: for humans and then not be.

Well as I understand it when the Sun becomes a Red Giant, it will swell in
size to be as big as Mars' orbit. So, terrestial planets will be engulfed.
But don't worry that won't happen for another several billion years.

Actually, this is something of a misperception. When the sun swells up,
it will also be rapidly losing mass. This, in turn, will cause the orbits
of
the planets to be pushed outward. The sun may swell up to the current
orbit of Earth, or perhaps even as far as Mars, but Mars, Earth, and
possibly even Venus may survive being engulfed.

A relevant reference is in the July 2004 Sientific American:

The Extraordinary Deaths of Ordinary Stars; July 2004; by Bruce Balick
and Adam Frank; 10 page(s)


quote
Within easy sight of the astronomy building at the University of
Washington sits the foundry of glassblower Dale Chihuly. Chihuly is
famous for glass sculptures whose brilliant flowing forms conjure up
active undersea creatures. When they are illuminated strongly in a
dark room, the play of light dancing through the stiff glass forms
commands them to life. Yellow jellyfish and red octopuses jet through
cobalt waters. A forest of deep-sea kelp sways with the tides. A pair
of iridescent pink scallops embrace each other like lovers.

For astronomers, Chihuly's works have another resonance: few other
human creations so convincingly evoke the glories of celestial
structures called planetary nebulae. Lit from the inside by depleted
stars, fluorescently colored by glowing atoms and ions, and set
against the cosmic blackness, these gaseous shapes seem to come alive.
Researchers have given them such names as the Ant, the Starfish Twins
and the Cat's Eye. Hubble Space Telescope observations of these
objects are some of the most mesmerizing space images ever obtained.
/quote

I believe this is where I read the description of what it would look
like to be on Earth's surface once Sol went through this first
death-throe.

/dps

"BB(`DG)" == Bill Bonde ( ``Soli Deo Gloria'' ) writes:

BB(`DG) Bruce Sterling Woodcock wrote:

Well as I understand it when the Sun becomes a Red Giant, it will
swell in size to be as big as Mars' orbit. So, terrestial planets
will be engulfed. But don't worry that won't happen for another
several billion years.

Actually, this is something of a misperception. When the sun
swells up, it will also be rapidly losing mass. This, in turn,
will cause the orbits of the planets to be pushed outward. The sun
may swell up to the current orbit of Earth, or perhaps even as far
as Mars, but Mars, Earth, and possibly even Venus may survive being
engulfed.

BB Can anyone put numbers or hints of numbers on the sort of
BB time frame we are talking about?

Hmm, I thought I had posted this, but I don't see it on Google.

See URL:
http://adsabs.harvard.edu/cgi-bin/np...J...418..457S& .

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No means no, stop rape. | http://patriot.net/%7Ejlazio/
sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html

Henry Spencer wrote:
Quite difficult, last I heard. A paper in Science a few years ago
reported simulation results showing that even if you gave Earth the
same amount of atmospheric CO2 that Venus has, the oceans would not
boil. (The resulting climate would not be pleasant even at the
poles, but the oceans would remain liquid.) Earth doesn't get quite
enough sunlight for that.

Nitpick: With that much CO2, climate can't really be said to be
pleasant or unpleasant, since nobody would live long enough to notice
the temperature.

The reason things happened quickly on Venus once boiling started, by
the way, is that water vapor is a greenhouse gas.

Even if the oceans don't actually boil, the vapor pressure of water
increases exponentially with temperature. Every additional degree
means a lot more water vapor in the atmosphere. If this wouldn't
quickly run away, then water must be a very weak greenhouse gas.
--
Keith F. Lynch - http://keithlynch.net/
Please see http://keithlynch.net/email.html before emailing me.

Keith F. Lynch wrote:

Even if the oceans don't actually boil, the vapor pressure of water
increases exponentially with temperature. Every additional degree
means a lot more water vapor in the atmosphere. If this wouldn't
quickly run away, then water must be a very weak greenhouse gas.

The problem is that the absorption saturates, so adding
more water blocks radiation only on the tails of the lines, where
the absorption is naturally very weak. IIUC, only when the pressure
gets high enough that pressure broadening widens the lines do things
get really dire, but don't quote me on that.

Paul

[water as a greenhouse gas]

In article ,
"Paul F. Dietz" writes:
The problem is that the absorption saturates, so adding
more water blocks radiation only on the tails of the lines, where
the absorption is naturally very weak. IIUC, only when the pressure
gets high enough that pressure broadening widens the lines do things
get really dire, but don't quote me on that.

The above sounds OK at first, and I believe it is true for carbon
dioxide, but I don't think it applies to water vapor.

There is something called the "water vapor continuum" in the 10-13
micron range. What it really is is the damping wings of the strong
water lines at 15 microns, which are saturated for normal atmospheric
temperatures and humidities. At typical mountaintop observatories
(not Mauna Kea!), the water vapor continuum absorption is about 10%,
and of course it is more from sea level. Most of the Earth's heat
escapes in the 8 to 13 micron window, so I would expect the water
vapor continuum to give a very powerful greenhouse effect.

I know virtually nothing about climate models, so I don't know what
effect the water vapor continuum really has. I suppose it competes
with cloud formation, which would decrease the incoming solar energy.

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
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"Bruce Sterling Woodcock" wrote in message . com...
"Eric Chomko" wrote in message
...
Bill Bonde ( ``Soli Deo Gloria'' ) ) wrote:
: Can anyone answer the following query or point me in a direction where I
: might find relevant information?: What are the supposed red giant
: heating effects on earth-like planets over time? I'm specifically
: interested in transition points, times, where a planet might be liveable
: for humans and then not be.

Well as I understand it when the Sun becomes a Red Giant, it will swell in
size to be as big as Mars' orbit. So, terrestial planets will be engulfed.
But don't worry that won't happen for another several billion years.

Actually, this is something of a misperception. When the sun swells up,
it will also be rapidly losing mass. This, in turn, will cause the orbits
of
the planets to be pushed outward. The sun may swell up to the current
orbit of Earth, or perhaps even as far as Mars, but Mars, Earth, and
possibly even Venus may survive being engulfed.
And IIRC, it only swells up because of excess silicon and iron waste
products, even though it still has 90% of its usable hydrogen fuel
left. So removing the silicon and iron waste products is just an
engineering problem, which we ought to be able to solve sometime in
the next 2 or 3 billion years before it happens. Piece of cake.
Probably easier than mass migration to another solar system.
Harmon

Harmon Everett wrote:

And IIRC, it only swells up because of excess silicon and iron waste
products, even though it still has 90% of its usable hydrogen fuel
left.

The sun will never produce silicon or iron. It's too small.

Paul