suppose solar system only had sun and earth?

On Mon, 04 Apr 2005 14:48:05 GMT, "rms" <rsquires DeleteThis @flashREMOVE.net>
wrote:
  >> The main problem of the "Sun and Earth only" scenario is its
  >> implausibility
 >
 > Current ideas of the Moon's formation seem equally implausible. See
 >_The Big Splat_

Is that about the giant impact theory? There was some recent work by
Edward Belbruno and Richard Gott III that suggests the impactor could
have formed in Earth's L4 or L5 point, making the geometry of the
subsequent impact much more likely to be similar to what's needed to
produce the Moon. <a style='text-decoration: underline;' href="http://arxiv.org/abs/astro-ph/0405372" target="_blank">http://arxiv.org/abs/astro-ph/0405372</a> has the
article and <a style='text-decoration: underline;' href="http://en.wikipedia.org/wiki/Giant_impact_theory" target="_blank">http://en.wikipedia.org/wiki/Giant_impact_theory</a> has a
diagram and animation.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: suppose solar system only had sun and earth? 

Sayeth Bryan Derksen <bryan.derksen RemoveThis @shaw-spamguard.ca>:
 > "John" <junk RemoveThis @junk.com> wrote:
  > >
  > >Having a large gas giant or two further out helps suck up a great deal of
  > >the potentially life-destroying asteroids that may otherwise splatter us off
  > >the face of the earth.
 >
 > This solar system doesn't have asteroids, though, so Lonely Earth
 > would be fine. One wonders where they all went after the Solar
 > system's formation, though, I'd expect there to be a lot of them
 > considering there were no other planets to soak them up. Something
 > smells artificial about this setup.

Ah, well, true. Although I read somewhere that our Oort cloud may
overlap with that of Alpha Centauri, so maybe we'd get some comets
and things anyway[*]. Unless all those pesky stars aren't there either.

To wind the question back a bit: is it conceivable that such a solar
system would accrete? Or is this not important for whatever purpose
the original asker of the question had in mind?

-----sharks<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: suppose solar system only had sun and earth? 

Since the Earth orbits the sun it would be worse off without Jupiter.

Think of it like this... The sun is pulling all these extra solar
bodies toward it, with nothing between us and them the Earth would be
hammered to splinters.

Jupiter eliminates those extra solar bodies before they even reach us.

With just Earth and the sun we would be an obstacle between a magnet
and a bunch of iron filings.

- Jordan
 >> Stay informed about: suppose solar system only had sun and earth? 

In article <1112670038.041556.49840 DeleteThis @g14g2000cwa.googlegroups.com>, smoothtoaster
says...
 >
 >But you could also argue that the actual odds of those asteroids
 >hitting earth are incredibly low, especially if you factor in the fact
 >that the Sun would act as that "astronomical goalie" instead of
 >Jupiter, either by sucking them in or making them into planets of their
 >own.

No. The Sun is a single body, and the common sense understanding of a
single body, however massive, "sucking in" other bodies, is mostly wrong.
Assuming point sources and Newtonian dynamics, it takes the combined effect
of *two* nearby bodies, and fortuitous geometry, to suck in, capture, or
eject a third body. Jupiter plus the Sun can do this. The Sun alone can
only keep asteroids, etc, in their orbits until they hit something.


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 >> Stay informed about: suppose solar system only had sun and earth? 

this has been bugging me for days now, sorry
 >> Stay informed about: suppose solar system only had sun and earth? 

"bubba griffith" <fatsgrobnik.RemoveThis@hotmail.com> wrote in
news:1112582420.588500.269160@g14g2000cwa.googlegroups.com:

 > suppose the solar system only had the sun and our planet. no jupiter,
 > no mars, no venus, no nuttin' except sun and earth. would life still
 > be viable on earth? or, do we need other planets to balance things
 > out? why and how?
 >

You really wanted to post this question in sci.astro.

The solar system wouldn't form in the way you describe. As the second
heaviest body in the ensemble, Jupiter directs the time evolution of
everything else in the system. Without Jupiter, everything would go to
hell.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: suppose solar system only had sun and earth? 

Multiple issues here. Supposedly, the large outer planets also
deflect a lot of asteroids that would otherwise impact the inner
planets (like Earth), rendering life far less likely, or at least less
hospitable.

An equally interesting question: With one planet, and one sun -- and,
let's say, no moon -- would astronomers have been able to figure out
the basic laws of planetary motion? Would we have physics, or be
stuck without science (or only biology, or bio and chem, both of which
would be impoverished without physics)? How crucial is astronomy as
the starting point for getting the basic laws of motion?

Steve O.

On Sat, 09 Apr 2005 01:27:14 GMT, John Schutkeker
<jschutkeker.DeleteThis@sbcglobal.net.nospam> wrote:

 >"bubba griffith" <fatsgrobnik.DeleteThis@hotmail.com> wrote in
 >news:1112582420.588500.269160@g14g2000cwa.googlegroups.com:
 >
  >> suppose the solar system only had the sun and our planet. no jupiter,
  >> no mars, no venus, no nuttin' except sun and earth. would life still
  >> be viable on earth? or, do we need other planets to balance things
  >> out? why and how?
  >>
 >
 >You really wanted to post this question in sci.astro.
 >
 >The solar system wouldn't form in the way you describe. As the second
 >heaviest body in the ensemble, Jupiter directs the time evolution of
 >everything else in the system. Without Jupiter, everything would go to
 >hell.


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 >> Stay informed about: suppose solar system only had sun and earth? 

Steven O. <null.DeleteThis@null.com> wrote in
news:f3jl51d1hgru9hskqm8sache5hnv5p7ss7@4ax.com:

 > Multiple issues here. Supposedly, the large outer planets also
 > deflect a lot of asteroids that would otherwise impact the inner
 > planets (like Earth), rendering life far less likely, or at least less
 > hospitable.
 >
 > An equally interesting question: With one planet, and one sun -- and,
 > let's say, no moon -- would astronomers have been able to figure out
 > the basic laws of planetary motion? Would we have physics, or be
 > stuck without science (or only biology, or bio and chem, both of which
 > would be impoverished without physics)? How crucial is astronomy as
 > the starting point for getting the basic laws of motion?

I say yes, since laws like conservation of linear and angular momentum have
simple terrestrial manifestations. Calculus was developed independently of
Newton by Russians Leibnitz and Lobachevsky.

Even discovering the 1/r^2 force law may have occurred in a timely manner,
since the ellipticity of the earth's orbit is clearly visible in the
apparent motions of the sun.

If we could only have this discussion in sci.physics, we would surely get a
number of erudite responses.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: suppose solar system only had sun and earth? 

John Schutkeker wrote:
 > Steven O. <null.TakeThisOut@null.com> wrote in
 > news:f3jl51d1hgru9hskqm8sache5hnv5p7ss7@4ax.com:
 >
  > > Multiple issues here. Supposedly, the large outer planets also
  > > deflect a lot of asteroids that would otherwise impact the inner
  > > planets (like Earth), rendering life far less likely, or at least
less
  > > hospitable.
  > >
  > > An equally interesting question: With one planet, and one sun --
and,
  > > let's say, no moon -- would astronomers have been able to figure
out
  > > the basic laws of planetary motion? Would we have physics, or be
  > > stuck without science (or only biology, or bio and chem, both of
which
  > > would be impoverished without physics)? How crucial is astronomy
as
  > > the starting point for getting the basic laws of motion?
 >
 > I say yes, since laws like conservation of linear and angular
momentum have
 > simple terrestrial manifestations. Calculus was developed
independently of
 > Newton by Russians Leibnitz and Lobachevsky.


Leibniz was German. Lobachevsky worked in geometry, specifically
non-euclidean geometry. Calculus had been around for quite some time
before he was born.

J. Del Col<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: suppose solar system only had sun and earth?