If We Had No Large Moon, would we Rotate like Venus?

- If we had no large moon, with a comon center of rotation,
(inside, but not in the center of the Earth) - would we likely
face the fate of Venus, - and furthermore, might Venus have
encountered the same "Mars sized object" that tipped it over?
And btw, what could have tipped Uranus 100 degrees?
Anyone? No SPAMN please, or email. Still workin on
filters. Regards, Terry S (newbie)

You might see if you can find the book:
'What if the Moon Didn't Exist?: Voyages to Earths That Might Have
Been'
by Neil F. Comins

Topics in the book a
What If the Moon Didn't Exist?
What If the Moon Were Closer to the Earth?
What If the Earth Had Less Mass?
What If the Earth Were Tilted Like Uranus?
What If the Sun Were More Massive?
What If a Star Exploded Near the Earth?
What If a Star Passed Near the Solar System?
What If a Black Hole Passed Through the Earth?
Seeing the World Through Infrarose-Colored Glasses
What If the Ozone Layer Were Depleted?

From the book cover:
"What if the moon didn't exist, for example? Well, Comins explains,
the earth would rotate more than three times faster than it currently
does, and our tides would be much lower. There would be recurrent
gale-force winds like those on Jupiter, making it a challenge for
"tall" beings (like humans) to evolve. And the atmosphere would have
taken millions of years longer to convert from one dominated by carbon
dioxide to the life-giving nitrogen/oxygen atmosphere of today (if it
could at all - the atmosphere surrounding moonless Venus is still
predominantly composed of carbon dioxide)."

Jack


(TerryS) wrote in message . com...
- If we had no large moon, with a comon center of rotation,
(inside, but not in the center of the Earth) - would we likely
face the fate of Venus, - and furthermore, might Venus have
encountered the same "Mars sized object" that tipped it over?
And btw, what could have tipped Uranus 100 degrees?
Anyone? No SPAMN please, or email. Still workin on
filters. Regards, Terry S (newbie)

(TerryS) wrote in message . com...

If we had no large moon, . . . - would we likely
face the fate of Venus, - and furthermore, might Venus have
encountered the same "Mars sized object" that tipped it over?
And btw, what could have tipped Uranus 100 degrees?

TerryS,

The high obliquity of Venus (178 degrees), which makes it appear to
rotate in a retrograde rotation, does not have to be the result of the
planet "tipping" over in response to a collision with an asteriod,
like a cosmic game of pool. (Retrograde rotation means that the planet
rotates opposite the direction that it revolves around the Sun.
Prograde rotation means the planet rotates in the same direction that
it revolves around the sun.)

A planet "tipping" over can also be the result spin-orbit resonances
building up over geologic time.

In the early 1990s, a geology professor, George Williams with the
Univ. of Adelaide, proposed that in past, the Earth may have been in a
highly oblique rotation - more than 54 degrees - and that the tilt
radically effected the Earth's paleo-climate.

In 1993, two french astronomers, Jacques Laskar and Philippe Robutel
did computer simulations of rotation of solar system planets, and
concluded that highly oblique orbits can be the result of such
spin-orbit resonances. They also concluded that the Earth's Moon
helped dissipate such tidal forces, and so the extreme oblique
scenarios proposed by professor Williams were unlikely.

That planets could "tilt" from their own momentum and gravitational
interraction with other solar system planets became significant to
another geologic theory that developed in the late 1990's - Harvard
Professor Paul Hoffman's "snowball Earth" theory. This theory sought
to explain why there is geologic evidence for the ice caps having
extended down near the equators as many as four times between 750 and
580 million years ago. One of the alternative theories that had to be
discounted was Williams' "tilted" earth explanation.

Since 1993, Lasker has worked on computer simulations of Venus and
concluded that its current tilt and rotation could have resulted from
the spin-orbit resonances and without an impact collision with an
asteriod.

The short answers a

If we had no large moon, . . . - would we likely face the fate of
Venus, . . .

Probably. - Jack Patterson's recommended book looks interesting on
what the Earth might have looked like without the Moon.

[M]ight Venus have encountered the same "Mars sized object" that tipped it over?

Not necessarily. It could have tipped over on its own without an
impact collision.

And btw, what could have tipped Uranus 100 degrees?

In 1997, Argentinian planetary scientists Parisi and Brunini modeled
that the Uranus "Great Collision," would have been the result of a
impact by a protoplanet between 1 and 1.5 the mass of the Earth.

I'm sure of your age, but I hopes this helps and is an age appropriate
answer.

Canopus (Kurt)

References:

Table of the obliquity of planets and their major moons
http://www.physics.vanderbilt.edu/as...tary_data.html

_Planetary Obliquity - Earth_

Laskar, J.; Robutel, P. Feb. 1993. The chaotic obliquity of the
planets. Nature 361:608-612
http://adsabs.harvard.edu/cgi-bin/np...atur.361..608L

Laskar, J.; Joutel, F.; Robutel, P. Feb. 1993. Stabilization of the
earth's obliquity by the moon. Nature 361:615-617
http://adsabs.harvard.edu/cgi-bin/np...atur.361..615L

Williams, G.E. 1993. History of the Earth's obliquity, Earth-Science
review, 34, (1-45)

_Planetary Obliquity - Uranus "Great Collision"_

Parisi, M.G.; Brunini, A. Sep. 2002. Constraints to Uranus' Great
Collision III: The Origin of the Outer Satellites. Icarus.
159:166-177.
http://adsabs.harvard.edu/cgi-bin/np...car..159..166B

Parisi, M.G.; Brunini. A. Feb. 1997. Constraints to Uranus' Great
Collision-II. Planetary and Space Science, 45:181-187.
http://adsabs.harvard.edu/cgi-bin/np...6SS...45..181P

_Planetary Obliquity - Venus_

Correia, A. C. M.; Laskar, J. 2000. The 3 Final States of Venus. AAS
DPS Meeting #32, #64.07
http://adsabs.harvard.edu/cgi-bin/np...PS....32.6407C

Correia, A. C. M.; Laskar, Jacques. May 2003. Long-term evolution of
the spin of Venus II. numerical simulations. Icarus, 163:24-45.
http://adsabs.harvard.edu/cgi-bin/np...car..163...24C

_Snowball Earth theory_

Hoffman, P., Kaufman, A. et al. August 28, 1998. A Neoproterozoic
Snowball Earth. Science 281, 1342.

Hoffman, Paul F.; Schrag, D.P. The Snowball Earth. August 8, 1999
online paper: http://www-eps.harvard.edu/people/fa...all_paper.html
access 8/16./2004

Scientific American: Snowball Earth: January 2000

Walker, Gabrielle. 2003. The Story of the Great Global Catastrophe
That Spawned Life as We Know It. Crown Publishing.

_Misc_

ScienceDaily.com. Encyclopedia. 2004. Prograde and Retrograde Motion.
http://www.sciencedaily.com/encyclop...rograde_motion

On 16 Aug 2004 18:37:42 -0700, (Canopus) wrote:


If we had no large moon, . . . - would we likely face the fate of
Venus, . . .

Probably. - Jack Patterson's recommended book looks interesting on
what the Earth might have looked like without the Moon.

I've heard that some scientists believe that Venus' incredibly thick
atmosphere sapped much of Venus' rotational energy, acting like a
giant brake, until the planet started rotating backwards in line with
the atmosphere's motion, resulting in the current situation.

There is even the possibility that Earth is a culprit in Venus'
rotation, since the same face of Venus is turned to the Earth at
closest approach. Perhaps a minor resonance effect. Who knows.

And btw, what could have tipped Uranus 100 degrees?

In 1997, Argentinian planetary scientists Parisi and Brunini modeled
that the Uranus "Great Collision," would have been the result of a
impact by a protoplanet between 1 and 1.5 the mass of the Earth.

I'm sure of your age, but I hopes this helps and is an age appropriate
answer.

If I recall one problem with explaing how Uranus became so extremely
tilted is it's moons...since they are in near circular equatorial
orbits. You would think with such a large impact and resulting chaos
that the moons' orbits would have become highly eccentric, if not
ejected in some cases.

-Drew

(TerryS) wrote in message . com...
- If we had no large moon, with a comon center of rotation,
(inside, but not in the center of the Earth) - would we likely
face the fate of Venus, - and furthermore, might Venus have
encountered the same "Mars sized object" that tipped it over?
And btw, what could have tipped Uranus 100 degrees?
Anyone? No SPAMN please, or email. Still workin on
filters. Regards, Terry S (newbie)

looking the other way, we might be rotating like Mars, which also has no large moon.

(TerryS) wrote in message . com...
- If we had no large moon, with a comon center of rotation,
(inside, but not in the center of the Earth) - would we likely
face the fate of Venus, - and furthermore, might Venus have
encountered the same "Mars sized object" that tipped it over?
And btw, what could have tipped Uranus 100 degrees?
Anyone? No SPAMN please, or email. Still workin on
filters. Regards, Terry S (newbie)

looking the other way, we might be rotating like Mars, which also has no large moon.

(TerryS) wrote in message . com...

- If we had no large moon, with a comon center of rotation,
(inside, but not in the center of the Earth) - would we likely
face the fate of Venus, - and furthermore, might Venus have
encountered the same "Mars sized object" that tipped it over?
And btw, what could have tipped Uranus 100 degrees?
Anyone? No SPAMN please, or email. Still workin on
filters. Regards, Terry S (newbie)

looking the other way, we might be rotating like Mars, which also has no large moon.

(TerryS) wrote in message . com...

- If we had no large moon, with a comon center of rotation,
(inside, but not in the center of the Earth) - would we likely
face the fate of Venus, - and furthermore, might Venus have
encountered the same "Mars sized object" that tipped it over?
And btw, what could have tipped Uranus 100 degrees?
Anyone? No SPAMN please, or email. Still workin on
filters. Regards, Terry S (newbie)

looking the other way, we might be rotating like Mars, which also has no large moon.

(TerryS) wrote in message . com...
- If we had no large moon, with a comon center of rotation,
(inside, but not in the center of the Earth) - would we likely
face the fate of Venus, - and furthermore, might Venus have
encountered the same "Mars sized object" that tipped it over?
And btw, what could have tipped Uranus 100 degrees?
Anyone? No SPAMN please, or email. Still workin on
filters. Regards, Terry S (newbie)
Note of Thanks to Drew, and Especially Canopus. See
threads below for further enlightenment. I have heard of
some of the phenomenon, yet not all of it. So thanks. It
reminds me of a "Saturn Effect" mentioned a couple decades
ago, or more. Forgetting what exactly that is, but it's nice to
learn more. Thanks folks, TerryS 47. Not into puns. Regards