I will try to keep this short. I have been wondering something for the past few days and I think you guys can help me. Here it goes:

How would things be different on a terrestrial-type planet that is more oblong than spherical? I dont mean slightly so, I mean proportioned like a chicken's egg. This could be due to interaction with another body while still molten or any number of things.

How would its climate, atmosphere, weather patterns, and the like be different from Earth's given that all else is equal. How would life develop if at all?

a very intersting thought. Andre- do you really think you would end up with a sphere of water around the center point of gravity? or would you end up with a water oblong, as the water centered around the center pole of gravity? (as the planet is no longer a shere, gravity would be spread out along a central pole running the length of the eeg shaped planted, wouldn't it?)


also, the shape of the surface of the world would come into play- if there was a huge bluge along the equator of the egg (due to the centripital force caused by the spin of the world), then it would displace some of the water, possibly resulting in a central ring of dry land, with two completly divided bodies of water. (after thinking about this, no it wouldn't. the bulge would be a very subtle thing, as all the world would be pulled outward. this would, if it happened at all, eventually pull the world into a shereical shape. Unless the world was totally locked into it's egg shape, at which point, the bulge wouldn't happen at all)



I guess what would determine the state of the world would be how far along the process between soidification->stellar dust the planet is (assuming heat death of the universe eventually)

might it also be possible that due to the shape of the planet, the spin would change itself so that the oblong shape would rotate towards the sun, resulting in the egg rotating lengthwise, layed out on it's side in relation to it's sun? then the equatorial "ring" would run a different path.


ONe last thing to consider is the speed of the planet's spin. if it did end up on it's side, then the fat end (more massive) would accelarate the plant as is turned toward the sun. It would slow the speed of rotation as it moved away from the sun. so maybe you'd end up with a very hot and dry fat end (more time in the sun), and a cold, wet small end. Maybe the spin of the object would eventually slow to the point where the moon is now, one end points toward it's orbiting source all the time. "Dark Side of the Egg", and such...

More variables? Other than its shape consider them the same as Earth's. Same sized moon, same distance from parent star, etc. Figure that it is not tidally locked with the moon or sun. Its bulge lies on the equator.

Wouldnt the rounded end have an extremely thick atmosphere and wouldnt the the pointed end extend outside the atmosphere? (because the center of gravity in closer) The round end possibly could be a pressure cooker while the pointed end is exposed to hard vacume. Of course this might depend on just how oblong this planet was.

You would get some interesting convection currents if that was the case.

May I talk a little about size?

If an egg-shaped planet existed, the size should be small enough to keep its form, or maybe its mass should be little.
Reason: I consider the non-spherical suface (sorry, lot-> lack of terms) as a very tall mountain on the planet. If the planet were to be massive, the 'mountain' would collapse.

Read Rocheworld by Robert L. Forward. It's all about the exploration of such a planet. http://www.amazon.com/exec/obidos/tg/detail/-/0671698699/qid=1061317630/sr=8-2/ref=sr_8_2/104-2431980-7658349?v=glance&s=books&n=507846

It probably would not rotate: the oblong shape would only be stable with the heavier end point the sun. this means continues day on one side and continues night on the other.

Rocheworld is a double planet with the two parts tidally locked to each other. They are so close that they share a common sea which flows between them. The huge tidal forces deform each planet into an egg shape with the pointed ends of the eggs almost touching.

I forget the details, but I think there is another larger planet in a highly eliptical orbit that periodically comes close enough to Rocheworld to also influence it tidally, and there is a synchronous lock between the three bodies.

Is Rocheworld analogical to binary stars?

They are merely in orbit around each other. In time they will hit each other or spin off into the distance but the same holds true for earth and the moon.

An egg shaped planet couldn't be more than 6-700 km in diameter before the irregularities would be smoothed out by plastic flow of the crust and mantle;

a rapidly rotating body would be an oblate spheroid, like Jupiter and Saturn are-
flattened at the poles, and fat around the middle.

Larry Niven made his planet Jinx an eggshape, but never explained how it could be maintained in that configuration; a high gravity world would be more closely spherical than any other type of world, even if tidally locked to the primary.

It could perhaps be possible for a tidally locked world in orbit around a red dwarf to be frozen on the dark side and habitable on the inner facing hemisphere... there would be bizarre weather on the twilight edge of such a world, though.

I dont think it would be possible for a world to spin and to point one of it's poles towards the primary, however; the poles of planets always point in one particular direction, which is independent of where the sun is.
Our pole points constantly towards the distant star Polaris, for example.
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nothing i guess

WellCooked is right, I think. were this planet to exsist, the centripital force would most likely drag the heavier end away for the central orbit point.

I doubt the world could stand on end, rotate, *and* remain an egg-shaped block of stone.


oh, well, a fun thought.

Perhaps it could exist for a short time before returning into a semi-spherical shape? The shifting of material would take a while. Even then I don't think it would be all that round.

The moon is egg shape (very slight) most moons are.

Perhaps one day someone will construct a Rocheworld for people to live on; I can't see it happening naturally.

It might look like this...
http://www.orionsarm.com/worlds/Harmonic-Resonance.html

All you have to have is two equal sized bodies go into orbit around one another. The universe is a big place and planets must smack into each other pretty regularly. Maybe one time the planets did a near-miss but couldn't quite get out of each other's gravity wells. I am sure somewhere it would have happened.

Originally posted by WellCookedFetus
The moon is egg shape (very slight) most moons are.

you mean that the end facing the earth is slightly more massive than the other side due to gravity? This would of course only work if the orbiting body had a rotation which matched it's orbital rate (what's that called? where one face of the moon faces us at all times?)


as for the Roche world- if Pluto had an atmosphere, it might qualify. though if it had an atmosphere, it would have been less likely for it to have become a binary planet as it is now. What shape are Pluto and its 'Moon'?

All most all moon do not "rotate" but have a heavier face always pointed towards their host planet.

learn new thing++

a moon of jupiture is egg shaped (forget which one its called), and it is QUITE interesting what the rock formations look like on that planet

gravity is twisting and pulling the planet (MOON, but i consider it a planet, dont ask me why) and it sending out volcanic erruptions this way and that, cooling and heating places faster and slower than other... its quite interesting
but as far as i know, the moon its self doesnt have a irregular axis or rotation or orbit

I suddenly wonder what if the Rocheworld has multiple rotation axis.... One axis is right in the middle of the two and the other one shoots through both centers of the planets.

You mean more egg-shaped than this I guess?

"Because of its high speed its shape is much more oval than round, wider at the centre than at the top or bottom. At its widest point, the planet is 120 000km and at its narrowest point it is 100 000km!"


http://nssdc.gsfc.nasa.gov/thumbnail/planetary/saturn/hst_saturn_nicmos.gif

Errr... actually, we're not considering that shape as egg-shape. Simply think about an egg and you'll know. Besides, that shape is pretty common in universe; every 'unsolid' object which rotates tend to shape that way.
But thanks to you, now that you mentioned that, I remember the strange rotational axis of Uranus. From what I've read, it's believed that in the past Uranus' rotational axis is pretty much perpendicular (if not exactly perpendicular) to it's revolutional orbit. One moment, a space object moving an a trail perpendicular to Uranus' axis hit Uranus near the pole and caused Uranus to turn over about 90 degs. Because of this, each of Uranus' hemispheres (not just the pole) experiences total darkness for half of Uranus' revolutional period. Seems convincing? I doubt that now. How can a solid object caused such a thing to a Jovian (gas) planet?

I wasn't referring to the rings. Saturn is oblate but not, I agree, egg-shaped.

I'm aware that you're not refering to the ring. The effect that happens to Saturn happens too to Jupiter, and tell you what, Jupiter, among other planets in this solar system, has the shortest rotational period: less than 10 earth hours.

curioucity

Yes, Uranus has an axis 98 deg and must have been knocked since the axes and spin of planets arise from the vorticity or spin inherent in the material of the disk. The spin is in the same sense as the orbital motions, and would mean that the rotation of any aggregation would be about an axis perpendicular to the plane of the disk.

Uranus is not all gas:

http://www.enchantedlearning.com/ugifs/Uranusinside.GIF


"Uranus is made up of a swirl of gases, liquids, and solids. It has no solid surface to stand on. The solids have settled to the center of the planet. These include silicon, iron, and a basalt like rock. The core of Uranus is about the size of Earth. At the outer edge of the core, he solid elements mix with the atmosphere around the rock. It is an ocean that is about 5,000 miles deep. It is thought to be mostly water and a mixture of liquid ammonia and methane. "

[library.thinkquest.org]

I think it could be knocked sideways. Think something big hitting Earth in an ocean.

Hmmm, okay, I get it..... so it's widely believed that Uranus was indeed struck.
But here's another question:
Did the object that turned Uranus that way hit Uranus near the pole with high speed, or near the equator with even higher speed?
Wait, I missed something here too.....
How did Uranus actually hit? You may ignore my earlier question then because what I asked implied that Uranus should have two rotation axis by now: one is its original axis and one is perpendicular to its original, but as we know now, it's not that way.

"Did the object that turned Uranus that way hit Uranus near the pole with high speed, or near the equator with even higher speed?"

Nobody knows. We can be pretty certain that the axis WAS perpendicular so something must have knocked it about 90 degrees.

Well okay.... I guess the simple theory of uranus being struck that way will not be sufficient to explain why it has only one axis, not two....
Anyone care to help?

Um it was struck off axis near a pole from either below or above, when the planet was hit it was pulverized with most of the material taking on the velocity of the impacting body and spinning in a polar like orbit, when the planet resettle its polar axis now points horizontal to the planetary plan.

And what made Uranus stop spinning in a way that its poles change places everytime if so? You mentioned that after the hit, Uranus somehow stabilize itself and thus it becomes what it is now. Friction cannot be the stopping factor, since vacuum can provide no friction, so how?

http://wapi.isu.edu/Geo_Pgt/Mod13_Uranus/Uranus_pages/mod13.htm

http://wapi.isu.edu/Geo_Pgt/Mod13_Uranus/Uranus_Images/uranus_montage_sml.jpg


http://www.marsacademy.com/amazsp/a12.htm

"And what made Uranus stop spinning in a way that its poles change places everytime if so?"

Its poles don't change places. Imagine the axis pointing to a fixed place. As Uranus orbits the sun you have the sequence one pole points to the sun; half way round one side faces the sun; next the other pole points to the sun. The poles alternate pointing to the sun but only by virtue of the planet going around the sun whilst its axis points in a fixed direction.

What made it stop spinning. Don't know yet.


http://www.seds.org/nineplanets/nineplanets/uranus.html

Open Issues

Why is its axis so unusually tilted? Was it due to a massive collision?

http://www.edu.pe.ca/southernkings/Uranus.htm

"Some astronomers believe that it was destroyed by a comet or asteroid and was put back together by gravity."

Surely this does not account for the 98 deg tilt of axis?

*stole a line of Mick Jagger*

I can('t->omitted, for the sake of ambiguity) get no satisfaction!!

*ahem, laugh...*

It is a good site you offered, Catasthrope, thank you. But sadly it failed to answer my question, either because it failed to present me the right answer or clear answer....
I even devise a theory myself:
After Uranus got struck, it might have been spinning aound for ages, flipping and switching its poles so many times until it was accidentally hit again by another space object such that it stopped spinning.....
Flawful, as always

Hit me

OK, I am looking for something better.

It cannot have been too early in its formation or the axis would not have been preserved after the tilt.

<b>It cannot have been too early in its formation or the axis would not have been preserved after the tilt.</b>

Why is that so? And which axis do you refer to?

There is only one axis of rotation isn't there?

If it were still in the accretion phase I would think that it was not 'together' enough to retain its axis. Don't know how collision would affect conservation of angular momentum.

:confused:

So I Google:
uranus "angular momentum"

and the 'best' I get is:


http://www.ssec.wisc.edu/~sanjayl/planets/qanda/longfelo.htm

"Why does Uranus appear to tilt on its side? Because it is tilted! "

*yawn*

simplicity at its worst....

http://www.enchantedlearning.com/ugifs/Uranusseasons.GIF


http://www.enchantedlearning.com/subjects/astronomy/planets/uranus/uranusseasons.shtml

Everything seems to be speherical, because of gravity. Even microscopic particles on Earth are sperical, however it must be remembered that these are all held in 'mid-air' (they are floating in space) as are the planets. This might be slightly off topic but it is similar to the seasons of Uranus that Catastrophe posted. The tides of the planets (or Earth at least) ar effected greatly by gravity just as the seasons are. At some points in space, during orbit, other bodies' gravities will interact and pull the water in one direction, while at other points it will be pulled in other directions. This is why the tides move, however because the molten core is also liquid, surely that should change 'shape' with the surrounding water. Just a thought. :)

As I posted above:


"Because of its high speed its shape is much more oval than round, wider at the centre than at the top or bottom. At its widest point, the planet is 120 000km and at its narrowest point it is 100 000km!"


http://nssdc.gsfc.nasa.gov/thumbnail/planetary/saturn/hst_saturn_nicmos.gif

Originally posted by A Canadian
a moon of jupiture is egg shaped (forget which one its called), and it is QUITE interesting what the rock formations look like on that planet

gravity is twisting and pulling the planet (MOON, but i consider it a planet, dont ask me why) and it sending out volcanic erruptions this way and that, cooling and heating places faster and slower than other... its quite interesting
but as far as i know, the moon its self doesnt have a irregular axis or rotation or orbit

The moon is called Amalthea. Galileo's last fly by of the moon showed that it may not actually be a solid mass, but may instead be a pile of rubble, consisting of ice and rocks which are closely packed together. But then Metis and Thebe also appear to be egg shaped. As does Io, which is one of Jupiter's largest moons (third largest I think). Although Io is stretched not so much by Jupiter but by two other moons. One of which, if I remember correctly is Europa and the other could be Ganymede (but please don't hold me to that). Io looks more like a planet as it has a solid surface and also has mountains and volcanic calderas.


:eek:

http://nssdc.gsfc.nasa.gov/thumbnail/planetary/jupiter/gal_amalthea_pia02532.gif

Courtesy of NASA:

http://nssdc.gsfc.nasa.gov/thumbnail/planetary/jupiter/gal_amalthea_pia02532.gif

Ditto

http://nssdc.gsfc.nasa.gov/image/planetary/jupiter/amalthea.jpg

Ditto:

Well, it's irregular rather than egg-shaped and a little moon rather than a planet, but never mind.

http://www.solarviews.com/thumb/jup/amalthea.gif

:)

Interesting. Does this also happen to other Jovian's satellites?

Family Portrait of the Small Inner Satellites of Jupiter
These images, taken by Galileo's solid state imaging system between November 1996 and June 1997, provide the first ever "family portrait" of the four small, irregularly shaped moons that orbit Jupiter in the zone between the planet's ring and the larger Galilean satellites.

http://www.jpl.nasa.gov/galileo/ganymede/PIA01076.html

http://www.jpl.nasa.gov/galileo/ganymede/PIA01076_browse.jpg

a moon of jupiture is egg shaped (forget which one its called), and it is QUITE interesting what the rock formations look like on that planet

gravity is twisting and pulling the planet (MOON, but i consider it a planet, dont ask me why) and it sending out volcanic erruptions this way and that, cooling and heating places faster and slower than other... its quite interesting
but as far as i know, the moon its self doesnt have a irregular axis or rotation or orbit

i think that ones IO or how ever its spelt....sure it has 3 letters "eye-oh"

i dont think you could get an egg shaped planet, how would the core and magma phases work out....but it makes me think...i've just had a brian wav...let me compile my data

Amalthea (in the Orion's Arm universe)
http://www.orionsarm.com/worlds/Amalthea.html

Bill and Bull, two more egg-shaped planets in each other's Roche nodes
http://www.orionsarm.com/worlds/Bill_and_Bull.html