Why are the planets in (broadly) the same plane?...

[botch]

...I'm sure someone here will know.

 

[mackan]

A star is born when a "cloud" of gas and dust collapses due to gravitation. This thickening cloud starts to spin and compact more, and due to centrifugal forces the outer materia of the cloud smears out in a plane perpendicular to the spinning axis. So in this plane the raw material for creating planets resides. The planets are then created by a similiar contraction of materia as created the star. Something like that I think. <img src="/images/icons/smile.gif" />

 

[botch]

Thanks<img src="/images/icons/smile.gif" /><br />So what causes the gas to spin, shouldn't it all head straight to the centre of gravity and stay there?

 

[mackan]

Not sure what actually causes the cloud to start spin. But I believe the spinning motion is there initially, and it spins slowly. Usually the starting process for spinning and contraction are shockwaves passing through the cloud, and disturbs the density distribution of it. So the spinning rate increases as the cloud collapses more.<br /><br />Hopefully someone else can give a more clear answer.

 

[spacefire]

why does all the gas have to spin around the same axis? is it because of collisions between particles that would eventually cause all of them to take roughly the same path? <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[5stone10]

Gravity isn't like magnetic force. Its a weak force.

 

[emperor_of_localgroup]

Interesting question I also wondered about.<br />Does it mean all solar systems in a spiral galaxy will be in one plane? If so, doesn't it also tell us solar systems (stars) are born due to rotation of the center of a spiral galaxy? Am I oversimplifying the whole scenario? <br /><br />One question. Is it possible to tell the direction of rotation of a star in our galaxy or other? From that rotation it'd be possible to predict the orientation of the plane if its solar system. <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

 

[botch]

Thanks for the answers everybody - sometimes you just have to ask the obvious questions and not feel foolish about it.

 

[vogon13]

If you have access to a copy of The New Solar System by Beatty, O'Leary and Chaikin, chapter 13, Planetary Rings, has a nice diagram and description of how a mass of particles (or gas for that matter) in randomly inclined orbits around a central body will over time collapse into the <i>LaPlacian plane</i>.<br /><br /><br /><br />Good reference book to have around on general principle.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[botch]

I looked it up on amazon on your recommendation, from the reviews it seems to cater to a level of enthusiast that might be above me. My education over the last few years has been in art and design so I can't claim to be scientifically adept. How complicated is it?

 

[vogon13]

You're holding your own here, nicely.<br /><br />Many fine photographs and handy charts and tables. I thought it was an easy read and great reference to have around. Maybe a local library would have a copy for you to peruse.<br /><br />One drawback, I am not sure how updated any copy you find will be. Mine is quite old, and there has been a revolution in solar system studies since my second printing copy.<br /><br />Hopefully, we will see some more feedback here.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[emperor_of_localgroup]

Steve:<br />Yes I forgot about the binary star systems. That will make planetary planes very complicated. Wish we had two suns just to see planetary motions around them. One thing for sure, graduate level mechanics classes in physics and astronomy would have been very hard studying this motion.<br /><br />This is just my guess. Discovering planets in other solar system is easier if the plane of that solar system is perpendicular to our line of observation (line of sight). Wobbling of the star, in such cases, will be more detectable for us.<br /><br />This is also another conclusion from my not-so detailed thinking. If we look at pictures of spiral galaxies, it appear to be results of a rotating liquid. If you place some sticky materials in a liquid and stir it faster and faster, eventually parts of the sticky materials will break off the main central portion in all directions due to centrifugal forces. Doesn't a spiral galaxy look pretty much the same?<br /><br /> <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

 

[robnissen]

"Discovering planets in other solar system is easier if the plane of that solar system is perpendicular to our line of observation (line of sight). Wobbling of the star, in such cases, will be more detectable for us."<br /><br />Yes and No. Yes for the wobble method. No for the transit method. And the transit method can give us more information about the planet, including the possibility to have some knowledge of the planet's atmosphere. <br />