Addressing the formation of the solar system

[newsgroups snipped]

In article ,
BURT writes:
But how do you get everything to move in the same direction.

Imagine a contracting gas cloud. If it is rotating _on average_ in
any direction, as the cloud contracts any atoms going the "wrong way"
are forced into the preferred direction of rotation. In other words,
angular momentum is conserved.

Also why is there a plane?

Relative to the plane, there are as many atoms going "up" as "down,"
and when they collide at the plane, the vertical motion is cancelled
out.

This is explained in much better detail in textbooks, which have
diagrams and (in advanced books) equations. I had a brief search for
a good popular source on the web but didn't find one.

By the way, there are many observed examples of protostellar disks,
and the same basic physical process of disk formation is also
important in spiral galaxies.

--
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
valid Reply-To address to receive an acknowledgement. Commercial
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On Apr 16, 2:18*pm, (Steve Willner) wrote:
[newsgroups snipped]

In article ,

*BURT writes:
But how do you get everything to move in the same direction.

Imagine a contracting gas cloud. *If it is rotating _on average_ in
any direction, as the cloud contracts any atoms going the "wrong way"
are forced into the preferred direction of rotation. *In other words,
angular momentum is conserved.

Also why is there a plane?

Relative to the plane, there are as many atoms going "up" as "down,"
and when they collide at the plane, the vertical motion is cancelled
out.

In how many billions years does this vertical colliding process take
place, until only a tight disk of the extremely condensed plane of
mostly hydrogen is formed?

~ BG

In article ,
BradGuth writes:
In how many billions years does this vertical colliding process take
place, until only a tight disk of the extremely condensed plane of
mostly hydrogen is formed?

Protostellar disks form in a few hundred thousand years and dissipate
in a few million years. For galactic disks, formation time scales
are a few hundred million years. No "billions" at all.

--
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
valid Reply-To address to receive an acknowledgement. Commercial
email may be sent to your ISP.)

On Apr 20, 12:15*pm, (Steve Willner) wrote:
In article ,

*BradGuth writes:
In how many billions years does this vertical colliding process take
place, until only a tight disk of the extremely condensed plane of
mostly hydrogen is formed?

Protostellar disks form in a few hundred thousand years and dissipate
in a few million years. *For galactic disks, formation time scales
are a few hundred million years. *No "billions" at all.

--
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
valid Reply-To address to receive an acknowledgement. *Commercial
email may be sent to your ISP.)

Many thanks for that straight forward information.

~ BG