singularity

Reguarding orbits being conic sections what is the shape of the cone? If the AU scale was used what would the cone look like as to the base/height ratio or the angle of the apex? Does the ratio matter or would any cone give the result TVF said would be a true orbit? I have seen cones being sectioned and I somehow fail to see how that relates to gravity fields.

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Reguarding orbits being conic sections what is the shape of the cone? If the AU scale was used what would the cone look like as to the base/height ratio or the angle of the apex?
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The orbits of the planets do not lie on a single cone, they describe ellipses of which one can get a similar shape by taking an appropriate slice through a cone. If the orbits were circular we could say that all of them are represented by a slice on a sphere but not that the orbits actually lie on a specific sphere. And if you take into account the Sun traveling through space we can describe the orbits then as helixes, it depends on our reference frame.

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[And if you take into account the Sun traveling through space we can describe the orbits then as helixes, it depends on our reference frame.
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Do we know the speed our Sun travels at?

You can figure the speed of the sun from the motion of the stars in the galaxy. But, this will lead to the speed of the galaxy and so on. The gravity issue can be resolved by staying near the solar system focused on the orbits of the planet and moon. Going out of the solar system things are far less clear for a lot of reasons and going beyond the galaxy is getting into even less clear issues. The nearby issues are not completly resolved and a clearer understanding of what is near will help.

i need to wrght an student essay on sometinhing in astronomy: what is the Nebula most likely to become a star in the earlkiest time or the most interesting? How much info is there on the rotten egg nebula?
(Please take the time to revise and correct your entry, and courtesy counts). moderator

There's quite a few links on the rotten egg nebula. just stick rotten egg nebula in any search engine and you'll come up with a stack of useful sites.

This link should give you some useful material for an essay -

[url] oposite.stsci.edu/pubinfo/pr/1998/15/pr.html [/url]

Don't expect to see the creation of a star in your lifetime; this process takes aeons. Basically the nebula will start to collapse through the influence of gravity, as the collapse continues the nebula will flatten due to conservation of angular momentum - L=mvR, where m=mass, v=rotational velocity and R=the radius (if you stick this formula in your essay, you'll probably pick up a couple of extra marks!<img src=icon_smile_wink.gif border=0 align=middle>). Eventually the disc will form a dense centre which will begin to glow through thermonuclear reactions - hey presto, a star. The spare nebula material circling the star may form further clumps which will become planets, or, if one or more of these reach critical density, a companion star.

This link shows a young star in early formation -

[url] jwisn.freeyellow.com/n-hubble.htm [/url]

Good luck with the essay!