Free Republic
Browse · Search
News/Activism
Topics · Post Article

To: RadioAstronomer
the fact that a circle is an ellipse with the value of e = 0,

Seems your statements and your table do not agree with each other. In your table the Earth is given a 1.0 and you say that it has the most circular path of all the planets diverging only by some 2% from a true circle (note that that still makes it an elliptical orbit). Please clarify.

683 posted on 04/07/2002 9:14:32 AM PDT by gore3000
[ Post Reply | Private Reply | To 593 | View Replies ]


To: gore3000
In your table the Earth is given a 1.0 and you say that it has the most circular path of all the planets diverging only by some 2% from a true circle (note that that still makes it an elliptical orbit). Please clarify.

More Holy Warrior Syndrome from you. You're not addressing me but I was intrigued how RA could possibly have assigned earth an ellipticality of 1.0. He didn't. The earth is (by definition) 1 astronomical unit from the sun. That's what the table says.

Will you admit now to misreading RA's table? Note that the ellipticity score for earth is very low, and destroys your whole argument. So what do you do?

686 posted on 04/07/2002 9:21:05 AM PDT by VadeRetro
[ Post Reply | Private Reply | To 683 | View Replies ]

To: gore3000
I think it's called "normalization", which apparently hasn't yet been crammed into the omnipresent work-in-progress "religious = nut" equation.
687 posted on 04/07/2002 9:22:05 AM PDT by apochromat
[ Post Reply | Private Reply | To 683 | View Replies ]

To: gore3000; RadioAstronomer
Seems your statements and your table do not agree with each other. In your table the Earth is given a 1.0 and you say that it has the most circular path of all the planets diverging only by some 2% from a true circle .... [snip]

Go back and try reading the table again.

The only thing that is "wildly eccentric" is your reading comprehension.

690 posted on 04/07/2002 9:33:50 AM PDT by longshadow
[ Post Reply | Private Reply | To 683 | View Replies ]

To: gore3000
Seems your statements and your table do not agree with each other. In your table the Earth is given a 1.0 and you say that it has the most circular path of all the planets diverging only by some 2% from a true circle (note that that still makes it an elliptical orbit). Please clarify

Glad you asked! :-)

If you go back and look at the table, the Earth is not the most circular (its e = 0.0167) Venus with an e = 0.0068 is the most circular. The 1.0 you are reading is the AU distance from the Earth to the sun. Astronomical distances are measured in EUs. 1 EU is the distance from the earth to the Sun. So that is the 1.0 you saw. As for the perfect circle, There never will be a perfect circle with the orbital elements. Remember the other planets are also "tugging" on each other. I brought up the perfect circle to show that a circle is a very special type of ellipse. The reason for that was that when we see ellipses in our mind, we see really elongated structures. Also when you look at a "map" of the solar system, they usually put it in a somewhat side perspective which exaggerates the appearance of the ellipse.

Most of the planets are so close to circles that on a piece of paper they would look just that. Again, the only two that would be even readily noticeable would be Mercury and Pluto.

For satellites orbiting the Earth, we have an added component of not only the atmospheric drag but the solar wind as well. To even further the complication our Earth is not a perfect sphere and has natural gravity wells due to the distribution of the landmasses and that it is an oblate spheroid instead of a perfect sphere (the difference is only about 15 miles between the equator and the poles). One more rub is that with long term measurements taken using a satellite in orbit (the LAGEOS), the Earth is very very slowly re-rounding itself out over time.

The other thing that is not readily apparent from most solar system maps is just how far apart the planets really are and also how tiny they are with reference to the solar system.

When you think of how far we are from the sun (93,000,000 miles) and the diameter of the Earth (7000 miles) the distance between the Sun and the Earth is over 13,000 times the diameter of the Earth. Now think of Mars. Its only 1/3rd the size of the Earth and it is 1/2 again further out.

Usually when we say we are approaching Mars, it means we are on the same side of the Sun as Mars. Not the orbits are getting closer. Oh they do, but by a very small amount.

Sorry for the confusion earlier.

706 posted on 04/07/2002 10:30:43 AM PDT by RadioAstronomer
[ Post Reply | Private Reply | To 683 | View Replies ]

Free Republic
Browse · Search
News/Activism
Topics · Post Article


FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson