Does Kepler's Third Law apply to circular orbits?

[enwar3]

But a circle is kind of like an ellipse with two foci at the same point...

 

[Gunslinger08]

Yes.

 

[destrekor]

Originally posted by: joshsquall
Yes.

it explains orbits of both the elliptical and round variety. And as you said, an ellipse is a circle.
So how the Third Law applies, is it calculates the orbit as an ellipse, but it can still be a perfectly circular ellipse.

 

[jagec]

All squares are rectangles, not all rectangles are squares.

All circles are ellipses, not all ellipses are circles.

 

[destrekor]

Originally posted by: jagec
All squares are rectangles, not all rectangles are squares.

All circles are ellipses, not all ellipses are circles.

nobody is debating that.

my astronomy class covered Kepler pretty well.
the Third Law applies to elliptical orbits. A perfectly circle orbit happens to be an elliptical orbit. And a circular orbit is a mathematically valid answer when determining the shape of an orbit when using Kepler's formula.

Kepler's Third Law
not the easiest to read, and we never really went into the full blown math in our class that actually comprises the formula, but nevertheless it's there.

 

[enwar3]

Wow! Thanks guys! I wasn't actually expecting to get an answer.....

i <3 atot

 

[2Xtreme21]

If you're still having trouble these might help:

http://en.wikipedia.org/wiki/Circular_orbit
http://en.wikipedia.org/wiki/K...7s_third_law#Third_law

 

[OutHouse]

Kepler was a hieratic and needed to burned at the steak!!!

Down with Hieracy!!!!!!! BURN HIM!!!

 

[destrekor]

Originally posted by: Citrix
Kepler was a hieratic and needed to burned at the steak!!!

Down with Hieracy!!!!!!! BURN HIM!!!

mmmm steak. juicy.

 

[YOyoYOhowsDAjello]

Originally posted by: destrekor

Originally posted by: jagec
All squares are rectangles, not all rectangles are squares.

All circles are ellipses, not all ellipses are circles.

nobody is debating that.

Someone is

Originally posted by: destrekor
And as you said, an ellipse is a circle.

 

[chuckywang]

Originally posted by: enwar3
But a circle is kind of like an ellipse with two foci at the same point...

Circles are just ellipses with eccentricity equal to 0.

 

[Triumph]

A circle is just an ellipse with the semi-minor axis = semi-major axis. Plug the numbers into Kepler's equation and you'll get the right answer.