Starship Asterisk*

Johannes Kepler, working with data painstakingly collected by Tycho Brahe without the aid of a telescope, developed three laws which described the motion of the planets across the sky.

1. The Law of Orbits: All planets move in elliptical orbits, with the sun at one focus.

2. The Law of Areas: A line that connects a planet to the sun sweeps out equal areas in equal times.

3. The Law of Periods: The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit.

Kepler's laws were derived for orbits around the sun, but they apply to satellite orbits as well.

Kepler has found planets orbiting double stars—something previously seen only in Star Wars—a six-planet solar system and a planet the size of Earth’s moon.

ErnieM wrote:How would would the new findings of planet orbiting double star systems change Kepler's laws?

geckzilla wrote:You're right, it's not just two bodies. That's why it doesn't even apply here. I must remember this now. I have a love hate relationship with being wrong.

Beyond wrote:

geckzilla wrote:You're right, it's not just two bodies. That's why it doesn't even apply here. I must remember this now. I have a love hate relationship with being wrong.

What kind of relationship do you have with being right

geckzilla wrote:

Beyond wrote:

geckzilla wrote:You're right, it's not just two bodies. That's why it doesn't even apply here. I must remember this now. I have a love hate relationship with being wrong.

What kind of relationship do you have with being right

A similar but decidedly more smug relationship.

It wouldn't change Kepler's laws in the slightest. Keep in mind that Kepler's laws are a special case of Newtonian gravity, applied to two bodies. Even in a simple system they are an approximation, although a very good one.

Depending on the dynamics of the multiple star system, Kepler's laws would either continue to be a reasonable approximation of reality, or they would not (the latter in most cases, I think). So you would need to analyze such a system by numerical integration, just like you need to do with our solar system if you want the most accurate results.

A heliocentric orbit (also called circumsolar orbit) is an orbit around the Sun. All planets, comets, and asteroids in our Solar System are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits as they orbit their respective planet.

While it is convenient to think of orbits around the Sun, bodies in the Solar System do not actually orbit the Sun. Instead, all bodies in the Solar System (including the Sun) actually orbit the barycenter of the Solar System. A similar phenomenon allows the detection of extrasolar planets by way of the radial velocity method.
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While in geometry the term barycenter is a synonym for "centroid", in physics "barycenter" may also mean the physical center of mass or the center of gravity, depending on the context. The center of mass (and center of gravity in a uniform gravitational field) is the arithmetic mean of all points weighted by the local density or specific weight. If a physical object has uniform density, then its center of mass is the same as the centroid of its shape.

lbsgville wrote:the center of gravity of the Jupiter-Sun system is a 11.8618 year period. Could this have an effect on the solar cycle a little and no one has thought about this yet?