Intro and a Question About Ellipticity

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    Intro
In summary, the astronomer was looking for a website that could calculate a planet's ellipticity, and after searching for a while, he was unsuccessful in finding it.
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arakish
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My first post here. And I am wondering why I never found this forum before now... :blushing:

I am an amatuer astronomer and astrophysicist in the truest sense. I have been interested in astronomy and astrophysics since watching ST:TOS when it first aired back in the 60s. I have also been interested in geography and cartography for the same length of time.

Without writing a novella, I am going straight to my question.

I suffered a severe HDD crash at the end of February. Like a dumb retard, I never kept backups. Some time back, I had found a website that listed an equation that would calculate a planet's ellipticity if one knew the planet's density, volumetric mean radius, and rotational period. I even wrote a program that would calculate this along with the planet's surface gravity, ballistic escape velocity, total surface area, equatorial mean radius, polar mean radius, mass, volume, and other data.

I have been searching the web trying to find this website again for the last two months. However, I have not been able to find it again.

My question: Anyone know of this website (or similar) and can me direct there? Or does anyone here know the equation?

Thanks for any help and for your valuable time spent reading and/or replying.

rmfr
 
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  • #2
Wish I could help you. Can you not find all of those equations somewhere else listed by themselves or something? I wouldn't expect it to be too difficult to find them again, even if you don't find that original website.
 
  • #3
arakish said:
Some time back, I had found a website that listed an equation that would calculate a planet's ellipticity if one knew the planet's density, volumetric mean radius, and rotational period.
The wikipedia http://en.wikipedia.org/wiki/Equatorial_bulge" [Broken]s.
 
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  • #4
IsometricPion said:
The wikipedia http://en.wikipedia.org/wiki/Equatorial_bulge" [Broken]s.

Thank you very much IsometricPion. I never thought of doing a search on "Equatorial Bulge."

I guess for being somewhat smart, I can be a dummy. Thanks again.

rmfr
 
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  • #5


Hello rmfr,

Welcome to the forum! It's great to have another passionate astronomer and astrophysicist join us.

To answer your question, I am familiar with the equation you are referring to. It is called the oblateness or flattening equation and it is used to calculate a planet's ellipticity. The equation is as follows:

e = (Rp - Re)/Rp

Where:
e = ellipticity
Rp = polar mean radius
Re = equatorial mean radius

This equation assumes the planet is a perfect oblate spheroid, meaning it has a slightly flattened shape due to its rotation. The closer the value of e is to 0, the more spherical the planet is. A value of 1 would indicate a completely flat or disk-shaped planet.

As for the website you mentioned, I am not familiar with it. However, there are many online calculators and resources available that use this equation and other methods to calculate a planet's ellipticity. I suggest doing a Google search for "planet ellipticity calculator" or "oblateness calculator" to find some options.

I also want to mention the importance of backing up your data, especially when it comes to important research or programs. I hope you are able to recover or recreate your program and continue your studies in astronomy and astrophysics.

Best of luck in your search and keep exploring the wonders of the universe!
 

1. What is ellipticity?

Ellipticity is a measure of the degree to which an object or system deviates from a perfect circle or sphere. It is often used in physics and astronomy to describe the shape of celestial bodies, such as planets and galaxies.

2. How is ellipticity calculated?

Ellipticity is typically calculated by taking the ratio of the object's minor axis to its major axis. This can be done using various methods, depending on the specific shape and properties of the object being measured.

3. Why is ellipticity important in scientific research?

Ellipticity can provide valuable information about the physical properties and origins of objects in the universe. It is also used in a variety of fields, such as geology and engineering, to analyze the shape and deformation of materials and structures.

4. How does ellipticity affect the motion and stability of objects?

The elliptical shape of an object can affect its motion and stability in various ways. For example, ellipticity can impact the trajectory of a planet or satellite orbiting a larger body, or the stability of a building or bridge under certain conditions.

5. Can ellipticity change over time?

Yes, ellipticity can change over time due to various factors such as gravitational interactions, rotational forces, and physical processes like erosion or melting. This change can occur on different timescales depending on the object and its environment.

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