# The world should revolve around me

by Alicia
(Sydney, Australia)

The World Should Revolve Around Me

I'm doing a maths investigation at the moment and I'm looking at how the speed of one complete rotation around the sun differs for each planet. I was wondering if you would be able to give me the formula in which you need figure this out?

Barry's Response - Good question, Alicia:

Depends on what you know about them. If you have the planet's year length, in days, and its average distance from the sun, in miles. Here's how it would go.

Speed = (approximately) pi (3.1415926) x distance from the sun (miles) x 2 divided by the number of days.

This will give a pretty good estimate in miles per day. Divide by 24 for miles per hour OR 86400 to get miles per second. If you prefer kilometres, you can then multiply the result by 1.609

It becomes more complicated if you consider the fact that these orbits are not perfect circles. For this exercise, you probably don't need to worry about that. It's a good way to estimate average speed.

The orbits of planets with low eccentricities, like Earth, are nearly circular, so they have relatively constant orbital speeds. High eccentricity planets have elliptical orbits and experience varying distances from the Sun, resulting in different speeds, and longer times to complete orbits because of extended periods in the slow-moving, distant part of the orbit.

Here's a list of relevant data you can use to calculate average speeds:

- - - - - - How Long - - How far (average)
Mercury: . . 88 days . 36,800,000 miles
Venus: .. . 225 days . 67,200,000 miles
Earth: .. . 365 days . 93,000,000 miles
Mars: . . . 687 days . 141,600,000 miles
Jupiter:. 4,333 days . 483,600,000 miles
Saturn:. 10,759 days . 886,500,000 miles
Uranus:. 30,687 days . 1,783,700,000 miles
Neptune: 60,190 days . 2,795,200,000 miles
Pluto: . . 2977 months 3,670,100,000 miles

### Comments for The world should revolve around me

Average Rating

 Rating This might help by: case It is mainly based on the radius of the orbit at which the planet is revolving around the sun. And it also depends on the gravity influence and the planet’s own magnetic influence which affects the rotation of the planet.From Barry - Factors like a planet's orbital radius, its gravitational force, and its magnetic field, which can affect its rotation and orbital characteristics, affect the length of a planet's year. Collectively, these things determine the planet's orbital period.

 Rating Great Formula! by: Anonymous This solution is very accurate and to the point!From Barry - It's designed to be as straightforward as possible, so there's nothing in it. It's also effective and based on a quick bit of research.As briefly mentioned above, it could be more accurate, but then it would be more complicated.

 Rating World by: Anonymous Very interesting. I learned a lot. I really enjoy these articles and reading them.From Barry - I tried to make them informative and easy to understand, engaging, relevant and interesting.Thank you.

 Rating Excellent article! by: Anonymous This is some food for thought Barry! Enjoyed reading it!From Barry - Hopefully it clarified some concepts and gave a better understanding of the technical aspects of what I was writing about. This was meant to be a great resource for anyone interested in learning more.

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