How Do You Calculate Orbital Period with Limited Data?

In summary, the table summarizes data about a planet that will be discovered in a distant galaxy. Moon 1 only has orbital radius of 5E7 meters, and Moon II has a much greater orbital radius. The orbital period of Moon I is closest to 1.2 *10^5s.
  • #1
blackbyron
48
0

Homework Statement


An Earth station receives data transmitted back in time from a future intergalactic expedition. The table summarizes the data for the moons of a planet that will be discovered in a distant galaxy.


Moon 1: only has orbital radius = 5E7 meters
Just only this information.


Question: the orbital period of Moon I is closest to:

Homework Equations


Using Kelpers Law

Force = GMeM/R^2


The Attempt at a Solution



How do I find out the orbital period if I don't know that acceleration, and the mass, and what's the difference between radius and orbital radius? I just don't understand what to do.
 
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  • #2
hi blackbyron! :smile:

what are the possible answers?

my guess is that you're expected to assume that the planet's mass is somewhere between Mercury's and Jupiter's
 
  • #3
Hi, tiny-tim, thanks for your reply.

No, I don't believe the moon on the mass has something to do with mercury and jupiter.
It only talks about the 3 moons.

Here is the table, that might make sense to you.


1zf1qx5.jpg







The possible answer is 1.2 *10^5s. Not sure if that asks you a question.
 
  • #4
You have period and radius information for Moon II. You could use Kepler's 3rd law to solve for the orbital period of Moon I by setting up the appropriate ratios.
 
  • #5
ohhh :rolleyes: …

then can't you find the orbital period of moon I from the orbital period of moon II ?
 
  • #6
@tiny-tim
hmm, I probably would give it a try, but I don't know if I'm going to to do it right. haha

gneill said:
You have period and radius information for Moon II. You could use Kepler's 3rd law to solve for the orbital period of Moon I by setting up the appropriate ratios.
Alright, so I use the ratio of Time to solve for time 2 using the Kepler's 3rd law.

So For example,

Tm1/Tm2 = kepler's third law?
m1 = moon 1
m2 = moon 2

Is that right?
 
  • #7
I think I got it. Finding out the ratio of Tm1/Tm2 gives me the right answer.

So, I think I did it right. My answer is 1.24e5. Do you guys agree? :)
 
  • #8
The value looks fine.
 
  • #9
Thank you so much guys. It's very helpful.
 

Related to How Do You Calculate Orbital Period with Limited Data?

1. What is an orbital period?

An orbital period is the amount of time it takes for an object to complete one full orbit around another object in space. This can be applied to any two objects that are in a gravitational relationship, such as a planet and a star or a moon and a planet.

2. How is the orbital period calculated?

The orbital period is calculated using Kepler's Third Law of Planetary Motion, which states that the square of the orbital period is proportional to the cube of the semi-major axis of the orbit. This means that the orbital period can be calculated by knowing the distance between the two objects and the mass of the larger object.

3. Can the orbital period change?

Yes, the orbital period can change for various reasons. One of the main factors is the gravitational pull from other objects, which can cause the orbit to become more elliptical or change its orientation. Another factor is the loss of orbital energy due to external forces or internal processes within the objects.

4. How do scientists measure the orbital period of objects?

Scientists use various methods to measure the orbital period of objects. For planets in our solar system, the orbital period can be measured by observing their positions and movements in the sky over a period of time. For objects outside of our solar system, scientists use techniques such as radial velocity or transit methods to detect changes in the position or brightness of the object, which can indicate its orbital period.

5. What is the significance of knowing the orbital period?

Knowing the orbital period of objects is crucial for understanding their dynamics and behaviors. It can provide information about the distance and relationship between objects, as well as their mass. It also allows scientists to make predictions about future movements and interactions between objects in space.

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