All Questions
Tagged with astronomy celestial-mechanics
49
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Estimate Saturn's mass [closed]
How can you estimate Saturn's mass using data from Cassini's final moments in September 2017 (apoapsis on September 12 at 1:27 a.m. EDT Saturn time at a distance of about $1.3*10^6$ km from Saturn, ...
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2
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155
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Why is $G*M_{sun}=4\pi^2$ when using AU/year units?
So, when using AU/year units, it turns out that 3rd Kepler Law: $\frac{r^3}{T^2}=\frac{G*M_{sun}}{4\pi^2}=1$, meaning $G*M_{sun}=4\pi^2$, any easy explanation for this? Cheers.
- 152
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What math predicted the eclipse of Betelgeuse?
It's amazing that scientists can predict something as small as last weeks eclipse of Betelgeuse. The general relativity aspects are quite specialized. Can someone point me to the math involved in ...
- 4,783
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2
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How to measure the ratio of a planet's radius to a star?
I was reading a physics problem related to astronomy, and upon re-reading it, I realized that it could be really indicated to extrapolate some really interesting physics-related information.
One of ...
- 439
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Orbital obliquity of the Earth
Consider that we have all the orbital parameters that characterize the Earth. How would one calculate the orbital obliquity of Earth?
One could argue that since the rotation of Earth doesn't change ...
- 1,213
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How do we know when the earth completes an orbit?
Two bodies in space always orbit their center of mass. So the relative motion of the Sun and the Earth happen in the same line, save for the rotation of the Sun. So, how do we measure
The time taken ...
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42
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Earth's motion in the universe
In the context of working with atomic clocks I have to obtain the orientation of the Earth for every given Julian date. I am trying to obtain a 3d vector summing up all of earth's motions in the ...
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An application of spherical trigonometry to the celestial sphere
In the book 'An Introduction to Modern Astrophysics' (Carroll and Ostlie, 2017), the first chapter presents an application of spherical trigonometry. At a certain point, the authors derive an equation ...
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How to represent orbital velocity of a planet on an elliptical path in terms of time?
Before reading this long message, please know that this is question is posted to know whether there is a method to find the relation between between the orbital velocity of a planet on an elliptical ...
- 115
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2
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Is there a way to locate celestial bodies indoors?
I mean, without being able to see the sky is there any analog way I can calculate where a planet/star/constellation is, and point in that direction?
I have found apps like Star Chart, which as an AR ...
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2
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2
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354
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Estimate the eccentricity of the Earth's orbit using equinoxes
I was reading the wikipedia article on Kepler's laws (https://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion) and I came across the following.
"The eccentricity of the orbit of the ...
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3
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Speed of planets orbiting Sun formula
What formula returns speed of a planet, e.g. Earth orbiting Sun, on its ellipse like trajectory orbiting Sun? Input variables have to be $a,b$ (ellipse) and some more, because the speed of the planet ...
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Astrodynamics Patched Conic Approximation [closed]
I would need some help as I don’t know how to find $p$ and $e$ of an heliocentric orbit in order to calculate the following formula.
2
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1
answer
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Is a 3 body system with a permanent eclipse possible and stable?
Is it possible to have a star, planet and moon where the moon orbits the planet in the opposite direction with the same period of the planet orbiting the star? So that there would be a never-ending ...
user86478
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Where I can find obliquity direction?
I can find axial tilt of planets easily, but that doesn't specify the direction of that tilt, i.e. planet's rotation axis may be anywhere in circle defined on a sphere by axial tilt value. And I can't ...
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