The orbital-motion tag has no wiki summary.
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4answers
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Angular momentum power plant on Earth
If tidal power plants are slowing down Earth's rotation then is it theoretically possible to build a power plant that would drain energy from Earth's angular momentum (thus slowing down it's ...
9
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2answers
155 views
Can an orbit be calculated using two points and transit time?
Working in only two dimensions and assuming that the central body is at the origin of the coordinate system, given two points in space and knowing the transit time between those points, as well as the ...
5
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1answer
85 views
Convert latitude of lowest altitude to argument of perigee?
I am designing an orbit around Mercury. I know the values I want for the semi-major axis, eccentricity, inclination, and RAAN. I want the altitude of closest approach (periapse) to occur at ...
3
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2answers
262 views
When is the right ascension of the mean sun 0?
I understand that the right ascension of the mean sun changes (at least over a specified period) by a constant rate, but where is it zero? I had naively assumed that it would be zero at the most ...
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0answers
66 views
How to calculate the mass of the Cygnus X-1 black hole?
I have received a question about how to calculate the mass of Cygnus x-1 (black star).
Since we are able to find the the mass through this Wikipedia page I know that we can find the mass through ...
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1answer
99 views
The validity of the Longitude of Perihelion
As I understand it from Astronomical Algorithms, by Jean Meeus, the Longitude of Perihelion is a very common numeric value associated with planets, even used as one of the planetary orbital elements. ...
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5answers
2k views
Is there a small enough planet or asteroid you can orbit by jumping?
I just had this idea of orbiting a planet just by jumping and then flying upon it on its orbit kind of like superman. So,
Would it be theoretically possible or is there a chance of that small body to ...
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2answers
94 views
Definitions of Lagrange points: $L_4$ and $L_5$
We have the the five Lagrange points (let consider Earth and Sun):
$L_1$ - lie between Sun and Earth;
$L_2$ - beyond the Earth;
$L_3$ - beyond the Sun;
And what's the difference between $L_4$ and ...
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4answers
658 views
Can a balloon float into space? (+orbital velocity)
After watching the recent "space jump" a question arose. Why can a balloon not float into space? Can one be made/designed to do this?
Next, everything in orbit is falling back to earth. It only ...
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1answer
80 views
What is the orbital motion where both foci are located at one point?
What is the orbital motion where both foci are located at one point? I know that an ellipse orbit is motion with two distinct foci.
1
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1answer
170 views
Result of increasing the radius of earth?
How can increasing the radius of earth may cause an impact on the solar system ? Like, would earth may start making a bigger orbit (due to increase in size and wait) or vice versa ? or else ?
PS: The ...
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1answer
370 views
What accounts for the discrepancies in my calculations of year lengths?
A common exercise in many introductory astronomy texts is to use the lengths of various kinds days to calculate the approximate length of the corresponding year.
For example, ratio $k$ of the length ...
3
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1answer
214 views
How long will it take for a bullet to reach a Geostationary orbit?
I'm curious to know this. Neglect air friction and imagine a bullet that were shot normal to the Earth's surface, from the Equator. I will have to consider the Coriolis effect and so I expect the path ...
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2answers
294 views
Does the length of the sidereal day vary systematically?
I'm confused about some properties of the sidereal day, in particular whether its duration varies systematically over the course of the year.1 It seems to me that that must be the case, but the ...
2
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1answer
505 views
Kepler Orbital Elements to Cartesian (xyz)
I'm not really sure if this is the place to ask this, but anyway here is my question:
Let's say I have the Kepler orbital elements of the ISS, for example, (NASA stuff). Now I want to compute the ...
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0answers
79 views
Is Earth/Luna tidal lock approaching faster?
Wikipedia pegs the mass of Earth at $5.972\cdot 10^{24}\,\text{kg}$ or $5.972\cdot 10^{21}\,\text{metric tons}$.
Assuming Earth accumulates approximately $30,000\,\text{metric tons}$ annually. To ...
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2answers
99 views
A particle of charge $-e$ orbits a particle of charge $Ze$, what is its orbital frequency?
A point particle $P$ of charge $Ze$ is fixed at the origin in 3-dimensions, while a point particle $E$ of mass $m$ and charge $-e$ moves in the electric field of $P$.
I have the Newtonian equation of ...
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1answer
343 views
Satellite Orbital Period [closed]
I know I can calculate the period of a satellite orbit by Kepler's third law, but somehow it does not work out.
The sattelite is 20200km from surface of the earth.
$r=$orbits radius=earths ...
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1answer
51 views
Single plane Ring system [duplicate]
Possible Duplicate:
Why are our planets in the solar system all on the same disc/plane/layer?
I've noticed this in many pictures, Planets are shown with a single ring around them (in some ...
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3answers
355 views
Uniform Circular Motion
Why does the object not go inward, into the circle if the acceleration is inward? I think its because the velocity to outward? So they sort of cancel each other out? But if the speed is kept ...
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1answer
67 views
What is the pause called at the apex of an object's trajectory?
My apologies for such a basic question--I am a musician, not a physicist. But I cannot anywhere find the word, if one exists, that describes that elegant pause of an object such as a ball, thrown ...
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1answer
112 views
What are “cycles of anomaly” and “cycles of longitude”?
In several early (pre-1600) astronomical texts I read about "cycles of anomaly" and "cycles of longitude", but it us unclear to me what these terms mean. They were clearly familiar to authors at the ...
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1answer
174 views
What path would advanced spaceships take to move between planets? [closed]
Right now, space travel is all about carefully moving between orbits. If you want to go from Earth to Mars, you wait until the two planets are correctly aligned, and then place yourself into an ...
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0answers
116 views
What is the angular distance between Ptolemaic perigees of Mercury?
In his excellent treatment of the history of the science of astronomical distances and sizes, Albert van Helden says (p.29) that
The complicated [Ptolemaic] model of Mercury has the curious ...
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0answers
81 views
Is the fuel burn for a satellite launch affected by the position of the moon relative to the launch site?
The gross mass of a satellite rocket is tiny compared to that of Earth, and Luna. Between them, however, the two bodies set up tides in bodies of water which itself is again considerable mass.
At ...
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1answer
233 views
When and how were relative distances to the planets first measured?
I understand that the absolute distance to a planet can be measured using earth-baseline (e.g., diurnal) parallax, and that the first reasonably accurate such measurement was made for Mars by Cassini ...
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2answers
269 views
Was Jupiter's mass “guessed at” by Kepler or Galileo?
Following Kepler's publication of his 3rd law of planetary motion1,
$$p^2 / r^3 = 1$$
in 1619, it would have been possible to use telescopic observations to arrive at an estimate of the orbital ...
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1answer
59 views
Why no image of the North or the South Pole Weather? [closed]
I was watching a youtube video which refers to National Geographic and other metereological sources that the US govenrment has banned access to the weather and metereological data of both Poles. What ...
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2answers
232 views
Consequences of destroying a space elevator
Suppose there is a fully functional space elevator built on Earth. The base is attached to coordinates
$
(\lambda, \varphi) = (0,0)
$
e.g., on the equator on the zero-meridian.
What would happen ...
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2answers
334 views
Does effective potential for a gravitational force have a maximum below $E=0$?
The relevant figure is below (taken from Goldstein's Classical Mechanics). This figure plots the effective potential for a gravitational force. Does the effective potential $V'$ go flat below $E_2=0$? ...
2
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1answer
164 views
Do Lagrangian points actually maintain a fixed distance?
I was reading on up Lagrangian points and the restricted three-body problem.
From what I was able to tell, the Lagrangian points are 5 points in a two-body system such that a third body would be ...
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1answer
151 views
Condition for circular orbit
I am a little confused about the condition for circular orbit. Goldstein's Classical Mechanics has the condition for circular orbit as $$f^'=0\tag1$$ where $f^'$ is the effective force. I understand ...
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1answer
173 views
Energy required to kick a planet orbiting the Sun from an elliptical to a parabolic path
I am trying to solve the following problem from Goldstein's Classical Mechanics:
A planet of mass $M$ is in orbit of eccentricity $e=1-\alpha$ where $\alpha<<1$, about the Sun. Assume that the ...
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2answers
200 views
Why is there this asymmetry between the two foci of an orbital ellipse?
Why does the Earth revolve with the Sun at one of its foci? Does the other focus do nothing? Why is there this asymmetry in our solar system?
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3answers
351 views
What is the difference between a bounded orbit and a closed orbit?
Goldstein's Classical Mechanics has a puzzling few sentences in his discussion of orbits.
Referring to the case of orbit where the energy is low enough for the orbit to be bounded, he says :"This ...
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3answers
166 views
The theory of moon creation when a Mars size planet hit Earth
As we know the predominant theory where does the moon come from is that a Mars size planet hit the earth and took a chunk out of it which eventually materialized into moon.
My question is that if a ...
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1answer
90 views
Cyclic co-ordinates implying the constant velocity motion of center of mass of a system of particles
I'm reading the section on Central Force in my textbook (Goldstein's Classical Mechanics has a similar argument in the chapter titled "The Central Force Problem", first section), where we have the ...
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1answer
572 views
What happened to Apollo's Saturn-third-stage rockets?
I read recently the original Apollo 11 press release and it mentions that the Saturn V's third stage (used for Trans-Lunar Injection) was deployed into a solar orbit of some kind:
I know that on ...
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1answer
118 views
Determining Orbital Velocity
Is there any way to determine the orbital velocity of a point around another stationary point, if I don't know the mass of either of the points but know the force that gravity exerts and the distance ...
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1answer
203 views
Is there a “map” of the interplanetary transport network?
To my understanding, the idea behind the interplanetary transport network is that areas near heavy objects and their Lagrange points are accesible with comparatively little energy, for example one ...
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2answers
110 views
Will Pluto be in the ecliptic plane when New Horizons passes by? Was this deliberate?
From the illustrations at the New Horizons website it seems that Pluto may be in or near the ecliptic plane when New Horizons passes by.
Is this intentional? Of course Pluto was to move to that ...
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2answers
104 views
Cannon on spacecraft: hitting yourself
Some Soviet space stations reportedly had anti-aircraft cannons installed. Could such a cannon hit the firing space station accidentally on a subsequent orbit? The muzzle velocity of the cannon is ...
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1answer
58 views
Sunrise time across the globe?
This question is more astronomy related, I started thinking when I heard from one of my friends living in Jiamusi, that Sun rise at 02:00 and sets at 14:00, I know that this place is more near to ...
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1answer
364 views
Might a planet perform figure-8 orbits around two stars?
Might a planet perform figure-8 orbits around two stars?
I'm thinking that if the two stars were equal mass (and not orbiting each other) then a planet that were to go right between them would ...
2
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3answers
188 views
Can a photon be made to orbit a known (or undiscovered theoretical) body?
Can a photon through some process be made to orbit a celestial or any other object?
Two follow-up questions.
Can this orbit be described as the photon crossing its own path.
Will this ...
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2answers
495 views
Why is the center-of-mass of 2 bodies at the focus of their elliptical orbits?
Why is the center-of-mass of 2 bodies (which interact only via Newtonian gravity) located at a focus of each of the elliptical orbits?
I know that when there are no external forces, the center of ...
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1answer
71 views
What's the amount of deviation of cellestial orbits from perfect ellipses
It's well known that the planets don't orbit the sun in perfect circles and the characteristics of the elliptical orbits which serve as better approximations to their motion have been calculated ...
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1answer
122 views
How does Lunar Orbit Injection work?
Just what the title states.
I read that LOI was used by the Apollo program (and possibly others) to achieve escape velocity. How does it work? Is it merely a matter of centrifugal/centripetal force?
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1answer
709 views
Why does it take so long to get to the ISS?
I don't understand why when first launched Space X's Dragon capsule had to orbit the Earth many times in order to match up with the ISS? Was this purely to match it's speed, or to get closer (as in ...
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0answers
230 views
How to find orbital radius of star in a binary system using redshift and orbital period data? [duplicate]
Possible Duplicate:
About binary stars and calculating velocity, period and radius of their orbit
I am given the non-redshifted wavelength of the EM radiation from one of the stars, the ...
