Questions regarding an object 'falling around' another object, due to a combination of gravity and momentum.

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2answers
63 views

Can a tidally-locked planet maintain an obliquity

If a planet is tidally-locked, can it have an obliquity? e.g. the Earth's rotation is being slowed by tidal forces. A long way in the future it will be tidally locked. As it slows, will the ...
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2answers
167 views

Has NASA confirmed earth now has a second moon orbiting the planet?

Several sites claim NASA has confirmed a second moon orbiting earth. This is the Asteroid 2016 HO3. One source states The newfound quasi-satellite/moon-2016 HO3, is likely larger than 120 feet (40 m) ...
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4answers
135 views

Would space-based telescopes need to remain in the shadow of Earth to avoid light interference from the sun?

So I am thinking about orbiting telescopes tonight and I was thinking that it would probably be beneficial to keep them in the shadow of the Earth or some other space body to avoid light interference. ...
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0answers
64 views

What is the shape (along the plane, not up-down) of stellar orbits in flat spiral galaxies

What I mean is, with a central mass orbits are relatively simple, but orbits around the galaxy are different, in essence as the star orbits through the dark matter halo, the further it moves away from ...
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2answers
4k views

Why do the planets orbit in the same direction?

Theoretically, planets would have an approximately equal chance of going one way in their orbit or another but in reality, this is not the case (at least in our solar system). Why is this?
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49 views

Send a rocket against orbit around the sun [migrated]

I presume it's a bit simplified, but ... What if we launch a rocket, the same speed but opposite direction of the orbit of our planet around the sun. Will that rocket fall into the sun?
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0answers
22 views

What are the requirements to become a planet? [duplicate]

A planet is taught to us (at primary school) as a ball of rock that orbits around the Sun and is similar to our own planet, Earth (in as a ball of rock). But of course, humans have to be more specific ...
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2answers
100 views

Could this three moons system be stable?

In my fictional world I have selected all parameters to maximize the Hills Sphere of my planet. The planet has three times Earth's mass and it is located in 2 AU from its star that's 1.4 times more ...
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2answers
169 views

Is it possible for a moon to continuously have a side facing its star whilst orbiting a planet?

For example; is there any possibility for the moon to always have a side facing the Sun whilst orbiting Earth? And if so then what would the day cycle be like?
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2answers
152 views

Is Earth slowing down in order to stay on its orbital track?

The Sun is losing some of its mass during explosions. The Gravitational force between Sun and Earth will change (probably decrease). If Earth maintains its speed, it will change its orbit. Hence, ...
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1answer
60 views

What causes celestial bodies to move like they do from Earth's surface?

As you probably know, the planets have pretty predictable orbits around the sun but what exactly causes the complex movement of celestial bodies in the sky from Earth's surface? Mars is an excellent ...
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0answers
46 views

Peculiar orbit of circumbinary planet

I've created a Mathematica notebook file which should theoretically allow one to simulate any n amount of bodies. Whilst looking at a three-mass system where $m_1=m_2=2000m_3$, I noticed some peculiar ...
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2answers
86 views

Is it possible to have a star orbiting around a brown dwarf?

I know a single star is almost surely more massive than a single brown dwarf, but consider a case: a very small star is orbiting a very massive brown dwarf which has a very massive moon, such that the ...
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1answer
87 views

What would happen if an astronaut orbiting Earth was exposed to radiation? [closed]

I know that astronauts are constantly being protected from radiation from the sun and the cosmos. They are normally very safe from the harmful effects of radiation but what if their protection wasn't ...
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0answers
27 views

Directly calculating lat/lon of a satellite directly from RA/declination

I have RA/declination values of a satellite and the observer's location in terms of lat/lon. I want to convert the values for satellite into lat/lon. I have tried to use the method which uses ...
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1answer
54 views

LLR & Orbital Motion

As I understand it, light that is emitted from a source is not imparted with the motion of the source and so always follows a "straight line". If this is correct, I am having a difficult time ...
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1answer
223 views

Why aren't all planets in the same plane?

Obviously all planets are not in same perfect plane. Because if at all they were in the exact same plane, it would mean that Mercury transits and Venus transits would not be that rare. Any ...
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1answer
87 views

How much time does the ISS take to repeat its orbit?

I used to go to my roof to see the ISS, but it is not always visible. Then it appears again but does it appear with the exact same orbit as I saw before? Thanks!
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3answers
260 views

Why do the gas giants in the Solar System have comparatively large orbits compared to the inner planets?

Ever since I observed the depictions of the Solar System, I was obsessed with the question of why the gas giants (outer planets) have very large orbits, compared to the planets that are closer to the ...
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31 views

How common are Stars that have no orbiting planets? [duplicate]

How common are Stars that have no orbiting planets compared to Stars that do?
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1answer
95 views

Two body orbit of equal masses

Given two bodies of equal mass in an elliptical orbit: I know they will be orbiting about a common center of mass, i.e. the barycenter. But, do the velocities have to be equal in magnitude and ...
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1answer
38 views

Longitude of the Ecliptic

I originally went to math.stackexchange.com and they suggested I try here as well. I'm trying to figure out how to calculate times of moonrise and moonset for a given position on the earth on a ...
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0answers
70 views

What would happen if we changed Earth's orbit? [closed]

If one day we have enough technology to push the Earth away a bit further from the sun to reduce global warming, is it true that it will start to distort the orbits of Mars and Venus, giving them a ...
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1answer
51 views

Simulates Orbit [duplicate]

I IT developer, and I would code a small program that simulates the orbit of two bodies, the problem of two bodies eventually. I have no problem on the part programming but I have a little trouble ...
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1answer
63 views

Can we apply Kepler's law of planetary motion to the moons motion around the earth?

I have been trying to understand Kepler's law of planetary motion for a while. So I was thinking, if it would even apply to the moon orbiting around the earth. Does the moon too orbit in an ellipse ...
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1answer
65 views

State vectors of “interesting” multiple stars

I'd like to show a demonstration of Runge Kutta integration of real systems using examples of interesting multiple stars, where "interesting" means you can see through a small telescope that they are ...
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1answer
106 views

Are there any hot jupiters orbiting red dwarfs?

Do we know of any hot jupiters that could be orbiting a red dwarf (or, more probably, orbiting a barycenter between the two)? Is this scenario even physically possible?
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2answers
24 views

Would it be possible to equip an asteroid to collect space junk in Earth's orbit? [closed]

We all have heard about the problem with space junk in low earth orbit. NASA has a plan to put an asteroid in orbit around the moon. Would it be possible to equip propulsion systems onto an asteroid ...
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2answers
71 views

Determining distance from semi-major axis and eccentricity

I am trying to obtain the distance covered by an object in orbit around the earth within a specified amount of time past its perigee passage. The object is in an elliptical orbit with eccentricity 0.2 ...
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1answer
116 views

Is this Universe scenario correct? [closed]

I will try to give you my reasoning behind my scenario. Ok I've researched and found That 95 percent of the galaxy has been formed already, And the other 5 percent is still to come.http://www....
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2answers
201 views

Lack of objects between heliopause and Oort cloud?

If we take a look at a logarithmic scale of the Solar System, there appears to be a large gap between the heliopause and the Oort cloud: Why is that? There are some objects in the gap, but why are ...
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1answer
204 views

Best planets profile for a tattoo of the solar system [closed]

I want to get a tattoo of the solar system. The gap between the planets should not be preserved and the differences in sizes will only be symbolic. I found the following My question is if all stars ...
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2answers
219 views

Are there ever any simultaneous transits of both Mercury and Venus as seen from the Earth?

Transits of Mercury happen fairly frequently due to its short period, but transits of Venus are less frequent. I've looked over the data available to me and found that there have been transits of ...
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1answer
84 views

Stability of orbital resonance

Recently I've become more interested in the topic of the stability of planetary systems. I have been reading about it and it seems that orbital resonances play an important role in the stability of ...
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3answers
57 views

What is the centre of rotation of Pluto?

I know that Pluto and Charon have been found to circle round each other, hence the reason Pluto is no longer a planet I believe, which would mean that the centre of rotation is an arbitrary (!) point ...
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1answer
134 views

What is the shape of the Sun's orbit around the Earth taking into account elliptical orbits?

Consider the non-inertial frame that is at rest with respect to the Earth's revolution around the Sun. (Ignore the Earth's rotation around its own axis.) My question is, what is the shape of the Sun'...
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0answers
37 views

Resources on planetary stability

I am a fifth (and last) year undergraduate student in Physics with good level of Mathematics formation and basic Astrophysics formation. I recently read some theories about Solar System formation and ...
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0answers
22 views

Accuracy of Laplace Method for determining orbital elements

Recently I had to implement Laplace method and apply it to 3 observations of Mars (10 days in between two observations). The results were pretty good, with discrepancies with real data well below 5% ...
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3answers
46 views

Is the duration of a sidereal year stable?

According to this essay by Phil Plait, the duration of Earth's sidereal year is 31,558,149 seconds. Is this figure stable? If I were to meaure Earth's orbit several million (or billions) of years in ...
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2answers
115 views

Why doesn't Jupiter increase the chances of an asteroid to strike the Earth?

I often hear the hypothesis that Jupiter decreases the chances of an asteroid strike on the Earth, but my question is, why does it only decrease the chances ? While Jupiter can deflect some ...
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1answer
213 views

Are there accurate equinox and solstice predictions for the distant past?

I am trying to find information on the equinox/solstice dates before 1600, more exactly referring up to 10,000 BCE so as to create a sort of calculator on an Excel spreadsheet. I have read about the ...
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2answers
115 views

Can planets have orbits other than elliptical or circular orbits?

Can planets have orbits other than elliptical or circular orbits? All of the planets in our solar system have either a circular orbit or an elliptical orbit (perhaps like Pluto).
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1answer
133 views

Do all planets rotate in the same direction in relation to each other?

In other words, does everything spin counterclockwise according to their axes (in relation to each other)? I suppose my question goes for stars, moons and other objects too. But then again, all you ...
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0answers
69 views

How to get the longitude of the perihelion to find the Heliocentric Equatorial coordinates of a planet

I'm writing a program to randomly generate star systems and I have been having a difficult time figuring this out. I've found the equations I need to get the heliocentric equatorial coordinates, but I ...
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1answer
78 views

How to cool down a moon?

I'm doing an Astronomy project and need to terraform a moon. It is about the size of Mars and orbits a gas giant which is at a distance of 1.28 AU of its star. I though about putting a sunshade at the ...
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3answers
3k views

What if Earth and Moon revolved around each other like Pluto and Charon?

What would be different for us if Earth and Moon revolved around each other like Pluto and Charon do?
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1answer
126 views

Simulate an orbit with orbital elements

I want to simulate the orbits of the planets from our solar system. I want to use orbital elements to calculate the current position(xyz) at a time t. The simulation doesn't have to be too exact, but ...
4
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1answer
100 views

Ambiguity in Earth's “Tilt”

It’s well-known that the axial tilt of the Earth (with respect to the ecliptic) is about 23.4 degrees. However, two angles is needed to specify the orientation of any rigid body, so it’s unclear to me ...
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1answer
145 views

Can a star orbit around multiple planets or a planet with massive moons?

Note: I'm not talking about a star orbiting around a single or lonely planet :) I know a star orbiting a planet is almost impossible because if a planet is more massive than a star, that "planet" ...
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2answers
99 views

Alignment of Semi-Major Axis of Orbits

So I'd like to ask whether the semi-major axis of planetary orbits are aligned? Logically, they shouldn't be, but many websites act as if they are. If they're not aligned, what's the angle between the ...