Questions tagged [orbit]

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

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Why can't ESA/NASA build a handful of Gaia telescopes and launch them into different positions in space for better accuracy?

I've noticed that many stars in GAIA DR2 have highly uncertain distances. Why can't a space agency send multiple Gaia spacecraft into orbit around different places (One in L2 Earth, one in ...
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If two stars collide, what is the probability that they merge to form a single star?

After looking at What are the odds that the Sun hits another star? and answering it (crudely), now I'd like to ask the following: What is the probability that if two stars collide, their cores merge ...
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What are the odds that the Sun hits another star?

The Sun moves around the Milky Way disk in the same direction as most of the other stars in our galaxy (prograde). But there are a number of older stars in the galactic halo that move in retrograde ...
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Does a star's rotation always match a planet's orbit?

For a planet orbiting a star, is it ever possible for a star to be rotating in the opposite way on it's own axis compared to the planet that is orbiting the star? Or do gravitational forces mean the ...
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Has the Earth's wobble around the Earth-Moon barycenter ever been observed by a spacecraft?

Pluto's motion around the Pluto-Charon barycenter has been imaged by the New Horizons spacecraft: Has anything like this been imaged of Earth? Yes, the barycenter lies inside of Earth, but it is 3/...
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If an orbit is shifting due to orbital precession, is it still a Keplerian orbit?

I was thinking about orbits a few days ago, and realized that orbits shift/precess naturally. Given that a two-body problem with a star and a planet, if the planet has an eccentric orbit that ...
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1answer
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Kepler's Law, focal points - Heliocentric or Barycentric?

It is known that all the mass in the Solar system moves around the Barycenter. For the two focal points in Kepler's law; is the first focal point $F_1$ a Heliocenter? Or is it actually a Barycenter? ...
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Is it at all possible for the sun to revolve around as many barycenters as we have planets in our solar system?

Though it is understandable that the sun and the earth may be revolving around a barycenter, but, if so, not only the sun and Jupiter should also be revolving around some barycenter, the same should ...
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Are there any planetary ring system other than “Phoebe ring” not aligned to the equatorial plane?

Continuation of: Is it possible for planetary rings to be perpendicular (or near perpendicular) to the planet's orbit around the host star? The answers discussed about Uranian ring system (how ...
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Will 1036 Ganymed's orbit be changed by its close encounter with Mars in 2176?

In 2176, the asteroid Ganymed will come as close as 0.02868 AU (4,290,000 km / 2,670,000 mi) from Mars. That's pretty close to Mars imho. Can Mars' gravity alter Ganymed's orbit significantly in 2176 ...
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How would the characteristics of a habitable planet change with stars of different spectral types?

The tidal forces a habitable planet experiences increase with decreasing spectral type. So a habitable planet orbiting a smaller, less massive, and cooler star would experience much stronger tidal ...
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Does the earth spiral around the sun's movement/motion path?

I have watched the following video (How Earth Moves by Vsauce) regarding how earth moves: Here are some screenshots: I have some questions: Does the earth spiral ...
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Is Jupiter really shepherding the main belt, and Neptune the Kuiper belt?

By "dominating another object's orbit" my understanding is that the most massive body's gravity has so much influence that, when they come close, it makes the other body/bodies' orbits shift ...
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Where are Moon's Apogee and Perigee? Do they rotate too?

Where are Moon's Apogee and Perigee? Which one is inside, towards the Sun, between Sun and earth? Do they rotate too just like the north, south node? Does Moon always need to be on Apogee/Perigee ...
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Why does the angular size of the Moon change?

I know that the orbit of the moon is elliptical. But I cannot understand this graph: The number of 'bumps' in the graph is around 13~14 in a year, so I concluded that the each 'bump' indicates one ...
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What would the Earth's peri- and aphelion have to be in order to have the same seasons due to its orbit?

Imagine the Earth had no axial tilt but had seasons due to a very elliptical orbit. How elliptical would the Earth's orbit have to be in order to have about the same seasons as it has now (just with ...
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Problem with Tychonian model of geocentric universe?

Just like other proposed models of universe in history, Since Tycho's aren't being used, there MUST be any flaws in compare with widely agreed today understanding Is there any detailed reference ...
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Does a parabolic trajectory really exist in nature?

It seems it is very difficult to have e=1 perfectly in nature. The final state (being captured or running away) of a celestial body with a parabolic trajectory, is determined by minor perturbation?
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North node, South node correct understanding

What is the correct concept of the North node and South node? There is some conflicting information on the internet. Which one of these two is correct? 1. Sourced from some Astrology material - How ...
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Is a three body gravitating system doomed to collapse?

Suppose we have two gravitating bodies, which are rotating around each other. They are bodies and are affected by deformation caused by tidal forces. Moving tidal waves suck energy from the axial ...
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Does anything orbit the Sun faster than Mercury?

Mercury's orbital period around the Sun is about 88 days. Comets and other things have gotten closer to the Sun than Mercury does. But has there ever been an asteroid or some other body discovered ...
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What would be the year length of a habitable planet of 40 Eridani A?

The planet Vulcan, in Star Trek, is one of the most famous fictional planets. The length of a Vulcan year comes up in my answer at: How old was Spock in Star Trek while he was serving on the ...
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Is a double quasi-binary system valid?

I was messing around with 4-body problems, and discovered a system where a close binary and a regular binary pair orbit each other. The regular binary gets disrupted every few orbits and one star ...
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What should be the “poles” for irregular shaped bodies?

Continuation of: What is the definition of a "pole" of a celestial body? From uhoh's answer, we can conclude that a distinct bodies should have a center of mass. If the body is spherical, ...
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Aligning the equinoxes to the cardinal points on a circular calendar

I want to draw a calendar as a circle, with the equinoxes at the top and bottom, and the solstices at the left and right. I am prepared to accept a little inaccuracy by having exactly 365 or 366 days ...
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What is the definition of a “pole” of a celestial body?

What is the definition of a "pole" of a celestial body? Earth's pole is defined as it's rotational pole. The North and South Poles are the two points on Earth where its axis of rotation ...
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“Periapsis” or “Periastron”?

I was taught from Bate Mueller and White, that the proper terms for the closest and furthest points and distances from a body in orbit around another unspecified body are "periapsis" and &...
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After what time interval do the closest approaches of Mercury to the Earth repeat?

The sidereal period of Mercury's revolution is 88 days and the synodic period — 116d. my solution, but in the question featured "the greatest rapprochement." And this is no longer so easy. ...
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Do planets have effect on velocity of Earth?

There is method for finding extrasolar planets called Transit-timing variation. If I understood correctly, exoplanets accelerate or decelerate each other (according on their position), so we can ...
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Do space objects stay in orbit once they get sucked in? Can they escape?

Think of my question with respect to 2020 CD$_3$ minimoon that's been recently discovered. If an object gets caught into a planet's orbit, can it ever escape it? Obviously it may escape on the first ...
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How small could an orbital system be in our solar system?

Answers to How does the Sun's gravity have so much force and pull on the solar system? How does it scale? Newton's law of gravity scales on orbits so that we can theorize very small orbits with very ...
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If an exoplanet transit we are seeing is 13000 light years away, are we seeing a 13000-year-old orbit? [duplicate]

If a star is 13000 light years away, doesn't that mean we are seeing 13000-year-old light? If it does, then does that mean when we discover a planet with dimming star light, we are seeing a planet ...
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Is a trefoil orbit around a trinary star valid?

Recently, I have been experimenting with weirdly-shaped orbits with a program called "My Solar System 2.04." While looking for interesting orbits of a spacecraft in a trinary star, I found ...
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Throwing a baseball from orbit to the earth

I just read a thought piece about what a war in space may look like, and it changed my thoughts on what orbit actually is. From what I read about orbits, it sounds like going faster in the velocity ...
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What makes protoplanetary disks start rotating? (Initial energy needed to rotate)

Planets form from a protoplanetary disk that has been rotating around its star. The initial energy that makes them rotate really matters to me. Why did the protoplanetary disk start rotating around ...
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If suddenly “knocked” or perturbed from its orbit, would gravity eventually return the Earth to its original orbit?

If suddenly "knocked" or perturbed from its orbit, would gravity eventually return the Earth to its original orbit? I am curious as to whether this is even possible. It seems to me that ...
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How does an object at L1 stay at L1?

I've recently been reading about the DSCOVR satellite, and I'm confused about it's orbit. According to NOAA A million miles away, DSCOVR orbits a unique location called Lagrange point 1, or L1. This ...
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Positions of planets before Christ?

All the solar system simulations I've come across showing the positions of planets only show the positions in a certain time period, at beginning of the first millenium the earliest. There was just ...
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What are “non-Keplerian” orbits? What are some familiar examples in our solar system, and can some still be closed?

This excellent answer to Forms of stellar orbits around the galactic center invokes the following concepts: non-Keplerian orbits closed orbits I have a fairly good idea what these mean and so might ...
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Is there anything like a timelapse showing the Alpha Centauri stars orbiting around each other?

It is my understanding that the angular separation between Alpha Centauri A & B is more than enough for even amateur telescopes to resolve as 2 separate stars. Going by the plot below, over the ...
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What would a moon with a six-month orbital period look like from the earth?

This is a kind of follow-up question to "What orbital period would produce one New Moon (and one Full Moon) each year?" Given the six-month orbital period that is needed to produce one New ...
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The possibility of rapidly changing the Earths orbit via a passing astronomical object

I assume that the Earth could be “gently” (without colossal tidal or volcanic catastrophe) displaced by a passing extra solar star, brown dwarf or planet and end up perhaps 10% further away from the ...
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What shape do satellites trace as they wobble in orbit around another body?

What shape does the center of gravity of a satellite trace in 3-d space as it wobbles in orbit around another body? How is this shape modeled geometrically? Is it a topological torus? Is it feasible/...
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What orbital period would produce one New Moon (and one Full Moon) each year? What other effects would this produce?

I am interested to know whether it's possible for the moon to orbit the earth at such a rate that we would see only one New Moon and one Full Moon a year. If so, what other effects would we experience?...
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Orbital Mechanics: where can I find initial conditions for orientations and angular rates of planets in our solar system?

I am looking to write the equations of motion (EOMs) for a 6DOF analysis of our solar system. I want to integrate the equations forward in time, and need a complete set of initial conditions to do so....
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Does Halley's Comet travel past the outer bounds of the Oort Cloud?

We know Halley's Comet returns every 75-76 years. We can reasonably compute its elliptical orbit. We know that the Oort Cloud is a cloud of predominantly icy planetesimals proposed to surround the Sun ...
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Cannot identify mistake in calculating orbital eccentricity vector; magnitude equals one instead of zero (with python code)

I have a gravitational nbody simulation, for which I would like to determine various orbital parameters. For each body, I have 3-D vectors (x,y,z -space) for position, velocity, and acceleration. I am ...
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Why is the height of a satellite greater than the apogee of its orbit?

I read in the German Wikipedia for the Indian Technology Experiment Satellite, that the apogee (Apogäumshöhe) is 567 km, while the height of the orbit (Bahnhöhe) is 572 km. I had always thought that ...
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What is the tightest orbit binary planets can orbit each other?

If there were two Earth-like planets in a tight orbit around each other, how close could they be to each other without colliding? How quickly would they have to orbit to be stable? Would they be ...
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Is there a possibility of finding a system where a star is orbiting a planet?

Is it possible for a star to orbit a planet IF the planet is bigger than the said star? Or is it possible even if the star is bigger than the planet and still the star is orbiting the planet? I have ...

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