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Questions tagged [planet]

Questions on astronomical objects orbiting a star massive enough to be rounded, not massive enough to cause fusion, and which have cleared its orbit of planetesimals.

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Astronomical events and Celebrations

In the past people celebrated important astronomical events and some of those events are still celebrated in some cultures and traditions. For example: March/September equinox, New Moon, Winter/...
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Proper Terminology For Satellite Going Into Planets Shadow

What is the proper terminology for when a satellite or spaceship passes into a planet's shadow or night side? Is it crossing the terminator? Passing into eclipse? If there is a different name for ...
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Visibility of a planet on the other side of the Sun

Context: I've been having a discussion with my vectors and mechanics professor (course Mathematics BSc) about a problem on a recent coursework. The following is the model I came up with. I'm not an ...
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Would planet explode without gravity?

A planet (as well as a dwarf planet) must, according to the IAU definition, have sufficient mass to assume hydrostatic equilibrium (a nearly round shape). Does it mean they would break apart or ...
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Why are we so quick to proclaim the geological inhospitability of other planets based on extremely minimal information?

Now, I'm not questioning claims that any planet in the Solar System is atmospherically or externally inhospitable, but claims made that other planets have geology that is extremely hostile to ...
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What's the difference between semi-major axis and apoapsis?

The semi-major axis is half of the diameter of the major axis of an ellipse by definition. So how does that make it any different from apoapsis, the furthest point an object is from a parent body in ...
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Can mean motion resonances make orbits more unstable rather than more stable?

This paper on closely packed orbit simulation seems to suggest that having the planets in first and second order resonances decreases the time till orbits cross each other. I'd got the impression that ...
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Why is the Earth's magnetic field stronger than its neighbors?

[Edited] I've learned that the Earth's core is hot due to decay of radioactive elements, causing the liquid part of the core to stay liquid. This was stated as an explanation to why the Earth has a ...
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What makes the planets to be symmetric [closed]

I have seen, in my text books, and on nasa sites, the all the planets are symmetrical. And universe also love symmetry. What cause this symmetry, why the symmetry is important. As we know that ...
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Could S5-HVS1 conceivably still hold on to any planets?

If the star (S5-HVS1) has been accelerated to 1,700 km/s by a close encounter with the super massive black hole at the centre of our galaxy (Sagittarius A*) what would happen to any planets orbiting ...
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Can we use Breakthrough Starshot spacecraft to detect any unknown massive object in our solar system?

For example, the hypothetical Planet Nine. Since we just want to prove or rule out the existence of Planet Nine in our solar system, we can avoid most of the technical challenges for StarChip (camera ...
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Are warm circumstellar debris disks still able to be detected at sub-millimeter wavelengths?

At these wavelengths a survey is more sensitive to detecting relatively cool disks (T<100k), but would a telescope operating in the sub-millimeter be less sensitive to warm debris disk than say, a ...
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Starting a fire in a cold planet that was full of flammable gas

What would happen to a cold planet that has a large amount of flammable gas, like Neptune, if we throw some fire into it? Will it burn, or would the flame be extinguished due to the cold?
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Coordinate system for space [closed]

I am high school student, I have doubt if I have to locate a planet or any star in space, how do I locate it, because we have no perfect coordinate system, I have read in some books, that time is ...
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Can fish and other sea creatures survive in watery planets like Neptune or any other planets that has water?

I'm a bit curious since Neptune does not have a land surface and it is covered with water, I mean water has oxygen right? What will happen if we put some sea creatures in these watery planets? Can ...
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Characteristics of the first planets in the Universe?

What would have the very first planets looked like, based on their most likely chemical compositions? For example: Were they mostly grey gas giants with atmospheres of hydrogen and helium, ...
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What is this object in this photo? [closed]

i took it and i don't know what planet or star is this and also there's our moon
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Latest Planet Collision 2019 [closed]

Scientist says that during the course of their billions of years, the planets collied with each other in the past. My question is: is there any latest or recent planetary collision in recent times?
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Brightest most colorful star in eastern morning sky not near any constellations; rises about 4 or 5 am?

I have been believing this is Saturn, but perhaps Antares instead? It is so colorful it shines blue, red, green and white. It is largest in sky in the East before dawn rises about 4 or 5 AM, seen ...
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Clearing the Neighbourhood: Definition of 'Orbital Region'?

I am trying to determine how wide a 'neighbourhood' a planet is expected to clear. However, the Wikipedia article on the matter provides no clarity, simply stating that a planet is expected to clear ...
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How do you call it when two celestial bodies come as close to each other as they will in their current orbits?

On Earth, we say Mars is in opposition when it is 180º from the Sun, which also marks the times when Mars and Earth come closest to each other. Is there a specific name for such proximity events? For ...
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Are there any simulations of the Grand tack?

The BBC program with Brian Cox "The Planets" involved some description of the Grand Tack hypothesis to explain the current state of the solar system. This theory has Jupiter wandering through the ...
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Planets positions (azimuth, altitude) API

I'm looking for a simple API that will allow me to get positions of planets and the moon for a given date, location and time. Does anyone know an API like that? Any suggestions or alternatives would ...
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Are red dwarfs (M dwarfs) known to be strong infrared sources?

If so, why? Are they known to be surrounded by large amounts of dust? Do they typically flare?
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Does this smartphone photo show Mars just below the Sun?

I live in Essex, England (51.7678° N, 0.0878° E). On 25 July 2019 (hottest day ever in the UK, btw), 06:43 BST, I took this smartphone photo of the Sun. Is that white dot just below and left of the ...
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Tilting cycle vs orbital cycle of earth

Common sense tells us a year is conveniently divided exactly into four seasons. I'm wondering whether that means the earth's tilting cycle is equal to its orbital cycle. If so, there must be a reason. ...
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Kepler space telescope undetected planets

The Kepler space telescope detects planets based on the dip in brightness caused by planets moving past the star. Wouldn’t that mean that there are an unknown amount of planets that have an orbit ...
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What keeps the planets of the solar system moving in their fixed orbits?

Models of the solar system show each planet moving around on its own orbit. Is is really because of the Sun that every planets remains in its own fixed orbit?
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How does time dilation from a large body fall off? [closed]

A magnetic fields generally fall off as 1 / r^3 rather than 1 / r^2 for gravity. How does time dilation fall off from a large body? Where would the gravity and magnetic field line be in this chart ...
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Has the effect of other planets on Earth's orbit been ever measured?

Since other planets have their own gravitational pull, I'm wondering if their effect on Earth's orbit has ever been measured? I know that in comparison with the Sun's pull the effect might be rather ...
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What is the radial dependence of the density of Jupiter or Saturn?

Can anyone point me to the reference where I can find the density of Jupiter or Saturn as a function of the distance from its center?
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Undisturbed planetary alignment after galactic collision

How do planets still orbit around the empty space where a black hole was after a black hole absorbs the milky way's black hole and keeps moving through space without disturbing surrounding planets ...
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How to calculate the orientation of planets at current epoch

For an application I am working on I am creating a simulation of the solar system. In this simulation, a user needs to be able to 'move' to any position on any planet, and have the sky be accurately ...
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Why is true and average anomaly of planet important?

Why is a true and average anomaly of the planet important? What useful information do they give us?
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If a solar system were surrounded by a cloud of debris, is it possible for a planet's orbit to intersect it?

I'm doing research for a story that I'm writing and I'd like some physics advice on whether a hypothetical system of celestial bodies is possible. Suppose the following: A system of planets orbiting ...
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How is the size of a distant planet determined?

How is an object's size determined from other solar systems than our own? How are new large bodies being found in our solar system currently?
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Historic observational data - position of the planets

Is there an online source where historic observational data regarding the position of the planets can be found? I was always intrigued by the fact that Neptune was mathematically predicted before it ...
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High quality, detailed images of planets on web

I have been looking for images of the planets and have found pretty decent ones of Earth and Venus from NASA. That detail is opposed to this one of Uranus: And these of Mars, (and this and this) I ...
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To show perihelion precession motion of Mercury in Python with matplotlib

I'm trying to make it more general code so I can trace even a parabola or hyperbola for $e=1, E=0$ and $e>1, E>0$ respectively. And after achieving that general code I want to make the same code ...
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Why isn't Earth tidally locked to the sun?

Given that the moon has long been tidally locked with the Earth, why isn't Earth (or any of our other solar system's planets) tidally locked to the sun?
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Why would tidal forces on planets become more intense when a star becomes a white dwarf?

I was puzzled by this press release by the Royal Astronomical Society: "Small, hardy planets most likely to survive death of their stars" - phys.org, May 14, 2019 Astrophysicists from the Warwick ...
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Why are cirrus clouds more common on Mars?

Mars water ice clouds are often associated with regional- to-global circulation and saturation conditions, as opposed to local convective overturning, and so typically exhibit cirrus rather than ...
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Are these real paths of planets as traced from Earth?

Few days a go, I came across these two pictures of paths of planets as observed from Earth. They have a perfect geometric shapes. Actually, to me they look so beautiful and perfect, that they appear ...
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A quantitive estimate of the size above which celestial bodies must be near-spherical [duplicate]

Asteroids and smaller celestial objects tend to be odd-shaped, whereas planets are always spherical (or slightly oblate due to their spin). The reason obviously is that for sufficiently large masses/...
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What is the most mass that matter likely to form?

If we plot graph between accumulate of forming mass (y-axis) and mass (x-axis), where is the maximum ? There is a story how I get this question. It start when I think about question "Is our sun is ...
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Frequency of Earth type cores?

I've read many interesting threads concerning the composition of different planet cores in the solar system while trying to see if this question has already been asked. It appears as if Earth is ...
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What is the distance from Venus to Jupiter in km?

I need to know this for a test. Please help. The question states "If a spacecraft was parked on Venus and needed to make a flight to Jupiter, how far would it need to travel? (Assume both planets are ...
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Difference of Gas Giant Planet and Ice Giant?

What is the Difference of or the Structure of a GAS PLANET AND AN ICE GIANT Why they called ICE GIANTS like Neptune and Uranus. Do they have a similarity ?
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Why not us interferometry to take a picture of Pluto?

Interferometry is among the best ways (if not, the best way!) to have an image of a very distant object. Recently a picture of the black hole at the center of M87 was released. It is the result of ...
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What causes “North-South ambiguity” when doppler radar imaging a planet surface equator on?

I'm having a hard time understanding why there would be this ambiguity. Also, why would this be not the case if the planet was viewed pole on? Edit: "NOrth SOuth ambiguity" is a term used in a paper ...