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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6
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1answer
95 views

“Pluto Time” for any solar system body

A while back NASA made a site called Pluto Time, where you can enter your address and find that "...moment near dawn and dusk each day, where the illumination on Earth matches that of high noon on ...
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0answers
63 views

On the anniversary of Pluto's discovery: the statement that Pluto is a planet [closed]

February 18 marks the 90th anniversary of the discovery of Pluto, the ninth planet from the Sun. For 76 years Pluto counted as the undisputed ninth planet until the International Astronomical Union ...
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2answers
146 views

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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1answer
65 views

Code/Package for multiple planet simulation

I want to do a quick study and some tests on the planet-star dynamics ( including the movement of the star). I'm looking for a code that simulates some planets orbiting a star. I've tried searching ...
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0answers
62 views

How can the download speed increase from space probes? [migrated]

It always seems to be a genuine question that is How can we download data from far away probes in instant. When New Horizons reached Ultima Thule, it took us quite a few months to have a great picture ...
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5answers
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How many planets are there in this solar system?

So, in school (that's a long time age) they have been teaching us there are 9 planets in our solar system. Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto But every now and then I keep ...
4
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2answers
265 views

What type of planetary-mass object would Planet Nine be?

Given that Planet Nine is hypothesized to be 10-20 times the mass of the Earth orbiting the sun some 200-2500 AU out, what kind of planetary-mass object would it be? Even given that it has apparently ...
6
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1answer
93 views

Electrical potential difference between planets

In dealing with electricity, we usually refer to Earth as the electrical neutral or ground. Is there any evidence that other planets' ground is at the same electrical potential level as the Earth's? ...
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1answer
31 views

Factors included in the average density of planets

When the average density for a planet is stated does it incorporate the mass of the atmosphere, when a planet has an atmosphere, or is the mass of the atmosphere ignored?
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1answer
42 views

How to calculate the true length of day on a celestial body?

When I only know the sidereal rotation period, how do I determine the true length of day on a body? We know the Earth's sidereal day doesn't have full 24 hrs unlike the true length of day. It's ...
8
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2answers
196 views

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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1answer
90 views

If you put all planets between earth and moon what would happen?

It's often discussed that you can fit all the planets in the space between the Earth and the Moon. But if they actually did teleport there instantly what would happen next? Assuming their initial ...
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0answers
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Who first named the planets Mercury, Venus, Mars, Jupiter, and Saturn? [duplicate]

Who first named the planets Mercury, Venus, Mars, Jupiter, and Saturn? Agnes Clerke's Catholic Encyclopedia article "Astronomy in the Bible" § Planets claims that "Venus and Saturn are the only ...
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0answers
98 views

How does the gravitation of Jupiter or other big planets affect Kepler's third law?

Does anyone know any good reference on this? I remember reading once about how Jupiter's gravitation can be treated as a perturbation, but I cannot find it again now. I think they expanded Jupiter's ...
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0answers
38 views

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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1answer
57 views

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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6answers
159 views

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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2answers
169 views

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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2answers
87 views

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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1answer
46 views

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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1answer
320 views

3 years later, how strong is the evidence for planet 9?

I came across post in quora where somebody said that "most astronomers no longer think Planet 9 exists" and being somewhat shocked by that, I did a google search and found a fairly recent article that ...
4
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1answer
697 views

How to get the axial tilt vector(x,y,z) relative to ecliptic

According to the orbital plane XYZ, I understand that the axial tilt is the angle between the planet axis rotation and any normal of the plane (actually Z in right handed system). BUT, this is not ...
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0answers
30 views

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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4answers
1k views

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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3answers
2k views

Could the earth become a star if more mass was added?

I've heard that the only difference between a star and a planet is mass, meaning that if planets accredited enough mass they would too become stars. Does this mean that the star started off as a ...
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1answer
70 views

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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2answers
706 views

Could planets explode in space?

Could a planet like the Earth or any other explode or be destroyed and did we see a planet explosion with Hubble?
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2answers
159 views

If gaseous planets have solid core, can they theoretically be considered as rocky planets?

I read that gaseous planets such as Jupiter and Saturn, have a solid core deep inside. So, I wondered whats the difference between them and rocky planets apart from the fact that they have - what can ...
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1answer
86 views

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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1answer
37 views

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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1answer
3k views

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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2answers
379 views

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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1answer
2k views

Reason for disqualifying Pluto as a Planet? [duplicate]

Pluto is no longer a member of the planets in the solar system. Why was it disqualified as a planet? What is the criteria for classifying an Astronomical Object as a Planet? Does this criteria apply ...
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3answers
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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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2answers
217 views

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 ...
5
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1answer
927 views

How big can a rocky planet get? [duplicate]

If I get the numbers right, at about 17 Jupiter masses a mainly gaseous planet would ignite into some type of star. What about rocky planets? Is there a theoretical limit to their size, so that they ...
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1answer
148 views

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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1answer
107 views

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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1answer
89 views

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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2answers
376 views

Do other planets affect the Earth?

Let say Mercury, Venus, the Moon were all in alignment between the Earth and Sun. They are all closest to each other in respective elliptical orbit. On the other side of the Sun you have the rest of ...
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3answers
4k views

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 ...
6
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1answer
135 views

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 ...
4
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1answer
101 views

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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2answers
283 views

Advancement of perihelion, data

I was looking for accurate and up-to-date data regarding the advancement of the perihelion of the planets in the Solar System, the only ones I've found so far are at least 90 years old bout I really ...
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1answer
54 views

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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6answers
9k views

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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4answers
122 views

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. ...
3
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1answer
551 views

“Official” time for other planets

I want to make clock that shows current time on different solar bodies. For that I need to know how to count time on those planets. Is there any official definition of times on other planets in our ...
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2answers
896 views

Why does each and every planet of our solar system have an unique axial tilt angle?

Why do planets have an axial tilt? From the above image we can see that each planet's axial tilt angle varies and differs from the others. What was the cause of this, was this from the beginning of ...
17
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2answers
3k views

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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