Celestial body that orbits following an elliptical path around a star or stellar remnant.

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13 views

Calculating Gravity: Small scale vs Large scale

In some calculations I've ran, I've noticed that when the gravitational forces between individual particles are calculated and when the gravitational force between bodies are calculated there tend to ...
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0answers
23 views

Best planets profile for a tattpp 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. No sun, no icy rocks before Jupiter. I found the ...
3
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0answers
18 views

Shapes of planets? [duplicate]

I was wondering if there was a general explanation as to why it is that all the planets we observe are roughly spherical, and never flat/planar like galaxies. Could there potentially be flat or ...
3
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2answers
47 views

A hollow planet [duplicate]

Consider a planet with the same mass and diameter as Earth, except that it is 1) perfectly spherical. 2) a hollow shell 1 meter thick, so the planet is almost like a massive ping-pong ball. ...
22
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11answers
2k views

Backyard experiments to falsify the Flat Earth theory [duplicate]

I recently became aware that the flat Earth theory still exists in the 21st century, and has colored the views of a friend of mine. Roughly speaking, the tenets are: The Earth is a flat disk, with ...
4
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3answers
59 views

What influence has the distance of the moon on the height of the tides?

As the Moon recedes from the Earth, are the tides getting taller or shorter? If the Moon is, someday, twice as far from the Earth, how many high tides will be there be each day?
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0answers
39 views

Orbit of a planet

Can a planet move around a star in an exact circle? Does Kepler's laws prevent this from happening. Answers with mathematical base will be accepted.
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1answer
65 views

How does Planet 9's perihelion and aphelion affect the Kuiper belt objects?

Assuming that the existence of Planet 9 is confirmed and it really exists, how does it affect the orbits of the Kuiper belt objects? My understanding is that the discovery came in part from the ...
55
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6answers
6k views

How can we see planets thousands of light years away but don't know if there are more planets in the solar system?

That is basically my question, it arose when I saw an article (here is the scientific paper, which should be free to read) saying two Caltech scientists might have found the 9th planet of the solar ...
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3answers
78 views

Could the recent evidence of a gravitational force orbiting the solar system indicate not the existance of a ninth planet, but rather a black hole?

In case you haven't heard already, researches at the California Institute of Technology discovered mathematical evidence of large object orbiting the sun at a distance about 20 times further than that ...
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4answers
67 views

Gravity effects when deleting stars or planets

In one of the latest SCIFI movies, they collect a star absorving it entirely in a kind of planet size gun/machine. As mass cannot disappear, I assume it was just concentrated inside their machine ...
3
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0answers
87 views

Nine Planets in the Solar System?

I just discovered that there is a Caltech team1 that suggests that there is "Evidence of a Ninth Planet": The object, which the researchers have nicknamed Planet Nine, has a mass about $10$ times ...
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14 views

Tidal Bulge on Earth due to Line of Action [duplicate]

I am in an intro to Statics course, and we briefly went over why tidal bulges occurred due to vectors in the line of action between the earth and the moon. I am confused because I do not understand ...
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38 views

How are planets distributed in elliptical galaxies?

I'm trying to figure out if planets are equally distributed in galaxies (I'm assuming they aren't) or if there is some logic behind their distribution.
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2answers
59 views

Can we decrease the value of $g$ (gravitational pull) without gaining height? [closed]

The value of $g$ on earth surface is $9.8\ \text{m/s}^2$ and when we gain height, then the value of $g$ decreases. Pilots experience same phenomena in air, but can we decrease the value of $g$ by ...
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2answers
93 views

How is it possible that Thermosphere can maintain so much heat? [closed]

Thermosphere is the Layer of Atmosphere in approx 100-1000 km altitude. Particles in thermosphere are typically at 1400 K temperature. But the sun activity can raise the temperature up to 2300 K. ...
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0answers
25 views

How to determine the position of a planet in our solar system? [duplicate]

I am trying to modelize our galaxy with a simple program. I know how to find the period speed and acceleration of a satellite but I don't know how to get the angle and the current distance between ...
1
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1answer
52 views

Angular Momentum and Kepler's Second Law

Let me preface by saying that I get the gist of the conservation of angular momentum, at least qualitatively. To better illustrate my question, I will consider the case of a planet orbiting a star. ...
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6answers
5k views

Can the average length of the day and night of a planet be different?

At one point in "Marvel's Agents of S.H.I.E.L.D.", some agents are on a planet where the day, defined as the length of time where the sun shines on the planet, occurs only once every 18 years for a ...
3
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1answer
42 views

How do molecules absorb heat?

How do molecules absorb and retain heat, and how is that heat able to still affect nearby molecules? On Venus there is a green-house effect where the large, dense Carbon-Dioxide atmosphere absorbs ...
4
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2answers
45 views

Hypothetical binary planet of different size and mass, would they tend to have the same size and mass?

Imagine a binary planet where one of the planet is of the size and mass of Jupiter (planet A) while the other would be like the Earth's moon (planet B). Imagine that this system is extremely stable ...
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1answer
40 views

Orbital motion and likelihood of bodies colliding

An asteroid is in a highly eccentric elliptical orbit around the sun. The period of the asteroid's orbit is $90$ days. Which of the following statements is true about the possibility between a ...
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2answers
141 views

Why Sun is not able to attract mercury closer?

As sun have a huge amount of attraction pull force , why its not able to pull tiny mercury? Is the whole solar system works in a push and pull network? Why bigger planets like earth, Saturn and ...
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1answer
47 views

Why aren't pictures of Pluto darker than those of other planets?

Just as the intensity of the light from a candle decreases with distance, I would expect the light from the sun to illuminate the distant planets less than the closer ones. However, the pictures of ...
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1answer
51 views

Is there any way to create a globe with gravitational or similar attractive force - earth simulator?

This may sound like a dumb question. Is there anyway to create a miniature version of earth or its gravitational force. A globe or sphere which have force inside it which can attract the things ...
6
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4answers
353 views

What is the general relativity explanation for why objects at the center of the Earth are weightless?

The idea that as you move through the earth you get a symmetric cancelling of gravitational acceleration which approaches zero acceleration due to gravity at the center of the earth makes a lot of ...
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0answers
60 views

Why are the cores of planets melted?

We all know that the core of Earth is in liquid form, as are most other planets as recently read. Why is this the case? Obviously, high temperatures are the cause, but what causes the high ...
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2answers
93 views

How will hovercraft work on Mars?

The facts are: On Mars atmosphere pressure is way much lower than on Earth. To hover hovercraft blows air under itself to create air cushion. This air cushion as I understand must have enough ...
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2answers
72 views

Rotational speed of a planet [closed]

Is there a way to calculate the rotational speed (or day length) of a planet? If not then what are the factors? I mean what affects the speed? Is it just the distance from Sun (like period of a ...
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1answer
72 views

Mercury's rotation, Disturbation's caused by thermodynamics

Mercury rotates sychronized like two-stroke machine. As it's solar day is 2 mercurian years.(Orbital periods) Or should we say 3:2-stroke machine, as it's Orbital period is 87.969 Earthdays, and it's ...
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2answers
247 views

How does rogue planet PSO J318.5-22 stay 800ºC?

According to this article, the rogue planet (meaning a planet which does not orbit a star) PSO J318.5-22 has a surface temperature of 800ºC and weather that features molten iron rain. Without a star ...
3
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1answer
48 views

Have we observed sufficient extra-solar planetary systems to establish a planetary distribution pattern? [duplicate]

From Kepler And Extra-Solar Planetary Observations As of January 2015, Kepler and its follow-up observations had found 1,013 confirmed exoplanets in about 440 stellar systems, along with a further ...
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3answers
149 views

What would be the minimum size of a planet which would allow a human being to walk around without falling out in the open space?

On the Earth you can walk - of course we all know it - in the southern hemisphere without falling out in the open space, and you feel no difference between being at the North Pole or on the Equator. ...
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0answers
12 views

What is the difference between a planet and a dwarf planet? [duplicate]

What is the difference between a planet and a dwarf planet? And is there a way to determine a dwarf planet from a normal planet in a unknown solar system? (If we discover a unknown solar system)
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3answers
125 views

How did planets start to spin and do all of them spin in same direction? [duplicate]

How did planets start to spin in the first place? Some say that gases which condense and form planets start spinning and hence planets acquire a spin. And some say that they start to spin to conserve ...
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1answer
158 views

Relativistic time dilation on Mars compared to Earth?

What is the time dilation in Mars, compared to earth? Can we accurately calculate it? What information is needed to do these calculations?
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3answers
2k views

Are we increasing the gravity of Earth with our population?

I have these questions related to my question title: Do we, other species and things have our own gravity? How much Gs a human have? Are we effecting Earth, nearby moons and planets with our ...
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1answer
31 views

Based on measurements of a moon's orbit with respect to the planet, what can one calculate?

Question: "We observe a very small moon orbiting a planet and measure the moon's min. and max. distances from the planet's center, and the moon's maximum orbital speed. Which of the following CANNOT ...
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2answers
48 views

Is it possible for a planetary system to orbit around something that wasn't a sun?

Say for example that at the center of our solar system you replaced the sun, with something that wasn't a star, lets say that it was electrified and still produced the same amount of heat, would that ...
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1answer
48 views

Would it be possible to have a planetary system where one planet is in continuous shade?

When I ask this I'm thinking of a system similar to ours, but the orbits are perfectly staggered and all planets involved have orbital periods such that when the planet (or small moon, whichever works ...
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1answer
70 views

Pluto's internal heat source

When the first images were announced from the New Horizons probe back in July, there was a lot of fanfare about how the surface is young and geologically active, thus requiring an internal heat ...
0
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1answer
51 views

What would antimatter planets look like?

Let's say – hypothetically – in the vastness of space, we found a planet made entirely out of antimatter and surrounded by barely any matter. If someone were to look at the planet, would they confuse ...
25
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1answer
2k views

Using nuclear devices to terraform Mars: Elon Musk's nuclear proposal? [closed]

Elon Musk has recently suggested Using nuclear devices to terraform Mars. In the past, comet related ideas were mooted, but Musk seems, to me anyway, to be a man in a hurry and perhaps his idea has ...
0
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4answers
89 views

$g=GM/r^2$; $M=$mass of Earth. So in center $r=0$, so $g$ should be infinity [duplicate]

From the equation of Newtonian gravitational force, we know that $$F=\frac{Gm_1m_2}{r^2}.$$ If one of the two objects is Earth, then from $F=GMm/r^2$ and we know $g=GM/r^2$. So 'g' should be infinity, ...
6
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1answer
165 views

Why doesn't space junk form a ring around Earth?

If ice and rock form rings around a planet like Saturn, why don't rings form around Earth from all of the broken satellites and other material around Earth, or will they eventually? I would expect at ...
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0answers
17 views

Calculating collapse factor in the crater equation [duplicate]

In the Crater Equation $$ D=0.07C_f\left(\frac{g_e}{g}\right)^{1/6}\left(E \frac{\rho_a}{\rho_t}\right)^{1/3.4} $$ where $\rho_a$ is the density of the impactor, $\rho_t$ that of the object, $g_e$ ...
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2answers
348 views

Was Leverrier-Adams prediction of Neptune a lucky coincidence?

According to historians both Adams and Leverrier used Bode's law to guess the distance to Neptune, which led to a vast overestimation of its orbital period (Adams - 227 years, Le Verrier - 218 years, ...
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1answer
208 views

Why do Uranus and Venus rotate from East to west?

Why do only Uranus and Venus rotate from East to west, while others rotate in opposite direction? Is it because of the angle of their tiltness? Or due to the process of their formation?
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23 views

Eccentricity of planetary orbits: What information is contained?

I'm having a little trouble understanding what makes a planetary orbit explicitly elliptical. Is it simply that the initial velocity was different from the circular orbit case for a given starting ...
10
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2answers
283 views

Would a rocky planet orbiting so close to a very hot star eventually vaporize?

I was thinking about the physics behind a hypothetical scenario where a planet the size and the mass of the Earth is orbiting so close to a very hot star and what the long-term fate of such a planet ...