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

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3answers
262 views

Falling through the rotating Earth

Suppose you were standing on the rotating Earth (not necessarily Equator or the poles) and suddenly your body lost the ability to avoid effortlessly passing through solid rock. Because the earth's ...
23
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6answers
5k views

Could there be a star orbiting around a planet?

I wonder if there ever could be a star (really small) which may orbit around a planet (really big)?
2
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2answers
137 views

Does Planet revolution time is always greater the more it's getting away from the center?

The entire question is in the title . It's the case for the solar system but is it always the case ? Can a planet do a revolution faster than another that is closer to the center ? As far as I ...
12
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1answer
275 views

Relationship between Mars and Earth rotation

Is it by pure random chance that Mars and the Earth have nearly the same day duration (Mars day is barely 40 minutes longer, which is just 3% difference), or there is some causal relationship between ...
3
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2answers
167 views

Does the Earth have a semi-solid body at its core because of lower pressure at the center of the Earth?

I have read that the Earth has a semi-solid iron body at its core, even though that object is surrounded by liquid magma.... I'm wondering if this is because of a pressure (and resulting temperature) ...
2
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1answer
939 views

Where to find the current positions and velocities of the planets?

I've written a program which simulates the motions of planets and other bodies. I'd like to run it on our own solar system, but to do so I need to know the current positions (preferably in ...
4
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3answers
758 views

Does Kepler's law only apply to planets?

Does Kepler's law only apply to planets? If so why doesn't it apply to other objects undergoing circular motion? By Kepler's law I'm referring to $T^2 \propto r^3$
7
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1answer
186 views

Atmospheric Circulation

What is the simplest simulatable model giving our rotating earth its 3 circulation cells (Hadley, Ferrel, Polar)? The model should also show 1 circulation cell if the earth's rotation were stopped (or ...
2
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2answers
607 views

How does one measure Earth's speed of revolution around the sun?

I know that there are several formulae that one can plug numbers into to arrive an estimate of Earth's speed around the sun (Kepler's third law for instance), but I'm wondering how these things are ...
4
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2answers
200 views

What is the mass distribution within the sun?

Jupiter is roughly 1/1000 the total mass of the sun. To get some idea of what effect Jupiter's gravity may have on the sun I'd like to know the approximate mass distribution of the sun. (i.e) the ...
6
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1answer
65 views

Is it possible to determine astronomically/astrophysically whether other planets have ever encountered polarity reversal?

We know of geomagnetic flip in Earth's history by studying geologic data. Given other planets in the system also possess a magnetic field leads to the assumption that such polarity reversal may not be ...
5
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1answer
735 views

Planetary Gravity and its effects

This is my first question on the Physics portion of Stack Exchange. I was hoping to get some light on the topic of gravity. I don't have much background knowledge of physics so I might as well start ...
4
votes
3answers
259 views

Can one predict mass distribution in a solar system given the mass of the star?

I'm trying to write a program to procedurally generate solar systems at a reasonably high level (I'm not interested in doing an n-body dust particle formation simulation). Is there some sort of ...
5
votes
1answer
202 views

Convert latitude of lowest altitude to argument of perigee?

I am designing an orbit around Mercury. I know the values I want for the semi-major axis, eccentricity, inclination, and RAAN. I want the altitude of closest approach (periapse) to occur at ...
16
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2answers
569 views

How deep is the Great Red Spot?

The Great Red Spot (GRS) is a very persistent storm system that's easily visible through a telescope on the surface of Jupiter. But what is the three-dimensional structure of the GRS, and how deep ...
3
votes
4answers
5k views

Is it possible for the planets to align?

We've all heard the statement that on the 21st of December, the planets in the solar system will "align" from the point of view of the Earth. I assume this means that they would all be in the same ...
49
votes
5answers
4k views

Is there a small enough planet or asteroid you can orbit by jumping?

I just had this idea of orbiting a planet just by jumping and then flying upon it on its orbit kind of like superman. So, Would it be theoretically possible or is there a chance of that small body to ...
2
votes
1answer
220 views

What is the critical mass of a planet to have an atmosphere like Earth's? [closed]

Small planets/orbits like Moon cannot have atmosphere because of their masses. They don't have enough gravity to hold an atmosphere. Then what is the critical mass that makes enough gravity to keep an ...
2
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2answers
2k views

Artificial planetary magnetic field

I wonder how difficult it is to create an artificial planetary magnetic field with generators? What power they would need? The question is inspired by thinking about possible colonization of ...
3
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1answer
129 views

What is the maximum mass of planet HD 40307 g

Recently discovered planet HD 40307g around HD40307 Star system is claiming that its inside a habitual zone of a solar system. Besides It has water where life could be evolved. I tried to calculate ...
4
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0answers
141 views

Hemispheric dichotomy of Mars and unstable spin axis

Is the following explanation plausible? Can you spot any flaws? Mars doesn't have a large moon to stabilise its axis of rotation. At some point early in its formation its axis might have been ...
4
votes
1answer
196 views

What day/night cycles, climate and seasons would experience Alpha Centauri Bb inhabitants?

Alpha Centauri Bb is an exoplanet orbiting Alpha Centauri B. It is asserted that given the close distance to the star the planet should be tidally locked. The orbiting period of the planet is about ...
2
votes
1answer
2k views

Why are the orbits of the planets in our solar system along the same basic plane? [duplicate]

Possible Duplicate: Why are our planets in the solar system all on the same disc/plane/layer? After watching this video I realized that the orbits of the planets in our solar system ...
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1answer
2k views

What is the relationship between mass, speed and distance of a planet orbiting the sun?

After reading this fascinating story about a new exoplanet, I was wondering about how mass, speed and distance determine a circular orbit of a planet around a star. Given the mass of the sun and ...
5
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2answers
2k views

What does the phrase “limb of the earth” or “atmospheric limb” mean?

What does the term limb of the earth (see this question, for example) or atmospheric limb mean? The phrase strikes me as very odd, since earth is nearly spherical. Do other planets with atmospheres ...
5
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1answer
2k views

How do astronomers measure the distance of the planets from its star?

I know they have accurate means of measuring the distance of the planets in the Solar System from the Sun. I'm skeptical how can they use the same tools or techniques for other systems so far away as ...
2
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1answer
74 views

Single plane Ring system [duplicate]

Possible Duplicate: Why are our planets in the solar system all on the same disc/plane/layer? I've noticed this in many pictures, Planets are shown with a single ring around them (in some ...
0
votes
1answer
402 views

Does the Earth's revolution around the Sun affect radioactive decay?

Premises: The radioactivity is either hastened or slowed inside a fast moving aircraft. Speed of fastest aircraft: 3,529.6 km/h. The earth's revolution is: 107278.87 km/h. The earth's ...
4
votes
1answer
212 views

Earth-Moon orbiting each other after being engulfed by Red Giant

Recently some exoplanets were discovered which are thought to be the leftover cores of giant planets that had survived a star becoming a Red Giant and then shrinking back to a subdwarf. If giant ...
4
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2answers
199 views

How could Horrocks have measured the AU?

I have always understood that the great historical significance of the transits of Venus, and the reason for the expeditions mounted to observe it, were that, by observing it simultaneously from two ...
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2answers
148 views

Elements of a Planet reveals nearby supernova remnant?

During a random reading through this site, I found this one: Origin of elements heavier than Iron (Fe)... The answer was "The formation of many elements in earth was due to Supernova nucleosynthesis" ...
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1answer
558 views

Atmospheric Escape of Gas Molecules

Most of the Bodies and Objects in space are likely to have an atmosphere. Since the space is empty, the gases in atmosphere should have either dissolved or emptied into space. But, Why doesn't this ...
4
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1answer
118 views

Direction of planetary tilt

I am building a 3d solar system simulation using WebGL and have come across the problem of establishing the direction of tilt of the various planets. No I know the tilt of the planets in degrees what ...
5
votes
3answers
178 views

Why are planetary systems so rare?

According to this site there are 258 know planetary systems and 302 planets. Mostly each of the listed system has only 1 planet of Mercury's or Mars' size, while our system has up to 8 planets. From ...
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3answers
400 views

The theory of moon creation when a Mars size planet hit Earth

As we know the predominant theory where does the moon come from is that a Mars size planet hit the earth and took a chunk out of it which eventually materialized into moon. My question is that if a ...
0
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2answers
123 views

Atmosphere above huge fire areas (e.g., “fire ocean”)? [closed]

My question is more about climate sciences, but I hope that it is still related to physics. What would be possible atmospheric conditions for planet with some kind of "fire" ocean? I had some ...
15
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1answer
228 views

The transit of Venus and solar neutrino rates

The following question was posed at the end of Maury Goodman's June 2012 long-baseline neutrino newsletter. During the Venus transit of the sun, were more solar neutrinos absorbed in Venus, or ...
1
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1answer
237 views

What equations/constants were used to calculate the Kármán Line for Earth?

I am interested in how the original value of ~100 km was calculated for the Kármán line of earth. What equations and constants would need to be used to reproduce this value? Note: By constants, ...
1
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1answer
127 views

What's the amount of deviation of cellestial orbits from perfect ellipses

It's well known that the planets don't orbit the sun in perfect circles and the characteristics of the elliptical orbits which serve as better approximations to their motion have been calculated ...
0
votes
1answer
64 views

What kind of light is needed to light up Venus?

Let's say I would want to light up Venus, such that we can see Venus all day long and not have to wait for a Venus Transit. What kind of light would I need for it? How powerful would it need to be?
6
votes
4answers
1k views

Are “broken” planets possible in the real world?

In the Star Wars universe, there are mentioned (or rather shown) two planets that had some kind of great explosion in their history. First is Peragus, with its exposed core, that partially exploded ...
6
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1answer
311 views

Does a tidally locked planet have seasons?

Could a tidally locked planet have seasons? According to my understanding, a tidally locked planet rotates around itself exactly once per rotation around its sun. However, if the axis of rotation of ...
2
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3answers
610 views

Would a Helium powered balloon vehicle work on Mars?

Would a Helium powered balloon vehicle work on Mars? Things that might need to be answered: How much liquidHelium would you need to pack in order to fill a balloon with enough helium gas to travel ...
2
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1answer
122 views

How should I be thinking about tides?

I am working on a project for physics that involves tides. This is my current mind set when thinking about tides: The earth applies a gravitational force on some mass ...
3
votes
1answer
1k views

How gravitation effect on tides

I know that tide is caused by the gravitational pull of moon but what I don't know is how it effects on water. I have actually these doubts. Why does gravity of the moon creates tides only in water? ...
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5answers
300 views

Age of universe estimates

I was recently involved in a discussion on a sister site regarding how tightly coupled Physics is with the age of the Universe (and Earth). I believe that the Earth and the Universe are both billions ...
5
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3answers
1k views

How do the Planets and Sun get their initial rotation?

How do the Planets and Sun get their initial rotation? Why do Venus and Mercury rotate so slowly compared to other planets and why does Venus rotate in a different direction to Mercury, Earth and ...
3
votes
2answers
994 views

How to correct flares and sharply focus on my telescope when viewing planets.

A month or two ago I purchased a “Skywatcher Explorer 130P Newtonian Reflector” telescope - which so far is brilliant when looking at the Moon, esp. using a neutral density filter. However, when ...
5
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3answers
4k views

Lowest gravity on Earth's surface?

I am trying to determine which on Earth's surface has the lowest gravity. Googling is not finding anything concrete. My natural inclination would be to think of Mount Chimborazo in Ecuador, being on ...
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2answers
529 views

How can I visualize a gas giant?

From wikipedia Gas giants are commonly said to lack solid surfaces, but it is closer to the truth to say that they lack surfaces altogether since the gases that make them up simply become ...