The Sun plus the collection of bodies in orbit around the Sun such as planets, dwarf planets, moons, asteroids, comets, etc.

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98 views

Why was Galilei “right”? [duplicate]

Considering that all frames are equivalent, isn't it up to the observer to say "The earth turns around the sun" or "The sun turns around the earth"? Isn't this more or less like arguing about which ...
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1answer
384 views

What is the electric charge has the sun and the corona of the sun?

What is the net electric charge (in magnitude and sign) of the sun and its corona?
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1answer
192 views

When the sun's magnetic field reverses, how can “the north pole (have) already (…) reversed, and (we are) waiting for the south pole to catch-up”?

I was reading a popular news account of the sun's upcoming magnetic field reversal at http://www.csmonitor.com/Science/2013/0807/Sun-s-magnetic-reversal-means-big-changes-for-the-solar-system-video, ...
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1answer
307 views

Is nuclear fusion possible on planets in our Solar system?

Apart from thermo-nuclear reactions in the Sun, (and in hydrogen bombs and other methods developed by scientists) does nuclear fusion occur naturally in the planets? If not, why? Also, do the Sun ...
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0answers
300 views

How would the solar system change if Earth was to just disappear? [closed]

Having just finished Arthur C. Clarke's "Childhood's End", my question is, what exactly will happen to the stability and configuration of our solar system if our planet Earth was to just disappear? I ...
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1answer
143 views

The Faint young Sun paradox: an alternative solution?

The faint young Sun paradox describes the contradiction between the fact that there must have been liquid water 3.5 billion years ago for life to have begun then and the fact that the Sun's power ...
17
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1answer
570 views

How fast is the Earth-Sun distance changing

This is inspired by Evidence that the Solar System is expanding like the Universe?, which referenced an article by G. A. Krasinsky and V. A. Brumberg, "Secular Increase of Astronomical Unit from ...
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0answers
93 views

Evidence that the Solar System is expanding like the Universe? [duplicate]

I've just come across Krasinsky and Brumberg's paper that claims, from an analysis of radiometric measurements, that the astronomical unit (earth-sun distance) is increasing at the rate: ...
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1answer
125 views

Is Pluto made out of ice? [closed]

Is Pluto made out of ice--as in frozen water? If so, wouldn't that provide evidence for alien life in the cosmos?
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3answers
152 views

What can we learn about physics by doing experiments at the end of the heliosphere?

My question is very naive, as I do not know cosmology and astrophysics. I am asking it just for general curiosity. All of us know that Voyager I is now going out of heliosphere, and now sending data ...
8
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1answer
310 views

What exactly is the composition of radiation in interplanetary space?

The articles I found on radiation in the solar system mostly dealt with solar wind, I wonder about other types. Is there a breakdown that tells me, withhin an order of magnitude, at least what ...
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2answers
172 views

What's the weight of the earth?

What's the weight of the earth? That is, what's the weight of the earth in the gravitational field of the sun? I imagine it's either $0$, because there's no net fall toward the sun, so the downward ...
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0answers
464 views

Map of the gravitational strength of the solar system

I am looking for a map or plot of the gravitational strength in the solar system. In an ideal world there should be something like google earth to move around in the solar system, zoom in and out and ...
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0answers
153 views

Does the earth really move round the sun? [duplicate]

Is there really any empirical proof that the earth moves round the sun? I've read simple explanations using mass-gravity relation. But then some questions remain, is gravity a function of mass alone? ...
2
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2answers
183 views

Properties of gravity

If all objects in the solar system suddenly went cold to the core, including the Sun, would it gravity play any different role? I guess what i am trying to ask, is there any relation between energy ...
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1answer
360 views

How do you calculate the Milky Way’s galactic year? [closed]

The Solar system moves at a speed of 220 km / s around the galaxy. It’s about 27,000 light years from the Galactic Centre. How long does it take for the solar system to orbit around the Milky Way? ...
5
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1answer
179 views

How reliant is the Solar System on being exactly the way it is?

We know that all objects with mass exert forces on all other objects of mass such that $$ F = \frac{GMm}{R^2}.$$ And as others have discussed the planets do interfere with each other ...
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0answers
143 views

Mercury's Orbital Precession in Special Relativity

I am researching Mercury's orbital precession. I have considered most perturbations and general relativity. I am still not satisfied. I need your help. I need a solution to Exercise 13, Chapter 6, in ...
3
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1answer
113 views

Has martian sunset same spectra than this earthly bluish-violet sunset?

Has martian sunset same spectra than this earthly bluish-violet sunset? What about sunset on Mercury?
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1answer
126 views

Rømer's determination of the speed of light

I am trying to understand Rømer's determination of the speed of light ($c$). The geometry of the situation is shown in the image below. The determination involves measuring apparent fluctuations in ...
7
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1answer
342 views

Has Voyager 1 entered a solar radiation belt?

The Voyager 1 probe was sent out in 1977 to go where no man made object has gone before, after more than 35 years it’s still going strong. It’s now 124 AU away from Earth and many are wondering when ...
0
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1answer
650 views

Has anyone on Earth ever seen the dark side of the moon and if so where are the pictures? [duplicate]

If the Moon rotates then we should see the dark side right? But as far as I know the Moon only shows one side to Earth, how can this be if it is rotating?
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4answers
327 views

Why a day is divided by 12/24 hours? Why the number 12?

Why a day is divided by 12/24 hours? Why the number 12? Why not using 10 or 6 or 14, 16? Who invented this? Any physical reasons behind this?
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1answer
593 views

Where do planets get energy to revolve around sun?

We know that every planet in our solar system revolve's around the sun in a particular orbit. But were to they get the energy to revolve around the sun. And why do they not drop into the sun there is ...
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3answers
2k views

Can the solar system really fit in a thimble?

Almost every time somebody talks about atoms, at some point they mention something like this: If we remove the spaces between the atoms and atomic components, we can fit the solar system in a ...
2
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2answers
384 views

Why does Venus transit so slowly?

I have calculated that because Venus is $d = 12,103.6~\mathrm{km}$ in diameter and moves at $v = 35.02~\mathrm{km}/\mathrm{s}$, it would take $$ t=\frac{d}{v} = ...
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4answers
755 views

Staying in orbit - but doesn't any perturbation start a positive feedback?

I am not a physicist; I am a software engineer. While trying to fall asleep recently, I started thinking about the following. There are many explanations online of how any object stays in orbit. The ...
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2answers
1k views

How to calculate linar velocity of planet orbit?

I try to simulate a solar system with planets (with random mass) placed randomly around a sun with a mass $X \times \text{solar mass}$. The simulation is going well when I use real data ...
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2answers
185 views

Planet's Moon attrated by sun [closed]

I'm currently writing a code to generate solar system and $N$ number of planets / moons. I use real data to test (earth / sun / moon data). I succeeded in placing the earth and make it orbit around ...
12
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1answer
268 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 ...
2
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1answer
914 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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1answer
79 views

Atmospheric hydrogen in Titan

In 2005, some astrobiologists proposed that methanogenic life on the surface of Titan would consume both hydrogen and acetylene from the atmosphere, causing a downward gradient in the concentrations ...
4
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3answers
252 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 ...
6
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2answers
543 views

How did pre-Copernican astronomers accurately predict planetary position?

Copernican elements (circular orbital elements) are not very accurate. But Copernicus simplified our understanding a great deal by placing the Sun at the center of the system. Im astonished by the ...
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0answers
68 views

Elimination of the node

Recently I have been reading a lot of astronomy papers on reductions in models of the solar system. A reoccurring concept is the elimination of the node. However, they never explain what the node is ...
3
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1answer
926 views

What size will the Sun become once it is a red giant?

How big will the Sun be once it becomes a red giant? How much of the solar system will it engulf?
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2answers
459 views

Result of increasing the radius of earth?

How can increasing the radius of earth may cause an impact on the solar system ? Like, would earth may start making a bigger orbit (due to increase in size and wait) or vice versa ? or else ? PS: The ...
5
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1answer
169 views

What is the likelihood of a long-period comet impact?

I always see lots of information about asteroid impacts, but very little is said about comet impacts. As I see, a long period comet impact is much more dangerous because a) we wouldn't have time to ...
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5answers
893 views

Imagining to speed up the Earth's revolution around the Sun until we feel its motion

If the Earth were revolving around the Sun much faster than it does, let's say 100 or 1000 times faster or whatever big-enough multiple of its actual speed, would we feel it? What sensation would we ...
2
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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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2answers
142 views

Most suitable metric for the Solar system?

If I wanted to solve the Einstein equations for the solar system, which choice of $g_{\mu\nu}$ and $T_{\mu\nu}$ is more suitable? I thought about using a Schwarzschild metric near each planet, but ...
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1answer
142 views

How is retrograde motion explained in Tycho's model?

Tycho proposed a model of the solar system where all planets but Earth move around the sun while the sun and the moon move around the earth. I wonder how this model could explain the retrograde ...
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2answers
330 views

The “official” mass of the sun as unit?

I'm searching for the "official" mass of the sun as a unit in astrophysics. The mass of the sun can be calculated by: $M_{\odot}=\frac{4\pi^2\times(1 \ \text{ua})^3}{G\times(1\ \text{year})^2}$ So ...
4
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1answer
115 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 ...
6
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2answers
379 views

Is dark matter really present around the sun?

Recently I read an article that there is dark matter around the sun but if it is so, than why can we see it clearly. If it is called matter than it shall show some hindrance in radiation we receive ...
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2answers
94 views

What allows new born suns to travel away from each other?

What allows massive new born suns to move away from each other, as they have been observed. I would think that their massive gravity would prevent this and cause them to slam into each other.
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1answer
158 views

What is the diameter of the sun as a function of wavelength/frequency (around 10GHz)?

I have this vague recollection of being told that the diameter of the apparent surface of the sun is a function of what band you observe it in. I'm looking for a model of this that works for bands in ...
6
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2answers
275 views

Why is there this asymmetry between the two foci of an orbital ellipse?

Why does the Earth revolve with the Sun at one of its foci? Does the other focus do nothing? Why is there this asymmetry in our solar system?
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1answer
140 views

Is there anything special about the Sun's photosphere in terms of density?

The Earth has a definite boundary between rocky/ watery surface and gaseous atmosphere. The same cannot be said of the sun. Even though the photosphere gives an apparent "edge" to the sun via the ...
6
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1answer
76 views

Does a celestial system exhibit a collective magnetic field?

Sol exhibits a magnetic field, most of the planets in orbit around Sol exhibit a magnetic field - strong and weak both. Does the solar system as a whole exhibit a magnetic field? Does the paradigm ...