# Tagged Questions

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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### What is the position and orientation of the Earth as a function of time

I would like to know the position and orientation of the Earth, relative to the sun, as a function of time. I.e. select any coordinate system with the Sun at the origin so that the earth lies in the ...
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### Earth's beginnings and early years, Re radioactive decay or not

It is said that the Earth and solar system are 4.6 billion years old. Presumably this date is achieved from radioactive decay. If this is the case, since most of the radioactive elements would have, ...
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### How do the Planets and Sun get their initial spin?

How do the Planets and Sun get their initial rotation? Why do Venus and Mercury rotate so slowly compared to other planets? Why does Venus rotate in a different direction to Mercury, Earth and Mars?
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### How can you calculate the exact position of the Earth taking into account the gravitational attraction of Mars and the Sun?

I think there must be a formula to calculate the exact position of the Earth taking into account the gravitational attraction of Mars and the Sun. Is it possible with vectors?
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### Simple model of the solar system. Parameters? Accuracy?

I was thinking of making a simple 2D model of the solar system, with planets moving along ellipses like $$x(t) = k_x \sin(t + k_t) (\sin(k_\phi) + \cos(k_\phi))$$ y(t) = k_y \cos(t + k_t) (cos(k_\...
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### Where will New Horizons go after sailing past Pluto?

The New Horizons Spacecraft is scheduled to whiz by Pluto around 2015, and my understanding is that it is going to do exactly that — whiz by it. Where will it go after that? Or what else can it do ...
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### Predicting solar storms?

Quote from BBC "A strong solar storm is expected to hit Earth shortly, and experts warn it could disrupt power grids, satellite navigation and plane routes." How is it that we are aware of a massive ...
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### What would happen to Earth if Saturn were to exit the Solar System?

Suppose Saturn simply vanished. How would that affect the rest of the Solar System, specifically Earth?
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### How big is the Solar System?

How big is the solar system? By "big", I guess I mean "wide", i.e. how far away from the Sun is the farthest object that is considered part of the Solar System? I've checked Wikipedia's pages on ...
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### Are Uranus and Neptune too big for their location?

So I was watching some TV, and I heard Dr. Plait mention that the planets Uranus and Neptune are too big to be located so far out in our solar system. Now, I heard his explanation on the show as to ...
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### Why does the debris from comets and former comets hang around so long?

So tonight's Quatrantids shower got me thinking. Why does the debris from comets and former comets hang around so long? Each year the earth sweeps through the region of space that the comet went ...
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### Why do the planets' orbital distances fall on an exponential curve?

Background: I was recently reading a book on the planets to my son and I noticed a pattern in the distributions of the planets. The planets' distances roughly follow an exponential distribution. ...
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### What is the fate of the asteroid belt?

From what I understand the asteroid belt never formed into a planet because Jupiter threw off the gravity of all the small objects and they never could gather to form a planet. As described here: Why ...
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### Solar wind and the Earth's magnetic field

I have again an old question from a comprehensive exam I took a couple of months ago. Lucky for me one could pick 5 out of 8 questions, because on some of the problems I didn't even know how to start. ...
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### How long does it take for radio or light waves to travel from Earth to Jupiter, Saturn, Uranus, Neptune and Pluto?

I know it roughly takes 20 minutes from Earth to Mars, and 8 minutes from the Sun to Earth, but don't know how long for the other planets on my list.
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### How many Pluto sized planetoids have been discovered?

How many planetoids have been discovered that are, say, 50% the size of Pluto or larger? Where are they? Incidentally, what is the difference between a planet, a planetoid, and an asteroid?
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### Why do 3d spheres and gravity tend to rotating discs on one plane?

Whether is it our solar system or a whole galaxy, there is usually a massive object (star or black hole) at the centre with gas and objects rotating around it. The gravitational effect of the star/...
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### Calculating the Suns vector and distance from the Earth at one time

I am developing a C++ program where I'd like to be able to see the Suns direction vector and distance from Earth at a given time, since 2000 Jan 0.0 TDT. The reference frame I want to calculate it is ...
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### Why doesn't our solar system run into other solar systems over billions of years?

Why doesn't our solar system run into other solar systems over billions of years. There is plenty of time for it to be attracted by gravity to other objects. So I thought, it should be a common ...
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### How plausible is a subsurface ocean on Pluto?

According to this article on physorg.com, it's likely that Pluto has a subsurface ocean of liquid water. It suggests that the ocean would be about 165 km deep, under an equally deep crust of solid ...
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### What are the facts that allow accepting the Oort cloud theory?

I admit without any fact that the Oort cloud (comet reservoir) should exist, and it seems to be accepted by far by the large majority of astronomers. But it is still a theory without any direct ...
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### Is it true that our solar system belongs to another galaxy which collides with the milky way galaxy?

I have just read an article about it here(http://www.greatdreams.com/2012.htm)(Scroll to bottom). I'm just a website developer, and I really want to know if this is really true. I'm curious. I'm ...
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### Why Aren't Saturn's Rings Clumping into Moons?

While reading with my son about how a Mars-like planet collided with the early Earth that resulted in our current moon, it said the initial debris also formed a ring, but that ring ended up getting ...
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### Will Neptune change Pluto's orbit some day?

My seven-year-old son loves astronomy-- so much so that we read space books before bed time. One of our books talks about Pluto's orbit crossing over Neptune's orbit and will be (or is) closer to the ...
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### “Reverse engineering” of a horoscope?

I'll start with a disclaimer -- this is not a question about astrology itself, I'm neither trying to refute nor to defend astrology. I'm interested in purely technical things, which are mostly ...
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### How does the earth move?

My son who is 5 years old is asking me a question about how the earth moves around the sun. What answer should I give him?
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### What are the known relationships between rotation of planets/moons and their distance to Sun?

What are the known relationships between rotation of planets/moons and their distance to Sun? Or any other known attributes? For example, the sidereal year for planets is directly related to their ...
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### Why do we always see the same side of the Moon? [duplicate]

I am puzzled why we always see the same side of the Moon even though it is rotating around its own axis apart from revolving around the earth. Shouldn't this only be possible if the Moon is not ...
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### Why are our planets in the solar system all on the same disc/plane/layer?

I always see pictures of the solar system where our sun is in the middle and the planets surround the sun. All these planets move on orbits on the same layer. Why?
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### Is solar wind positively charged?

Many times I heared that the solar wind consists of protons and alpha particles. The both are positively charged, but are there electrons in solar wind?
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### What is the irregularity in Uranus' orbit that is caused by Neptune?

I carefully read the Wikipedia article Discovery of Neptune, and I don't get what the irregularity of Uranus orbit was that lead to the discovery of Neptune. Years ago, I watched some educational film ...
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### Does the Earth help stabilize changes in the moon's obliquity as well?

We know that the moon helps stabilize changes in Earth's obliquity. But what about Earth and the moon? Are some of the obliquity-stabilizing effects (of the moon on the Earth) communicated through ...
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### How do the day/night temperature variations of moons compare to those of their planets?

Does the planet's eclipse have a significant impact on the flux of light hitting the moon? Does tidal locking have any effect on the day-night difference of the planet?
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### Is a water world possible, and for how long could it be stable?

I have several questions regarding this topic. First, could a water world be stable for thousands of years with most of its surface remaining covered in water. What would it take for this to be ...
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### Meteorites from Mars?

So I've heard of meteorites "originating from Mars" (e.g. AH84001), but the phrase confuses me. I'm interested in what this means - have these rocks somehow escaped Mars' gravity and ended up here; or ...
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### How does the average Mars-Jupiter distance compare with the average Earth-Jupiter distance?

One thing is certain: Mars can be further from Jupiter than Earth can ever be (when they're on opposite sides of the solar system), but Mars can also be closer from Jupiter than Earth can ever be. ...
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### How did micrometeorite flux change with the age of the solar system?

Do we also have functions for the micrometeorite flux on the Moon, Mars, and even any random body in space as a function of solar distance too?
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### When will Enceladus run out of water?

So its geyser eruptions are the primary source of water in Saturn's atmosphere (from this thread). And they even manage to contaminate Titan's atmosphere with it. But has the outgassing rate ...
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### Are the inner planets on planar orbits because there was more dust in the inner solar system (early on in planetary accretion)?

Question inspired by a question thread here. So when there's lots of dust in a galaxy, the galaxy tends to collapse into a spiral galaxy (to maintain angular momentum and to minimize gravitational ...
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### Distribution of each element and molecule as a function of distance from the Sun and as a function of time

Are there any graphs that show the distribution of each element and molecule as a function of distance from the Sun? And maybe even the time-evolution of each distribution over the solar system's ...
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### Vesta dwarf planet status

Now that we have close-up photos of Vesta, which the IAU had previously said was a candidate dwarf planet, when is the IAU going to decide the issue? Personally, Vesta doesn't look round enough to me.
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### At what temperature does water become a liquid on Mars? On the asteroids? And in a vacuum?

I know that I can just read off the phase diagram for water (for the surface atmospheric pressure on each object). But could there possibly be some nuances that someone might miss just from viewing ...
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### Why did the asteroid belt between Mars and Jupiter form as it did?

I'm curious about why the asteroid belt wasn't pulled by Mars's or Jupiter's gravity or formed into either moons or planets. Why did it form into an asteroid belt instead?
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### Could Jupiter's gravity destabilize Earth's artificial satellites over a long timescale?

Could Jupiter's gravity destabilize Earth's artificial satellites over a long timescale? After all, it can destabilize Mercury's orbit, and it can also destabilize orbits in the asteroid belt.
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### When the Sun goes red giant, will it “vaporize” away a significant fraction of Jupiter and Saturn moons?

Since Jupiter and Saturn's moons are composed of a rock+ice mix. For example, Callisto is 50% rock and 50% ice. When the Sun finally goes red giant, could it melt a significant portion of the 50% of ...
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### Are orbits interior to Jupiter's orbit less stable than orbits exterior to Jupiter's orbit?

Or in other words, are there differences in average Lyapunov timescale between orbits interior to Jupiter and orbits exterior to Jupiter? I'm trying to answer a question at http://www.quora.com/Why-...
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### Is Jupiter a failed star?

In my physics lessons, my teachers have always been keen to tell my class that Jupiter is considered a 'failed star' by scientists. Is this true? In my own effort I wondered if maybe this could just ...
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### Why did the ancients fail to discover that the Earth orbits the Sun?

The ancients observed that the Sun and the 'fixed' stars rotated about the Earth. They were also aware that the Earth was spherical. They performed many astronomical measurements on the planets - ...