# Tag Info

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The Sun has lots of features "like the red spot", but they are dissimilar too. Similarities: The Sun's photosphere - the bit we can see - is entirely gaseous; the photosphere rotates differentially with solar latitude; the gas is turbulent. There are features that can be seen quite easily - these are the dark magnetic sunspots, typically of size a few ...

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The earth in its early stages was far too hot for water to be in liquid form and the water vapor that would have been around at the time would have been blasted away via solar wind (http://en.wikipedia.org/wiki/Solar_wind). Anyone claiming to know exactly how water came to be on Earth is likely daft, but comets and asteroids seem to be the most common theory ...

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I'm not an astronomer, just an enthusiast but I believe the only way that it could become a black hole is if when the Andromeda galaxy and the Milky Way galaxy collide and our star combines with another star and the mass of the two is great enough to create a black hole. From what I've read, despite the enormous size of galaxies and the absurd number of ...

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No. Our star is to SMALL to become a black hole.

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I think your question is answered by the duplicate mentioned: but here are the relevant highlights. Humphreys & Larsen (1995) suggest, using star count information, a distance of $20.5 \pm 3.5$ pc above the Galactic plane; consistent with, but more precise than the Bahcall paper referred to by Schleis. Joshi (2007) is more guarded, investigating some ...

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I want to expand on the use of an AU in comparing planetary systems a bit. When we look for example at this image of the (instantly famous) protoplanetary disc imaged last year in HL Tau: In observational astronomy, when we look at an object at a distance $d$ and it has a certain angular size $a$, thanx to the use of the century old parsec we know the ...

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I guess the use of one unit over the other (AUs, parsecs,lightyears, etc.) will depend mainly on the distances of the object under study. If you work with Solar System objects, it will be easier to use AUs, whereas if you work with Galaxies, AUs are not much use and you'd probably work better with lightyears.

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Yes indeed, the Sun (and other stars) has an oscillatory velocity perpendicular to the galactic plane. According to this Nature article, the Sun crosses the galactic plane roughly every 30 million years, reaching a max height of 150-300 lightyears. Depending on how you measure it, a more recent analysis by Joshi (2007) finds that we are currently somewhere ...

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Certainly. Astronomical Unit is probably one of the most used distance units used in astronomy. It is of course only used when discussing the distances within a stellar system, such as the distances between the Sun and its planets or other bodies in the solar system. It is also used to discuss distances in other stellar systems, e.g. the distances between ...

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Cavemen were able to see the first six planets, up to Saturn. All these planets were named after the Roman and Greek mythological characters. The rule they followed was something like this: The planet will be named after the Roman god and all its satellites will be named after the corresponding Greek gods. For example, Jupiter was named after the Roman King ...

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Despite of the explanation of your question, it is a valid question to ask why planets all have Roman names. First of all, the Romans could, like the Greeks and Sumerians, could only see Mercury, Venus, Mars, Jupiter and Saturn. These planets can be seen with the naked eye. However, the fact that the Romans could see these planets, didn't give all the ...

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The orbit of the Sun around the Galaxy is quite complicated, because unlike the solar system, the mass is not completely concentrated at the centre. So, in addition to the roughly circular 230 million year orbit in the plane of the Galaxy, there are superimposed motions in and out of the plane and towards and away from the Galactic centre. These roughly ...

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Based on what I can access right now, the precession of Earth's axes are in a cone shape, so there isn't much wobble. But with all of those Near-Earth Objects, and nearby planets, there is probably some wobble (I'm no professional). There's also this thing called the Milankovitch Cycle, which shows how the combined effects of precession, external forces, ...

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They are not exactly in the same plane, but roughly are. For example this graph representing the centaurs, the Kuipier belt and scattered disc objects show that most objects are around the same plane, with few objects with more than 30 degrees of inclination: This is the inclination of the asteroids: Again, few have more than 30 degrees of ...

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