How can you tell the diference between a star and a planet in the solar system by watching the night sky?

So i have two questions to ask!



1. How can you tell the diference between a star and a planet in the solar system by watching the night sky?



2. Would you expect galaxies to move more differently than the planets and stars across the night sky? If you could explain your reasonging too pls :)How can you tell the diference between a star and a planet in the solar system by watching the night sky?Both of these answers require watching the night sky over a period of time.



1) You can tell the difference between stars and planets because stars always stay in the same relative locations. That is, Orion's belt will always look like Orion's belt (at least within a few million year time frame). But planets move all over the sky. In fact the word planet comes from a greek word literally meaning "wanderer". So you can identify a planet by the fact that night after night, it does not stay in the same relative position in the sky. One night it may be next to the star Sirius, and a month later it may be next to the star Regulus. Stars don't wander, planets do.



To be more technical, planets can undergo something known as retrograde motion (at least the planets outside our orbit can). This is when the planet actually travels backwards in the night sky with respect to the motion of the rest of the stars as the planet Earth overtakes that planet in it's orbit. So if you see a "star" traveling in the opposite direction in the sky as the other stars, it is definitely a planet.



2) This one has to do with parallax. Galaxies (and stars which are very very far away) are the only truly fixed things in the sky. Stars which are close will change their apparent position very slightly as we travel around the earth. It's the same principle as how an object appears to move as you look at it with one eye open, and then the other. First we look at a nearby star on one side of the sun, then half a year later we can look at it again and it will have appeared to have changed it's position very very slightly. This is actually a method used to detect distance to nearby stars. But galaxies are so far away we can never detect a change in position. This is the only real difference between the motion of stars and galaxies in the night sky.How can you tell the diference between a star and a planet in the solar system by watching the night sky?
1. How can you tell the difference between a star and a planet in the solar system by watching the night sky?



A. Usually stars will twinkle and planets will not unless the atmosphere is very unstable (then planets will also twinkle). This is because the stars are so far away and so small that you are just seeing their light which will be scattered by the earth's atmosphere. Planets on the other hand are much closer, and besides viewing their light, you also are viewing the actual disc of the planet. Over several days or weeks planets will move in relation to the background stars. Not that the stars are not moving, but they are so far away, you can't see them move over the course of a humans lifetime.



2. Would you expect galaxies to move more differently than the planets and stars across the night sky? If you could explain your reasoning too pls :)



Galaxies will move the same as the stars, but not planets.How can you tell the diference between a star and a planet in the solar system by watching the night sky?1. Over several days or more a planet moves more in relation to the "fixed" stars than the "fixed" stars do because of the rotation of the Earth and the Earth's revolution around the sun. The planets are moving along their own orbits, which is why their position relative to the background stars changes over time.

2. Galaxies and stars move the some way across the sky because of Earth's rotation and its revolution around the Sun.

After 58 years of life I can visualize in three dimensions when I want to without having to simplify it to two dimensions. 3 dimensional thinking is learned, and that takes time.How can you tell the diference between a star and a planet in the solar system by watching the night sky?
Knowledgeable astronomers tell the difference by knowing the normal patterns of the constellations, and instantly recognize objects which "don't belong." Planets move, but this usually takes a week or two to detect. Stars usually twinkle; planets usually do not. When in doubt, we just point a telescope at the object and see whether it is a point or a disk.

[Edit] I forgot you were asking about galaxies too. Galaxies move much more slowly than stars or planets because they are much much farther away. In fact, no motion of galaxies has ever been detected except by spectroscopic means. There are only about 5 galaxies visible to the naked eye, and they don't look _anything_ like a star or a planet, so there's absolutely no chance of confusing them with anything.

The five naked eye galaxies are the Milky Way, the two Magellanic Clouds, and the Andromeda and Triangulum Galaxies.How can you tell the diference between a star and a planet in the solar system by watching the night sky?If you watch the sky every night for months, you will notice that most of the stars stay in the same places. They rise and set because Earth is rotation, but they stay in the same positions with each other. The constellations do not change shapes; the stars that make the constellations don't wander away from each other or move to another constellations. But 5 stars do wander from constellation to constellation. It may take months for them to move to another constellation, but the point is they do wander around while all the other stars don't. Those 5 stars are Mercury, Venus, Mars, Jupiter, and Saturn.



Galaxies stay put, just like the stars do. Now, stars and galaxies are moving in space, but they are SO far away that the seem to be going really slow. Just like how an airliner flying over at 500 MPH can seem to be going pretty slow, because it is to far away, while a car going 50 MPH in the street next to you seems ti be going pretty fast.
with the naked eye, its hard to tell which one is a planet and which one is not. Me personally, I know which planet is Jupiter, Mars, Venus, I could recognize those easily in the night sky because I know their brightness and position in the sky, but without knowing this you could not tell the different between a star and a planet.



Only visible Galaxy with the naked eye is Andromeda, and it moves like stars in the night sky. Planets move different, but you notice the difference after observing them for few weeks or months.How can you tell the diference between a star and a planet in the solar system by watching the night sky?
1. You really can't tell just by looking at them with your own eyes. You would need to find out if a planet is in the sky that night (by newspaper or computer) and use a telescope to see it. Most of the stars you see at night are actually starts and not planets.



2. They would move to us because Earth rotates on its axis and around the Sun, but they move just like anything else in the sky. Unfortunately all the stars/ planets you see in the night sky are stars and planets (or the moon). You might be able to see the Andromeda galaxy or the M81 galaxy in a really dark place though.
From Greek, Planet is derived from "wanderer.' These celestial bodies would not follow the stars, in this case, wandered alone separately in a strange path.



Hubble's law elaborating on galaxies motion: http://www.infoplease.com/ce6/sci/A08586鈥?/a>How can you tell the diference between a star and a planet in the solar system by watching the night sky?
planets tend to be brighter (Although not always). they also do not appear to twinkle, except when close to the horizon. The only sure way to tell is that stars don't move in relation to each other from night 2 night.
In the short term stars are point sources and twinkle, while planets are tiny discs and don't.
stars twinkle and planets don't because the reflect sunlight!
1. You can definitely tell if you are seeing a star or a planet in the night sky by how bright the object is, and what position it is in the sky. Position isn't always reliable because the position of planets each day in the sky isn't always uniform because we rotate around the sun, spin on our axis, and don't stay in the same place in space all the time. If you see the star twinkle or light up and get brighter, that tells you that it is a star because stars are the only things in the universe that make light in the night sky that we know of, and that light shining in the sky must be a star because the light from the big star could have taken many years for it to travel to your eyes. It is not possible to see Jupiter without a telescope like the other person answered, and it is hard to see Mars unless you are at the right place at the right time. Venus is the easiest planet for us to spot and see in the night sky because it is really close, and Mercury too, but not as much because it is small and a lot of the planet gets blocked out by the sunlight we see on Earth.

2. Galaxies are many planets, stars, asteroids, comets, and meteors , so since the closest galaxy to Earth is the Andromeda galaxy which is about 2.5 million light years away, and some stars aren't even that close, most likely the galaxy would appear to actually move slower than the star because since the star seems like a smaller object in the sky to the rest of the universe, it would seem to take up more area in a shorter amount of time. It depends on the distance of the star and galaxy too. Galaxies from a distance may only look like a couple of stars moving, but it is really billions of stars moving, it's just that it is too far away and there are too many stars to make out all of the stars. Planets would appear to not move that fast, and since they have less gravity than stars, and since stars have less gravity then all of the gravity of a galaxy combined, planets would appear to move slower and do move slower than stars, and stars would appear to move slower than galaxies. Sometimes galaxies are so far away though that it just seems like a big mob of stars slowly gliding in the sky, but the reality is that stars and galaxies both move really fast. Planets do too, but not that fast. Also, you might mistake planets like Venus moving as a shooting star, when really it is just a planet and it just seems like that because stars are much bigger than Venus and Venus is much closer than any star to Earth, so it's going to seem bigger than it really is.
I hope I helped!
Maxwell
YOU TELL BY IF YOU LOOK HARD ENOUGH A STAR WILL ACTUALLY TWINKLE. THE PLANET WILL NEVER BLINK