Stars...same spot?

Question

How come at night, when one looks up at the stars, the stars don't differ in position from the night before or the night before that?

Answer 1

dunno, im puzzled about this as well..

Answer 2

I used to ask the same question, before I learned how the night sky "works." Remember that the stars are so far away that they appear to move very slowly relative to each other. All those TV specials with shifting stars and galaxies that visibly spin are just designed to get your attention. Therefore, the star patterns are generally constant (except for the moon and the planets, which are a little different). It is just our view of these same patterns that changes from season to season.

Remember that all the stars rise and set just like the sun does, based on the earth's rotation on its axis. Also remember that the earth's night side is pointing in a different direction in the winter vs the summer, because it's on the other side of the sun. If you spend some time outside getting familiar with the stars, you will see that they do change slightly from night to night. In the winter you will see Orion in the south, in the summer you will see Scorpius. As you progress from winter to summer, Orion will begin to set earlier and earlier until you can no longer see it in the evening at all. Then in late spring you will begin to see Scorpius rising in the east after sundown. Right now Scorpius is pretty close to due south in the early evening (you can easily recognize the red giant star Antares just behind his head). So, the stars do change in position - just slowly. The secret is to really look at them every now and then, and get some advice from a friendly local amateur astronomy club.

Answer 3

They do differ a little bit. Look at where they are at exactly 9:00 tonight. Tomorrow, they'll be in that position at about 8:56. The next night, they'll be in that position at about 8:52. There's about 4 minutes' difference in their position every night. Another way to look at it is, it takes about 23 hours, 56 minutes (i.e., 4 minutes shy of a full day) for them to reach the same spot in the sky while they appear to move around the earth.

The change is hard to notice if you watch for just a few days, but it's obvious if you watch over the course of several months. The stars and constellations you see in the summer are different from the ones you see in the winter.

Answer 4

They do, they just do so slowly. As we orbit the sun, different portions of the sky become visible to us throughout the year.

This time of year, the night side of the Earth faces towards the center of the galaxy and the disk is visible as "the milky way", a swath of trillions of stars which appears as a faint white glow running from the constellation Cassiopeia in the north, through the constellation Cygnus, which looks like a large cross, and to the constellation Sagittarius to the south, which looks like a tea kettle to some.

Here's a photo of the Milky Way: http://www.flickr.com/photos/jpstanley/283595009/

Six months from now though, we'll be facing the outer portion of the galaxy at night, and different stars and constellations will be visible. At the moment, these constellations are out during the day, and of course the sun blocks them out because it's so bright.

Also, the people in the northern hemisphere and the people in the southern hemisphere don't see entirely the same thing. The people in Australia, for example, can see things from their location that people in North America, or Europe can't see, such as the large and small magallenic clouds (dwarf galaxies to our own). Likewise, the people in Australia can't see things people in the northern hemisphere can see, such as the North Star (Polaris). This is because the Earth is spheroid and blocks the view. It also blocks the view to the west and east past the horizon but since the Earth rotates from west to east, causing the sky to appear to move from east to west through the night, things eventually rotate into view if they are east or west, and this isn't true of things to the south for the northern hemisphere, and things to the north to the southern hemisphere.

Answer 5

If you look at the stars 24 hours later, the Earth has done a complete turn and is aligned the same way as it was the previous night. So, if you look in the same direction (relative to the ground), you'll see the same stars.

Answer 6

Great Answers so "Logic's Logic"

If you notice on star charts that the chart shows for 9 pm, 8 pm 2 weeks later and 6 pm two weeks after that. So it takes about two weeks for the stars to appear to make up the 4 min a day difference.

Answer 7

cause the stars are far away and/or that the earth rotated and is back in the same position as it was last night or the night before

Answer 8

They do slightly due to the motion of the Earth around the Sun, but not really enough to notice from night to night. Maybe from week to week. Or maybe you're referring to proper motion - the random motions of stars not related to the motion of the Earth? Even though stars do move on their own due to local gravitational interactions, they are so far away you'd really never notice unless you sent up a spacecraft to measure it (like Hipparcos).

Answer 9

The stars are so far away that their proper motion from our perspective is very small

Answer 10

D. x marks the spot