Why do you see different constellations at the same time of the night in different months?

Answer 1

We can generally see 50% of the stars in the sky during any given night. The 50% we cannot see are the ones that are on the opposite side of the Sun from us.

But the Earth moves around the Sun, at very nearly 1 degree per day. The Sun rises about every 24 hours, but any specific star rises every 23 hours 56 minutes; this means that the stars appear to rise about 4 minutes earlier every day. So if a particular star is rising in the east just as the Sun sets in the west today, in a month that star will be rising about an hour BEFORE sunset.

This is why the constellations appear to move. They don't move - but the Earth does. So the constellation of Orion the Hunter rises in the east at sunset every fall, and every constellation has its own season.

Answer 2

Visualize (or draw) the earth orbiting the sun over the course of a whole year. Daylight for you is when your part of the rotating earth is facing the sun. Night time is behind you, and you can see that over the course of the year night time 'sweeps out' across the sky, always opposite the sun. The brightness of the sun obscures our view of the stars behind it.

Answer 3

-- Go outside tonight, around midnight. Find an interesting constellation or group

of stars in the sky, somewhere roughly toward the south. Gaze and enjoy.

-- Now it's 6 months later. The Earth, with you riding on it, has gone half-way around the sun.

Where is that same constellation or group of stars now ?

-- It's in the direction from you toward the sun.

-- Now it's in your southern sky around Noon, not around midnight.

Answer 4

Since the world is always revolving around the Sun, and spinning to make days, the sky is moving. Like the Moon's phases, it is always "changing" shape, since we can't see the entire sky all the time. It is the same with constellations; the Earth revolving around the Sun and lets us see different portions of the sky at different seasons. I hope this helps!

Answer 5

You can only view stars and constellations at night (aside from the sun, which itself is a star). It is daytime, where you live, when the part of the earth you live on is pointed toward the sun; conversely, it is nighttime, where you live, when the part of the earth you live on is pointed away from the sun. Thus, on any particular day, half of the stars are invisible to you because they are overhead when the sun has risen (and you can't see stars, aside from the sun itself, during daylight aside from during an eclipse or when a star goes supernova and is bright enough to be visible during the day).

A year is a complete orbit of the earth around the sun; as a year progresses from day to day, the sky you can see from night to night changes slightly. Half a year from now, you will be able to see the stars that are right now on the far side of the sun from you and thus not visible right now since they are above you, in the sky, during the daytime when sunlight making the sky blue makes those stars invisible to you.

To try to put it to a simpler analogy, imagine you are on a merry-go-round at night. At the very center of the merry-go-round is a very bright spotlight, so bright that it is blinding and you cannot see past it because it is so bright. You can only see if you look away from the light, toward the outside of the merry-go-round. What you see, looking away from the spotlight, changes as the merry-go-round spins in a circle.

Answer 6

-- You only observe them at night.

-- "Night" is the time when you look away from the sun.

-- The Earth revolves around the Sun, so "away from the sun" means different directions

at different times of the year.

-- Ergo, you look in different directions to see the stars at different times of the year.

Answer 7

Mainly because you always do your stargazing at nearly the same time of night.

If you looked up there at different times of night, covering all the hours of dark

from sunset to sunrise, you'd discover that

-- some constellations can be seen for a few months,

-- most constellations are somewhere in the sky at some time of night

for nearly ten months of the year, and

-- some constellations are always in the sky.

Answer 8

Because Earth moves, and it appears that the constellation moves. It just seems that we see it at a certain time of year.

Answer 9

Observations of redshift and blueshift indicates that the earth is expanding.