The Pole Star
One star that seems to stay still.
Stars at night
Stars seem to move across the night sky. But one star hardly seems to move.
Do all stars seem to move in the same way?
What this lesson covers
The idea
The Earth's axis of rotation points very close to the Pole Star in the Northern Hemisphere, so the Pole Star appears nearly stationary and all other stars appear to move around it.
Stars at night
Stars seem to move across the night sky. But one star hardly seems to move.
Do all stars seem to move in the same way?
- Yes, all of them move the same way
- No, one star seems to stay almost still
- No, none of them seem to move
A night in the northern sky
The chart shows the northern sky. Let some hours pass. Then draw the line from the pointer stars to the Pole Star.
The star the axis points to
The Earth’s axis points almost at the Pole Star. So as the Earth turns, the Pole Star stays nearly in the same place and the other stars circle round it.
The Earth’s axis of rotation points very close to the Pole Star in the Northern Hemisphere, so the Pole Star appears nearly stationary and all other stars appear to move around it.
Notes
The Earth’s axis of rotation points very close to the Pole Star in the Northern Hemisphere, so the Pole Star appears nearly stationary and all other stars appear to move around it.
Check yourself
Which star seems almost still in the northern sky?
Why does the Pole Star seem nearly stationary?
All the other stars appear to …
The Pole Star is seen from the …
- The Pole Star — correct. Yes! It is the star the Earth’s axis points to.
- Whichever star is brightest. Brightness does not decide it. The star that seems still is the one the axis points to.
- A star near the horizon. A star near the horizon moves across the sky like the other stars.
- The Earth does not rotate at night. The Earth rotates all night. That is why the other stars seem to move.
- The Earth’s axis points very close to it — correct. Yes! The turning happens round that line.
- It is switched off for the night. Stars shine all night. The Pole Star only seems still because of where the axis points.
- stay at the same place. Only the Pole Star stays nearly in the same place. The others seem to move.
- fall towards the ground. Stars do not fall. They seem to go round the Pole Star as the Earth turns.
- move around the Pole Star — correct. Yes! They seem to go in circles round it.
- Northern Hemisphere — correct. Yes! It is a star of the northern sky.
- South Pole, high overhead. The Pole Star is a star of the northern sky. It is not seen from the South Pole.
- In the bright daytime sky. Stars are hard to see in the bright daytime sky. The Pole Star is seen at night, in the north.