The sun appears to move across the Earth's sky as a consequence of the Earth's rotation. As Earth turns on its axis, an observer on the surface sees the sun appear to come up somewhere over the eastern horizon, rise to a peak around midday and then begin its descent toward the west. This cycle varies slightly from one latitude to another, as well as from one day to another.Know More
Earth spins once on its axis every 24 hours. To a stationary observer at most locations on the surface of the Earth, this motion imparts the appearance of motion to the sun. The exact spot on the local horizon where the sun appears to rise is dependent on where on the Earth the observer is located and what time of year it is.
In addition to spinning on its axis, the Earth inclines at about 23 degrees. This tilt brings first one and then another hemisphere into position to point more directly toward the sun. For observers in tropical latitudes, this motion causes the sun to cross the sky higher and higher throughout the spring until the summer solstice, when it begins moving back down toward the horizon. To an observer near the pole, the sun rises above the horizon only from late spring to early fall. It appears to circle the horizon during this time and disappears entirely through the winter months.Learn more about Our Sun
Relative to its planets, the sun is actually a stationary body, but it appears to move due to Earth's rotation. However, it is important to recognize that nothing is ever truly stationary.Full Answer >
When a ring appears in the sky around the sun, it is called a halo. Halos have also been observed around the moon in the night sky.Full Answer >
Copernicus’ heliocentric model shows how an observer on Earth orbiting the sun would see a planet with a longer orbital period appear to move backward and then forward again. Ptolemy’s model, with the Earth at the center, required complex additional mechanics to explain retrograde motion that never matched the observed motion.Full Answer >
Stars appear to move across the sky due to the rotation of the Earth in its orbit. As the Earth rotates the view of what can be seen changes along with the planets' positioning in the solar system. The location of a person on the planet and the tilt of the planet both affect what stars can be seen in the night sky and when they can be seen.Full Answer >