We frequently claim that the sun is "rising" or "setting," although the sense of the sun rising or sinking beyond the horizon is caused by the Earth's rotation. When we gaze at the moon or stars at night, we notice that they appear to rise in the east and set in the west. This is also caused by the rotation of the Earth. If the Earth were not rotating, these objects would still rise in the east and set in the west, but because they move relative to the fixed stars they will do so more slowly.
The Earth is spinning at approximately 1,000 miles per hour, which means that anywhere on its surface you are traveling about 57,000 miles per hour. It takes the Earth 24 hours to rotate around its axis, so if you started at one point on its surface and kept running with the same speed, you would reach another point 56 million miles away in exactly eight days. Because the distance between those points is equal to the average radius of the Earth (6,371 miles), all points on the surface of the Earth are said to be at the same geographical latitude.
If you were to travel at a constant speed from any location on Earth to somewhere else completely different, you would need only seven days, five hours, and fifty-one minutes to reach the opposite pole. The reason for this is that the closer you get to the center of the Earth, the faster you go.
The sun continues to be at the core of our solar system. It does not rise or set. However, it seems to rise and set as a result of the Earth's revolution on its axis. The sun appears to be going west while the Earth rotates toward the east. This is why we see the sun rise over one part of the world and set over another.
Sunrise and sunset are two different things. They are both effects of sunlight being refracted through the atmosphere but they occur under different conditions. Sunrise occurs when there is enough atmospheric water vapor for some of that moisture to act as a lens, focusing the sunlight into a thin horizontal band around the horizon. As this band moves east across the sky, it gets brighter until it reaches the point where all the water in the air has evaporated. At this time, the sun will be directly above the horizon in the east. Sunset works in reverse: When the sun drops below the horizon in the west, it leaves a ring of color around it that gradually fades as it approaches mid-day in the center of the earth's shadow.
At high elevations, such as those found in mountains, there is less atmospheric water vapor so sunrise and sunset happen later than at lower levels. At low latitudes, near the equator, there is more atmospheric water vapor so sunrise and sunset happen earlier there too.
Every 24 hours, one complete turn is completed. It takes a left turn and heads east. This is called "apparent motion." Night falls when the sun is west of the earth, and day breaks when the sun is east of the earth.
The sun appears to rise and set because we on the ground are standing still. If you were riding a bike, it would seem like the sun was moving across the sky because you'd be going east if the sun was rising or west if it was setting. But since you're not moving, the sun appears to stay in the same place relative to other objects that aren't moving.
It takes light from the sun eight minutes to reach the surface of the earth. So during those eight minutes, we see things such as sunrise and sunset because they're on the far side of the planet where it takes longer for light to reach them. When night falls, we don't see anything more brilliant than the stars because there's no land mass between us and the moon. The moon doesn't get any brighter at night because there's no more sunlight reaching it; instead, it gets darker because more of the earth's surface is blocking its light.
The Sun, Moon, planets, and stars all rise and set in the east and west, respectively. This is due to the Earth's rotational axis, which is oriented eastward. Because the Earth rotates or spins toward the east, the Sun, Moon, planets, and stars all rise in the east and move westward across the sky. At some point during its orbit around the Earth, each day's worth of sunlight reaches the North Pole after traveling over the Atlantic Ocean and South Pole.
The Earth also turns or spins toward the south, so that the southern part of our planet gets light for a longer period of time than the northern half. This is why the Moon appears to glide across the sky from east to west: it is actually going northwardly against the backdrop of the south.
Astronomers used to think that the Earth was at the center of the Universe and everything else was orbiting us, but now we know this isn't true. The Sun, Earth, and all the other planets travel through space around a giant ball of gas called the Milky Way Galaxy. There are many billions of galaxies in the Universe, each with hundreds of millions if not billions of stars in it. So in reality, we're just a tiny part of something much larger than ourselves.
The reason we can see far away objects is because they too are embedded within large collections of atoms.