HOW FAST IS THE EARTH SPINNING AROUND ITS AXIS?

The Earth is spinning around its axis. At the equator, the Earth's surface moves 40,000 kilometers in 24 hours. That is a speed of about 1040 miles/hr (1670 km/hr or 0.5 km/sec). This is calculated by dividing the circumference of the Earth at the equator (about 24,900 miles or 40,070 km) by the number of hours in a day (24). As you move toward either pole, this speed decreases to almost zero (since the circumference of the spinning circle at the extreme latitudes approaches zero).

HOW FAST IS OUR SOLAR SYSTEM MOVING WITHIN THE MILKY WAY GALAXY? The sun is about 26,000 light-years from the center of the Milky Way Galaxy, which is about 80,000 to 120,000 light-years across (and less than 7,000 light-years thick). We are located on on one of its spiral arms, out towards the edge. It takes the sun (and our solar system) roughly 200-250 million years to orbit once around the Milky Way. In this orbit, we (and the rest of the Solar System) are traveling at a velocity of about 155 miles/sec (250 km/sec)

   •How fast is the Earth spinning? 0.5 km/sec

   •How fast is the Earth revolving around the Sun?

30 km/sec

   •How fast is the Solar System moving around the Milky Way Galaxy?

250 km/sec

   •How fast is our Milky Way Galaxy moving in the Local Group of galaxies?

300 km/sec

The Complex Motion of the EarthThe Earth spins around its axis as it orbits the Sun. Our entire Solar System slowly orbits around the Milky Way Galaxy. The Milky Way Galaxy belongs to the Local Group of galaxies, where it is also moving.

Aphelion - the point in an orbit that is farthest from the sun.Perihelion - the point in an orbit that is closest to the sun.Sun - the star in our Solar System.Planet - a large celestial body that orbits a star.

1. Name the four seasons. _____________________________________________________________ 2. Are the Earth's seasons caused by the differences in the distance from the Sun throughout the year or the tilt of the Earth's axis? _____________________________________________________________ 3. What is the tilt of the Earth's axis (in degrees)? __________________________________ 4. During which season do the Sun's rays hit the Earth at the most direct angle? __________________________________ 5. During which season are the days the shortest? __________________________________ 6. What is the name of the shortest day of the year (and the beginning of winter)? __________________________________ 7. What is the name of the longest day of the year (and the beginning of summer)? __________________________________ 8. What is the name of a day in which the day and night are of equal duration? __________________________________ 9. How many times each year do we have days in which the day and night are of equal duration? ___________________________ 10. What are the names of each of these days? ____________________________________________________________