What in the world is a solstice?

If you live in the Northern Hemisphere, the summer solstice (the word solstice is Latin for stand still), falls on June 21 and marks the longest day of the year. On this date, the sun is at its greatest distance from the celestial equator and shines most directly in the Northern Hemisphere. The sun pauses at this northernmost point for several days. The summer solstice was an important date in the past as it marks the midpoint of the summer. There is another solstice in the year--winter solstice--that is around December 21.

What are the reasons for the seasons?

Two obvious answers include the fact that it is usually warmer and the hours of daylight are longer in the summer than in the winter. But what causes these differences? Try your hand at these true-false questions below.

. T F Summer occurs during June, July, and August of each year.

. T F During the summer the Earth is closer to the sun.

. T F The sun is hotter in the summer.

If you answered true to the three statements above, you are not alone. Many people have lots of ideas about the summer season. For the first statement, the answer is true only if you are located in the Northern Hemisphere. For the second statement, the answer is true only if you are in the Southern Hemisphere. The third statement is false. The temperature of the sun does not change with the seasons. Let's take a look at why we have seasons. Many people believe that the distances between the sun and Earth are the reason for the seasons. This is not true. There are two causes for the changes of seasons. The inclination of the Earth's axis, or the tilt of the Earth is always the same at 23.5Á. This angle does not change as it travels in its orbit around the sun. Summer occurs when the rays of the sun are the most vertical on a particular place on Earth. Winter occurs when the sun's rays are the most slanted on a particular place on Earth. Since the rays of the sun are most direct in the tropics all year, the seasonal temperature there change very little except at higher altitudes.