Earth moon sun system part 2

The tilt of the Earth was first calculated over 3000 years ago using vertical poles and shadows. It was observed that at latitude 23.5N (the Tropic of Cancer) the pole would not cast a shadow at exactly noon on the day of the Summer Solstice. A pole placed at 23.5S (The Tropic of Capricorn) would not cast a shadow at exactly noon on the day of the Winter Solstice. A pole placed on the equator will not cast a shadow at exactly noon on the days of the Equinoxes. How did these observations lead to the conclusion that the tilt of the Earth is 23.5 degrees?

• The sun appears to move up and down in the sky by 23.5 degrees from the equator over the course of a year.

• At the solstices the earth is at its maximum tilt compared to the sun. The lack of a shadow on these days proves how far the earth is tilted.

• Because the earth is a sphere the distance from its equator to its poles is 90 degrees. If you can measure the distance from the equator in degrees a location is and then observe the shadows cast on an equinox or solstice you can calculate the tilt of the earth.

• All three statements provide support for the calculation of the tilt of the earth.

Why does the moon not appear to rotate?

• Because it does not rotate.

• Because from our point of view from Earth we can never see the back of the moon.

• Because Earth's gravity pulls the moon into a rotation that matches its revolution.

• Because the moon is too close to Earth for us to observe a change in its motion.

The invasion of Normandy by Allied Forces marked a turning point in World War II. It remains the largest seaborn invasion in military history. It was several years in the planning and one important aspect of the plan was that it would occur under a full moon. Why would this part of the plan be an important part of a seaborn attack?

• History has shown a relationship between the position of the moon and the success of military operations.

• During a full moon the tides are not especially high or low so there would be less risk in a seaborn landing.

• During a full moon the high tide would be higher than usual and the distance the soldiers had to cross to get off the beach would be shorter.

• If the moon is directly overhead the height of a tide is lower. This would make it easier for ships to land their troops.

"Many moons ago" is an old saying that means "a long time ago". Why is this saying a pretty accurate description of a length of time?

• The moon makes one revolution around Earth every month so it is a good way to keep count of how much time has passed.

• The moon rotates around the sun at the same speed as Earth so watching the moon helps us count the time it takes to equal a year.

• Watching the moon and stars helped ancient people find their way across great distances without getting lost.

• If you watch the moon as it moves across the night sky you can use its motion to count the number of years that pass.

The timelapse video of the sun near the Arctic Circle must have been taking during which time period?

• The Winter solstice because the sun does not go below the horizon.

• The polar region because the tilt of the Earth is not evident.

• The Summer solstice because the North Pole never rotates out of the light of the sun.

• The Spring Equinox because that is the longest day of the year.

Earth's rotational axis ranges from 22.1 to 24.5 degrees of tilt over a cycle of 26,000 years. Earth is in about the middle of this cycle and the tilt of its rotational axis is slowly decreasing. How will a decrease in the tilt of the axis affect the seasons?

• The seasonal changes will become more extreme because the amount of sunlight a given place receives will have greater variation over the course of a year.

• The seasonal changes will become less extreme because with less of a tilt the the amount of sunlight a given place receives will show less variation.

• The tilt of Earth's rotational axis does not play a role in the severity of seasons.

A friend invited you over to spend the night and watch a lunar eclipse. You said that you would like to spend the night but there would not be a lunar eclipse because there was only a quarter moon. How does knowing the phase of the moon help you to predict the possibility of an eclipse?

• The Earth, Moon and Sun have to form a right angle in order for an eclipse to occur. This does not happen during a quarter moon.

• A lunar eclipse only happens during a new moon because this is when the earth passes through the moon's shadow

• Lunar eclipses don't happen because the moon revolves around the earth at a tilt so the earth, sun and moon never line up perfectly.

• Lunar eclipses only happen during a full moon because that is when there is a possibility of the earth sun and moon lining up so that the shadow of the earth falls on the moon.

The white particles in the video are charged particles released by the sun. The video shows a view of the sun just before and during a solar flare. What is a possible impact of Earth getting hit by the cloud of charged particles?

• The charged particles cause mutations in lower life forms resulting in frogs with six eyes.

• The charged particles cause water to condense into clouds, resulting in severe weather.

• The charged particles may overload electrical power grids, resulting in power black-outs.

• In one of the first privately funded research space flights, a group of astronauts gained super powers as a result of being exposed to the charged particles released by a solar flare.

Why was the analemma adopted as the mathematical symbol that means "infinity"?

• The analemma traces the path of the sun, which has been unchanged for the entire memory of Mankind's existence, so it is a good symbol for "forever".

• The ancient mathematicians who came up with the idea of infinity spoke Greek so they used a word from their own language.

• The idea of infinity is a fairly recent mathematical concept and the symbol of the analemma was one of the few symbols from the Greek alphabet that had not been used to represent something in math.

• Who can ever explain the motives and actions of mathematicians? They look at the world from a completely different perspective compared to normal people.

NOAA, the National Oceanic and Atmospheric Agency, tracks solar activity and releases solar weather predictions. Why is solar weather significant enough to monitor it 24 hours a day?

• Solar storms cause extremely high tides.

• Predictions allow people to protect sensitive electronics so they don't get fried by charged particles in the atmosphere.

• Tracking solar weather helps plan satellite launches so that the solar wind does not blow the satellite off course.

• No one should go outside during a solar storm so solar weather predictions help people plan outdoor activities.