# Selected Topics in Contemporary Astronomy and Space Science

## CONTENTS OF CURRICULUM UNIT 98.06.10

## Astronomy and Your Place in the World

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## EARTH

Life as we know it is carbon based, Why? you may ask: Carbon has an affinity for hydrogen and oxygen. This planet has the ideal temperature and pressure range for water, an apparently essential molecule for life. In this solar system no other planet has it.

If we wanted to leave the planet earth to explore other planets we would have to escape the pull of gravity and travel at a speed called escape velocity. Gravity is the weakest of the four forces, yet it is ubiquitous and the most far reaching.

Galileo proved at the Tower of Pisa, that air resistance did not affect two objects dropped from the same height at the same time. They would hit the ground at the same time, regardless of their mass. Newton went a step further by comparing two identical objects one dropped and one thrown horizontally from the same height at the same time. They both hit the ground at the same time. The object that was thrown was further away. The curvature of the Earth is stated as a downward curve of 5m for every 8-km. If a super human were able to throw an object into orbit how fast would it have to travel? The answer may be difficult to arrive because of the square root and metric conversions. It is 17,500 mph. It is the escape velocity for earth.

____ The formula for Escape Velocity is Ve = 2GM

R

Where G is the gravitational constant, m is the mass of the Earth, and r the radius of the Earth.

I have included a rocket launch lab from the U.S. Space Foundation. One might also find the lab making a theodolite, helpful for ascertaining altitude. The task of making a rocket should take about a week and half in a fifty-minute class. After the rocket is finished and properly decaled, special care should be taken to make sure each student has a turn at the delegated positions, such as, launch master, rocket retriever, and official measure. The Theodolite is used to find the angle the rocket traveled. By measuring the distance from the launch site to the observer, the altitude of the rocket can be determined by multiplying the tangent of the angle by the observer/launch site distance.