discussion questions - h. Explain what causes weightlessness. j. Explain the effects we see in the sky when the earth revolves. l. How do we know the earth is spherical? o. Where is the ecliptic and what constellations are along there? Please answer only if you know something about Astronomy. Thanks.

Ptolemaic theory - How did Galileo's observations show that the Earth-center theory (Ptolemaic) was wrong?

Why do astronomers infer that the Sun's energy comes from nuclear fusion reactions... - c. Why do astronomers infer that the Sun's energy comes from nuclear fusion reactions? How do we know it does not come from chemical burning? d. Explain how the Sun produces energy by nuclear fusion. e. When we look at stars in the sky we see a wide range of brightness. Explain the factors that would make o...

What would an imaginary terrestrial observer see as the Sun runs out of hydrogen in the future? If life is confined to Earth when this happens, would life perish from heat or from cold? - What would an imaginary terrestrial observer see as the Sun runs out of hydrogen in the future? If life is confined to Earth when this happens, would life perish from heat or from cold? Explain. What kind ...

Venus and Earth are about the same size and mass, yet carbon dioxide is a major constituent of the atmosphere of Venus, while oxygen is much more abundant in the Earth’s atmosphere. Explain why the atmospheres are so different. - g. Venus and Earth are about the same size and mass, yet carbon dioxide is a major constituent of the atmosphere of Venus, while oxygen is much more abundant in th...