The+Earth,+Moon,+and+Sun


 * //Can you describe the various ways that the Earth Sun and Moon interact? Pictures always help. Think about eclipses (lunar and solar), tides, time keeping, and seasons.//**

**__ Chapter 2 __**
====4. Q: Imagine that someone suggests sending a spacecraft to land on the surface of the celestial sphere. How would you respond to such a suggestion? A: I would politely tell them that sending a spacecraft to land on the surface of the celestial sphere is impossible because the celestial sphere is imaginary. ** NICE. **==== ==== **8. Q: Is there any place on Earth where you could see the north celestial pole one the northern horizon? If so, where? Is there any place on Earth where you could see the north celestial pole on the western horizon? If so, where? Explain your answers. A: Yes, anywhere in the north hemisphere you could see the north celestial pole on the northern horizon. No.** ** GOOD. **====
 * YOU ANSWERED THIS ONE! :)** **Do we ever relate stars to other planets celestial spheres? 3. Q: What is the celestial sphere? Why is this concept still useful today? A: The celestial sphere is the apperent sphere in the sky. This concept is still useful today because it provides a useful tool of positional astronomy.** ** Good work but this sounds like a book definition. It's fine as long as you understand it. **

**__ Chapter 3 __**
What is the difference between a lunar eclipse and a solar eclipse?

13. Q: The maximum duration of totality of a lunar eclipse is 1 hour, 42 minutes. But none of the lunar eclipses listed in Table 3-1 lasts this long. Why is this? A: A lunar eclipse does not always take 1 hour, 42 minutes because the Moon is not exactly in the center of the Earth's umbra.

A: The saros is a more accurate way to predict an eclipse by adding one thirds of a day longer. In my book it said that astronomers couldn't predict the eclipses, they just used various degrees of reliability to make fairly accurate guesses.
 * 19. Q: What is the saros? How did ancient astronomers use it to predict eclipses?

21. Q: How did Aristarchus try to estimate the distance from the Earth to the Sun and Moon? A: Aristarchus knew that the Sun, Moon, and Earth from a right triangle at the first and third quarter Moon phases. Using geometrical arguments, he calculated the relative lengths of the sides of these triangles, thereby obtaining the distances to the Sun and Moon.

How does the gravity of the moon affect the ocean tides? **What did you come up with for this one now that you got through that chapter? A: The moon effects the Earth's ocean tides because of the different gravitational pulls from the moon on different points on the Earth. For example if the moon was perpendicular to the Earth's north and south poles. A person at the equator would be at a high tide and a person on the north or south pole would be at a low tide. GOOD WORK!**

How long does it take for light from the Sun to reach the Earth at its nearest point? A: I takes 8 1/3 minutes for the light from the Sun to reach the Earth.

__**Chapter 6**__
What kind of heat affects ground telescopes and how?

1. Q: Describe reflection and refraction. Explain how these processes enable astronomers to build telescopes. A: Refraction is the change in direction of a light ray when it passes into or out of a transparent medium such as glass. Reflection is when beams of light are bounced back at an object, usually from a mirror or polished object. Reflection and refraction both enable astronomers to build telescopes because both processes focus a larger area into a much clearer, smaller area. **Good.**

5. Q: Do most professional astronomers actually look through their telescopes? Why or why not? A: Most professional astronomers do not actually look through their telescopes. This is more beneficial because if you take long exposures with a camera mounted at the focus of a telescope, an astronomer can record features too faint to be seen by simply looking through the telescope. This also enables astronomers to use recent technology so that they don't have so be at the sight of the telescope. **Also the types of telescopes are in wavelengths other than visible light.**

9. Q: Explain some of the disadvantages of a refracting telescope compared to a reflecting telescope. A: A reflecting telescope is better than a refracting telescope for a couple of reasons. One of them is that light reflects off the surface of the glass rather than passing through the glass, you don't have to worry as much about defects in the glass. Another is that they do not suffer from chromatic aberration unlike refracting telescopes that do. **Good.**

21. Q: Compare an optical reflecting telescope and a radial telescope. What do they have in common? How are they different? A: If you compared a radial telescope and an optical telescope you would see that they both have a place where data from the focal point is collected. They both would have the same problem, the angular resolution was bad. But on the reflecting telescope, the problem would be atmospheric turbulence, and the radio telescopes problem would be that the longer the wavelength, the larger (and worse) the angular resolution and the fuzzier the picture. Astronomers using radio telescopes over come their poor resolution by: A) making the telescopes huge, or B) they combine the signals from radio telescopes at different observatories thousands of kilometers apart.

27. Q: Why must astronomers use satellites and Earth-orbiting observatories to study the heavens at X-ray and gamma-ray wavelengths? A: Because the telescopes outside the Earth's atmosphere see radiation that does not penetrate the Earth's atmosphere. **Great!**