7) Earth is always exactly 1 AU (astronomical unit) from the Sun. True/False - explain? 8) What was discovered with the "Hubble Deep Field" images and the "Ultra Deep Field" -that we were not expecting to find - explain? 9) Why don't we have a solar eclipse every month and a lunar eclipse every month - explain?

7 - With the advent of spacecraft and radar, more precise methods emerged for making a direct measure of the distance between the Earth and the sun. The definition of AU had been "the radius of an unperturbed circular Newtonian orbit about the sun of a particle having infinitesimal mass, moving with a mean motion of 0.01720209895 radians per day (known as the Gaussian constant)" We can say that one astronomical unit (AU) represents the mean distance between the Earth and our sun. An AU is approximately 93 million miles (150 million km) . It's approximately 8 light-minutes.

8 - One of the main scientific justifications for building Hubble was to measure the size and age of the Universe and test theories about its origin. Images of faint galaxies give 'fossil' clues as to how the Universe looked in the remote past and how it may have evolved with time. The Deep Fields gave astronomers the first really clear look back to the time when galaxies were forming.

The Hubble Ultra Deep Field from 2004 represents the deepest portrait of the visible universe ever achieved by humankind. The Ultra Deep Fields show the furthest away galaxies that can be observed in visible light.

9 - It’s true that the moon goes around Earth every month, but it doesn’t always get in Earth’s shadow. The moon’s path around Earth is tilted compared to Earth’s orbit around the sun. The moon can be behind Earth but still get hit by light from the sun.