L&S 117: Astrobiology Last Year's Midterm #1 Answer any 10 questions. Use separate sheets of paper except for questions 10-12 which you can do on this exam itself.

1. Diagram the Solar System, including all the objects that we can see. Label those elements with their proper names or type of object. What shape overall is the Solar System? Sketch the habitable zone of the Solar System.

   Diagram should show the Sun with Mercury, Venus, Earth, Mars, Asteroid belt, Jupiter, Saturn, Uranus, Neptune, Pluto and the comet belts outward from the Sun, with some indication of which planets have moons. The overall shape is a disk with the Sun at the center. The habitable zone stretches from outside of Venus to just inside of Mars.

2. Many scientists allow that extraterrestrial aliens may exist. Why do they then consider the UFO phenomenon pseudoscience?

   There is no solid evidence of UFO’s that can be examined and documented scientifically. Photos and videos are not evidence, nor is hearsay, even if the US Air Force put it out. What evidence that has been presented has been accounted for by other phenomena. No the government is not covering things up, because there is no evidence that they did that either.

3. How and where did the light elements, like H, He, Li, originate? How and where did the heavier elements, like Fe, U, Pb, originate?

   The light elements formed during the initial expansion of the Universe. The heavier elements are formed in exploding Supernovae, cast into the nearby Universe and incorporated into other objects, including planetary systems.

4. Write in words the following:
   

   
   10¹ = ten.?
   273^oK = Two hundred seventy three degrees Kelvin (the freezing point of water).
   4.5 X 10⁹ = Four and a half billion.
   100^oC = One hundred degrees Centigrade (the boiling point of water).
   10^-2 = One one hundreth?
   10⁶ = One million.
   10K = Ten thousand
   550,000,000 = Five hundred fifty million. 

5. Where did the materials for life come from?

   These include C & H chiefly, together with S, N, P, and some others. The organic elements and simple molecules were brought to earth in meteorites, asteroids, and perhaps comets. They were assembled by energy sources on earth (lightning, volcanism, UV, sunlight, etc., into more complex molecules.

6. What is science particularly good at? What is it not so good at?

   Science is very good at learning about and understanding the material universe around us. It is not good at morality or spiritual issues or matters of hope and comfort.

7. Why cannot the answer to the Drake Equation be 0?

   If we consider our entire Universe or galaxy, then the answer must be 1 because we know we exist.

8. Why is the surface of the moon very old most places and the surface of the Earth much younger most places?

   The Moon’s surface is much like it was soon after it formed because plate tectonics and water/atmospheric weathering and erosion do not occur there. On Earth, the older rocks have been mostly destroyed and recycled by these processes.

9. How did biological protocells develop, at least in theory and lab experiments? Draw the steps with brief captions for each drawing.

   A drying and wetting process will cause the assembly of lipids into membrane-like bound structures with the hydrophobic tails and hydrophilic heads of the lipids directed inward and outward respectively. Drying could take place in tidepools, lagoons, lakes or ponds.

   10. Draw below a cross-section of the Earth’s lithosphere and asthenosphere from roughly Iceland to Hawaii.
   
   
   

   
   11. What is this object? What does it show? Why is that significant?
   The image was taken Monday, Valentine’s Day. So, is that Cupid’s arrow?
   
   

This is an image of the asteroid Eros taken on Valentine’s Day by a NASA spacecraft. It shows many craters on its surface, in spite of the fact it is rather small. The significance of the craters is that they demonstrate impact events occur on all planetary bodies in the Solar System, supporting the idea of formation of objects by the accumulation under gravity of smaller dust and rock, and even larger objects., into still larger ones. No, that’s not Cupid’s Arrow, that’s NASA’s arrow pointing out Eros.

12. Draw the habitable zone on the following image?
Why did you put it where you did?

		The arrow shows the estimated "habitable zone" of this galaxy. Not too close to the core, with its high heat and gravity, and not too close to the extremities, with their cold and less dense materials, of the spiral.