Ch. 19 Lecture Quiz

[Joey Lee]

Dr. Mayes,

I keep getting one question wrong on this quiz and I am unsure why. It says, "the scientists of the 17th century had not fully grasped the fact that" and then there are 4 check boxes:

1. the sun is a star

2. they were just describing a small part of the universe

3. there are other solar systems other than our own

4. there are other stars in our universe

If I remember correctly, I think the above are the available answers, or at least something like it. I know it is not the exact words. So, I looked back at the lecture slides to try to find these answers, since I kept getting them wrong and I still keep getting them wrong. I feel like 1. cannot be an option because it says in lecture that "So they could conceive of the possibility that the sun was a star, which had been suggested by Anaxagoras as far back as 500 B.C."

I feel like 2. is true since they thought they were describing the entire universe, not a tiny little speck of it, as mentioned in lecture.

I feel like 3. and 4. are implications of 2., and I could be wrong in thinking this.

Regardless, I took this multiple times and I still cannot get it. The only thing from lecture that seems clear is when you said "But that does not mean they thereby conceived of the possibility that the planetary system they were describing was something that absolutely any star in the sky might possess"; clear as in, this seems like this is the clear answer to this question above. However, I am beginning to feel like I don't even know what this statement is actually suggesting.

I appreciate your help and your time. Thank you!

[G. Randolph Mayes]

Hi Joey, good question and this is exactly the right way to ask it.

I agree with you that this one is a bit confusing. 

So you are right that they could conceive of the sun of the star, but it would not be correct to say that they fully grasped that it is a star. I think this is reasonably clear from the lecture and just requires you to distinguish between 'conceive' and 'fully grasp'.

However, while they had not fully grasped the magnitude of the universe, they had definitely come to realize that the universe extended well beyond what anyone could observe, so they knew the could not be describing the entire universe. I think this particular answer is confusing, though, so I have changed it in the the quiz and the test to something that is more obviously false according to lecture, viz., "the solar system is not the entire universe, but just a small part of it."  (I mean here that it is false that they did not grasp this.) 

3 and 4 are not really implications of 2, though 2 permits these possibilities where previously they were perhaps not imaginable.

Of course they had always known that there are many stars in the universe, so this would imply that there are other stars in the universe, but this answer is also confusing because "other" tends to suggest that they grasped that our sun is a star, which they did not. So I have changed this quiz question by substituting "many" for "other". It now reads: "there are many stars in our universe". It is false that they failed to grasp that, and of course false that the ancients failed to grasp that. 

Very, very few people imagined that there could be other solar systems. And you're right, this would tend to require realizing that the sun is a star. So since they did not fully grasp that, they did not even come close to grasping this.

Since this is a long answer to your question and the question itself is not well written, I'll simplify for others by saying that the answer as it is written above is: 1 and 3. This is preserved in the slight rewordings of the question as well..