Updated (in bold) 11/9/08
Since I haven't posted in a while, here is a quick Torah-Science question with a very nice answer from the Baal Shem Tov:
In parashas Lech Lecha, we read: "And He took him outside, and said, "Gaze now, towards the Heavens, and count the stars if you are able to count them!" And He said to him, "So shall your offspring be!" (15:5).
I always had a question on this verse. With modern Astronomy, we can estimate the number of stars in the Universe. The number comes to anywhere between 10^22 to 10^25. This is a huge number. The number of people on the Earth today is roughly 6.5x10^9.
Now, if we are to take this pasuk completely literally, this would mean in the future, the population of the Earth will reach 10^22! I haven't done the calculations, but I am almost certain that that many people cannot fit on the Earth!
(Update: After learning through Isaiah, I found the pasuk which speaks of a "new Earth". Thus, the huge amount of people could fit on this new, potentially larger, Earth).
One possibility I thought of, is that the pasuk is only referring to stars that we can see with the naked eye. This however, doesn't help things because even in the best conditions, and the best pair of eyes, there are only around 2000-10000 stars the human eye can see from the Earth. (And there are a lot more than 10,000 Jews in the World!)
Which brings me to the Baal Shem Tov:
The Baal Shem Tov on parashas Lech Lecha (sif 27) states the following (in my free translation):
"In the name of the Baal Shem Tov the holy, remembered for a blessing, that he explains; That just as the stars when seen from the Earth (the bottom) are small, but above in the Heavens they are extremely big, so too the Children of Israel are seen as small in the lower, present World (Olam Hazeh), but in the Upper World (Olam Haelyon) they are extremely great (big).
This solves the problem. According to this Baal Shem Tov, the second part of the pasuk, "So shall your offspring be!" is not referring to the number of stars counted earlier in the pasuk, but rather is referring to the stars themselves.
This could also answer the question of why the pasuk needs to be split up into two "sayings" of Hashem. Although it would seem like both statements could have been combined into one longer statement, by splitting them up, Hashem is possibly telling us here that we will be like the stars, not like the number of the stars.
(As a side note, according to rough estimations, the number of stars in the Universe and the number of grains of sand on the whole Earth are the same (around 10^22), a possible parallel to elsewhere in Chumash where it mentions the count of the stars in the sky and all the sand together.)