And more, sort of, on the solar energy riff, "the Rebbe" being Menachem Mendel Schneerson, the seventh and last Lubavitcher rebbe and, from the hagiographies I've been reading, a rather amazing individual:
What is the characteristic—the Rebbe asked—that determines more than any other that people consider the sun to be a blessing? Obviously it is its ability to radiate, “to shine upon the earth” (Genesis, 1:15). What would happen if the sun was just as hot, and had the same amount of energy, but did not radiate? Indeed, there are stars of that sort, which are known as “black holes,” whose gravitational pull is so intense that not a single ray of light can escape. Who then would be interested in the sun? What purpose would it have? The same applies to a Jew. One’s main purpose is to shine, to radiate, to do good for the other . . . otherwise one turns into a black hole, while one was actually created with the mission to be a sun.