One of the more seminal thinkers of the late 20th century may have been Carl Sagan who, through his work producing the "Cosmos" television series and other venues, sought to educate the public about science.
Sagan believed humanity's destiny was to explore space and colonize other planets, but he also believed that the humanity of his time wasn't capable of that.
Humans will need to stop fighting among themselves, and take better care of the planet they have, he said, before they can think about reaching others.
One Sagan acolyte believes the adoption of Tesla electric cars is a step in the right direction.
And he's a good example of the devotion Tesla Motors can generate: the electric-car maker benefits from fans so loyal that they actually create free video "commercials" for the carmaker.
This one, posted by YouTube user Loren Booker, features Sagan reading a passage from his 1994 book Pale Blue Dot: A Vision of the Human Future in Space.
2016 Tesla Model S
The phrase "pale blue dot" comes from a photograph taken of Earth from 3.7 billion miles away by the Voyager 1 spacecraft in 1990.
To Sagan, the barely-visible speck that represented Earth was the clearest indication ever of humanity's need to protect the planet, and ultimately to spread itself to other worlds.
Sagan's speech is combined with stock footage of Tesla electric cars and solar panels, which the video's creators view as steps toward the goal of preserving the planet.
The video alternates between shots of electric cars and oil wells as Sagan talks about a future version of humanity with "more of our strengths and fewer of our weaknesses."
NASA's famous 'Blue marble' image of Earth (Wikimedia commons)
Those "weaknesses" clearly include, in the video maker's eyes, the use of carbon-emitting fossil fuels and other environmentally irresponsible practices.
Humanity's need to colonize other planets in order to preserve itself is an idea shared by Sagan and Tesla CEO Elon Musk.
Musk has talked repeatedly about colonizing Mars, a goal he had even before founding the SpaceX company that could eventually produce the rockets to do that.
Imagine the ads his fans will create if that first manned mission to Mars ever happens.
[hat tip: George Parrott]