Questions: In "Future of Space Exploration Could See Humans on Mars, Alien Planets," what main point does Mae Jemicon make regarding Provima Contaun, the nearest star? It probably will be reached by NASA's Voyager 1 spacecraft within her children's lifetime. It cannot be reached for thousands of years, given our present technology. It is unlikely to have a planetary system that can support human life. It is farther away than the distance from New York to Los Angeles.

The answer is the second one: It cannot be reached for thousands of years, given our present technology.

Explanation for each option:

1. "It probably will be reached by NASA's Voyager 1 spacecraft within her children's lifetime." - This is incorrect because Voyager 1, while traveling at a significant speed, is not on a trajectory to reach Proxima Centauri and would take tens of thousands of years to get there even if it were.
2. "It cannot be reached for thousands of years, given our present technology." - This is correct. Mae Jemison likely emphasizes the vast distances involved in space travel and the limitations of our current technology, making it clear that reaching Proxima Centauri would take thousands of years with the technology we have today.
3. "It is unlikely to have a planetary system that can support human life." - This is incorrect because Proxima Centauri does have at least one known planet, Proxima Centauri b, which is in the habitable zone where conditions might support liquid water and potentially life.
4. "It is farther away than the distance from New York to Los Angeles." - This is incorrect because it is a gross understatement. Proxima Centauri is about 4.24 light-years away, which is vastly farther than the distance between New York and Los Angeles.

Summary: Mae Jemison's main point regarding Proxima Centauri is that it cannot be reached for thousands of years, given our present technology.