The people that first climbed Mt. Everest weren't scientists, right, they were adventurers. If you're an adventurer, you want to go yourself. It's different than a scientist, who is simply wanting to learn.

In any case, the leading edge of our "on purpose" radio signals is 30 light-years away and, if intercepted, may mend the aliens' image of us based on the radio bubble of our television shows. But this will happen only if the aliens can somehow determine which type of signal comes closer to the truth of who we are, and what our cosmic identity deserves to be.

Robots are important also. If I don my pure-scientist hat, I would say just send robots; I'll stay down here and get the data. But nobody's ever given a parade for a robot. Nobody's ever named a high school after a robot. So when I don my public-educator hat, I have to recognize the elements of exploration that excite people. It's not only the discoveries and the beautiful photos that come down from the heavens; it's the vicarious participation in discovery itself.

Many people are unhappy because there was some point in their past where there was some glory day, and as they get older they're not creating more glory days. They reflect on a time that they will never reach again, and it brings some level of dissatisfaction into their lives. I have circumvented that by simply making incumbent upon myself to always be productive in ways that are consistent with my physical body, my mental state of knowledge, but more important, my presumed growth in wisdom that would come with age.

Let us not fool ourselves into thinking we went to the Moon because we are pioneers, or discoverers, or adventurers. We went to the Moon because it was the militaristically expedient thing to do.

The remarkable feature of physical laws is that they apply everywhere, whether or not you choose to believe in them. After the laws of physics, everything else is opinion.

The universe's destiny has very little to do with the near-term destiny of Earth.