It is first necessary to establish what, precisely, is being asked by that question, since most casual answers are actually responding to the perceived question ‘how is time measured,’ and not to the actual question ‘what is time’.
While Zeno’s Paradoxes appear ridiculous, even silly, on the surface, considering them with greater seriousness reveals that they begin to plumb concepts of physics and mathematics that remain unresolved today.
A Rational Defense of Manned Spaceflight
As computers have become more advanced, faster, and more capable, the arguments in favor of manned spaceflight have become weaker, and space travel has increasingly become the domain of machines. Long before the invention of the microchip, Isaac Asimov proposed exactly this, describing unmanned, computer-controlled space exploration vehicles that would be able to venture into territories too extreme and too dangerous for humans. That vision has come to pass, and it is now commonly argued that humans are indeed too soft, vulnerable, and unreliable to utilize in spaceflight, and that removing them from the paradigm removes the weakest link. Manned spaceflight has largely been relegated to an oft-maligned holdover of Cold War international competition and patriotism. This is a mistake.
Don’t Trust the Science
We've been hearing a lot recently about how we need to "trust the science," and "follow the science." Anyone who does not agree with the science or the above statements tends to be labeled as unintelligent, ignorant, or otherwise mentally backward, perhaps irresponsible. It is one thing for politicians to use such phrases for political leverage and advantage: science has been invoked for political purposes for about as long as science has existed. To me, it is far more dismaying to see people who claim to be scientists themselves undermining the very essence of what science is supposed to be.