I remember a Physics problem that required us to figure the amount of fuel required to get a 100-kg payload to the nearest star at 1/10 G acceleration/deceleration, assuming total conversion of mass to energy. I can't recall the number, but it was a vast amount of mass... comparable to a planet.

People just don't understand how difficult it is to get around the cosmos. I think belief in UFOs would plummet if this could be gotten across to the general public, in some visceral way.

Unfortunately, shows like Star Trek (much as I enjoy them) have made it impossible. Hey, we can just zip around from star to star, no problem! Engage!