What could inflation theory have to do with the Fermi paradox? Quite a lot, if at least one recent paper is to be believed. The question 'where are they' about extraterrestrial visitation becomes even more pointed when faster-than-light technologies move out of the realm of the impossible to something that may be seriously investigated by physicists. Inflation theory, which holds that the early universe underwent a vast expansion as spacetime itself stretched far beyond the velocity of light, opens the door to technologies that might use this effect to create spacefaring civilizations spanning entire galaxies. Just how fast did inflation occur? In a space of time lasting about 10-35 seconds, the universe could have expanded by a factor of 1030 to 10100. As Brian Greene puts it in The Fabric of the Cosmos: An expansion factor of 1030 -- a conservative estimate -- would be like scaling up a molecule of DNA to roughly the size of the Milky Way galaxy, and in a time interval that's much...

When physicist Geoffrey Landis reviewed interstellar concepts at the American Association for the Advancement of Science's 2002 meeting, his wide-ranging presentation considered where we stand on nuclear propulsion, solar and lightsail technologies, and particle-pushed sails. He also addressed the question of the Bussard ramjet, which would use an electromagnetic scoop to collect atoms from the interstellar medium to fuel a fusion reactor. Finding serious problems here (he cites, among other things, the fact that the scoop technology acts more like a brake than an accelerator), Landis went on to consider an alternative: "These problems can be alleviated if, instead of using the ambient interstellar medium, fuel is deliberately emplaced in the path of the spacecraft before flight. In this way, the fuel (probably in the form of small 'pellets') can be chosen to be the optimum composition... The 'runway' of fuel pellets could be emplaced, for example, by a dedicated craft which drops...