We've had a long-running series here at UT on potential solutions Fermi paradox—why aren't we able to detect any alien life out there in the Universe? But more possible solutions are being developed all the time. Now, another paper adds some additional theory to one of the more popular solutions—that aliens are just too busy to care about us.

The paper, released on arXiv, was written by Amri Wandel of the Racah Institute of Physics at the Hebrew University of Jerusalem. It makes two basic assumptions. First, aliens don't really care about planets with life on them. Second, they would care if they could detect intelligent life on one.

For the first assumption to be valid, it would help if the occurrence of "biotic" (i.e., having biology) planets is widespread. In that case, even advanced civilizations might not have enough resources to devote to fully exploring those planets, especially in the form of an actual probe.

A team of researchers from McGill University and the Tau Zero Foundation is proposing a new idea for faster spacecraft propulsion that involves dynamic soaring. In their paper published in the journal Frontiers in Space Technology, the group outlines the idea of dynamic soaring as it applies to a speedy way to move through space and other possible uses for it.

Over the past several decades, as human-built space vehicles have made their way to many of the planets and moons in our solar system, it has become clear that a means is required for creating spacecraft that can get to distant destinations in space much faster.