Extraterrestrials may arrive in 500 years, but not in flying saucers

30 April 2024

In the late 1960’s, former United States President Jimmy Carter, reported seeing an Unidentified Flying Object (UFO). Today unexplained objects, or phenomena, seen in the skies, are referred to as Unidentified Anomalous Phenomenon (UAP). Carter, however, was not expecting to participate in any historic close encounter of the third kind:

While puzzled by the object and its origins, Carter himself later said that, while he had considered the object to be a UFO — on the grounds it was unexplained — his knowledge of physics had meant he had not believed himself to be witnessing an alien spacecraft.

Some people may be unhappy that Carter allowed physics to get in the way of a good story. Because wouldn’t it be great if we could whiz about the galaxy in a vessel the size of the average suburban house, which every other intelligence in the galactic neighbourhood seems capable of, except us.

House-size flying saucers defy the laws of physics, because, you know, their builders seemingly are able to defy the laws of physics. It would however be awesome to zap back and forth to say the nearest star system, Alpha Centauri, in a house-size vessel that could travel (presumably/somehow) faster than the speed of light. At least I’m not breaking the laws of dreaming there.

But if close-to-light-speed interstellar travel, together with the possibly of extraterrestrials visiting Earth (from the far side of the Milky Way, no less) intrigues you, read this Twitter/X post, by American physicist Casey Handmer. Visitors from civilisations, from maybe fifty thousand light years across the galaxy, may be mere centuries away from reaching our solar system:

Let’s say that any civilization that can figure out interstellar travel can develop from slow to 99% of the speed of light in 500 years, and they’re coming from the other side of the galaxy — 50,000 years ago. By the time the light of their first (presumably highly energetic, fireworksy) relativistic travel reaches us, they’re already 99% of the way here – just 500 years to roll out the welcome mat.


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