Three scientific constraints — vast distance, extreme energy demands and Earth’s unique biosphere — make alien visits to Earth highly unlikely despite renewed UAP attention.
Proxima Centauri sits about 40 trillion kilometres away, and even the Parker Solar Probe’s 191 km-per-second top speed would need roughly 6,650 years to get there.
Near-light-speed travel would also impose severe penalties: time dilation would leave travelers returning to a much older home world, while the energy required rises toward impossible levels and interstellar particles become destructive radiation.
Earth itself may be inhospitable to visitors, the analysis argues, because our oxygen-rich atmosphere is a product of local evolution and could be chemically hostile to alien life.
The piece separates visitation from existence: scientists have identified about 6,200 exoplanets and continue SETI searches, but no evidence of extraterrestrial intelligence has yet been found.