Moon and Twins

Traveling to any astronomical object beyond Earth takes time. Apollo astronauts left Earth at 25,000 miles per hour, yet it took three days for them to reach the Moon — our closest neighbor. And present-day missions take even longer.

Yet that’s nothing compared to the time it would take to reach the stars — even the closer ones. A couple of examples appear near the Moon tonight — Pollux and Castor, the “twins” of Gemini, with Pollux closest to the Moon.

Pollux is only 34 light-years away. A light-year is the distance light travels in a year — almost six trillion miles. So Pollux is about 800 million times farther than the Moon. An airliner traveling at about 550 miles per hour would need more than 40 million years to get there. And assuming it could maintain a constant speed, even an Apollo spacecraft would take a million years to cover the gap.

Castor is roughly 50 percent farther than Pollux. That means 60 million years by airliner and a million-and-a-half by spacecraft. There’s one caveat, though. Castor is a system of at least six stars, which makes it a little more difficult to measure its distance. So there’s an uncertainty of about three light-years. That means you could spend all that time in transit and find out that you still had hundreds of thousands of years to go — or that you flew past it and had to double back to reach this nearby star.
 

Script by Damond Benningfield