A Shout Out to the Heavenly Hero
Looking for ET with Hercules
Given the scorching temperatures of late, you might be surprised to know that earth is at its farthest point from the sun this time of year, called, aphelion. On July 4, Earth reached the apex of its elliptical orbit around the sun at 94,505,851 miles. That’s about three million miles farther than at perihelion, earth’s closest point to the sun.
That may seem like a significant distance, it’s little more than three percent, not enough to account for earth’s seasonal temperature fluctuations. Instead, it’s earth’s 231⁄2-degree tilted axis that causes our seasons. During our summer months, the Northern Hemisphere is tilted toward the sun, bathing us in several hours more sunlight each day than our brethren in the Southern Hemisphere, which is tilted away from the sun and where it is winter.
Sunset reveals Hercules, which by midnight is directly overhead. While none of its stars are brighter than third magnitude, Hercules is the fifth-largest constellation and is easily recognized by the four stars outlining the hero’s body, called the Keystone. What these stars lack in brightness, they make up for in potential, as astronomers have discovered planets orbiting 15 of them, with seven of those planets smaller than Jupiter.
Look to Hercules’ hip for M13, the brightest globular star cluster in the Northern Hemisphere. At fourth magnitude it is visible to the unaided eye but appears as nothing special. However, a telescope or even binoculars unveil some its hundreds of thousands of stars. More than 20 years before scientists had the means to tease out the presence of extra-solar planets, they deemed M13 a worthy object in the search for extra-terrestrial life, beaming one of the first radio messages toward it. At the speed of sound, it should reach any alien beings in 20,000 years, give or take a few millennia. Perhaps we’ll get their reply in another 20,000 years.