The full moon Friday night, December 12, 2008, will be the biggest one of the year as Earth’s natural satellite reaches its closest point to our planet.
Earth, the moon and the sun are all bound together by gravity, which keeps us going around the sun and keeps the moon going around us as it goes through phases. The moon makes a trip around Earth every 29.5 days. But the orbit is not a perfect circle.
The moon’s average distance from us is about 238,855 miles (384,400 km). Friday night it will be just 221,560 miles (356,567 km) away. It will be 14 percent bigger in our sky and 30 percent brighter than some other full moons during the year, according to NASA.
Tides will be higher Friday night, too. Earth’s oceans are pulled by the gravity of the moon and the sun. So when the moon is closer, tides are pulled higher. Scientists call these perigean tides, because the moon’s closest point to Earth is called perigee. The farthest point on the lunar orbit is called apogee.
Some other strange lunar facts:
· The moon is moving away from Earth as you read this, by about 1.6 inches (4 centimeters) a year. Eventually it’ll be torn apart as an expanding sun pushes the moon back toward Earth for a wrenching close encounter.
· There is no proof the full moon makes people crazy.
· Beaches are more polluted during full moon, owing to the higher tides.
The moon will rise Friday evening right around sunset, no matter where you are. That’s because of the celestial mechanics that produce a full moon: The moon and the sun are on opposite sides of the planet, so that sunlight hits the full face of the moon and bounces back to our eyes.
At moonrise, the moon will appear even larger than it will later in the night when it’s higher in the sky. This is an illusion that scientists can’t fully explain. Some think it has to do with our perception of things on the horizon vs. stuff overhead.
Try this trick, though: Using a pencil eraser or similar object held at arm’s length, gauge the size of the moon when it’s near the horizon and again later when it’s higher up and seems smaller. You’ll see that when compared to a fixed object, the moon will be the same size in both cases.
You can see all this on each night surrounding the full moon, too, because the moon will be nearly full, rising earlier Thursday night and later Saturday night.
Interestingly, because of the mechanics of all this, the moon is never truly 100 percent full. For that to happen, all three objects have to be in a perfect line, and when that rare circumstance occurs, there is a total eclipse of the moon.
Update December 4, 2008… The 36-year wait for the last remaining tortoise of its kind to mate has ended in 13 sterile eggs.
80 year old Lonesome George, the conservation icon of the Galapagos Islands and last surviving tortoise of his kind, looks set to stay lonely after again failing to produce offspring.
Galapagos National Park officials announced yesterday that eight eggs laid by the giant tortoise’s two female companions are infertile.
Conservationists’ hopes were raised in July when George’s mates produced eggs after no fewer than 36 years of encouragement by park rangers.
The eggs were placed in an artificial incubator but they did not develop embryos. There are now fears that George, who is thought to be around 80 years old and the last remaining member of the Geochelone abigdoni species, is sterile.
The most recent prospective mothers have accompanied George in captivity since 1993 but did not begin mating with him until late 2006. They belong to the Geochelone becki species – believed to be the closest existing relative of George.
Between them, the females laid 13 eggs on Santa Cruz Island in July.
The Galapagos National Park director general, Sixto Naranjo, said George could be sterile, or else the female’s adjustment to captivity could have left them infertile.
Another possibility is that the diet in their breeding centre negatively affected their reproductive systems, he said.
But the conservationists have vowed to continue trying. A team of seven biologists and 26 park rangers have begun taking blood samples from tortoises on nearby Isabela Island in search of hybrid species that share as many or more genes with Lonesome George.
The conservationists may have many more years to assist George – a tortoise called Jonathan on the island of St Helena is now thought to be the world’s oldest living creature after a photograph of him has just emerged, confirming that he is likely to be at least 176.