Sky watch: Sun's closest to Earth in winter
As you gather with friends and family over the New Year holiday, ask a question that's sure to inspire a fun conversation: "During which season does our planet lie closest to the sun?"
Many people believe that our cold wintertime temperatures are somehow caused by our greater distance from the sun. But this isn't the case. In fact, our planet's nearest point to the sun actually occurs in early January!
It was little more than four centuries ago that mathematician Johannes Kepler discovered that the Earth orbits the sun not along a circular path, but along an ellipse. An ellipse is a circle that's been squashed, and the amount of squashing an orbit shows determines its "ellipticity."
After struggling for years to fit circular orbits to the measured motions of Mars, all Kepler had to show for his work was 900 pages of calculations and 70 worthless orbits. And then, around Easter of 1605, he decided he had seen enough circles for one lifetime. He concluded that all he had left to try was an ellipse.
As Kepler drew an ellipse over his data, his eyes lit up. It fit beautifully. In this single moment of unrivaled genius, Kepler solved a problem that had confounded astronomers for centuries. With unbridled joy, he sketched on his work the goddess of victory riding her chariot above the clouds. "The truth of nature, which I had rejected and chased away," he later wrote, "returned by stealth through the back door, disguising itself to be accepted . . . ah, what a foolish bird I have been!"
In 2011, our planet reaches its nearest point to the sun - called "perihelion" - around 2 p.m. on Jan. 3. Its farthest point in 2011 - "aphelion" - won't arrive until July 4.
Of course, if you live in the Southern Hemisphere, where seasons are reversed, our planet's closest point to the sun does occur during summertime. But that's a story for another time.
And now, as we turn the page on yet another year, I'd like to wish all my readers a happy and healthy 2011. And remember: Keep looking up!
Out East with Doug Geed: Wine harvests, a fish market, baked treats and poinsettias NewsdayTV's Doug Geed visits two wineries and a fish market, and then it's time for holiday cheer, with a visit to a bakery and poinsettia greenhouses.
Out East with Doug Geed: Wine harvests, a fish market, baked treats and poinsettias NewsdayTV's Doug Geed visits two wineries and a fish market, and then it's time for holiday cheer, with a visit to a bakery and poinsettia greenhouses.
