THE MOON APPROACHES MARS: Last night, the crescent Moon passed by Venus. Tonight, it is approaching Mars. Look south after sunset to see the waxing lunar crescent not far from the Red Planet. Sky maps: Dec 3rd, 4th.
LARGE CORONAL HOLE TURNING TOWARD EARTH: A large hole in the sun's atmosphere has formed and it is turning toward Earth. NASA's Solar Dynamics Observatory took this extreme ultraviolet image of the structure on Dec. 4th:
This is a "coronal hole"--a region where the sun's magnetic field has opened up, allowing solar wind to escape. A stream of solar wind emerging from this coronal hole could reach Earth as early as Dec. 7th and influence the near-space environment of our planet for several days. G1-class geomagnetic storms and high-latitude auroras are possible when the solar wind arrives.
Note: The forecast will improve in the days ahead as the hole rotates into better view, revealing its form and dimensions. Stay tuned!
WATCH OUT FOR THE DA VINCI GLOW: If you go outside tonight to witness the meeting of Mars and the crescent Moon, pay special attention to the Moon. Cradled between the arms of the slender crescent is a display of light and shadow that puzzled sky watchers for thousands of years--until Leonardo da Vinci figured it out. It's the "Da Vinci glow," also known as Earthshine:
Jo Smeets of Itteren, the Netherlands, took the picture last night as the Moon was passing Venus en route to Mars. "The Earthshine really popped in this 5 second exposure with my Canon digital camera," says Smeets.
For much of human history, people marveled at the faint image of the full Moon inside the arms of the bright crescent. Where did it come from? No one knew until the 16th century when Leonardo figured it out. He realized that dark lunar terrain was being illuminated by sunlight reflected from Earth.
Visualizing this in the 1500s required a wild kind of imagination. No one had ever been to the Moon and looked "up" at Earth. Most people didn't even know that Earth orbited the sun. Copernicus' sun-centered theory of the solar system wasn't published until 1543, twenty-four years after Leonardo died.
Above: Da Vinci's sketch of Earthshine in 1510 vs. Italian astronomer Riccardo Di Nasso's photo of Earthshine in 2006.
Wild imagination, however, was one thing Leonardo had in abundance. His notebooks are filled with sketches of flying machines, army tanks, scuba gear and other fantastic devices centuries ahead of their time.
In Leonardo's Codex Leicester, circa 1510, there is a page entitled "Of the Moon: No Solid Body is Lighter than Air." He states his belief that the "ghostly glow" is due to sunlight bouncing off Earth's oceans and, in turn, hitting the Moon. 500 years later, we know that Earth's clouds (not oceans) do most of the reflecting; but that is a quibble. Leonardo understood the basics well enough.
Go outside tonight and look to the sky. The Da Vinci Glow is waiting....
Realtime Space Weather Photo Gallery
FLIGHT OF THE SPACE PICKLE: Did you know that cosmic radiation in Earth's atmosphere is increasing? It's true. These and other findings of the Earth to Sky Calculus ballooning program are funded not by government grants or corporate donations. Instead, we rely on crowdfunding. Hence, the flight of the space pickle:
To raise funds for their ongoing research, Spaceweather.com and the students of Earth to Sky Calculus have flown a payload-full of Christmas pickles to the stratosphere. On Nov. 20th, the glass gherkins ascended to an altitude of 111,900 feet, experiencing temperatures as low as -55 C and cosmic ray dose rates more than 100x Earth normal.
You can have one for your own tree. Price: $49.95. All proceeds are used to support cutting-edge student research. The space pickle and other edge of space gifts may be found in the Earth to Sky Store.