Skywatch for the week of January 2, 2023
Mon Jan 2, 2023 JANUARY AND THE NEW YEAR
January is named for Janus, the Roman god who had two faces: one looked back to the past, the other looked forward to the future. This is also the year Twenty-Twenty-Three, which according to the calculations of a Roman monk, Dionysius Exiguus, marks the two thousand and 23rd year following the birth of Christ – AD – Anno Domini – in the year of Our Lord - 2023. But Dionysius’s count was off by one year. Our calendar goes from 1 BC to AD 1 – there is no zero year, because the numerical concept of zero was not used in Europe back then. Now if you’re outside tonight after sunset you can find the waxing gibbous moon just to the west of a very bright red star, which is actually the planet Mars! Four other planets – Jupiter, Saturn, Mercury and Venus are also in the western sky.
Tue Jan 3, 2023 THE QUADRANTIDS
Tonight, as we make our closest approach to the sun, we also have a meteor shower going on, called the Quadrantids. Most meteor showers are the result of comets passing through our part of outer space; they deposit ice and debris in our path and the earth sweeps it up as it orbits the sun. the Quadrantids seem to come from an asteroid – in this case, 2003EH1, which has a five and a half year orbit (and some astronomers think it may actually be a burned-out comet!) This is not a very big shower, but it’s always nice to see a “shooting star” on a crisp winter night. Because of the waxing gibbous moon, this shower is best seen for a few hours before dawn. Face toward the northeast and look up toward the top of the sky.
Wed Jan 4, 2023 PERIHELION
The earth's distance from the sun changes. Today at 11:17 am, our planet reaches perihelion, a point in its orbit where we’re closest to the sun. On average, we're about 93 million miles from the sun, but right now, we are just a little under 91 and a half million miles from it. So if we're a million and a half miles closer to the sun, how come we're having winter? Well, not everyone on earth is having winter; summer has just begun for folks who live below the equator. Our seasons are caused not by distance, but by the earth’s 23 and a half degree tilt as it orbits. Like a gyroscope, the earth‘s north pole points toward the North Star. Now our north hemisphere is tipped away from the sun; this puts the sun lower in our sky, and with less direct sunlight we get cooler temperatures.
Thu Jan 5, 2023 RIDDLES IN THE DARK
J.R.R. Tolkien was born on January 3rd, 1892. In his fantasy story, “The Hobbit,” the hero Bilbo meets a strange creature named Smeagol down in a deep cave, and they ask each other riddles. One goes like this: “It cannot be seen, cannot be felt Cannot be heard, cannot be smelt. It lies behind stars and under hills And empty holes it fills.” And the answer is, “darkness.” Now, here’s an astronomy riddle I made up: “At weddings they appear; and at front doors it’s them we hear. They’re found on Elven hands and soda cans; ‘Round Saturn they appear.” And the answer is, “rings.” Let’s try another astronomy riddle. “It’s always on, and never off. It’s more when nearby, and less when far off; It keeps the sun from spilling out. And in the end, it stops us going up and about.” The answer is “gravity.”
Fri Jan 6, 2023 JANUARY FULL MOON
The moon is full today, rising out of the east at sunset. To ancient Celts, January’s full moon was the Storm Moon, because they believed that storms raged both before and after its appearance in the sky. To the Passamaquoddy Indians, this is the Wolf Moon, a time of year when wolves that normally avoided humans, would be forced by winter famine to scavenge from the villages. Wolves were seen more frequently, especially at night when the moon was full and bright. To the Sioux, this is the Moon of Strong Cold; the Zuni know it as the Moon When the Limbs of Trees are Broken by Snow. The Tewa Pueblo peoples call it the Ice Moon, the Cherokee the Windy Moon. And to the Omaha Indians, it is the Moon When the Snow Drifts into the Tepees.