Mon May 4, 2020 ETA AQUARID METEOR SHOWER
The Eta Aquarid meteor shower is at peak activity tonight; unfortunately the nearly full moon is likely to spoil our view. These particular meteors are bits of dust from Halley’s Comet, plunging into our atmosphere, where they are vaporized, heating up the air around them and causing that momentary streak of light you see in the night sky. But the waxing gibbous moon’s bright light will wash out the sky until it finally sets a couple of hours before sunrise. So the best time to view this shower will be from about 4 am until dawn. If skies are free of interfering clouds or streetlights, face east and look up toward the top of the sky. Dress warmly, protect yourself against mosquitoes, get away from the bright lights, and use a lounge chair so you can recline and enjoy the shower. Meteor showers are not like fireworks displays – sometimes you can go for an hour and not see anything; but every so often, you’ll be rewarded by the appearance of a streak of light in the sky, a shooting star or meteor.
Tue May 5, 2020 SHAPLEY-CURTIS DEBATE
A hundrTed years ago, on April 26, 1920, a debate took place concerning the Milky Way. The astronomer Heber Curtis thought we were at the center of our galaxy, for when you looked along the milky band of stars that defines the galactic disc, you saw roughly the same number of stars throughout. Curtis also thought that spiral nebulae were distant galaxies, like our Milky Way. But Harlow Shapley suggested that interstellar dust clouds blocked our view of the galaxy’s center, and that a concentration of star clusters in the direction of the constellation Sagittarius marked the true center of the galaxy. Shapley said the Milky Way was much larger than anyone realized, but he didn’t think spiral nebulae were other galaxies. It turns out that our solar system is not at the center of the Milky Way, but more than halfway out. And the galaxy is big, 600,000 trillion miles across! But those other spiral nebulas – as Curtis had said, they really are other galaxies, other island universes, far, far away.
Wed May 6, 2020 THE MOON AND THE HORSESHOE CRAB
The moon is nearly full tonight; if you look at it with binoculars, you’ll notice that its western edge or limb is still in shadow. Tomorrow that shadow will disappear. May’s full moon always makes me think of horseshoe crabs out in the Atlantic Ocean. Not a true crab at all, but a distant relative of spiders and scorpions, the horseshoe crab is often called a living fossil because its kind has existed unchanged for hundreds of millions of years. In the springtime, usually in the month of May when the moon is full and the tide is high, the horseshoe crabs mate and lay their eggs in the sand at the water's edge, continuing the process that has brought them unchanged to the present day. Far above, the moon shines down upon them from a distance of a quarter of a million miles. The horseshoe crabs hardly see the moon, lacking proper eyesight for the task, but they are nevertheless driven to perform their mating ritual to the rhythm of the lunar spring tides.
Thu May 7, 2020 FULL MAY MOON IN LIBRA NEAR SCORPIUS
The moon is full tonight and it can be found between the stars Zubenelgenube and Zubeneshamli in the constellation Libra the Scales. Until a few thousand years ago, Libra was part of the constellation Scorpius, and those two stars, Zubenelgenube and Zubeshamale, mean “southern claw,” and “northern claw.” May’s full moon is the Planting Moon of springtime, also the Milk Moon, the Hare Moon or the Frogs Return Moon. Since it’s May we also call it the Merry Moon. In oriental culture it’s known as the Buddha Full Moon. Here in America the Creek and the Seminole Indians call this the Mulberry Moon, The Cheyenne say it is the Moon When the Horses Get Fat, but to the Sioux, it’s the Moon When the Ponies Shed. Other Native American tribes have similar names that suggest the tending of crops, and the beginning of warm weather. To the Winnebago peoples, this is the Hoeing Corn Moon; To the Salish, it is the Flower Moon, but the Osage tribes call it the Moon When the Little Flowers Die.
Fri May 8, 2020 ANNIE CANNON’S OBAFGKM
On May 9th, 1922, astronomers formally adopted Annie Jump Cannon’s stellar classification system. Annie Cannon worked at the Harvard Observatory, where she sorted and catalogued stars by their spectra. When you look at the light of a star through a specialized prism, a spectroscope, you can see that within the rainbow spectrum of the star’s light there are thin gaps where the color is missing. These gaps result when the outer atmospheres of those stars absorb the light, and the spacing of the gaps can be matched up with similar lines made by gases on earth, which tells us what elements are present in those far-away stars – kind of a cosmic bar code. Cannon sorted the stars, and after some adjustments that had to be made because of things like high temperature ionization, resulted in a ranking of stars from hot to cool: O, B, A, F, G, K and M, which countless astronomy students have memorized by using this simple phrase – “Oh, Be A Fine Girl (or Guy,) Kiss Me!
