Skywatch for the week of November 21,2022
Mon Nov 21, 2022 EDWIN HUBBLE AND HARLOW SHAPLEY
Two American astronomers were born this month: Harlow Shapley on November 2nd, 1885; and Edwin Hubble on November 20th, in 1889. Each made great discoveries. Shapley discovered that our sun and solar system were not at the center of the Milky Way Galaxy, but instead a little over halfway out, and that the Milky Way was much larger than anyone had previously thought, almost 600,000 trillion miles in diameter: big. But Shapley thought that the Milky Way was all there was to the Universe.
It was Hubble who measured the distance to the Andromeda Nebula, that is galaxy, some 15 million trillion miles away, which placed it far outside our own galaxy. Hubble also found evidence that the Universe was expanding, suggesting that everything began billions of years ago in what is now called, the Big Bang.
Tue Nov 22, 2022 FARTHEST NAKED-EYE OBJECT
What’s the farthest thing you can see without a telescope? High in the northeastern sky this evening, you can find the answer to this question, but only if the skies are very clear, and very dark, and you know just where to look. It’s a very dim smudge of light that lies in the direction of the constellation Andromeda. But this small spot lies well beyond the stars of Andromeda, which are merely trillions of miles away.
It’s another galaxy, comprising hundreds of billions of stars and approximately two and a half million light years away. One light year, the distance light can travel in a year, is roughly six trillion miles. So when you see the Andromeda Galaxy, you’re looking at something that is fifteen million trillion miles away – and that’s how far out your eye can see.
Wed Nov 23, 2022 HERCULES’ AUTUMN ZODIAC
The adventures of Hercules are displayed by the constellations. The zodiac reveals many of his twelve great labors. Soon to set after the sun are the stars of Sagittarius the archer. This centaur is a depiction of Hercules’ teacher, Chiron. Well-placed in the south are a scattering of stars which mark Aquarius, the Water Carrier. This is symbolic of Hercules’ releasing the flood of river waters that cleaned the Augean stables.
High in the east is Aries the Ram, a representation of the golden fleece, which Hercules pursued with his good friend Jason while he was between labors. Nearer toward the eastern horizon is Taurus; this was a wild bull which Hercules subdued in a kind of a “capture and release” program.
There are more constellations connected with Hercules, but they won’t show up in our evening sky until next month.
Thur Nov 24, 2022 CHRISTIAN HUYGENS AND HIS DISCOVERIES
The planet Mars shines brightly in the northeast sky this evening. The first good map of Mars was drawn by the astronomer Christian Huygens on November 29, 1659. Early telescopes were primitive. A lot of patience and sometimes a lot of imagination were needed to see details through the eyepiece.
When, for example, Galileo first saw Saturn through a twenty-power telescope in 1610, he thought it had "handles" on either side of it. When Huygens observed Saturn though a better telescope, he announced that the planet possessed "a thin, flat ring..." Most astronomers didn’t believe him, until they too were able to see for themselves. Four years later, Huygens made his sketches of Mars, and by watching its dark features drift across the Martian surface, figured out that Mars rotated about once every 24 hours, same as Earth.
Fri Nov 25, 2022 NAME THAT CONSTELLATION - NOVEMBER
Can you identify the 15th largest constellation? It is bordered on the north by Scutum, Aquila and Serpens Cauda, on the south by Telescopium and the Southern Crown, on the west by Scorpius and Ophiuchus, and on the east by Microscopium and Capricornus.
The center of the galaxy lies in the direction of its western border, and it contains many star clusters as well as the Trifid and the Lagoon Nebulae. This constellation has no first magnitude stars, but a handful of 2nd magnitude stars trace out the crude shape of a teapot and this evening the moon shines within the teapot’s lid.
In Greek myth it represented Chiron, a centaur who guards other constellations by keeping Scorpius at bay with his bow and arrow. Can you name this star figure, the ninth constellation of the zodiac? The answer is Sagittarius the Archer.