Skywatch for the week of August 9, 2021
Aug 9, 2021 New Moon
Mon Aug 9, 2021 THE “TEARS OF ST. LAWRENCE”
Every year at this time, the earth travels through a portion of its orbit that is littered with bits of ice and dust left in the wake of a passing comet. As we plow into this region, we are treated to a display of shooting stars, as those particles plunge through our atmosphere. None of this debris strikes our planet, but vaporizes, lighting up the sky in a brief flash of light – a meteor. This particular meteor shower is called the Perseids, so named because they seem to come out of the part of the sky near the constellation Perseus; it’s a reliable shower viewed by millions of people for many years: in medieval times it was known as the “tears of St. Lawrence,” in honor of the Christian martyr whose feast day is tomorrow, August 10th. Grab a reclining lounge chair, protect yourself against mosquitoes, go out late in the evening or after midnight, face east, and look up toward the top of a clear, dark sky for the best views.
Tue Aug 10, 2021 MOON AND VENUS TOGETHER, PERSEID METEORS
If skies are clear tonight, you can see a conjunction of the moon and the planet Venus. Both will appear together in the western sky after sunset. Also, for the next couple of nights, the Perseid meteor shower will be at its peak. These “shooting stars” are bits of comet dust that fall to earth at high speeds. When the dust hits the atmosphere, the atmosphere hits back, superheating the dust, which in turn lights up the air around it, leaving a momentary bright streak in the night sky. Dress warmly, protect yourself against mosquitoes, find a safe spot that’s away from bright streetlights. Bring a lounge chair that lets you lean all the way back; but if it’s cloudy you won’t be able to see them, or the moon-Venus conjunction either.
Wed Aug 11, 2021 NAME THAT CONSTELLATION - AUGUST
can you identify the second largest constellation? It is bordered on the north by Boötes the Shepherd and Coma Berenices; on the south by Hydra the swamp monster and Corvus the Crow; on the west by Leo the Lion and Crater the Cup; and on the east by Libra the Scales and Serpens Caput. Its brightest star is the blue giant Spica. Planets have been discovered orbiting many of its other stars, and a huge cluster of galaxies lies within its borders. In mythology this star figure is associated with the planting and harvesting seasons, and often portrayed as Persephone, daughter of the earth goddess Demeter. Sometimes this constellation represents Astraea, Winged Justice, who holds the scales of law, the constellation Libra. Tonight the waxing crescent moon and the planet Venus can be found together near its western border. Can you name this constellation, the sixth sign of the zodiac? The answer is Virgo the Maiden.
Thu Aug 12, 2021 LAST GOOD NIGHT FOR PERSEIDS
The Perseid meteor shower reached peak activity yesterday, but tonight should still be pretty good for viewing it. These “shooting stars” are bits of comet dust that fall to earth at high speeds, superheating the air and lighting it up, leaving a momentary bright streak in the night sky. Most meteor showers are best after midnight, and this one’s no exception, especially as the bright light from the waxing crescent moon spoils the view during the early evening hours this year. Dress warmly, protect yourself against mosquitoes, find a safe spot that’s away from bright streetlights. Bring a lounge chair that lets you lean all the way back, and of course refreshments such as iced tea and chocolate chip cookies, are always welcome. Meteor showers are fun, but you can go for several minutes before spotting one. And if it’s cloudy you won’t be able to see them. Face east and look toward the top of the sky for best results.
Fri Aug 13, 2021 HOW TO SEE A BLACK HOLE
In the summer evening sky, there are three bright stars high overhead which are known as the Summer Triangle. Inside this triangle, in the neck of the constellation Cygnus the Swan, there is a great mystery - something which is invisible to the eye, but which nevertheless can be detected by the astronomer - that enigmatic phenomenon known as a black hole. It is called Cygnus X-1, and we can't see it directly because its gravity field is so intense that light can't escape it. But we know that it is there, because we've discovered an incredible amount of x-rays pouring out of this part of the sky. Cygnus X-1 is part of a binary star system. Gas from its companion, a massive blue giant, is being pulled from it to feed the accretion disc surrounding the hole; it’s here that the x-rays are being made, just outside the black hole's event horizon - its point of no return, about 2500 parsecs, or a little less than 48 quadrillion miles from Earth.