This is the Dudley Observatory Skywatch Line for Wednesday, November 7th, and Thursday, November 8th, written by Louis Suarato.
The New Moon occurs at 11:02 a.m. Wednesday. Thursday, the binocular challenge will be to spot the 2% illuminated, waxing crescent Moon before it sets at 5:49 p.m. low in the west-southwest, 10 degrees to the right of Mercury. Mercury consists of a thin layer of rock over a 60% liquid metal core. When Mercury’s molten metal core cools, it was theorized, the thin crust above it would shrink. When NASA’s Messenger spacecraft provided the first global view of Mercury in 2011, its ph0tos proved this theory. Scientists studied 6,000 escarpments, or steep slopes, imaged by Messenger, and concluded the planet had shrunk by about 1% since its creation.
Mars is moving from the constellation Capricornus into Aquarius. Aquarius is the tenth largest constellation, covering an area of over 980 square degrees, and is best visible from July through November. Aquarius consists of relatively faint stars, but its size occupies a large area of the Autumn sky. The brightest star in Aquarius is Beta Aquarii, also known as Sadalsuud. This yellow supergiant star is 600 light-years away, and shines at magnitude 2.9. The jewel of Aquarius is globular cluster M2. At 175 light-years in diameter, M2 is one of the largest globular clusters. M2 was discovered by Jean-Dominique Miraldi in 1746. Containing an estimated 150,000 stars, and 13 billion years old, M2 is one of the oldest globular clusters in the Milky Way galaxy. Look for M2 5 degrees north of Beta Aquarii. On these nights, look about 16 degrees to the upper right of Mars for this globular cluster.
On November 7, 1631, Pierre Gassendi became the first to observe the transit of Mercury across the face of the Sun. Using a telescope invented by Galileo to project an image on paper, Gassendi was surprised at the small size of the celestial object predicted to transit on this date by Johannes Kepler. Gassendi’s observation, however, was further proof of Kepler’s heliocentric model of the solar system.