Mountain Skies: Moon And Two Planets Appear Before July 4 Fireworks
Last updated 7/1/2019 at 2:56pm
Mercury and Mars are quickly disappearing from the evening sky along with Venus in the predawn sky. As the earth continues to pull away from Mars, that brilliant red “star” from last summer, is finally heading into the evening sunset. By Labor Day, the red planet will be behind the sun only to reappear in the predawn sky in late September. For the next few nights, Mars is joined by little Mercury, which began an evening appearance in late May and is now diving into the evening sunset to pass by the sun in inferior conjunction on July 21. So, early this week we can spot them together very low in the west as the evening twilight fades. By Wednesday, we just might spot the thin waxing crescent moon below them. By Independence Day evening, the moon will have moved above the two planets and serve to help us spot them. So, 1) if you are out awaiting Independence Day fireworks and 2) if the weather is clear and 3) if you have an unobstructed view of the Western horizon, look for the moon and, below it, Mercury on the left and Mars on the right. Good luck!
The beautiful Venus is still in the predawn twilight, but barely. After the first few mornings this month, Venus will slip behind the sun in superior conjunction, set for Aug. 14. She will return to our view in early September as our “Evening Star.”
While we have had all five visible planets available to us if we observed both evening and morning, we are now down to two planets. The giant Jupiter is already in our evening sky, rising a little before sunset; it can be viewed low in the southeast as night falls. Until Venus returns, Jupiter is the brightest object other than the moon in the evening sky. The beautiful ringed Saturn will stand at opposition a week from tomorrow. When a planet is at opposition, it rises at sunset, is up all night long, and sets at sunrise. So, into early in the new year, we will have this beautiful object in the evening sky.
The Summertime Milky Way is a beauty to behold if we can view it under clear, dark skies. The mountains of Western North Carolina often present us with such opportunities. Becoming more and more prominent as the summer progresses are the constellations of Scorpius, the scorpion, and Sagittarius the archer. These constellations are extremely important to astronomers, as the Milky Way stretches from Scorpius and Sagittarius up across the sky through Aquila, the eagle, and Cygnus, the swan, and then into the northeast where Cassiopeia, the queen, is rising.
Of all the constellations in the sky, Scorpius (not Scorpio, please), probably along with Orion, the hunter, in the winter skies, looks most like what the ancient Greeks envisioned it to be. Low almost due south on a summer evening, three stars mark the head and claws of this critter. Below the head of the scorpion its body stretches downward with a bright red star marking the heart. This star looks strikingly similar in color to the red planet Mars, called Ares by the Greeks. Therefore, the Greeks named the star Antares (literally “Rival of Mars”) so that the observer would not mistake it for the god of war. We have kept this name on modern star maps. Continuing down the body of the scorpion, we can trace the tail that loops eastward and upward to two prominent stars marking the stinger at the end of the tail. To the Pawnee Indians of North America these were two swimming ducks.
Rising in the southeast and following the scorpion up into our southern sky during the summer months is Sagittarius, the archer, with the body of a horse and torso of a human. It is one of two celestial centaurs, the other being Centaurus. But it is difficult to envision such a creature among these stars. Instead, look for a pattern of stars in the form of a “teapot.” The spout is directed towards neighboring Scorpius to the west and the haze of the Milky Way appears as steam coming out of the spout. The center of the Galaxy is in Sagittarius and this area of the sky is rich in star clusters and nebulae of interest to both astronomers and casual viewers of the sky. Try exploring this area of the sky with a pair of binoculars.
July 2, 3:16 p.m. EDT - New moon, Total solar eclipse visible from the South Pacific, northern Chile and central Argentina.
July 4, 6:22 p.m. EDT - Earth at aphelion (farthest point from the sun: 94,513,221 miles)
July 9, 6:55 a.m. EDT - First quarter moon.
(The Learning Center at PARI is a public not-for-profit 501 (c) (3) organization established in 1998. Located in the Pisgah National Forest, the Learning Center provides STEM educational programs at all levels, from K-12 through post-graduate research. For more information about the Learning Center at PARI and its programs, visit http://www.pari.edu.)