The Transylvania Times -

Mountain Skies: The Moon Passes Three Planets This Week

 

Last updated 4/6/2020 at 1:31pm

The Planets

They're getting closer! The classical planets are those visible to the naked eye and, thus, seen and named in historical times. Each day four of the five classical planets are a bit closer to Earth. No, there are no collisions forecast since each one has its prescribed orbit and they don't overlap. So, while collisions with asteroids pose grave danger to Earth, we have nothing to fear from the major planets.

So, what exactly is happening? If we look at the accompanying chart of the solar system out through Jupiter (with Saturn offstage left), we can see that four of these planets, all except Venus, are on the west side of the sun as viewed from Earth and, thus, appear in our predawn sky. Since the closer a planet is to the sun, the faster it moves, Earth is basically chasing all four of these planets around the sun. We are gaining on three of them - Jupiter, Saturn and Mars - and will pass between the sun and the planets - Jupiter on July 14, Saturn on July 20 and Mars on Oct. 13. When we do so, they will each be on the opposite side of Earth from the sun and we say they are in opposition. Mercury and Venus never come to opposition since they are closer to the sun than Earth. Jupiter, Saturn and Mars are easy to spot, but Mercury is now very close to the sun, well down in its twilight glare. We will never catch up with this elusive planet since it moves faster than we do. In fact, it will come around the sun and catch up with us on June 30. We are also losing the race with Venus (as we always do). Venus is gaining on Earth and now appears high in the Western sky after sunset. It will catch up with us and pass us in inferior conjunction on June 3.

Mercury is deep in the morning twilight before sunrise. It's not easy to spot. It will pass behind the sun in superior conjunction on May 4 and move into our evening twilight.

Venus is still well up in the west after sunset. It will be at its brightest on April 28 and will remain our "evening star" until late May. In June it will be in the predawn sky.

Jupiter rises about 2:20 a.m. followed by Saturn and Mars at 20-minute intervals. By dawn they are in a line well up in the southeast.

The Stars

Early evening in April catches us betwixt and between the prominent constellations of the receding winter skies and those of the quickly rising spring skies. In the former, the great hunter, Orion, can still be seen in the west. But now, as the sky darkens, he is leaning downward as he follows the bull, Taurus, towards the horizon. The Gemini twins, Castor and Pollux, stand to the North of their mentor as they follow him across the sky. Two bright stars mark their heads. Following these folks as the sky turns are the two dogs. The Dog Star, Sirius, the brightest star in the nighttime sky, is in the southwest. Above Sirius is the lesser or little dog consisting of only two naked eye stars, Procyon, sometimes called "the pup," and the much dimmer Gomiesa.

Meanwhile, to the east, we find the springtime constellations becoming more apparent. Leo, the lion, is standing high in the east. The front or Western portion of the lion has traditionally been called the sickle and can be found labeled as such on many star charts. It consists of an almost complete circle of stars with the bright star Regulus lying below it. In more modern times, we view this pattern as a coat hanger or a backward question mark with Regulus as the dot below the question mark. The hindquarters and tail of the lion are found in a triangle to the east of the sickle.

Between the twins and the lion is Cancer, the crab, basically an open area without any bright stars. However, in the middle of Cancer is a pretty cluster of stars popularly known as Praesepe or the "Beehive Cluster," since, with a pair of binoculars or a small telescope, it looks like a swarm of celestial bees. To the astronomer this cluster is known as M44 for Messier 44. Since the Beehive lies in the zodiac, it is often occulted, i.e., covered up, by the moon. The planets also appear to pass through this swarm of bees as they pass in front of Praesepe.

Celestial Calendar

April 7, 2 p.m. EDT – Moon at perigee (only 221,772 miles).

April 7, 10:35 p.m. - Full moon equals large tides.

April 12 – The sun in its apparent annual path around the sky moves from the constellation of Pisces, the fish, into Aries, the ram.

April 14, 6:56 p.m. EDT – Last 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.)

 
 

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