The month of May is named after Maia, the Roman goddess who is the mother of Mercury and the daughter of Atlas. We are halfway into spring already and our landscape is just beginning to be transformed by the hue of the fresh grass and the tender, light green leaves beginning to show up on the trees. The spring peepers and wood frogs are getting louder and braver as they add their sonic contributions to the symphony involving all your senses that is the reawakening earth in spring.
The nights will be getting considerably warmer this month, so this will be a good month to spend more time under the night sky to get reacquainted with the celestial treasures residing just above us. The highlights this month include a meteor shower on May 6, three planets putting in their best appearances for the year, and some nice conjunctions.
The Eta Aquarid Meteor Shower peaks on the Tuesday the 5th into Wednesday morning the 6th. The moon will be full just three days before this shower, so the waning gibbous moon will be rising a few hours after sunset to spoil the show. However, you can still try to catch some of these tiny pieces of Halley’s Comet for a couple of hours after sunset if it is clear.
Halley’s is the only comet that causes two different meteor showers for us on earth each year. The other one is the Orionids on Oct. 21. The earth passes through its debris trail twice every year. After its appearance in 1985 and 1986, this most famous of all comets is still heading farther out into space. It already passed the planet Uranus and it will reach out beyond Neptune by 2024, which marks the halfway point of it 76-year orbit. It will return to grace our skies again in 2061 and 2062. That appearance should be brighter than its last one, but not as bright as its 1910 apparition.
All of these tiny flakes of dust from this most famous of all comets will appear to originate in the constellation of Aquarius, just to the east of Capricorn and near Pegasus. They will be smashing into our upper atmosphere at about 40 miles per second, creating brilliant streaks of light lasting for less than one second. Most of them will disintegrate at around 70 miles high. If the moon would not be out during the peak of this shower, you could expect up to 50 meteors per hour, but we will see far less than that because of the nearly full moon. In any case, it is always a thrill to see a meteor and experience something of the real nature of comets and the true nature of our atmosphere at the same time. Remember that this is a roughly 4 1/2 billion year old primordial speck of dust that had never encountered our atmosphere before the instant that you see it and become aware of it.
Venus keeps getting higher and brighter and larger in our sky even as it gets less illuminated by the sun. Our sister planet is now catching up with us in its faster orbit around the sun. Venus will be cruising through Gemini this month and the waxing crescent moon will be close to it for three evenings from the 20th through the 22nd.
Mercury will also be at its best early this month. You can see our first planet in Taurus between the Pleaides and Aldebaran, about where Venus was last month. If you look very low in the western sky you might also be able to catch the last vestiges of Mars as it finally sinks below the horizon for the rest of the month before reappearing in our morning sky next month.
As you watch Venus and Mercury also look for Orion the mighty hunter slowly sinking into the western sky to the left of this pair of planets. You know summer is not far off when Orion finally exits our celestial stage just as it entered our evening stage half a year ago to mark the beginning of autumn.
Saturn will be at its best this month as it reaches opposition on Friday the 22nd. That means it will rise at sunset, reach its highest point at midnight, and not set until sunrise. The ringed planet will still be well placed for viewing all summer long and will rise earlier, which means that it will reach its highest point in the sky earlier at night as we approach summer. Right now it appears as the fourth star in the head of Scorpius. Below it you can easily see Antares, the brilliant orange giant star that is about 700 times larger than our own sun. If you could place Antares where our sun is in the sky, all the planets out to Mars would be orbiting inside this enormous star. The biggest star in our galaxy, Canis Majoris, is about twice the size of Antares, which means that it would engulf the orbits of all of our planets out to Saturn.
In contrast to the trio of planets at their best this month, Jupiter is slowly getting dimmer and smaller as it falls farther behind our orbit. The king of the planets is about seven times fainter than Venus, but it certainly holds its own for its part of the sky in Leo, two constellations over to the east of Venus. These two bright planets are now 50 degrees apart, but watch as Venus will catch up with Jupiter at the rate of almost one degree per day. There will be a spectacular conjunction of this pair on July 1st.
The waxing crescent moon will pass just below Jupiter on Saturday, May 23.
May 1: This is National Space Day. On this day in 1949, Gerard Kuiper discovered Nereid, the third largest moon of Neptune. The Kuiper belt consists of trillions of icy objects, similar to the asteroids in the asteroid belt between Mars and Jupiter. However, Kuiper belt objects tend to be icier than the rocky asteroids. There are thousands of Kuiper belt objects up to 100 km in diameter. Many more of these will probably be found soon and they will be classified as icy dwarf planets or Kuiper Belt Object. Pluto is now the largest and closest Kuiper belt object and no longer a full- fledged planet. Most of the Kuiper belt is about 50 astronomical units from the sun, or 50 times the earth-sun distance. By comparison, the Oort cloud of trillions of potential comets stretches all the way out to 100,000 astronomical units, forming a giant sphere all the way around our solar system. Look for Venus, Mercury and Mars in the western sky. Spica, the brightest star in Virgo, is about 6 degrees from the nearly full moon.
May 3: Full moon is at 11:42 p.m. This is also called the Flower, Milk or Planting Moon.
May 4: The waning gibbous moon appears 5 degrees from Saturn tonight.
May 5: On this day in 1961, Alan Shepard became the first American in space in a sub-orbital flight aboard Freedom 7. Yuri Gagarin became the first human in space on April 12 of 1961 when he completed one full orbit of the earth in about 100 minutes.
May 6: The Eta Aquarid Meteor shower peaks this morning.
May 11: On this day in 2009, STS-125, the Atlantis, was launched with the fifth and final servicing mission to the Hubble Space Telescope. Last quarter moon is at 6:36 a.m. EDT.
May 12: On this day in 1930, The Adler Planetarium in Chicago opened the first planetarium in the western hemisphere.
May 14: On this day in 1973 Skylab was launched. On this day in 2009 the Herschel and Planck space observatories were launched.
May 15: On this day in 1958, Sputnik 3 was launched.
May 18: New moon is at 12:13 a.m.
May 21: The waxing crescent moon is near Venus tonight.
May 23: Jupiter is 6 degrees from the moon tonight.
May 27: A double shadow transit occurs on Jupiter tonight.
May 29: On this day in 1919, Einstein’s General Theory of Relativity passed its first major test. Eddington proved this during a total solar eclipse.
— Bernie Reim is an amateur astronomer and teaches astronomy lab courses at the University of Southern Maine.
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