Geminid Meteor Shower Mooned Out and Other Celestial Offerings

As quickly as it started, 2019 will soon be in the history books. I for one am happy to see it go. A cloudy and rainy spring, hot and humid heat waves during the summer, then the EEE mosquito threat have conspired to prevent casual stargazers and amateur astronomers alike from enjoying the night sky and all the wonders it holds. It would be great if we could end the year on a high note, but the sky gods are not smiling down on us for December.

Though the Geminids are the best meteor shower of the year, peaking on the night of December 13-14, the Full Moon on the 12th will overwhelm all but the brightest meteors. To complicate matters further on the peak night, that bright moon will be sitting right in the middle of the Gemini constellation. While you won’t require my usual star map to find Gemini, the proximity of the Moon to the region of the sky from where the meteors appear to radiate (near Gemini’s brightest stars, Castor and Pollux), will certainly reduce your meteor count. .

However, one does not have to look directly at Gemini to catch a few of the brightest shooting stars. In fact, the Geminids are fairly bright and also have a reputation for producing exploding meteors called fireballs, My point: if the weather cooperates on peak night do not give up on the Geminids. You might just glimpse a few bright Geminids as they enter our atmosphere at 21.75 miles per second.

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Transit of Mercury: A Unique Astronomical Event November 11, 2019

Venus and Mercury transits occur when these worlds, which orbit between the Earth and the Sun, can be seen to pass directly in front of the solar disk and transit across the face of our star. Why don’t we experience a transit of Venus or Mercury every time they pass between the Earth and the Sun (called inferior conjunction)? It all has to do with the orbits of these planets and our ever-changing viewing angle. Most of the time Venus and Mercury pass above or below the solar disk as seen from the Earth. This concept is simply stated here, but it took the greatest astronomical minds of the past to solve this great mystery. The process took much observation, dedication and deduction to determine the solar system design and the celestial mechanics that govern its motion.

Venus transits are rare astronomical events. They always occur in pairs, eight years apart. We last experienced transits of Venus in 2004 and 2012. Their immediate predecessors occurred back in 1884 and 1882. And the next pair won’t be until 2117 and 2125!

However, another planet can transit the Sun—Mercury. Though not as rare as Venus transits, transits of Mercury occur 12-13 times per century. The last one occurred on May 9, 2016 and it was observed in its entirety locally. The Mercury transit prior to that occurred on November 8, 2006, but in Southern New England we were clouded out. Unfortunately, the next one visible here after the upcoming November 11 event won’t be until May 7, 2049.   

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November Meteor Showers

First up for November is my reminder to be sure to set your clocks back one hour on Sunday, the 3rd. That’s when most of the United States switch back to Eastern Standard Time from Daylight Saving Time. The mnemonic is “spring ahead and fall back/behind”. Thank goodness for most of us it occurs on a weekend!

While the premiere astronomical event during November will be the transit of Mercury between the Earth and the Sun (which I will preview in a separate column), there are two meteor showers as well.

From November 4th thru the 6th watch the sky for no more than a half dozen or so Taurid meteors. These often very bright yellow fireballs (meteors that explode and fragment into multiple pieces) are fairly slow and enter our atmosphere at approximately 17 miles per second. Observe after midnight to increase your chances of seeing one. Look in the general direction of the constellation Taurus. To locate Taurus find the V-shaped pattern that defines the bull’s face, or locate the Pleiades — the Seven Sisters star cluster. A waxing gibbous Moon will overshadow all but the brightest of the meteors this year.

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October meteor showers

If recent events during the last few months are any indicator, Chicken Little may have been right. The sky is falling. The sky is falling. Back on July 24 at approximately 2:44 a.m. EDT, a soccer ball-sized meteor entered the Earth’s atmosphere above Lake Ontario and became a bright fireball as it disintegrated. Click here to learn more about this event. Fragments of this “space invader” most likely reached the ground. That same day, at around 11:04 p.m. a similar object was sighted along the east coast from Virginia to Maine. But wait! There’s more. The very next day a previously unknown asteroid estimated to be 187-427 feet across zipped past the Earth at 11:22 a.m., travelling around 45,000 miles per hour. Talk about close encounters!  That one would have wreaked havoc had it collided with the Earth.

There’s a lot of space debris that the Earth passes through on its journey around the Sun. The vast majority are harmless remnants of comets or small pieces of asteroids. Everyday the Earth is bombarded with this material, and with greater frequency security cameras are recording the demise of the brightest of these visitors to our planet. After careful examination of eyewitness accounts, astronomers can determine the orbit of these bodies and determine if they are associated with a particular meteor shower. Two meteor showers were in progress at the time of the fireball reports. Many folks were lucky to view such a “fiery” display.

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Solar Variability: Our Inconstant Sun

I went to bed last night wondering where the Sun had gone. Then it dawned on me. A little astronomy humor to begin a serious discussion on our life-giving star—the Sun.

Our Sun coalesced out of a vast cloud of gas and dust some 100 times the size of our solar system roughly five billion years ago. Gravity contracted this mass until the core of this proto-star reached about 24.5 million degrees Fahrenheit. At that time nuclear fusion began, converting about 600 million tons of hydrogen to helium per second. This process has been ongoing since then.

Most folks take for granted that the Sun rises and sets every day due to the Earth’s almost 24-hour rotation. The only change most people recognize is the seasonal cycles caused by the fixed 23.5 degree tilt of our planet’s axis in its orbital path about the Sun. Reference this video to refresh your memory on the Earth’s annual journey.

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