Sky's Up - Fall 2015 - Page 4

Meteor showers galore! O ur bustling solar system is littered with rocky particles of space debris known as meteoroids. Although most are unimpressive in size, these pebble-sized pieces of cosmic clutter can still put on quite a show for earthbound observers. When a meteoroid plunges into the Earth’s atmosphere, it is traveling at phenomenal speeds. The drag caused by the air it encounters, heats both the meteoroid and the air molecules. This intense interaction ionizes surrounding atmospheric gases to create the fleeting glowing trails of light we know as meteors. Although the potential is there on any given night, witnessing a sporadic meteor is not a frequent experience for most. Luckily, some cyclical celestial objects like comets and asteroids leave behind streams of orbiting debris that the Earth will cross paths with on a regular basis. When this happens, meteor activity increases noticeably and, sometimes, dramatically. Known as meteor showers, these predictable events are a great time to try and catch multiple shooting stars. The final quarter of 2015 is packed with offerings for meteor shower enthusiasts. These include: Oct. 8-9 - Draconid Meteor Shower Although it usually does not result in an impressive amount of meteors per hour, the Draconid event is a notable rarity among meteor showers because these meteors are best seen in the early evening instead of in the more common post-midnight hours. The radiant point for this meteor shower, which is caused by debris from Comet 21P/Giacobini-Zinner, is in the head of the Draco the Dragon constellation. Set to peak around October 8th, the shower usually only produces a few meteors per hour, but it is unpredictable and has produced hundreds per hour in some years. Oct. 21-22 - Orionid Meteor Shower Generated when the Earth crosses paths with the dust left behind by Halley’s Comet, the Orionids radiate from the constellation Orion and generally last for about a week in late-October. Observers can typically see 10-25 meteors per hour during the shower‘s peak activity time, which will begin late evening on October 21st and last into the predawn hours of October 22nd. Although the Orionids move fast, they have been known to leave a glowing gas trail that lasts for a few 4 Left, astrophotographer Babak Tafreshi captured this stunning image of a persistent meteor train over a lake in northern Maine during the 2012 Orionid meteor shower. For a timelapse video, click here. COURTESY OF ALBERTO LEVY This time-lapse photo captures the progression of the last total lunar eclipse, which took place on October 8, 2014. Lunar tetrad wraps up with September eclipse O bservers in the Americas — especially South America — will be perfectly positioned to witness the Moon take on a red hue as a total lunar ecl ipse unfolds on September 27th. The last total lunar eclipse, which occurred on April 4, lasted just under 5 minutes making it the shortest total lunar eclipse of the century. This time, the total phase of the eclipse will last a leisurely 72 minutes. A total lunar eclipse occurs when a nearly perfect alignment of the Sun, Earth and Moon causes the Full Moon to be shrouded by Earth’s deepest shadow. During the event, the same phenomenon that gives our sunsets their beautiful, colorful glow will cast the Moon in some shade of burnt reddish-orange. How red the Moon will actually appear depends on Earth‘s atmospheric conditions, such as dust levels and humidity, that COURTESY OF BABAK TAFRESHI, TWAN (The World at Night) stunning seconds. Nov. 17-18 – Leonid Meteor Shower Set to peak in the predawn hours of November 18th, the always-anticipated Leonid meteor shower is an annual November presence caused by the Earth’s passage through debris left behind by Comet Tempel-Tuttle. Although it has a history of producing stunning meteor storms every few decades, the shower usually generates a steady 15 to 20 meteors per hour, which is this year’s expected rate. The Leonids radiate from the Leo constellation. Dec. 13-14 – Geminids Meteor Shower The Geminid meteor shower is traditionally one of the year’s most prolific – producing more than 100 bright meteors per hour during its peak, which will be between midnight and dawn on December 14th this year. It is not just the high activity that makes the Geminids notable. In fact, their origins make it truly unusual because instead of being generated by the debris left behind by a comet, they are caused by the asteroid 3200 Phaethon, which orbit’s the sun every 1.4 years. This year the show should be particularly impressive because the thin crescent Moon will provide little if any interference. viewing tips • When selecting an observing spot, try to find a dark open sky away from light pollution. • Remember the best viewing hours are usually between midnight and dawn. • Look at the whole sky for meteors, and do not confine yourself to the radiant point. • Bring a blanket to stretch out on or a reclining chair for comfortable viewing. • Bring extra layers (jackets, blankets, etc.). • Once you are settled at your observing site, give your eyes time to adjust to the darkness so that you will be able to see more. Be sure to avoid using flashlights or checking phone screens, which will disrupt this vital adjustment. • Consider bringing a telescope or binoculars to explore some of the night sky’s other treasures while you wait for the meteor shower to amp up. • Be patient! Sky’s Up affect the way sunlight is filtered and refracted to light the lunar surface. The eclipse’s total phase begins at 2:11 UT on September 28th (10:11 p.m. EDT on September 27th). The partial phase, which begins at 1:07 UT on September 28th (9:07 p.m. EDT on September 27th), will last a generous three hours and 20 minutes and give many an opportunity to watch the Earth’s shadow’s colorful march across the lunar surface. In addition to putting on a spectacular show in the Americas, the September 27/28 eclipse will be visible in part or in full to observers in Europe, Africa and parts of Asia. It is the last in a series of four consecutive lunar eclipses that are all total eclipses. The series, which is known as a lunar tetrad, began in 2014. The next lunar tetrad will begin in 2032. save the date • Sept. 19 – International Observe the Moon Night Each year, International Observe the Moon Night is held to encourage people around the globe to take a good long look at the Moon whether it is through a telescope, binoculars or even with the naked eye. The evening’s goal is to generate appreciation for this stunning celestial beauty and inspire people to delve deeper into the intriguing lunar landscape. For Sky’s Up information on the vast range of activities scheduled throughout the world in relation to the event, click here. • Oct. 4-10 – World Space Week Designed to inspire and enlighten, World Space Week is a global celebration of space, science and technology coordinated by the United Nations with the aid of the World Space Week Association. The theme for this year’s event is “Discovery,” and event organizers will be encouraged to highlight deep space discovery efforts. Launched by a declaration of the U.N. General Assembly in 1999, World Space Week begins every year on October 4th to recognize the anniversary of the 1957 launch of Sputnik 1, the first man-made Earth satellite. It wraps up on October 10th in commemoration of the signing of a 1967 treaty that provided the basic framework of international space law. For information on the events scheduled throughout the world to celebrate the week, click here. 5