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Frostburg State Planetarium presents Winter 2014 Sky Sights for Middle School & Intermediates by Dr. Bob Doyle Next Edition: April 2014

Big Topics Treated Horizon, Finding directions, Sunrise/Sunset How Day Sky Works, Twilight AM & PM Moon basics, It’s Origin Why has varying shapes? Bright points seen at night? Easy Winter Planets Best Stars & Star Groups Seen on Winter Evenings 3 Built in Mini Quizzes with answers supplied Winter ‘14 Moon Schedule & Star tables

Horizon & Directions When looking at sky, we may view ½ of universe ! Horizon surrounds us, the sky/ground boundary At top of sky is zenith, 90 degrees from horizon From North to right, East, then South and West. Sun rises in East, face sunrise, left is North Midday shadow N (12 Noon Jn & Fb, 1p Mar.) Sun sets nearly in West, face sunset, right is North Can use Big Dipper’s pointers to find N. Star

Sunrise & Sunsets? Earth’s daily rotation makes it look as if sun rises each morning & sets each afternoon Time of sunrise, sunset varies thru year Earliest sunrise & latest sunset in late June Latest sunrise & earliest sunset in late Dec. Longest days when sun highest, farthest N Shortest days when sun lowest, farthest S Change in sunrise/sunset reduced closer to equator Change in sunrise/sunset increased near poles

Let’s review these ideas What point in sky is farthest from horizon? Is it Celestial Pole? Zenith? Nadir? Which direction recipe WON’T work? S. Side of tree with moss? Shadow in mid day? Place where biggest changes with seasons? Polar Regions? Mid Latitudes? Equator? Write down your answers for these questions. Answers: Zenith, Mid day shadow, Polar regions

Interesting facts about day sky Noon sun million x brighter than full moon Day Sky max. polarization 90 deg. from sun Maximum sunlight energy in early summer Sun peaks around Noon Jan,Feb. 1 pm Mar. Minimum sunlight energy in late Dec. To find North, face where sun goes down and extend your right arm out, points North.

Twilight or Dusk? When sun disappears from our view, the air overhead is still ‘seeing’ sun and glowing. When sun 6 dg. below horizon, turn on lights When sun 18 dg. below horizon, sky darkest To see faint star groups, sun must be 12 dg. below Arctic Circle cities have no darkness in June Equatorial places have shortest twilights Our twilights last about 90 min. at dusk & dawn

What about Moon? Our moon is 2160 miles across, ¼ Earth’s width Moon ¼ as big as Earth; if Earth a regular globe (1 ft.wide), moon is a tennis ball. If Earth-moon distance about 30 x Earth’s width. As Earth, Moon lit by sun with day & night halves As Moon orbits Earth, see varying part of day side After line up with sun, moon waxes (grows) 14 d After full moon, moon wanes (shrinks) 14 days Moon phase cycle 29.5 days, approx. month long

Just a little bit more about Moon Moon rocks reveal moon matter from Earth! Moon due to planets colliding, debris hurled Moon formed from ring of orbiting debris Early moon closer, much stronger tides Moon slowly spiraling out, lengthen our day Earth has 1 st natural moon from sun, 6 th largest moon in solar system

Half full moon shows craters near its straight edge where sun there is rising or setting. Dark areas are lava plains – few craters there

Winter 2014 Moon Schedule Early Jan.: ½ evening Moon 1/7 (craters) Mid. Jan. : Full Moon 1/15 (lava plains seen). Late Jan. : ½ morning Moon 1/24 (craters) Early Feb. ½ evening Moon 2/6 (craters) Mid. Feb. : Full Moon 2/14 (lava plains seen) Late Feb. : ½ morning Moon 2/22 (craters) Early Mar. : ½ evening Moon 3/8 (craters) Mid Mar. : Full Moon 3/16 (lava plains seen) Late Mar. : ½ morning Moon 3/24 (craters)

Another review of ideas.. As you face sunset, what points North? Back of Head? Right arm (out)? Left ear? If Earth 1 ft. wide, how far away is moon? Is it 10 feet? 30 feet? 100 feet? 300 feet? How long does moon ‘grow’ or ‘shrink’? Is it A week? A half month? A month? Write down your answers to above 3 questions. Answers: Right arm (out), 30 feet, A half month

Bright points we see at night? Even the nearest planets appear as * (points) as we see them with our eyes; for even these objects far away Venus at closest 100x farther than our moon To tell a planet from a star, all night stars twinkle and planets usually shine steady. Also satellites (especially Space Station) shine steadily as creep eastward across sky Night stars are distant suns, really, really far away compared to our planet neighbors. If Earth penny size, moon 22” away, sun 730 ft. away (6.3 ft. wide), nearest star is 37,000 mi.away

Easy Winter 2014 Planets Jupiter is bright, steady point in evening sky Moon & Jupiter close 1/14, 2/10 & 2/11, 3/10 Mars in Virgo, best seen in South at dawn Saturn best seen in Southeastern sky at dawn Venus brilliant point of light in dawn late Jan. on Mercury at dusk late Jan., early February Mercury best viewing in May in Western dusk In April, Mars closest: In May, Saturn closest

Winter Stars & Groups Evening: Big Dipper upright in North Northeast Top two Dipper * point left to North Star. Same Dipper * point right to sickle of Leo Sirius is brightest evening star in South Orion has 3 star belt that points left to Sirius Stars in and around Orion make big ‘W’ in South Bright golden star Capella high in Western sky

Big Dipper & N. Star in Winter North Star Big Dipper

Orion & Friends Rigel Belt Betelgeuse Aldebaran Sirius Procyon Jupiter

Let’s review once more… Planet prominent in winter ‘14 evening sky? Is it Venus? Mars? Jupiter? Saturn? When closest to us, neighbor planet is invisible? Is it Venus? Mars? Jupiter? Saturn? Orion’s belt points left to what star? North Star Sirius Capella Write down your answers Answers: Jupiter, Venus, Sirius

Frequently asked questions What are shooting or falling stars? Pea sized space grit impacting upper atmosphere and bursting into flame. What if planets aligned (as beads on string)? They can’t as orbits are not in 1 plane. But even if they could, their pull very weak next to our moon. Why study other worlds? won’t ease our problems By understanding other worlds, better know Earth Your questions are welcome at our public programs.

Send any questions to…. Bob Doyle Be sure that questions involve basics about sky, moon, planets and stars