Talkeetna Mountains Photo by Fred Hirschmann
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Photo by Fred Hirschmann Talkeetna Mountains Pentax 654N, 45mm f/2.8 20 sec., @ f/2.8, ISO 400 Fuji Provia Aurora Science Notes by Prof. Neal Brown Sunday Monday Tuesday Wednesday Thursday Friday Saturday NEW YEAR’S DAY SPACE WEATHER 29 30 31 1 2 3 4 DEFINITIONS SUNSPOT: Dark, cooler areas on the solar surface that contain strong, constantly shifting magnetic fields. Full moon 10:21 AM SOLAR STORMS: There are two 5 6 7 8 9 10 11 kinds of solar storms that can result in ejected particles that travel close to the speed of light. Storms peak during the solar maximum. CORONAL MASS EJECTION (CME): Explosive outbursts of plasma 12 13 14 15 16 17 18 from the sun’s outer atmosphere. The plasma expands to more than 30 million miles by the time it reaches Earth. SOLAR FLARE: Huge explosions on MARTIN LUTHER New moon Chinese New Year the sun, typically lasting minutes KING, JR. or hours. 19 20 (observed) 21 22 23 24 25 SOLAR WIND: A stream of charged particles (a plasma) released from the upper atmosphere of the sun, consisting mostly of electrons and protons. INTERPLANETARY MAGNETIC FIELD: 26 27 28 29 30 31 1 The sun’s magnetic field carried by the solar wind among the planets of the Solar System. The Aurora Calendar DECEMBER 2019 FEBRUARY 1 2 3 4 5 6 7 1 2020 8 9 10 11 12 13 14 2 3 4 5 6 7 8 15 16 17 18 19 20 21 9 10 11 12 13 14 15 22 23 24 25 26 27 28 16 17 18 19 20 21 22 29 30 31 23 24 25 26 27 28 29 January Photo by Todd Salat Portage Lake Nikon D800E, 14mm f/1.8 2.0 sec., @ f/2.0, ISO 1250 Aurora Science Notes by Prof. Neal Brown Sunday Monday Tuesday Wednesday Thursday Friday Saturday What Causes the Aurora? 26 27 28 29 30 31 1 Marmot Day Full moon (Alaska) 10:33 PM The aurora are caused by solar 2 3 4 5 6 7 8 storms that throw huge numbers of fast-moving electrons and protons away from the sun in a twisting mass of electric and magnetic fields. These microscopic particles typically Abraham Lincoln Valentine’s Day take two days to travel the 9 10 11 12 1809-1865 13 14 15 150-million kilometers from the sun to Earth. These energetic electrons and protons initially move past Earth for several thousands of miles before traveling back Elizabeth Peratrovich PRESIDENTS’ DAY Heritage Day George Washington Day (Yukon Territory) 1732-1799 along Earth’s magnetic field lines 16 (Alaska) 17 18 19 20 21 22 into Earth’s atmosphere. Then, through a process similar to that of a neon sign, they collide with the atoms and molecules of Earth’s atmosphere to create the light we call the aurora. Not all solar storms produce aurora. We New moon Ash Wednesday have a chance to see the auroras 23 24 25 26 27 28 29 only when the solar storm’s magnetic field couples with the Earth's magnetic field. The Aurora Calendar JANUARY MARCH 1 2 3 4 1 2 3 4 5 6 7 2020 5 6 7 8 9 10 11 8 9 10 11 12 13 14 12 13 14 15 16 17 18 15 16 17 18 19 20 21 19 20 21 22 23 24 25 22 23 24 25 26 27 28 26 27 28 29 30 31 29 30 31 February Photo by Carl Johnson Turnagain Arm Tidal Flats Nikon D800E, 14-24mm f/2.8 6 sec., @ f/2.8, ISO 3200 Aurora Science Notes by Prof. Neal Brown Sunday Monday Tuesday Wednesday Thursday Friday Saturday Susan Butcher Day (Alaska) THE 11 YEAR SOLAR CYCLE 1 2 3 4 5 6 7 Daylight Savings Full moon Time begins 9:47 AM 8 9 10 11 12 13 14 The gigantic electric and Purim begins magnetic sun storms that create the aurora follow an 11-year cycle of activity, with the recent peak that occurred in 2013. St. Patrick’s Day Spring Equinox It is an 11-year cycle (or half of a 15 16 17 18 19 20 21 22-year cycle) because sunspots appear in pairs with a signature of magnetically "north" or magnetically "south." At the end of 11 years, the spots switch their signature from "south" to "north" (or vice versa) and begin a new New moon solar cycle. 22 23 24 25 26 27 28 The 11 year sun cycle is not always exact, and throughout history it has seen periods of significant variation. Vietnam Veterans’ Seward’s Day 29 Day (Alaska) 30 (Alaska) 31 1 2 3 4 The Aurora Calendar FEBRUARY APRIL 1 1 2 3 4 2020 2 3 4 5 6 7 8 5 6 7 8 9 10 11 9 10 11 12 13 14 15 12 13 14 15 16 17 18 16 17 18 19 20 21 22 19 20 21 22 23 24 25 23 24 25 26 27 28 29 26 27 28 29 30 March Photo by Daryl Pederson City Skyline, Anchorage Nikon D810, 17-35mm f/2.8 5 sec. @ f/2.8, ISO 800 Aurora Science Notes by Prof. Neal Brown Sunday Monday Tuesday Wednesday Thursday Friday Saturday Can we Predict Auroras? 29 30 31 1 2 3 4 Full moon Passover begins Good Friday 6:35 PM 5 6 7 8 9 10 11 NOAA Space Weather Prediction Center We cannot accurately predict when aurora will occur on Earth. Easter Easter Monday U.S. tax returns due However, we can predict how (Canada) close we are to the most active 12 13 14 15 16 17 18 sun storms based on the current solar cycle. The storms originate well below the visible surface of the sun and can’t be seen until they pop out to New moon Arbor Day the outer layers of the sun, where Earth Day we can then use many kinds of 19 20 21 22 23 24 25 instruments to diagnose what that storm consists of and what it might do. Using instruments aboard the broad array of Sun-Earth orbiting space craft, we can now estimate the energy of these sun storms 26 27 28 29 30 1 2 and determine if the solar storm will get to Earth and result in aurora. The Aurora Calendar MARCH MAY 1 2 3 4 5 6 7 1 2 2020 8 9 10 11 12 13 14 3 4 5 6 7 8 9 15 16 17 18 19 20 21 10 11 12 13 14 15 16 22 23 24 25 26 27 28 17 18 19 20 21 22 23 29 30 31 24 25 26 27 28 29 30 April 31 Photo by Ronn Murray Spruce Trees, Interior Boreal Forest Canon 5D Mark III, Nikon 14-24mm f/2.8 5 sec., @ f/2.8, ISO 3200 Aurora Science Notes by Prof. Neal Brown Sunday Monday Tuesday Wednesday Thursday Friday Saturday THE AURORA COLORS 26 27 28 29 30 1 2 Full moon 2:45 AM 3 4 5 6 7 8 9 The aurora occur most frequently from 60 to 200 miles (100-to Mothers’ Day Armed Forces Day 320 km) above Earth. Because 10 11 12 13 14 15 16 the composition of atmospheric gases varies depending on their distance from Earth’s surface, altitude influences aurora color. The green and the deep red colors Victoria Day (Canada) New moon that often occur high in auroras Arbor Day appear when electrons collide 17 18 (Alaska only) 19 20 21 22 23 with atoms of atomic oxygen. The bluish-tinged vertical rays appear when electrons impact singly ionized molecules of nitrogen. The common magenta lower borders appear when MEMORIAL DAY electrons impact molecules of nitrogen and oxygen. A faint 24 25 26 27 28 29 30 band of blue appears when protons impact hydrogen atoms in Earth’s high upper atmosphere. 31 The Aurora Calendar APRIL JUNE 1 2 3 4 1 2 3 4 5 6 2020 5 6 7 8 9 10 11 7 8 9 10 11 12 13 12 13 14 15 16 17 18 14 15 16 17 18 19 20 19 20 21 22 23 24 25 21 22 23 24 25 26 27 26 27 28 29 30 28 29 30 May Photo by Myron Wright Turnagain Arm Ghost Forest Nikon D800E, Nikon 14-24mm f/2.8 8 sec., @ f/2.8, ISO 4500 Aurora Science Notes by Prof. Neal Brown Sunday Monday Tuesday Wednesday Thursday Friday Saturday Full moon D-Day, 1944 Magnetic Midnight 11:12 AM 31 1 2 3 4 5 6 7 8 9 10 11 12 13 Magnetic midnight is when the Flag Day New moon magnetic pole, which is offset Summer Solstice 11 degrees from the geographic 14 15 16 17 18 19 20 pole, is opposite the high-noon sun on the other side of Earth. This actual time will vary based on your geographical position. This dark midnight sector makes the auroral crown of light Fathers’ Day that hovers over the northern 21 22 23 24 25 26 27 hemisphere appear brighter. This is why the brightest aurora are visible not at midnight by the clock but at magnetic midnight. As Earth spins on its axis during the half hour before and after magnetic midnight, there is an arc of proton and electron light 28 29 30 1 2 3 4 emissions that causes the aurora to go crazy and “break up” in bright, fast motions.