12:30 PM | Interesting facts about the sun and solar eclipses

A current image of the sun reveals another spotless day.  In fact, this is the 7th day in a row with no sunspots on the sun and the 51st day of the year.  The sun will likely feature even more frequent blank days over the next several months as we continue towards the next solar minimum.  The current solar cycle (#24) has been the weakest in more than a century since cycle 10 peaked in 1906. Image courtesy spaceweather.com, NASA/SDO.

-Hundreds of millions of years ago total solar eclipses were not visible since the moon was too close to the Earth and it completely blotted out the sun’s disk and outer atmosphere.

-Hundreds of millions of years from now total solar eclipses will not be visible on Earth since the moon will be too far away.  The moon is drifting slowly away at just over 2 cm per year.

-In the current epoch, the alignment of the sun, moon and Earth is nearly perfect for viewing total solar eclipses. The beautiful symmetry of a total solar eclipse happens now because—by pure chance—the sun is 400 times larger than the moon, but is also 400 times farther from Earth, making the two bodies appear the exact same size in the sky.

-Total solar eclipses occur somewhere on Earth every year or so, but generally cast their shadows over oceans or remote land masses. 

-Everyone in the continental U.S. will see at least a partial eclipse on August 21st (of no less than 48% of totality). 

-The last time a part of the contiguous US saw a total solar eclipse was in 1979 and the next total solar eclipse on US soil will take place in April 2024. This is the first “coast-to-coast” total solar eclipse in the US since 1918.  Also, this will be the first total solar eclipse visible in the US and in no other country (i.e., since 1776).

-The next total solar eclipse over the continental U.S. occurs April 8, 2024. It’s a good one, too. Depending on where you are (on the center line), the duration of totality lasts at least 3 minutes and 22 seconds on the east coast of Maine and stretches to 4 minutes and 27 seconds in southwestern Texas. After that eclipse, it’s a 20-year wait until August 23, 2044 (and, similar to the 1979 event, that one is visible only in Montana and North Dakota). 

-Since the moon’s shadow is round, the longest eclipse occurs at its center line because that is where you’ll experience the moon’s shadow at full width.  The center line for the August 21st total solar eclipse crosses ten states beginning in Oregon and ending in South Carolina.

-The end of the August 21st total solar eclipse for the US in not on land, the center line’s last contact with the US will at the Atlantic Ocean’s edge just southeast of Key Bay, South Carolina.

-This solar eclipse will be the most-viewed ever.

-Only one “large” city has a great view of totality during the the August 21st eclipse - Nashville, Tennessee.

-If the sun is active during a total solar eclipse, observers should be able to see solar prominences, loops and flares.

-A solar eclipse happens at new moon.

-During the time that the moon’s disk completely covers the sun - i.e., during totality - it is actually supposed to be safe to look at the sun. In fact, to experience the awesomeness of the event, you should look at the sun during totality without a filter according to first-hand observers. Looking at the sun during a partial eclipse without proper protection from specially designed glasses can cause permanent eye damage.  

-The moon’s shadow zooms across Earth’s surface at up to 5,000 miles per hour.

-Just before full eclipse in the totality zone, dazzling “Baily’s beads” appear where sunlight shines through valleys on the moon. The last bead creates the impression of a diamond ring in the sky. 

-After a total solar eclipse, it takes about an hour before total day light is restored.

 -In case you were thinking about relocating: Earth is the only place in the solar system where this kind of solar event happens.

-China produced the first known astronomical recordings of solar eclipses, inscribed in pieces of bone and shell called “oracle bones,” from around 1050 B.C. or earlier.

-Ten great places to view the eclipse in the totality zone: Madras, Oregon, Snake River Valley, Idaho, Casper, Wyoming, Sandhills of western Nebraska, St Joseph, Missouri, Carbondale, Illinois, Hopkinsville, Kentucky, Nashville, Tennessee, Great Smoky Mountains National Park (NC/TN border), Columbia, South Carolina.

-Perhaps the luckiest place on Earth is Carbondale, Illinois: they will experience totality on August 21, 2017 AND again on April 8, 2024.  [In any given location, a total solar eclipse happens just once every 360 years on average].

-The atmosphere of the sun is composed of several layers, mainly the photosphere (source region of solar flares), the chromosphere and the corona.  It is in these outer layers that the sun’s energy which has bubbled up from the interior, is detected as sunlight.

-The lowest layer of the sun’s atmosphere is the photosphere and it is about 300 miles thick. The next layer is the chromosphere which emits a reddish glow as super-heated hydrogen burns off.  This red rim can only be seen during a total solar eclipse.  At other times, light from the chromosphere is usually too weak to be seen against the brighter photosphere. The third layer of the sun’s atmosphere is the corona and this can be seen only during total solar eclipses as well.  [Not even a 99 percent eclipse will reveal the sun’s corona or chromosphere - it must be total].

-The corona appears as white streamers or plumes of ionized gas that flow outward into space. Temperatures in the sun’s corona can get as high as 3.5 million degrees F making the region much hotter than the solar surface, which is just 11,000 °F (6,000 °C) or so. How the corona gets so hot has puzzled scientists for decades and solar scientists aim to gather some useful data during this upcoming total solar eclipse.  This discovery is counterintuitive, because the body of the sun is the source of its heat; it's as if the air around a bonfire were hotter than the fire itself. 

-The sun is the main driver of all weather and climate, the entity which occupies 99.86% of all of the mass in our solar system.  It is the ultimate source of energy for the Earth.  Without the sun, life on Earth would not exist as it would be so cold that no living thing would be able to survive and our planet would be completely frozen.

-The sun goes through a natural cycle approximately every 11 years.

-The current solar cycle (#24) has turned out to be historically weak with the lowest number of sunspots since cycle 14 peaked more than a century ago in 1906.

 -The solar wind is one aspect of solar weather. It comes from the corona of the sun, travels around 1 million miles per hour, and is not constant. The solar wind has a direct impact on the ability of cosmic rays to penetrate the Earth’s upper atmosphere.  

-Galactic cosmic rays are high-energy particles originating from space that impact the Earth’s atmosphere. Usually, cosmic rays are held at bay by the sun's magnetic field and its solar winds sweep them aside when they pass by Earth.  As the sun plunges towards a minimum phase, there is typically less and less solar activity (e.g., solar storms, coronal mass ejections), and the weakening magnetic field and solar wind provides less and less shielding for the Earth; consequently, there is an increase in the penetration of cosmic rays into the Earth’s upper atmosphere.

-Sunlight reaches the Earth in about 8 minutes.

-Sunspots appear to move across the sun.  This observation led astronomers to realize that the sun rotates on its axis.

-The sun is a ball of gas with no solid form and different regions rotate at different rates.  The sun equatorial regions rotate in about 24 days while the polar regions take more than 30 days to make a complete rotation.

-While we can accurately predict when the next solar eclipse will occur, we cannot with any confidence predict when the next super solar storm will take place.  Nor can we accurately predict when the next solar cycle (#25) will begin, how long it will last, and how weak or strong it may be.  

-If the super solar storm known as “The Carrington Event of 1859” were to take place in today’s world, it could wreak havoc given today’s reliance on electronics and satellite systems.

Age: 4.5 billion years old
Diameter: 860,000 miles diameter (about 110 Earths)
Distance: 93 million miles away from Earth
Composition of mass: 75% Hydrogen and 25% Helium with about .1% made up of other elements
Layers: From the center out, the core, the radiative zone, the convective zone, the photosphere, the chromosphere, and the outermost layer, the corona.
State of Matter: Plasma (not a solid, liquid, or gas)
Hottest part of the Sun: The core at 28 million degrees Fahrenheit
Energy created by: Fusion (the fusing of Hydrogen to create Helium, plus mass and energy)

Meteorologist Paul Dorian
Vencore, Inc.
vencoreweather.com