Unlike the vigorous storms that march across the Pacific Ocean and slam into California with all their might, stargazing sometimes can seem a little uneventful for many of us without a telescope. However, that’s about to change.
On the morning of Aug. 21, the new moon will be in direct alignment with the sun and Earth and will pass in front of our star creating a total solar eclipse. The 60- to 70-mile-wide band of totality will block the sun’s light for several minutes as it travels eastward across a swath from Oregon to South Carolina.
Total solar eclipses are rare events.
The last total eclipse in the United States occurred in February 1979 when the dark center of the moon’s shadow (umbra) traveled across the northern United States into Canada. If you can’t make this August’s event, the next North America occurrence will transpire on April 8, 2024.
That total eclipse will reach the west coast of Mexico a little south of the Baja Peninsula and travel northeastward across Mexico into Texas and across the country into Maine. After that one, another total solar eclipse doesn’t happen in the United States until Aug. 12, 2045. It will take a similar route as this year’s event but will be further south and take a path across far Northern California into Florida.
Other factors make these events even rarer to view. If you don’t have clear skies, you’re not going to see it. Along the Oregon coastline, there’s a chance that marine stratus clouds will partially cover coastal regions, except on the top of the mountains in the morning hours.
As the eclipse moves through Missouri, Illinois, Kentucky, Tennessee and South Carolina during the afternoon hours, there’s the likelihood of thunderstorms due to the heat and humidity of August or subtropical moisture as the Atlantic hurricane season nears its peak.
To make matters more challenging, enormous numbers of people will either travel north or south to the path of totality, perhaps causing one of the worst traffic jams in the country’s history. Without a doubt, drivers will be distracted and will probably pull over at unsafe locations along highways for viewing.
Despite this, I’m going to make every effort to see this event as it’s something I will remember for the rest of my life. I’ll probably head to eastern Oregon, where the climate is dry and the skies are mostly clear at this time of the year. I would get to your destination either on Saturday or Sunday as the highways will probably become parking lots by Monday morning.
Along the Central Coast, we will see a partial solar eclipse. This condition means that the moon will only partially block the sun and reduced the amount of solar radiation reaching the Earth’s surface. In other words, California will be in the secondary shadow called the penumbra, which gets larger as it reaches Earth, unlike the umbra which gets smaller.
If you’re in the penumbra, you will see a partial eclipse. If you are in the umbra, you will see a total eclipse. The partial solar eclipse will begin at 9 a.m., peaking at 10:15 a.m. and conclude at 11:40 a.m. At the peak, about 65 percent of the sun’s energy will be blocked by the moon along the Central Coast, but please protect your eyes if you view it.
There are other types of solar eclipses. An annular eclipse occurred back in May 2012 when a 200-mile-wide path of the moon’s shadow reached the rugged Northern California coastline. An annular eclipse happens when the moon lines up perfectly with the sun but is too far from Earth to completely cover its diameter as it does during a total eclipse.
This condition creates a “ring of fire” in the sky as the moon forms a “black hole” in the center of the sun. So, why are some eclipses annular and others total? The moon’s orbit around Earth is an ellipse. At perigee — closest to Earth — the moon comes within 225,000 miles of us. At apogee — farthest from Earth — it’s 250,000 miles away.
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I will be speaking at the Rotary Passport Club of the Central Coast’s first quarterly meeting on our weather and climate change. This event will be held at the PG&E Energy Education Center, 6588 Ontario Road, San Luis Obispo, at 6 p.m. Thursday. Please visit portal.clubrunner.ca/2824 for information and tickets. I would love to see you there.
John Lindsey’s column is special to The Tribune. He is PG&E’s Diablo Canyon marine meteorologist and a media relations representative. Email him at firstname.lastname@example.org or follow him on Twitter @PGE_John.