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This weekend (tonight into early Saturday and Saturday into Sunday, August 11-12 and August 12-13) will be the peak nights of the 2017 Perseid meteor shower.

The Perseids get their name because they appear to come from the constellation Perseus. Perseus is a mythological Greek hero. He beheaded the Gorgon Medusa and saved Andromeda from a sea monster Cetus. Perseus was the son of the mortal Danaë and the god Zeus. In the night sky, constellations named after other ancient Greek legends surround Perseus, including Andromeda to the west and Cassiopeia to the north.

In 1866, after the perihelion passage of the Swift-Tuttle comet in 1862, the Italian astronomer Giovanni Virginio Schiaparelli discovered the link between meteor showers and comets. A meteor shower is the result of an interaction between a planet, such as Earth, and streams of debris from a comet.

In John Denver’s song “Rocky Mountain High”, he alludes to watching the Perseid meteor shower in the mountains near Aspen, Colorado – “I’ve seen it raining fire in the sky.”

A much stranger reference is the Catholic religion’s reference to the Perseids as the “tears of Saint Lawrence.” The belief was that his tears returned to Earth once a year on August 10 which is the canonical date of that saint’s martyrdom in 258 AD. Saint Lawrence was said to have been burned alive on a gridiron. From that came the origin of the Mediterranean folk legend that the shooting stars are the sparks of that fire. Furthermore, it was believed that during the night of August 9–10, the cooled embers of that fire appear in the ground under plants, and are known as the “coal of Saint Lawrence.” I checked around my garden Wednesday night. No coals.

This weekend you can watch from late evening until dawn. The meteor showers have been “falling” for several weeks, but this weekend should be the peak. The greatest number of meteors typically fall in the hours before dawn. In a remote location and on a “moonless” night, you might see 50+ meteors per hour. For 2017, there will be a bright waning gibbous moon after midnight. And I will be in Northern New jersey, not far from New York City, which will make viewing more difficult. But I still should be able to see those bright enough to overcome the city and moonlit glare.  This year they may be a “Perseid outburst” with 200 meteors per hour at the peak.

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sun500nc

The year just started but just a moment ago (22:49 Universal Time, 5:49 p.m. EST) Earth reached its closest point to the Sun for this year. We are at Earth’s perihelion (Greek peri “near” + helios “sun”).

Nothing extraordinary about this. Earth is closest to the sun every year in early January. This is isn’t why we moved into winter in the Northern Hemisphere. That is from the tilt of the planet, not the distance. In fact, we will be farthest away from the sun in early July, during our summer.

How much closer? About 3 million miles (5 million kilometers) closer. Big numbers but relatively not a big change in distance. Still, it wouldn’t be a bad idea to acknowledge the big star’s presence today. It’s already dark here in Paradelle, but the Sun is out there keeping us alive even on these wintry and cloudy days. Thanks, Helios!

aphelion-perihelion-earth
Before dawn this morning (from my North American longitude) the Earth reached its closest point to the sun for this year. Did you feel it?  No, but this annual event (this time at 6:36 UTC or 01:36 a.m. EST) is called perihelion from the Greek roots peri (near) and helios (sun).

Our planet gets closest to the sun every year in early January. Obviously, that doesn’t make it any warmer in the Northern Hemisphere, and we aren’t any cooler in early July when the aphelion occurs and we are farthest away from the sun. I’ll bet this confused the ancients (and some modern readers) if they knew it was occurring, though the Southern Hemisphere ancients must have thought it made perfect sense.

Earth is about 5 million kilometers (3 million miles) closer to the sun in early January than it will be in early July. That sounds like a big difference, but it’s not really significant enough to cause temperature changes across the planet and it doesn’t explain the seasons.

Mostly, it is the tilt of our planet’s axis that creates winter and summer. In winter, your hemisphere is tilted away from the sun and in summer it is tilted toward the sun. Those days of maximum tilt toward or away from the sun are the December and June solstices.

There’s a page on perihelion and aphelion and all the upcoming dates at astropixels.com if you want more information.

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Every end is also a beginning. First snow of the season.  Not enough to start the snowblower, but enough to start a fire. If you have to make shavings to start the fire, you may as well whittle something useful, then have a sip and do some #readingbravely in the snow. I’m the first human here.  Today. Sunset before a snowstorm.

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