Last month we posed the question, “What makes our Nederland summers hot?” with four possibilities provided as a puzzle by our resident astronomer, Luna. She emails us this month with her answer.

“Nederland summers,” she writes, “are hot for two reasons: high sun angles and long days.” She continues, “The vertical component of the rays is absorbed. The more vertical the sun’s rays, the greater their absorption and the warmer we become.” Plus, she says, “Longer days contribute, too, because the more hours of solar absorption every day, the greater the total heat storage.”

I asked, “Isn’t the earth also closer to the sun during our summer?” To which Luna replied, “Sorry, Frank. You totally fell for that one. The earth is closest to the sun on January 6 and farthest away on July 6! The sun’s greater July distance tends to moderate northern summers.”

However, she adds, “In 13,000 years, precession (see the May Night Skies column) will reverse these dates, making Nederland summers and winters more extreme. If Nederland still exists in 15,000 AD.”

As for Volcano Gnomes, Luna writes: “Gnomes are a little jokey, but massive volcanic eruptions cause cooling by catapulting vast ash clouds into the upper atmosphere, reflecting sunlight backward into space. Some readers might recall the distinct cool-off that lasted for two years after Mount Pinatubo popped in 1991. And we still remember 1816, the year following Mount Tambora’s cataclysmic explosion, as “The Year Without a Summer.” Harvests failed and starvation was feared in America and Europe due to dramatic chilling from the eruption’s globe-encircling stratospheric dust layer.”

She notes, too: “The sun-angle-andday length duality for hot summers in Nederland is a particular feature of our mid-latitude position between the equator and the pole. If you live on the equator, your days are always, monotonously, 12 hours long and the sun is always, boringly, nearly overhead at noon. Equatorial temperatures are mostly just hot. Seasonal variation there is reckoned not in temperature but in rainfall: dry months versus monsoon months.”

“In contrast,” Luna continues, “at the poles the sun is always low in the sky, when it’s there at all, and day lengths vary dramatically through the year, from zero hours to 24 hours. At our globe’s top and bottom, seasonal variations are almost solely due to varying day length.”

Luna now poses another puzzle, for next month: “All of earth’s temperatures, everywhere, are vastly warmer than physicists would predict by looking only at incoming solar radiation. Based only on arriving sunlight, earth’s average temperature should be -2 degrees Fahrenheit, fully 34° -below- water’s freezing point. Brazil ought to look like Antarctica. What makes our planet so much warmer than that, at a comfortable average of 57° F?”

Backyard Astronomy Lecture Series: This correspondent is conducting a lecture series, Backyard Astronomy, at the Nederland Public Library on the first Wednesdays of May through August, with a bonus talk, How Far is That Star, on September’s first Wednesday. Details and registration at https://nederland. colibraries.org/backyard-astronomy/. The next talk, at 6 p.m. on August 2, will describe basic astrophotography techniques.

Also in July skies: The sun begins the month in Gemini, entering Cancer on July 20. At mid-month, days and nights are 14 and 10 hours long, respectively.

The moon’s dates are: Full (Buck or Thunder) Moon July 3; Last Quarter July 9; New July 17; First Quarter July 25.

July Meteor Showers: The Piscis Austrinids (parent unknown), Southern delta-Aquariids (parent, Jupiterfamily comet P/2008 Y12), and alpha- Capricornids (parent, Jupiter-family Comet 169P/NEAT) peak on July 29 and 30. The Piscis Austrinids are best seen between midnight to dawn. The Aquariids peak around 4 a.m., and the Capricornids are best around 2 a.m.

Best Sky Viewing Nights (Minimal Moon): July 9-25.

Sunset (Mid-Month): Altair is rising in the east and Deneb is low in the northeast. Hercules with the beautiful M-13 globular cluster is nearly overhead. Libra (twin bright stars Zubeneschamali and Zubenelgenubi) is low in the south with brilliant Spica to the right. The box of Corvus is low in the southwest. The Big Dipper is high in the northwest, and Arcturus is high in the south. Distinctive Scorpius with red Antares is rising in the southeast.

Midnight (Mid-Month): Sagittarius, marking the center of the Milky Way, our home galaxy, glows in the south. Scan its varied wonders with binoculars or a wide-angle telescope.

Sunrise (Mid-Month): Orion is rising while the bright Pleiades cluster glints high in the east. Our nearest neighbor galaxy, M-31 Andromeda, is perfect for binocular viewing directly overhead.

Mercury reaches its highest altitude above the horizon in the evening sky on the 31st.

Venus is low in the western evening sky, close to Mars. It sinks lower, toward the sun, every night this month.

Mars is faint in the western evening sky near Venus, getting lower through the month.

Jupiter rises around 1 a.m. and is low in the east at sunrise.

Saturn rises around 11 p.m.; it is high in the south-southeast at dawn.

Notable Space Missions: The first launch of the United Launch Alliance’s new heavy-lift booster, the Vulcan Centaur, may occur this month from Cape Canaveral. The mission payload includes a newly designed, private sector, commercially oriented Peregrine lunar lander built by the Astrobotic company.

Frank Sanders, a spectrum scientist at the U.S. Department of Commerce in Boulder, takes astronomy-related inquiries at backyardastronomy1@gmail.com.