TUNGSTEN VALLEY — As a scientist, this correspondent likes to think beyond our immediate issues and challenges, looking down the road. Way down the road. Beyond when we’ll have exhausted all of our planet’s fossil fuel in a century and we’ll have stopped pumping out CO2.

Beyond when the next ice age kicks in 5,000 years from now, due to the earth’s orbit-and tilt-dependent Milankovitch cycle.

Beyond 250 million years from now, when the Atlantic Ocean’s current widening will have reversed, the Americas will have crunched into Europe and Africa, and much of the earth will be a Pangaea-like desert.

I’m talking about a billion years from now. When the sun will be getting bigger, brighter, redder, and hotter. Sol will do this as his hydrogen peters out and he starts fusing heavier nuclei.

The effects of a bouncing-baby red-giant sun? As things heat up, temperature-sensitive chemical equilibria will shift. Soil acidity will increase. Carbonate rocks will absorb most of the atmosphere’s CO2.

The Good News: Decreasing atmospheric CO2 will partly offset the solar heating.

The Bad News: When CO2 levels plunge as low as 10 parts per million (compared to our current 425 ppm), photosynthetic plants will go extinct. That’s about a billion years out.

In 1.3 billion years, average temperatures will hit 122 F, killing everything except bacteria. At 1.5 billion years the earth will reach 212 F, water’s boiling point. Baked dry, the earth will be sterilized.

Be not faint of heart! This correspondent, a veteran problem-solver, presents here a solution: As the sun goes red-giant, move the earth farther from the furnace.

We might imagine bolting rocket engines to our planet to boost our orbit outward. Unfortunately, pushing on our crust won’t work because of the squishy mantle below and the pesky atmosphere above.

But wait: We luckily have a rigid, airless, gravitationally coupled body right next door, which we can use as a tug. It’s Luna, our moon. We can make this work.

My concept is, about a billion years from now we cover one side of the moon with solar-powered ion-engine rocket motors. A lunar hemisphere is 19 million square kilometers. Figure ten motors for each, for a total of 190 million ion engines. (That’s fewer than the cars currently on American roads. The motor and fuel factories will be on the moon.)

Once a month, twelve times a year, the motors are fired in unison for a few hours when the moon is positioned as shown in the diagram. Luna’s orbit will be gradually boosted, year after year. And its gravity will pull the earth behind it. At only 1/81 of the earth’s mass, the moon will be boosted 81 times more than our planet. But Luna’s tug on the earth will inevitably nudge our planet outward from the sun, cooling it.

Ultimately, the red-giant sun will still prevail. But this lunar-tug rescue could buy our planet another few million years before the sun bakes the life out of it.

You saw it here first, in The Mountain-Ear.

August fun Astro-Fact: Gravity-tug maneuvers cause planetary asteroid captures. A pair of close-coupled asteroids swings past a planet. One asteroid drops into orbit while its partner flies violently outward, never to be seen again.

In August skies:

The sun begins the month in Cancer, entering Hydra/Leo on August 9. At mid-month, days and nights are 13.5 and 10.5 hours long, respectively.

The moon’s dates are: Last Quarter August 5; New August 12; First Quarter August 19; Full (Sturgeon or Corn) Moon August 27.

August Meteor Showers: The Perseids (parent Comet Swift-Tuttle) and kappa-Cygnids (parent possibly Asteroid 2001 MG1) peak on August 13 and 18. The famous Perseids are best seen shortly before dawn. The k-Cygnids peak around 11 p.m.

Best Sky Viewing Nights (Minimal Moon): August 5-19.

Sunset (Mid-Month): Deneb is high in the east; Vega is nearly overhead; Altair is mid-sky in the northeast. Hercules with its striking M-13 globular cluster is overhead. Libra (twin bright stars Zubeneschamali and Zubenelgenubi) is low in the southwest. Antares is due south in Scorpius.

Midnight (Mid-Month): The Teapot in Sagittarius, marking the Milky Way’s center, glows in the south-southwest. Scan its wonders with binoculars or a telescope.

Sunrise (Mid-Month): The Gemini twins are low in the east. Our nearest neighbor galaxy, M-31 Andromeda, gives great binocular viewing directly overhead.

Mercury, in Cancer, reaches maximum elevation in the east before sunrise on August 2. It conjuncts with Jupiter just before sunrise on the 15th.

Venus, in Crater, is our very-low-in-the-west Evening Star at sunset. Spica is above and to the left.

Mars, in Taurus, rises at 2 a.m., then medium-high in the east at sunrise.

Jupiter, in Cancer, conjuncts low in the east with Mercury just before sunrise on August 15.

Saturn, in Pisces, rises at 10 p.m., is high in the SSE at 3 a.m., and medium-high in the southwest at sunrise.

Notable space missions: The Nancy Grace Roman Space Telescope launches from Cape Canaveral on August 30. It will help settle critical questions about dark energy, dark matter, exoplanets, and infrared astrophysics. 

Frank Sanders, a spectrum scientist, takes astronomy-related inquiries at backyardastronomy1@gmail.com.