Bob Berman

If you're hearing this on Sunday, Saturn is at its closest point to Earth, and its rings appear as a straight white line due to their edge-on alignment — a rare event that occurs every 15 years during its equinox. Earth’s own equinox arrives Monday at 2:10 PM, marking the start of autumn in the Northern Hemisphere. This equinox often falls on the 22nd or 23rd because, as Kepler explained, Earth speeds up in its orbit when closer to the sun in January and slows down in July. That means winter is shorter than summer by about a week — a fact disguised by our calendar and the uneven placement of long and short months.

This year brings a rare lunar event called the Lunar Standstill, which happens only once every 18.5 years. Due to the Moon’s wobbling orbit aligning with Earth’s tilt, the Moon is reaching extreme positions in the sky. Recently, it appeared unusually low at first quarter, the third quarter Moon stood directly overhead—something typically impossible from the continental U.S. Even in daylight, the Moon remains high and visible, especially through sunglasses, offering a striking sight in the sky.

Vega, one of the brightest stars, is often mispronounced as "VAY-ga" but should be "WEE-ga," meaning "falling eagle" in Arabic. Visible at nightfall, it shines blue overhead, contrasting with the orange Arcturus. Located 25 light-years away, it’s 58 times brighter than the sun and spins much faster, completing a rotation in just 11 hours. In 12,000 years, Vega will become Earth's pole star. It also displays a rare blueshift, pointing to the direction we're traveling in space.

This week’s half Moon will appear unusually low in the sky—so low it might be hidden behind the trees. It sits far below its usual path due to the Moon’s wobbling orbit, which currently aligns with Earth’s tilt. This rare positioning, part of a cycle called the Lunar Standstill, places the Moon near the constellation Scorpius and its bright star Antares. Its light, filtered through thick atmosphere, may appear honey-colored and cast moonbeams at odd angles into places that rarely see moonlight. Look south to see this striking celestial oddity.

Arcturus: A Star Worth Saluting: On the next clear evening around 8 p.m., look west and halfway up the sky—you’ll spot Arcturus, a bright pastel-orange star and the fourth brightest we can see from Earth. It once famously opened the 1933 Chicago World's Fair with its light and is unique among bright stars for its wild, plunging path through space. Unlike stars that circle with the Milky Way, Arcturus is just passing through—so catch a glimpse while you can. It's the brightest thing in tonight’s sky… and it won’t be there forever.

Wednesday August 13 around 5:15–5:30 a.m., early risers with a clear view of the eastern horizon can witness a rare celestial lineup: the crescent Moon alongside Venus—the dazzling Morning Star—with Jupiter shining above and Mercury low near the horizon. This nearly vertical arrangement of the three brightest night sky objects, plus elusive Mercury, happens only in late summer and early fall when the solar system’s plane aligns upright at dawn—making it well worth setting an early alarm.

The Perseid meteor shower has begun. While the best viewing typically occurs after midnight when your location faces forward into the meteor stream, this year’s full moon is bright enough to interfere with visibility. To get around this, it's best to start watching at dusk, before the moon rises. The Perseids are tiny bits of ice from comet Swift Tuttle, disintegrating as they enter Earth's atmosphere. About one in 20 meteors, however, is a background meteor from the asteroid belt, which can survive their fiery descent. These "sturdy" meteors can even crash through roofs at speeds of up to 250 miles per hour. Despite the rarity of such impacts, insurance usually covers the damage.

We explore the quirky world of units—from the 1999 Mars Orbiter disaster caused by a metric vs. imperial mix-up to the colorful ways we measure everything from chili pepper heat to cotton and paper. You'll learn why U.S. territorial waters were once based on the range of a cannon shot, how Fahrenheit’s scale reflects geometric symmetry, and why a "barrel" of oil isn’t the same as a barrel of beer. With oddball units like skeins, quires, and cords still in use, maybe it’s finally time we all bolted over to metric!

On Wednesday, July 23, we saw a rare cosmic pairing as the Moon passes unusually close to Spica, the brilliant blue star in Virgo. Thanks to a unique tilt in the Moon’s orbit — an event that won’t repeat until 2043 — this striking alignment becomes visible to the naked eye. Learn why Spica shines so hot and bright, and how to pronounce its name the right way. Look up between 9:30 and 10 p.m. for a glimpse of this fleeting spectacle.

This week marks the statistically hottest time of the year—a fitting moment to reflect on the nature of heat. At its core, heat is just atomic motion: room temperature atoms zip around at 1,000 mph, and even freezer-chilled ones aren't far behind. Combustion happens when atoms move fast enough to sustain a reaction, with ignition temperatures varying by substance—wood around 400°F, gasoline at 495°F, and paper at the symbolic 451°F. Pyrophoric materials like sodium don’t even need a spark to ignite. Ultimately, heat is motion—your feverish 102°F body is just your molecules moving faster than usual. Tune in this week to hear more about atomic speed.