The Earth is round.
Now, while most of my readers will find this no great revelation, there are some folks who choose to believe otherwise.
Certainly a number of proofs exist that our planet is round, but there's one I'm reminded of every time I lead a group of excited sky watchers to experience a total solar eclipse, as I will again in early March. The calculations that predict the eclipse — and where we need to stand to see it — are based on the premise that our planet is spherical. If it weren't, people would have strung me up long ago for leading them across the world only to miss the eclipse.
Another demonstration of our planet's roundness appears low in our southern sky at night. The farther south on the spherical Earth that you live or travel, the higher the southern-most stars will appear. In fact, the stars that we Northerners see low in our southern sky are visible to Southern Hemisphere stargazers high overhead. This is a direct result of the roundness of our planet.
But you don't have to travel far to see these; in fact, this week after dark, some are visible to many of us in the Northern Hemisphere. To find them, first locate the constellation Orion, the hunter, the brilliant rectangle of four stars with three equally bright stars that trace a straight line at its center.
Immediately below the great hunter's feet lies the figure of Lepus, the hare, a faint and ancient constellation that represents the prey of Orion. To its east we find Canis Major, the great dog, marked by the dazzling star Sirius.
To the east of Lepus — and below Canis Major — we find Puppis, the stern. This is one of the larger Southern Hemisphere constellations, and was originally part of a now-defunct and even larger constellation known as the ship Argo Navis.
To the west of Lepus, and beginning near the foot of Orion, begins the long, winding constellation of Eridanus, the river. In Greek mythology, Eridanus is the waterway in which young Phaethon crashed after his failed attempt to fly the chariot of the sun.
Even farther south — very close to the horizon for many in North America — lie three additional small constellations. To see these, however, you'll need a very clear and dark sky, with no obstructions on the southern horizon.
Almost due south after dark, we find the tiny star grouping of Caelum, the chisel or engraving tool, a constellation invented by Abbe Nicolas Louis de Lacaille in the mid-1700s.
Another constellation invented by the Abbe lies on the opposite side of the great celestial river: Fornax, the furnace.
And finally, to the east of the chisel, we find Columba, the dove. Columba was probably invented by the 16th-century Dutch theologian, cartographer and astronomer Petrus Plancius, to represent the dove sent out by Noah in search of dry land after the great biblical flood.
So the next time you take a long trip north or south, pay close attention to the stars of the southern sky. Their changing elevations will show you what people have known for millennia: The Earth is round!