Mon Jan 26, 2026 ARISTOTLE AND THE EARTH’S REVOLUTION
The Greek philosopher Aristotle argued that the planet earth did not orbit the sun, because if it did, then the stars would exhibit parallax – that’s when you see something not too far away shift against a distant background when you look at it from two different places. The closer a star is to you, the greater the parallax. So nearby stars ought to shift position when we look at them from either end of the earth's orbit. Since they don't seem to do this, then the earth doesn't move. Either that, or even those nearby stars must be really, really far away. And as it turns out, they are – after the sun, the nearest star to us is Alpha Centauri and it has a stellar parallax shift less than 1 four-thousandth the width of your little finger held at arm's length - that’s too tiny a shift to see without a really good telescope!
Tue Jan 27, 2026 WHERE’S THE BIG DIPPER?
The constellation Orion the Hunter is in the southeastern sky after sunset tonight. You’ll recognize him by his belt: three bright stars close together in a straight line. Another easy pattern to identify is the Big Dipper, seven fairly bright stars that form the outline of a giant saucepan in the heavens. Folks up north can see the Big Dipper at any time of night throughout the year. But in Florida, when the Big Dipper is at its lowest, it’s below our northern horizon. So to find the Big Dipper, you either have to wait until late winter to see it in the early evening, or go out tonight around 10 o’clock when the Dipper stands up on its handle low in the northeastern sky. Or you could take a trip up north and then you’d be able to see the Big Dipper in the early evening while you’re shoveling all that snow off the sidewalk.
Wed Jan 28, 2026 HEVELIUS
415 years ago the Polish astronomer Johannes Hevelius was born on January 28, 1611. His family owned a brewery in Danzig, and he used his fortune to build an observatory and study the heavens. Hevelius made the first moon atlas, and named many lunar features, such as the Ocean of Storms, the Sea of Rain, the Sea of Tranquility – all in Latin, of course – Mare Imbrium, Mare Tranquilitatis, and so on. He also took the names of various mountain ranges on earth, such as the Alps, the Appenines, and the Caucasus, and applied them to the mountain-like walls of lunar craters. And Hevelius made up many new constellation patterns that we recognize today, such as Lynx the Bobcat, Vulpecula the Fox, Scutum the Shield, Lacerta (la-sir’-tah) the Lizard, Leo Minor the Little Lion and the hunting dogs called Canes Venatici. (ven-a-tee’chee).
Thu Jan 29, 2026 MOON AND JUPITER TOGETHER
Tonight the moon can be found above the head of the constellation Orion the Hunter. You’ll find them both over in the eastern sky after sunset. The moon is in its waxing gibbous phase, looking a little lopsided because the eastern limb of the moon is still covered in its own shadow. Now down to the east of the moon is a very bright, solid-looking star, which is really the planet Jupiter. Because the moon revolves about the earth, it very slowly drifts against the background of stars. Tonight it is between the horns of Taurus the Bull, but tomorrow night it will be alongside Jupiter, which can be found among the stars of Gemini. A small telescope will allow you to see the cratered surface of the moon as well as the four largest moons of Jupiter, appearing as tiny stars on either side of the giant planet.
Fri Jan 30, 2026 SELENOLOGY
The moon, now nearly full in our sky, is about a fourth of the diameter of the Earth. Technically, it doesn’t revolve about us, but about a common center of gravity knowns as a barycenter, that happens to lie about a thousand miles below the surface of the Earth. The Earth and the moon have a lot of common characteristics, but also quite a few differences. The Earth is somewhat denser, containing more metals for instance. The composition of earth rocks and moon rocks is similar, but the mineral content is slightly different and moon rocks are amazingly dry! The study of the moon and its geology and landforms is called selenology – Selene is a very old name for the moon; in Greek mythology she was the sister of the old sun god Helios.
