Mon Feb 17, 2025 SIRIUS
There are many bright stars in winter’s early evening sky. In the southeast, down and to the left of the constellation Orion, there’s a star called Sirius, a name derived from the Greek “seirios,” which means, scorching, or sparkling. So you could say Sirius is the star you meant when you recited “Twinkle, Twinkle” as a kid. This brilliant star does twinkle, owing to our earth’s atmosphere, which causes the star to flicker and flash. Sirius is also called the Dog Star, because it's supposed to mark the nose of the Big Dog in the sky, Canis Major. Stars have different brightnesses. Some are bright because they're close to us; others are bright because they're either hotter or bigger. With Sirius, it's a little of both - a big, white-hot star, very close to us, a mere 54 trillion miles away.
Tue Feb 18, 2025 THE DISCOVERY OF PLANET X
On February 18, 1930, Planet X was discovered by Clyde Tombaugh at the Lowell Observatory in Arizona. Tombaugh was a talented amateur astronomer who was hired to make photographic plates of the sky, and search them, looking for anything that might shift its position from one night to the next, as seen when comparing one photo to another picture of the same part of the sky taken a few nights later. It was painstaking work but rewarding; Planet X was discovered out in the direction of the constellation Gemini, which is well up in the eastern sky after sunset tonight. But Planet X isn’t there anymore. This distant world is now six constellations over to the east, in Sagittarius. Oh, and it’s not called Planet X anymore; shortly after its discovery it was renamed Pluto.
Wed Feb 19, 2025 NICOLAUS COPERNICUS
The Polish astronomer Nicolaus Copernicus, born on February 19th, 1473, advocated the heliocentric theory, which placed the sun in the center of the solar system, with the earth and other planets revolving about it. Copernicus received praise and encouragement from the Bishop of Kulm and the Archbishop of Capua and some scholars, but his ideas were also ridiculed by others including Martin Luther, who once said, “This fool wants to turn the whole art of astronomy upside down!”. Until the mid-1600’s, the teachings of ancient Greek philosophers like Aristotle were considered the final word on science, and Copernicus’ predictions weren’t any more accurate than the old earth-centered model. But this Copernican model was a simpler way to explain the motions of the planets.
Thu Feb 20, 2025 SPAGHETTIFICATION AND BLACK HOLES
If you ever jumped into a black hole, you’d find that the hole’s gravity would pull on your feet a lot harder than your head, which would stretch your body out as thin as a piece of spaghetti, which of course is not a natural state for the human body to be in, so you would disintegrate, and eventually all of your atoms would spiral into the black hole - so stay out of black holes! The nearest known black hole in the sky this evening is V616 Monocerotis, in the faint constellation Monoceros the Unicorn, which is in the southeastern sky tonight just to the east of Orion the Hunter. It’s about 3,000 light years away, or 18,000 trillion miles. So even the nearest black hole is so far away that nobody is in any danger of falling in!
Fri Feb 21, 2025 JOCELYN FINDS A RADIO STAR
In 1967, Jocelyn Bell, then a graduate student at England’s Cambridge University, made an incredible discovery: while going over the data from a radio telescope she’d help build, Bell found a rapidly recurring signal, which spiked every 1.3 seconds. Bell had found the very first pulsar, although the source of the signals was not known at the time (Bell and her advisor dubbed them “L.G.M.”s, light-heartedly suggesting they could be signals from an alien civilization consisting of “Little Green Men.”) Pulsars are the rapidly spinning cores of exploded stars. Her discovery was announced on February 24, 1968 and her advisor was soon awarded a Nobel prize (Wait, what?) But in 2018 Bell finally received her Nobel, in the category of Fundamental Physics.
