Mon June 30, 2025 TUNGUSKA
Several years ago, an early morning fireball lit up the sky over Chelyabinsk, Russia. Shock waves from the impact shattered windows, injuring over a thousand people. Now this wasn’t the first time such a thing had happened. Back on June 30th, 1908, something really big blew up in the atmosphere above the Tunguska region in Siberia. Eyewitness reports sound a lot like the Chelyabinsk event. A brilliant blue light, like a second sun, flashed across the early morning sky. It was followed by a sonic shock wave that broke windows, killed wildlife, knocked people to the ground, and shook the earth. The Chelyabinsk impactor was a rock over fifty feet across, which broke apart about ten to 15 miles above the surface. The total energy of the blast was roughly equal to that of dozens of atomic bombs. The Tunguska blast was at least five hundred times more powerful.
Tue July 1, 2025 VEGA IN THE EAST – VULTUR CADENS
This evening, look toward the east. There’s a bright star over there – its name is Vega, and it’s the fifth brightest star in the night sky. Vega is from an old Arabic word meaning, “falling, (or “swooping,) eagle (or vulture)”. Vega is part of an ancient star pattern known as vultur cadens, which also means, “falling vulture,” although the official constellation here is Lyra, the Harp. On star charts you can sometimes see it pictured as a vulture with a harp inscribed within it. Above Vega are some fainter stars which trace out a simple letter H. The H stands for Hercules, and for his sixth labor, this mythical Greek hero shot arrows at this vulture, and also at two nearby constellations, Cygnus the Swan and Aquila the eagle, driving them away from Lake Stymphalus, where they had picked up the unfortunate habit of swooping down and attacking any unsuspecting people who wandered by.
Wed July 2, 2025 PRINCIPIA
On July 6 1686, Principia Mathematica was published in England. Principia was Isaac Newton’s great book on gravity and motion, which became a major breakthrough for our understanding of how the Universe works. His three laws of motion – inertia; force equals mass times acceleration; and action-reaction, plus the relationship between gravity, mass and distance, are still in use today, showing us how we can send rockets to the moon and beyond. Edmond Halley paid for Principia’s publishing, because he wanted it to help him work out comet orbits. Halley asked the Royal Society to pay for it, but they’d tied up all their money in a beautiful book, the “History of Fishes”, which nobody bought. Years later, when Halley wanted payment for his duties as secretary, they just gave him a lot of the fish books and suggested he could sell them and make some money that way.
Thu July 3, 2025 EARTH AT APHELION
Today at 3:55 pm Eastern Daylight Time, the planet Earth will be roughly 94 and a half million miles from the sun, a point in its orbit known as aphelion. The earth’s orbit is slightly elliptical, so sometimes we’re a little closer to the sun than at other times. That near point is called perihelion, and the far point is known as aphelion - that’s where we are right now. So how come we're having summer? Well, it’s summer now where we are, but winter has just begun for folks south of the equator. Temperature changes occur because our planet is tilted over a little, about 23 and a half degrees, from straight up and down. Right now, our hemisphere is leaning inward, which puts the sun higher in our sky, and causes summer; in the winter the top half of earth leans away from the sun, putting it lower in our sky, which cools things down. Over the next few nights, you may see the waxing gibbous moon in the evening sky, adding its light to the fireworks displays.
Fri July 4, 2025 4TH OF JULY COSMIC FIREWORKS
On the 4th of July in the year AD 1054, a bright star appeared in the eastern predawn sky. It was near the star Al Hecka, the forward horn tip of the constellation Taurus the Bull. For the next month this new star, this “nova,” was so bright that it could even be seen in the daytime! As summer drew to a close, the star faded out of sight and was seen no more. In Europe there is no written record of this star’s appearance: either no one was looking up then, or more likely, the skies were overcast throughout its appearance. But Chinese astronomers made note of this “guest star,” as they called it, and that’s how we know about it today. If you’re out before sunrise this month, aim your telescope at that part of space behind the forward horn tip of Taurus, and you’ll find the Crab nebula, the exploded remains of a supernova - cosmic fireworks from nearly a thousand years ago.
