Posts Tagged ‘astronomy’
“Sure, black holes can kill us, and in a variety of interesting and gruesome ways. But, all in all, we may owe our very existence to them”*…
If you want to see a black hole tonight, just look in the direction of Sagittarius, the constellation. That’s the center of the Milky Way Galaxy and there’s a raging black hole at the very center of that constellation that holds the galaxy together.
- Michio Kaku
So, which came first: the galaxies spread through the universe, of the black holes that hold them together? Ethan Siegel answers and explains.
* Philip Plait, Death from the Skies!: These Are the Ways the World Will End…
As we raise our eyes, we might send star-struck birthday greetings to Johann Rudolf Wolf; he was born on this date in 1816. A distinguished astronomer and mathematician, Wolf wrote on prime number theory, geometry, probability, and statistics; but he is best remembered for his work on sunspots. Working from Heinrich Schwabe’s suggestion that sunspot activity was cyclical, Wolf calculated the period of the cycle at 11.1 years; he was among the first to establish the connection of sunspot activity to geomagnetic activity on Earth; and he developed a way of quantifying sunspot activity– the Wolf number, as it is known– that remains in use.
A few years back, 12 million of us clicked over to watch the “Pachelbel Rant” on YouTube. You might remember it. Strumming repetitive chords on his guitar, comedian Rob Paravonian confessed that when he was a cellist, he couldn’t stand the Pachelbel Canon in D. “It’s eight quarter notes that we repeated over and over again. They are as follows: D-A-B-F♯-G-D-G-A.” Pachelbel made the poor cellos play this sequence 54 times, but that wasn’t the real problem. Before the end of his rant, Paravonian showed how this same basic sequence has been used everywhere from pop (Vitamin C: “Graduation”) to punk (Green Day: “Basket Case”) to rock (The Beatles: “Let It Be”).
This rant emphasized what music geeks already knew—that musical structures are constantly reused, often to produce startlingly different effects. The same is true of mathematical structures in physical theories, which are used and reused to tell wildly dissimilar stories about the physical world. Scientists construct theories for one phenomena, then bend pitches and stretch beats to reveal a music whose progressions are synced, underneath it all, in the heart of the mathematical deep.
Eugene Wigner suggested a half-century ago that this “unreasonable effectiveness” of mathematics in the natural sciences was “something bordering on the mysterious,” but I’d like to suggest that reality may be more mundane. Physicists use whatever math tools they’re able to find to work on whatever problems they’re able to solve. When a new song comes on, there’s bound to be some overlap in the transcription. These overlaps help to bridge mutations of theory as we work our way toward a lead sheet for that universal hum…
Read the harmonious whole at “How Physics is Like Three-Chord Rock.”
* Henri Poincare
As we hum the tune eternal, we might send astronomical birthday greetings to Allan Rex Sandage; he was born on this date in 1926. An astronomer, he spent his career first at the Palomar Observatory, then at the Carnegie Observatory in Pasadena, where at the outset, he was a research assistant to Edwin Hubble, whose work Sandage continued after Hubble’s death. Sandage was hugely influential on his field; he is probably best remembered for determining the first reasonably accurate value for the Hubble constant (there ate those chords again) and the age of the universe– and for discovering the first quasar (again, those chords).
* Oscar Wilde
As we pause to celebrate the birth of the archetypical “Renaissance man,” quite possibly the greatest genius of the last millennium, Leornardo da Vinci (born on this date in 1452), we might also send starry-eyed birthday greetings to Friedrich Georg Wilhelm von Struve; he was born on this date in 1793. A renowned astronomer, Struve is known both as the founder of the modern study of binary (double) stars, and as the second in a five-generation-long dynasty of great astronomers: he was the son of the son of Jacob Struve, the father of Otto Wilhelm von Struve, the grandfather of Hermann Struve, the great-grandfather of Otto Struve.
As October, National Pizza Month, draws to a close, Flowing Data offers a rigorous examination of pizza chains across the U.S. and the relative proximity of their outlets in different areas. It’s the handiest of guides– and one to use: surely Americans can improve on last year’s statistics; surely we can do better than 251,770,000 pounds of pepperoni consumed…
As we ask for extra crushed red pepper, we might recall that it was on this date in 1937 we– the entire population of the earth– narrowly avoided (by twice the distance of the Moon… but that’s only three seconds) obliteration as the 500,000 ton asteroid/planetoid 69230 Hermes failed to collide with our planet. (In 1989, the earth had an even closer approach, but by the smaller 4581 Asclepius.)
Brian and Peter, the keepers of Plurib.us, have gifted us with perspective: Explore our solar system and its environs– planets, dwarf planets, and moons– comparing each celestial body’s size as it might appear from earth, as it is in “true” scale (as above)… and as it routinely appears n a child’s play set…
Check it out at Planet Resizer.
* Mark Twain
As we boldly go, we might recall that it was on this date in 1947, after 11 years of grinding and polishing, that what had begun as 20 tons of molten glass finally became a 200-inch diameter telescope lens for Cal Tech’s Mount Palomar Observatory. It was mounted in the Hale Telescope (named in honor of the late Dr. George E. Hale who had initiated the project).and was first used on February 1, 1949 to capture pictures of the Milky Way.