Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.

Tuesday, February 21, 2023

A tadpole in the cosmic sea

If you've taken some college-level physics, you can readily attest to the fact that analyzing the motion of objects in perfectly regular, symmetrical orbits is hard enough.  The various bodies orbiting the Sun are, by and large, in elliptical orbits as per Kepler's Laws; there are only tiny deviations from the predicted paths for a couple of them, notably Mercury (whose orbit precesses -- the long axis of the ellipse gradually shifts position -- its proximity to the Sun causes it to experience larger effects from General Relativity than other planets in the Solar System) and Uranus (which experiences small alterations in its orbit due to the gravitational pull of Neptune; in fact, that's how Neptune was discovered).

If you look farther out into space, however, you find that there are some really oddly-shaped conglomerations of matter out there, and it's been difficult for astrophysicists to account for their configurations and patterns of motion.  One example is the peculiar Tadpole Nebula, located 27,000 light years away, in the constellation of Sagittarius:

Artist's depiction of the Tadpole Nebula [Image courtesy of Keio University]

The strange shape of the Tadpole is odd enough, but an analysis of the light emitted from it, and the motion of the gas and dust within it, suggests something stupendous; the Tadpole has been stretched out because it's orbiting a black hole -- with a mass a hundred thousand times that of the Sun.

The Tadpole Nebula is near the center of the Milky Way; from our perspective, the galactic center also lies in Sagittarius.  (In fact, when you're looking toward the constellation of Sagittarius in late summer, consider the fact that if it weren't for the dust clouds in the way, you'd be able to see the glorious spectacle of the Milky Way's nucleus -- other than the Sun, it'd be far and away the brightest thing in the sky.)  And the Milky Way itself has at its center a stupendously large black hole, this one estimated to be four million times the mass of the Sun.  But the Tadpole shows that there are other enormous gravitational attractors out there, capable of taking a huge cloud of gas and stretching it out into a celestial question mark.

My wife and I just finished rewatching the old series Cosmos last week, and I was struck over and over at how delighted Carl Sagan would have been to see the developments and discoveries that have been made since his tragic death of bone marrow cancer in 1996 at the age of 62.  His wonder at the beauty of the universe shines through in every word.  I more than once remarked while watching the series, "He's not only a scientist, he's a poet."  How much more would he be awestruck by what we know today -- the sparkling clarity of the images coming in from the James Webb Space Telescope, the information we're learning about the planets and moons in our own Solar System, the thousands of exoplanets that have been discovered.

I'll conclude with a quote from Sagan, which seems a fitting way to end: "Who would not feel awed?  There is a wide, yawning black infinity.  In every direction, the extension is endless; the sensation of depth is overwhelming.  And the darkness is immortal.  Where light exists, it is pure, blazing, fierce; but light exists almost nowhere, and the blackness itself is also pure and blazing and fierce...  The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars.  We are a way for the universe to know itself."


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