Looking back

For today's post, some physics (including astrophysics) retrospectives ....

And ... it's beautiful

My first interest in any kind of science -- likely before I knew the word science -- was with astronomy. Who among us wasn't fascinated at a young age with the fascinating show that is the night sky? And so (with added interest because of the University of Chicago connection), I was sad to read that "Yerkes Observatory is closing its doors." Yerkes is historic both for the uniqueness of its primary instrument -- a 40-inch refracting telescope -- and the many prominent astronomers who at one time or another worked there. Edwin Hubble. Subrahmanyan Chandrasekhar. Gerard Kuiper. Carl Sagan.

Looking a lot further back, consider an inference drawn from orbital peculiarities of a set of Oort Cloud objects. To wit: "An alien star sideswiped our solar system and sent comets reeling, scientists say."

But not this one (Halley's)

Some 70,000 years ago, when humans and Neanderthals shared the planet, an alien star streaked through the outer edges of our solar system and jostled its contents, astronomers say. In a study of hundreds of solar system objects with unusual orbits, the scientists also noted eight comets that may have interstellar origins.

The close-encounter conclusion is said to be 98 percent certain. That's far from the five-sigma level of statistical significance (which is ~99.9999% certainty) used in some branches of physics before a discovery is believed solid -- but nonetheless strongly suggestive.

Finally, to emphasize that not only modern-day observations are sometimes unexpected, consider these "Five Discoveries In Fundamental Physics That Came As Total Surprises." Some of these findings date back more than a century.

Cheers.