Jason Kelly '95 | May 12, 2019
Here’s a simple fact of geography and physics: Relative to where I’m standing at my particular “you are here” dot on the planet, people in Australia are upside-down, sort of hanging off Earth, held there by the grace of gravity. If you’re anything like me, that’s both an obvious reality of a spherical world — they don’t call it “down under” for nothing — and a disorienting challenge to your intuition.
From the Australian perspective, perception of what’s up and down changes. They don’t feel like bats suspended from a galactic rafter. Defining what’s right-side-up, in human terms, depends on where you’re standing.
That’s only reality as we see it through our narrow viewfinders. The universe has no use for our illusions. The truth is out there.
People have been struggling to reconcile local experience and cosmic truth for millennia. In his book The Order of Time, the physicist Carlo Rovelli cites an unnamed, 2,000-year-old text that evinces ancient, freshman-philosophy-whoa-dude noodling toward a conception of what it means to live on an orb: “For those standing below, things above are below, while things below are above . . . and this is the case around the entire earth.”
So far this is all just an extrapolation from the most rudimentary truth in the Milky Way: We don’t just believe that we live on a globe. We know. But we don’t experience the sensation of somersaulting over the equatorial belly during a flight to Sydney, either.
Nor do we perceive the globe spinning at 1,000 miles per hour, revolving around the sun at 67,000 miles per hour in a solar system itself whirring through space at 515,000 miles per hour.
Read more here.