By Dan May
On Our Land
Dan May
One of the legacies of the COVID pandemic is that most of us developed skills using video conferencing tools. There are many platforms, but Zoom is among the most used, and the term has become synonymous with planning remote meetings, like a Xerox copy or a Kleenex tissue.
For camera buffs, zoom refers to a lens that magnifies a distant object and makes it appear closer. Telescopes and binoculars accomplish the same thing. So perhaps naming a conferencing tool Zoom refers to the intent to bring remotely located people together.
One of the early skills an earth scientist or naturalist needs to learn is to develop a sense of perspective and analyze features over different scales – to zoom in and out. This is both for spatial attributes (length, area and volume) as well as for time. In this column, I will introduce some spatial features by orders of magnitude.
Human eyes can discern details over about six orders of magnitude, ranging from a grain of sand about 1 millimeter in diameter to features in objects about 1 kilometer away. Our sense of touch is very sensitive and can distinguish particles 100 times smaller than sand grains. And if the object is large enough, we can “see” it in the distance. So on a clear day at Silver Sands Beach in Milford, one can make out individual trees on Charles Island about 1 kilometer away, but the nearly 100 meter tall health sciences center at SUNY Stonybrook 25 kilometers away on Long Island is a blurry shadow.
To help intrigued people expand their sense of scale, I recommend a 1982 Scientific American book: “Powers of Ten: About the Relative Size of Things in the Universe.” This picture book sequentially tours the physical universe over 48 orders of magnitude, from the outer limit of the visible universe as viewed by telescopes to subatomic particles explored at high energy labs.
Physicists address all this range, but geologists ponder features in the middle – from submicroscopic features of crystals (at one ten billionth of a meter, or 10 to the -10th power in meters) to the diameter of our solar system, spread out over 10 to the +14th power in meters.
If we start an expanding spatial tour sitting across from each other at a picnic table in the pavilion at High Plains Community Center, we are about one meter apart. If one of us walked to Orange Center Road, we would be about 100 meters apart, and if we made it to Fred Wolfe Park, we’d be about 1 kilometer from the pavilion.
Orange at its widest point is nearly 10 kilometers across. This may not seem that far, but it also about the height of the lowest portion of the atmosphere, which hosts all clouds, rain and snow. When you’re in a plane looking down on cloud tops, that’s about the elevation you are at.
Connecticut is about 100 kilometers across from north to south. We are a small state, but if we go straight down into the solid Earth, at 100 kilometers deep the “solid” Earth is a hot plastic solid that is slowly moving, occasionally breaking the cold rigid surface to yield earthquakes like those of recent years in New England.
Zooming outward about 100 times, Earth has a diameter of nearly 13,000 kilometers, and our nearest planetary neighbor, the Moon, orbits us about 30 Earth diameters away. Twice daily Earth’s rotation and the Moon’s orbit generate local tides. The Sun itself is about 400 times the Earth-Moon distance away from us. The Sun is having an active year and news of brilliant aurora have been commonplace as Earth passes through jets of hot plasma emitted by the Sun as our planet revolves around it.
Zoom also means to go fast, and our sense of speeds is perhaps even harder to grasp than those of distance. Relative to the center of the planet, the outer surface is everywhere moving centimeters per year. Bur relative to the Sun, Earth is orbiting it at a rate of almost 30 kilometers per second. It is perhaps equally apt to say Earth crashes into meteorites or asteroids as vice versa.
Even the solar system is zooming through our Milky Way galaxy. Just last week scientists announced that it passed through a “wave” of interstellar debris about 12 to 15 million years ago. This correlated in time, perhaps coincidentally, with major changes in rates of climate change and mammalian evolution on Earth. Standing still is not an option.
Dan May is a local geologist.