July, 2013

Richard FriswellEditor's Letter fine art criticism 0

“Observation, yes, but true art lies in a reality that is felt.” ~Odilon Redon~

Calculating the Weight of the Sun:

ARTES, a fine arts magazine, welcomes summer (at last!) and presents a little thought exercise related to our new-found BFF, the sun. The editor opts to wear his ‘Mr. Science’ hat just this once—I promise—because it relates to art, in this, a monumental year in the art world!

But first, don your white coats; it’s into the science lab for a little show-and-tell… artes fine arts magazine

We all know what centrifugal force feels like: that unweighted feeling, after a slow, anxiety-filled climb, on the downhill plunge of a rollercoaster ride; that moment of suspension (and suspense) when we let go of the swing rope over chilly lake water, hanging in the air for an instant before our big splash; the invisible force that loosens a child’s tight grip as they swirl, faster and faster, on a playground spinning saucer, only to lose the battle and be rolled, with senses reeling, to the ground. Centrifugal force allows us to momentarily fool with the laws of nature and delight in the games of summer, when nature seems closer to our skin and heightens our sense of connectedness to the natural world around us.

Another force is at work every moment of our lives—one less apt to evokes awe and wonder because of its mundane, utilitarian properties—that is, gravity, or centripetal force. Centripetal force is the invisible hand of physics that keeps our feet on the ground, maintains the moon in its celestial orbit above our heads, assuring that billions of tons of seawater will ebb and flow each day to form the tides. It is also the gravitational pull of the sun that holds out galaxy together, helping to maintain our secure place in the order of planets on the their annual semi-circular course through the void of space. Centripetal force is the glue that maintains order in the universe.

Early in the 20th century, scientists determined that they could use that universal law of push and pull to calculate the weight of the Sun. Picture this: grip a bowling ball and allow it to hang down by your side. Now, guess its weight. Difficult, right? unless you slowly allow it to swing. Once that ball begins to move, your experienced brain will begin to run calculations on the amount of muscle strength needed to maintain a trajectory toward the pins and how firmly your fingers need to clench the ball to not lose control of the object. The same rules of expended energy (control) and momentum (object wanting to escape control) can apply to any object moving through space (the bowling alley, Daytona Speedway turns, or elliptical orbits of planets around the Sun!). Mass—or weight of the object—is key to designing mechanisms to keep it in line.

So, knowing the weight of an object makes it possible to calculate the amount of force needed to keep that object on a true course (remember, the bowling ball rolling down the alley?). If you care, Newton’s Law of Universal Gravitation applies here. The amount of centripetal force (gravity) generated by any celestial object is proportional to its mass (weight). If Earth’s gravity is 1.0, then our moon’s gravity is 1/6th of that, making that sphere about 18% the weight of Earth. Corresponding, you, too, will ‘weigh’ one-sixth as much on the Moon. By knowing the composition of a nearby planet or asteroid, and its distance and speed in orbit around the sun, it’s possible to calculate the mass—or weight—of the Sun as it holds that orbiting body, with its known metrics, on track. Without getting into the weeds on how that formula is arrived at, let’s just say that the Sun’s weight is about two nonillion kilograms. That’s 10, with 30 zeros after it. Here’s what it looks like in a formula:

M= (1.98855 +/- 0.00025) x 10 to 30^th kg

The Sun’s mass then, is about 332,946 times the mass of the Earth.

To learn more about the relationship between this scientific tid-bit and the world of fine art, please stay tuned to this space. In the meantime, we welcome our glowing, solar friend into our everyday lives and look forward to that next swing on the rope through the warm summer air, before we take that slow-motion plunge into the cooling waters of our favorite lake.