One of the unrivaled joys of my morning walk these days, which starts around 5.50 a.m. after putting in about two hours of work, is the subtle yet distinct change of the sunlight. It is at once imperceptible but still quite perceptible.
When I begin, the light is darkish grey as if someone has knifed away the darker layer from the sky. Dawn is in the process of dawning or as I said to myself in Hindi this morning “होते होते सुबह का होना”. In barely a minute or so or perhaps even less that darkish grey turns to gentle white depending on whether there are clouds on the horizon. On a cloudless day the early hue is gentle white. Within couple of minutes the surroundings are clearly visible as the sunlight settles into its normal shade.
Apart from this visual experience I am more interested in numbers behind the so-called “sunrise”. We all know that the sun never rises or sets. That experience is a direct consequence of Earth’s spin arounds its axis. That number at the equator is 1,037 mph (1,670 km/h). In Chicago area, where I live, that spin is a bit slower because it is 2,891.56 mi (4,653.52 km) north of the equator. As one moves away north or south of the equator the spin slows down a great deal.
We forget, if many of us even bother to know this at all, that no matter what we do we are spinning at about 1,000 miles an hour on a planet that orbits its sun at about 67,000 mph (107,000 km/h). It has been calculated that Earth travels about 1.6 million miles (2.6 million km) a day. That makes it 66,627 mph (107,226 km/h). In one year, Earth travels some 584 million miles (940 million km) in a single orbit around the sun. Think about this, we do absolutely nothing and yet we travel so much minute after minute, hour after hour, day after day, week after week, month after month and year after year. We are born frequent frequent fliers. It is no wonder then that Earth lets you travel free.
I have written about these motions a few times before. For instance, scientists have calculated that our solar system moves at 200 kilometers per second which is an average speed of 448,000 mph (720,000 km/h). That is dizzying fast and yet our solar system takes about 230 million years to travel around the entire Milky Way. Despite orbiting at that speed since the formation of the solar system some 4.571 billion years ago it has done only a little over 19 rounds of the Milky Way so far.
Despite such enormous numbers in spinning and orbiting through the duration of our lives we feel no motion sickness. We also do not get tossed around on the surface nor get flung out into space because of Earth’s powerful gravity. And what is magical is the exquisite subtlety with which dawn dawns and dusk dusks (Dusk is not a verb but I have used it with literary license.)
