Last week I watched water racing down a creek slam up against a boulder and break into a frothy spray of droplets and blobs. My eyes struggled to make sense of it. The camera proved a far better instrument to dissect the spray into a series of moments, so I could better appreciate the water’s ephemeral shapes and patterns.
We can stop movement and hold time still for a moment, but that’s all. You and I and everything around us are in constant motion. Take the rotation of the Earth. As I type, my keyboard, home, and the entire city of Duluth, Minn. are all moving together at 708 miles per hour toward the east. Speed varies according to latitude, ranging from 0 mph at the poles to 1,041 at the equator. Folks in Nome, Alaska are traveling at 455 mph on the merry-go-round, while those in Los Angeles zip along at 860 mph.
The reason rockets are launched in Florida and not North Dakota is because Florida is closer to the equator, giving them a 250 mph edge compared to Fargo as they head into orbit.
To determine how fast you’re moving, multiply Earth’s circumference times the cosine of your latitude and divide by 24 hours like this: 24,902 mph x cos (latitude) / 24 hours. Cosines are easily found by heading over to the handy Cosine Calculator and keying in your latitude. With that number in hand, use your computer’s calculator to arrive at your personal velocity.
Spinning is just one of Earth’s several motions. We’re also orbiting the sun at 18.5 miles per second or nearly 67,000 miles per hour. At that speed our planet traverses 600 million miles in one year. Since Earth’s about 8,000 miles in diameter, it moves about 202 times its own size in one day. Even sitting still we’re putting on miles at a fantastic rate. Live till you’re 80 years old and you’ll have 48 billion frequent orbital-flyer miles to show for it.
So far we’ve only talked about Earth, but the sun isn’t standing still either. Our star is one of several hundred billion stars in the Milky Way galaxy, all of which are moving. Based on studies of the motions of stars in our neighborhood, astronomers have determined that the sun hauls it family of planets, comets and asteroids at 43,000 miles per hour in roughly the direction of the bright star Vega in Lyra.
In the course of a lifetime we will have moved 40 billion miles closer to the star. Unfortunately that huge figure will hardly begin to close the gap between the two stars. Vega is not only 25 light years away (150 trillion miles), but it’s not standing still either. If you’d like to see where we’re headed, face northeast around 11 o’clock the next clear night. The bright, twinkling star low in the sky is Vega.
If you guessed that we’re not quite finished yet, you’re right. The Milky Way is a gigantic starry pinwheel, where the speeds of stars vary with distance from its center the same as the speed of a planet varies with its distance from the sun. The spinning of the galaxy carries the sun and neighboring stars around the galactic center at 483,000 mph or nearly 7 times faster than Earth orbits the sun.
Good thing the sun is holding onto us or we’d soon be lost among the stars like change dropped from a pocket. Our solar system is located about 2/3 the way from galaxy’s center to its edge and takes 225 million years to complete one orbit. Each year we celebrate our birthday after completing another cycle around the sun. Since the sun and planets first formed 4.6 billion years ago, the sun has orbited the galactic center 20 times, making it 20 galactic years old. Hey, that means in another 225 million years it will finally come of age!
The Milky Way is one of more than 50 galaxies in a small cluster of galaxies called the Local Group. Ours and the Andromeda Galaxy, located 2.5 million light years away in the constellation Andromeda, are the group’s two biggest members. As if we weren’t moving in enough ways, these two galactic behemoths are hurtling toward one another at 50 miles per second or 270,000 mph.
2.5 billion years from now we’ll collide in a spectacular display of fireworks as merging gas clouds fire up brand new clusters of stars. Over time, the two spiral galaxies will evolve into one much larger elliptical galaxy some like to call “Milkomeda” (milk-AH-meh-duh).
The Local Group is a small cluster on the outskirts of the much larger Virgo Supercluster of galaxies. Consider Virgo as downtown New York and our gang as a small town in the boondocks. Like my daughters, who are drawn to the dazzle and glitter of the big city, the Local Group is falling at more than half a million miles an hour toward the center of the Supercluster.
Still not dizzy yet? Let’s take one final step and put the pedal to the metal.
Relative to the cosmic background radiation – the ever-expanding , steadily cooling energy left over from the Big Bang that permeates all of space – the Milky Way galaxy is moving at the amazing rate of 1.3 million miles per hour roughly in the direction of Leo and Virgo. The reason for our great haste? New space created between the galaxies as the universe expands causes them to appear to rush apart from each other. The Local Group holds together through the combined gravitation attraction of its members, but when you take in the bigger scene, galaxies have been rushing away from each other at alarming speeds since the Big Bang 13.75 billion years ago.
OK, even I need a little help at this point, so let’s sum up:
* We’re rotating around 700-800 mph depending on latitude.
* Orbiting the sun at 67,000 mph
* Traveling among the nearby stars at 43,000 mph
* Orbiting the center of the Milky Way at 483,000 mph
* Moving toward Andromeda at 270,000 mph
* Diving into the core of the Virgo Supercluster at 540,000 mph
* Riding aboard the Milky Way in the expanding universe at 1,300,000 mph
And yet, in spite of all the whirl and flow, we can still find quiet moments under a dark sky to contemplate it all.