The incredible vastness of the Universe is often mentioned, yet so hard to visualize. We hear of light years and millions, billions and trillions. For all its immensity, the stars remain as near as your sky above your backyard. Though from the highest mountain, you try and reach out and grasp one of those stars, only air fills your fist.
The nearest star system to the Sun, Alpha Centauri, lies 4.3 light years away. Our entire Milky Way Galaxy is approximately 100,000 light years across. If we spoke of miles, we would understand. Many of us have, or had, cars reaching 100,000 miles. Some of us can boast our car would have reached the Moon, at 238,000 miles.
"Light year" is not a measure of time; it is the distance light travels in one Earth year, at the constant speed of 186,282 miles a second. In a year’s time, light reaches 5.865696 trillion miles. Alpha Centauri is 4.3 times that. Can we grasp even one trillion miles- or one trillion of anything?
What were you doing a mere million seconds ago? A million seconds is 12 days. A billion seconds is 31 years. A trillion seconds is 31,688 years.
A million hours ago was in 1889. A billion hours ago, man was not yet on the Earth.
We probably shouldn’t talk about dollars, but here goes. It is said that a million dollars ago was five seconds ago at the U.S. Treasury and a billion dollars, late yesterday afternoon at the U.S. Treasury. A trillion dollars is so much that only politicians can talk about it in conversation, and are ever glad you cannot visualize how much is a trillion.
If you could walk, or swim at sea level around the Earth at the equator, you would travel only 24,859.82 miles. To reach one trillion miles you would have to circle the Earth more than 40 million times (40,225,552.71). To circle the same the distance as Alpha Centauri, you’d need to go around the Earth almost 173 million times (172.969.876.69). Don’t try it.
Most stars you see tonight are hundreds, or thousands of lights years away. Yet you see them. Imagine the brilliance they must have!
The Sun, by the way, is on average, 93 million miles from the Earth and it takes eight minutes for the light to reach here. Imagine the Earth right next to the Sun. First, you could forget about the snow and ice and global warming would take on a whole new meaning. If the Earth were a golf ball, the Sun would be 15 feet wide.
Yet consider other stars.
Betelgeuse, which shines fiery red-orange in the constellation Orion, is a "super giant" star, as much as 1,000 times the diameter of the Sun. VY Canis Majoris is one of the largest and most luminous stars known, may be as big as 2,100 times the Sun’s width. If the Sun were replaced by this star, its surface would reach the orbit of Saturn. It would take 7 quadrillion Earths to fill VY Canis Majoris (a thousand trillion, times seven)!
Galaxies you can see tonight in even a small telescope are millions of light years distant. One of the nearest, M31 the Andromeda Galaxy, is 2.5 million light years away. That’s about 150 quintillion miles, give or take.
Whatever one’s belief system, what a wonder it is to ride this lovely speck of dust we call the Earth, and look up and out at the grand scheme laid out before us every clear night. Or you can stay inside and see what’s on TV.
The Moon is full on Jan. 26
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Keep looking up!