The People's Guide To the Cosmos

Astronomy is the exploration of the Cosmos. The mother of all adventures. A journey through the looking glass, to infinity and back. A trek among the stars, that started when the first Man looked up... and wondered. To the first Man, it was all magic. In the ages since, Man has learned much about the Universe around him, but each new scientific discovery just seems to pose more questions, and as science solves one cosmic mystery, it seems two more suddenly appear to take its place. We have developed technology to leave our planetary home and journey as far as the Moon, and send spacecraft throughout the solar system and beyond. We can now explain many things about the Universe, and every day we learn more. But as much as science can explain, there is much more that it can't. There are forces at work in the Universe that are still completely beyond our comprehension. The magic just won't go away.

The words of the poetess Avvaiyar are as true today as when they were recorded over 2,000 years ago:

As Einstein was so fond of saying: it's all relative. In other words: reality is all a matter of perception. It's not how much you know, but how much you actually perceive that forms your own personal version of reality. Here's an example: We all know that when we watch a sunset, we aren't really watching the Sun set. We are watching the Sun appear to move down the sky and sink into the horizon, when in actual fact the Sun is stationary, and it's the piece of Earth we are standing on that is moving, slowly rotating away from the Sun, and carrying us with it, stuck like so many microscopic little fleas on its back. But even though we know  that, we still can't seem to help but see ourselves as stationary, and the Sun moving. A grand and glorious illusion indeed, but the truly perceptive Man has an even grander and more glorious experience. He watches the horizon come up to meet the Sun, feels the mighty Earth rumble beneath his feet as it turns, and the cosmic wind at his back as he is carried away from the warmth and light of the Sun, into the cold blackness of space.

The perceptive Man isn't satisfied with seeing the Moon as just a glowing two dimensional crescent hanging in the sky, as amazing and beautiful as that vision may be, but tries to perceive the even more amazing beauty of a massive three dimensional white ball floating in space, and the Sun like a giant spotlight, hidden in the wings on the other side of the Earth, lighting up the side of the Moon like the profile of a lone actor on a dark and desolate stage.

To get the most out of the study of astronomy, we must constantly endeavour to transcend the stubborn illusions of our limited consciousness, and try to wrap our brains around the true nature of the Universe we live in, each small step on the path to perception rewarded by a wonderful rush of endorphines... - like sugar on our tongue: a taste of the infinite.

Some realities, sadly, are beyond our perception, no matter how hard we try. The capacities of our "frail and feeble minds", as Einstein put it, are limited. Nowhere is this perceptual inadequacy more prevalent than in our measurement of distances in space, and the unit of measurement: the light year. A light year measures both time and distance. At a speed of 186,000 miles per second, light travels a million miles in the time it takes to count to five, measuring both distance (a million miles), and time (five seconds).

Here is an exercise to see how close we can come to actually perceiving the distance/time of a light year. Most of us can perceive a distance we've actually travelled, so try to form a mental picture of your longest journey. It might be 3,000 miles, or 6,000, or even 10,000. If you've travelled all the way around the world, you would have travelled about 25,000 miles. Now how about circling the planet 40 times, to travel a million miles? It's a long way, and it would take a long time. In a commercial jet that never landed it would take more than two months. Now stretch that distance in a straight line out into space. Can you really conjure up a mental image of how far away the end of that line would be? If you can, you're doing good. Now, how about twice that distance? Three times? Not so easy, is it?. How about ten times? (There are people falling off the wagon now.) How about ninety-three times that distance? If there's anyone left on the wagon at this point, they have the outstanding ability to actually perceive the distance (93 million miles) between Earth and the Sun, and they are to be envied. Not many people can even imagine such a distance.

But here's the rub: the light from the Sun only takes eight minutes to reach Earth, making the Sun only 8 light minutes away. In order to be one light year away, you'd have to move the Sun 65,700 times further away, out to a wopping distance of 5,865,700,000,000 miles! And anyone who claims they can actually perceive that kind of a distance is someone with their pants on fire.

And that's only one light year. The closest star to our Sun, Proxima Centauri, is 4.3 light years away. And most of the stars in our sky are much farther away than that. Our galaxy stretches an amazing 100,000 light years across. And once we leave our galaxy, the next closest galaxy, the Andromeda galaxy is 2.2 million light years away!

When it comes to the number of stars in our Universe, Carl Sagan's "Billions and billions..." says it all. In 2004 the Hubble Space Telescope focused on one very tiny, very empty-looking spot of sky, and it held that focus for a million seconds, taking a continuous time exposure that lasted 11.6 days, to capture even the faintest of light, to see what - if anything - was out there. The resulting photo was called the Hubble Ultra Deep Field, pictured below, and it was, in a word: astonishing! After looking 13 billion light years away, and 13 billion years back in time, Hubble discovered the Universe just kept going, and going, and going...

There are only four individual stars in the above Hubble Ultra Deep Field photo. Everything else, every blur, every smudge, every pinprick of light - too many to count - is a galaxy. Galaxies behind galaxies behind galaxies. Untold numbers of galaxies stretching 13 billion light years back through space and time. Each galaxy an island universe, containing hundreds of billions of stars like our Sun. And that is just one microscopic piece of the sky. So you can see that it is just as impossible to perceive the number of objects in the Universe, as it is to perceive the distances between them. But you can try, and if you try hard enough, you might just catch a glimpse. And sometimes a glimpse is all it takes to shift your perception, and change your life.

As Einstein proved, space and time are inseparable. They are two components of the same thing. When we look at a star 10 light years away, we are transported ten years into the past, because it took ten years for the light from that star to reach us. We are being visited by a ghost who lived ten years ago. When we look at the spectacular Andromeda galaxy, we are being visited by a very old ghost indeed. A ghost that lived over 2 million years ago! We have no idea what the status of the Andromeda Galaxy is right now, if it still exists at all. We're just too far away.

Einstein also proved that the faster you move through space, the slower you move through time, and at the speed of light - 186,000 miles a second - time comes to a complete stop. Einstein discovered that time was not a linear constant as it appeared on the surface, but that time was in fact a non-linear variable, that was subject to manipulation, and change. A concept as difficult to perceive as a light year, or the true mechanics of a sunset - but just as true, and just as real.

Someday Man will learn to move through time, just as he learned to move over the oceans, and up into the air, and out into space.

But first things first. Let's get our bearings, and find our way around, starting with our own neighbourhood: a group of planets held captive by the gravity of a star we call the Sun - our solar system.

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SOLAR SYSTEM - All Things Held Captive By The Sun	KEEP MEXICAN SKIES FREE - Ways you can help...
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PLANET WATCH - Weekly update of the planets in our sky.	GUITAR TUTORIAL - Learn the basics of playing the guitar.
E. T. WATCH - The scientific search for extraterrestrial life.	HIGHWAY 61 - An original novel about polar bears, suicide bombers, and God.
CLOSE ENCOUNTER WATCH - Comets and asteroids heading our way.	PHOTO GALLERY - A collection of original observatory photos.
SHUTTLE WATCH - The exploits of NASA's Space Shuttle.	HUMOUR GALLERY - A collection of humour from the web.
INTERNATIONAL SPACE STATION - The latest news from the first Human home in space.	THE FRANK GALBRAITH LEGACY - The legacy of a Cariboo musician.
FREE ASTRONOMY SOFTWARE - The best things in life really are free.	THE MEXICAN SKIES OBSERVATORY - Santa Elena, Oaxaca, Mexico.
ASTROLOGY - Astronomy's Evil Twin?	MEXICAN SKIES ARCHIVES - Selected articles from previous years.

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