I’m so glad all of you could make it out tonight – and what a truly glorious night it is!
It’s my pleasure to introduce you to the night sky but I would also like to show you how astronomy affects everyone, everyday.
As human beings we evolved to become creatures of the day since our senses are poorly adapted for the night. So we’re made to sleep at night to keep us out of trouble and consequently not only do we learn to fear the night – we miss experiencing a good half of what our beautiful planet has to offer.
I’ve been an amateur astronomer for only a little more than a decade and my primary interest is in taking photos or images of the Sun, the Planets and deep space objects like galaxies and nebulae. I was never interested in astronomy as a kid probably because I was born too late to watch the Space Race and Moon landings firsthand. But I did watch Star Trek on perpetual reruns in the 1970s and became a big fan and by extension a fan of astronomy. My wife even bought me a real telescope for Christmas one year while we were dating and living on oceanfront property in Vancouver. We used it to watch bald eagles, sailboats and ocean liners on their way to Alaska but somehow I never aimed it skyward. Our son was born a year later and all sorts of night activities changed. I was taking the garbage out one night in the Spring of 1997, and I could easily see with just the naked eye Comet Hale Bopp in the western sky with its enormous tail. And then I went inside. No telescope. No camera. Nothing.
So how did I get from that to here? Because astronomy is all about the past and everyone knows that sooner or later the past catches up with you. When you look through the estate’s telescope later, and it‘s a serious professional grade telescope they have up there in the observatory dome, one of the best targets to see tonight is the Andromeda Galaxy. Even though Andromeda is our closest neighbouring galaxy, it’s still 2.5 million light years distant. That means it takes light 2.5 million years to travel here so the light forming the image we will be looking at tonight left Andromeda 2.5 million years in the past. Every glance through a telescope is a glance into the past, your own personal time machine. When I moved back to Toronto in 2000, my denied past did catch up with me and I suddenly developed a passion for astrophotography and wanted to take photos just like the one you see in astronomy magazines. And a decade later, some of my photos have now been published in those very magazines.
When I talk about astronomy I typically use a Powerpoint presentation but tonight the entire night sky will be my slide show. And this is where my Star Trek fandom reveals itself. To commemorate 50 years of Star Trek, I modified this vintage phaser II by placing a high powered blue laser into it and as you can see it has become a very effective star pointer complete with authentic stun and disintegrate sounds! You’ll notice that I didn’t choose a red colored laser because only the blue lasers put out a visible beam that makes pointing to distant objects possible. This is also why the sky appears blue. Sunlight contains all the colors of the visible spectrum, ROYGBV, but because blue wavelength light has a shorter wavelength than red light, it tends to collide with the nitrogen and oxygen atoms in the atmosphere and gets scattered or bounced around, painting the sky blue. Red light just passes straight through the atmosphere and is absorbed by the earth. We can see the blue laser beam for the same reason. If we look to the SW, you’ll see a bright orange tinted star low near the horizon. This is actually not a star but the planet Mars. And to the right this fainter star is the planet Saturn. Hopefully you’ll get a chance to see the two in the telescope before they set. Mars really looks red and you can often see wonderful surface features like valleys and clouds and its polar icecap. Saturn has its famous and beautiful rings made of suspended rock and ice particles and is the rock star of our solar system. You can also make out subtle pastel colored horizontal bands on the planet itself. Jupiter and Venus are the other visible planets in the night sky but at this time of year they have already set, they will be visible again in the Spring. Uranus and Neptune are present in the NE sky but they are so far away that even in the telescope they will only appear as bluish green orbs. If Saturn is a rock star, then Jupiter is your best friend. Because Jupiter is the largest planet in our solar system, it enormous gravity field actually attracts errant comets and meteors and prevents most of them from hitting the Earth. 65 million years ago a small asteroid the size of Mississauga impacted into the Gulf of Mexico releasing the energy of a billion nuclear bombs, superheating the atmosphere and incinerating all surface life which at that time meant the demise of all dinosaurs. Lucky for us, small underground mammals survived and evolution gave us the chance to becomes the dominant species.
We can’t see the Moon right now because it’s not scheduled to rise until after 2 AM but it’s presence is critical to life as we know it. The Moon is about one third the size of Earth and its unusual for us to have a moon as large as the Moon is. Mercury and Venus have no moons and Mars has a pair of very tiny moons. The reason the Moon is so large is because shortly after the Earth was formed, a planet the size of Mars collided with us, tore part of the Earth away and the resultant debris coalesced into the Moon. Most planets have a marked wobble as they spin and revolve in space but the large mass and gravitational pull of the Moon has all but eliminated Earth’s wobble resulting in very stable climate patterns. A planet with wild, rapidly fluctuating shifts in climate would not be able to evolve large complex organisms like us.
Astronomy can save your life in less profound ways. Here’s the constellation known as the Big Dipper and the lip of it points to the end of the handle of the Little Dipper. That end star on the Little Dipper is Polaris, the North Star – because it’s always located in the compass north direction. So if you’re lost in the Death Valley and you’re trying to walk out of the desert only at night to conserve water and avoid the daytime heat, you can make sure you’re not walking in circles by orientating yourself to Polaris at all times. The Polynesian peoples of the South Pacific learned to navigate by the night sky alone and were able to confidently sail from Hawaii to New Zealand and onwards to the Western Coast of South America in their small outrigger canoes and stop at all the tiny scattered Pacific islands in between to reprovision and trade. It would take a Polynesian navigator years to comprehensively learn the names and positions of all the bright stars in the night sky and what time of night they rose and set in the sky during the night. Those times would also depend on the season of the year and also on your latitude position so you could determine your direction of travel and how many degrees below the equator you were.
Modern amateur astronomers often learn the major constellations of stars to help them align their telescopes to see faint deep space objects. On the tail end of the Big Dipper is the star Alkaid and just below that is the Whirlpool Galaxy which you might be able to see in the big scope tonight and it does look like a Whirlpool. It takes about 30 minutes to get your night vision so that you can see these objects so try not to use your cellphone because that bright screen can ruin your night vision.
If you draw a line from Polaris through this W shaped constellation called Cassiopeia to this straight line of stars in Andromeda, the Andromeda Galaxy lies around here. And we look for the brightest star in the summer sky, that would be Vega and to its West is this rhomboid shaped constellation called Hercules where we can find the Great Hercules Cluster. This is a cluster of some 300,000 stars about 25,000 light years away – an unusually densely populated place in space – because space is indeed mainly empty space.
And also beside Vega is a the Ring Nebula, a ghostly looking donut that is the remnant of a supernova or a star that exploded and all that is left is a cloud of hydrogen gas that glows from the radiation of the dead star’s solid core. Our sun is absolutely in no danger of exploding and has enough fuel to continue to burn and shine for another 5 billion years.
If we look to the Eastern sky this bright star is Capella, and this one close to the horizon is Aldebarran and where they intesect is the Pleiades or the Seven Sisters. It’s a cluster of stars that’s very close to Earth, about 400 ly away. Because they are so close, we can measure their distance quite accurately and then use that information to more accurately estimate how far away more distant star clusters are. The Japanese name for the Pleiades is Subaru and that is why the Subaru car company has this group of stars as their logo.
But we haven’t addressed the elephant in the room. What is this bright cloudy band we see in the sky above us? It’s our very own galaxy, the Milky Way galaxy home to over 400 billions stars. If there are over 200 billion galaxies in the known universe then there are a lot of opportunities for life out there. Our galaxy resembles the blurred shape of a spinning pinwheel with a central rectangular bar from which all the spinning arms protrude from. And we are looking at that rectangular bar, the center of the galaxy is down here near the horizon where its setting. If we were here in August you could see the center is the brightest part because that’s the most densely star populated region of our galaxy. We are about 27,000 light year from the center. So if Ontario is the Milky Way and Toronto is naturally the center of the galaxy, we aren’t Moose Factory but more like Muskoka. But that’s a good thing. Just like killer asteroids. Because the people living in Toronto have no night sky because the stars are so close to each other the night sky never gets dark. But by living outside the center of the galaxy we can appreciate how truly large the cosmos really is and this perspective shapes our basic nature to explore and innovate. If there is no night sky, if the night is as bright as the day then there is nothing out there so nothing left to explore once your planet is colonized so your attitude is more inward navel gazing.
So in closing, I hope you appreciate that astronomy has made us who and what we are. Literally. Because just like on earth, there is the cycle of life and death out there in the cosmos. Young stars are born while some old ones like our sun will die a quiet death. Others explode and when they do they seed new stars and their planetary systems with the heavy elements we need to form life. Because life can’t exist with just hydrogen alone. So we are in essence the products of past supernova.