Jared Melrath is an old friend and fellow Astronomy-Liker. He has volunteered to write articles from time to time for the blog, as well as doing a lot of behind the scenes work that few will truly appreciate. Please enjoy all of the hard work that has been put together below.
June 10, 2014
A PERFECT NIGHT
The seasons are changing as the direct rays of the sun move from the Southern hemisphere to the equator on vernal equinox. Then into our own hemisphere where we now begin to feel the effects of those warm rays of energy. We witness once again our entire environment transform, and its great news for the backyard astronomer. When last we spoke my fingers were numb, clutching hot chocolate and the image of Jupiter entering my eye shook right along with my entire body as it tried to stay warm. Now, I’m sitting on a blanket next to the water facing the eastern sky with the three most important people in the world to me at the moment. We are enjoying cold beverages this time, waiting patiently for the last light from the sun to disappear behind us and for a planet to rise. Its Reece’s tenth birthday tonight, and I promised him a very special gift: Saturn. With the telescope set up, the stereo playing music from teenage past and huddled close to the people I care about I could wait a lifetime for Saturn to rise.
Saturn rises all summer just after sunset here on the Chesapeake Bay. The planets rise in the same exact place the sun does. In fact, the planets, the moon and the sun are all on the same plane, called the ecliptic. The solar system is like one gigantic pizza, and all of the planets are like pepperonis. They rise in the east in the same place as the sun, they reach the same high point in the sky as the sun, and they set in the same place as the sun. I knew we’d be able to catch Saturn tonight, but I didn’t realize that I was about to experience the greatest night of backyard astronomy in my life.
It begins before its dark. It’s a half moon tonight, which of course you can see before its dark. The moon is the only object bright enough to us for us to see while the sun is still up. A half moon is great to look at through the telescope because the shadows on the moon allow you to see craters. You can’t really see any craters on a full moon because its getting the direct rays of the sun so there are no shadows. With me tonight are three first time backyard astronomers who have never seen the craters of the moon through a telescope. Already we are off to a good start. I show Mason, the 14 year old, how to use the telescope, and like all things, he picks it up very quickly. He repositions the telescope to face the Eastern sky to catch our true target. Saturn has just risen above the horizon at around 8:15PM.
Saturn is the second largest planet, but it’s about twice as far away from the sun as Jupiter so we would barely be able to see it with the naked eye if it weren’t for its most stunning feature. I am of course talking about its massive rings. Saturn is my favorite object to look at through a telescope because you can see those rings. There’s nothing like seeing those rings with your own eye, not in some picture in a science textbook or on the internet. I know Reece is going to be impressed because everyone is impressed when they see it, every time. Through the telescope it almost looks like a planet with gigantic ears. The kids look at it first and are amazed. They look at me with wonder and excitement and I am a happy man because I know I just made someone’s birthday a little more memorable. But the night is far from over.
The sky is half of a circle: 180 degrees. Mason points to another object on the ecliptic about 40 degrees higher in the sky than Saturn. It’s Mars. He expertly repositions the telescope and finds Mars all by himself. Now I’m the one that is impressed. Mars is smaller than Saturn but it’s also much closer to us, so it actually appears to be bigger. If you follow the ecliptic another 40 degrees higher in the sky the moon sits almost at where the sun reaches at high noon. And on that spectacular night if you followed the ecliptic down into the western sky where the sun had recently set there was Jupiter. Mason repositions the telescope again. And all four of Jupiter’s Galilean moons spread out evenly spaced through the lens of the telescope.
I fall back down onto my blanket in the yard with a huge smile on my face. I hold my girl tight and as we look up at the sky we see two shooting stars. This is getting ridiculous. Its their first night looking through a telescope and they’ve seen the craters of the moon, the rings of Saturn, Mars, and all four Galilean moons of Jupiter ,all spaced regularly at 40 degree intervals throughout this beautiful Spring night sky. And now two shooting stars. As I carried the birthday boy back into the house I thought to myself I’m never going to be able to top this. It was a perfect night.
March 5, 2014 Hunting
Tonight I’m hunting. But my prize is not the poor little deer I see in my back yard, or even one of the great animals of the African Savannah. The thing that I hunt for is in the night sky. Humans have been around for about 200,000 years and from very early on they stared at this sight I seek in wonder. It didn’t seem to follow the same rules as the other stars in the sky. It was a rogue, a rebel, something that escaped classification. Indeed some even thought it was a God. It was the Romans that gave this object the name we still use today: Jupiter, the greatest of all their gods. The name stuck and it was fitting. Jupiter is the largest of all the planets in our solar system by far. It’s actually 2.5 times the mass of all the other planets combined. It’s brighter than any star in our sky, and it’s the 4th brightest thing we can see in our sky, next to only the sun, the moon and Venus. It’s massive. If it continued to get larger when our solar system formed it would’ve become a star itself. And it would’ve already had plenty of planets orbiting it. Currently, Jupiter has 67 moons. Sixty-seven.
The true objects of my hunt are not just Jupiter, but four of those sixty-seven moons. The four largest moons, also called the Galilean Moons Ganymede, Europa, Io and Callisto. Even though people have been gazing at Jupiter since the beginning of human history, no one, no matter how hard or long they looked could even see just one of them. And today, even beginner backyard astronomers can see these four moons with the help of a small telescope. They are named the Galilean moons of Jupiter because the first person to use a telescope on the night sky, Galileo Galilei, was also the first the first person to ever see them. In 1610, when Galileo saw these four moons rotating around another planet, he changed the world. He proved through experimentation and observation that the Earth was not the center of the universe, and this revelation sent shock waves throughout the scientific and religious communities of the world. The Catholic Church had always argued that the Earth was the center of all creation, and therefore, everything must rotate around it, even the sun. But Galileo’s observations proved that this was not true, and that the Earth rotated around the sun, an idea first put forth by Copernicus. Galileo published these observations, which enraged church officials, and was eventually convicted of being a heretic, someone who believes in or teaches an idea that goes against church doctrine. Galileo was given a choice: tell the world that he was wrong, or spend the rest of his life imprisoned in his own home. He refused to recant and spent the rest of his life confined to his home.
Galileo when he became the first person to see these four moons through a telescope changed the way we view the entire universe. As I bundle up, pour myself a fresh glass of hot chocolate and prepare to hunt down these moons in my backyard, Galileo is on my mind. In March, Jupiter is in the constellation Gemini, and rises long before the sun sets at about 1 PM EST. Unfortunately this means, that by 9PM Jupiter is already very close to your Zenith, the spot in the sky directly above your head. It is very difficult to set up a telescope to view an object directly above your head. So I set up my Meade refracting telescope right at sunset so that I can catch Jupiter a little lower in the southeastern sky. Jupiter sets at around 330 AM EST, so the other option for you night owls is to try to catch Jupiter on the way down. It’ll be in the South West sky at a very good height for viewing at about 1 AM EST. I am a history teacher who gets out of bed at unholy early hours in the morning, so a 1 AM hunt of Jupiter is completely out of the question.
As soon as the light from our sun dims and the magnificent night sky begins to reveal herself, I find Jupiter very quickly. Jupiter is brighter to us here on Earth than any star in the sky, so it should be the very first thing in the night sky you are capable of seeing. Though it’s going to have to get a little darker to see its moons, even with the help of the telescope. Even with a small telescope you can see some of the details on the planet Jupiter. There is some pretty severe weather on Jupiter. There are massive storms that never end. One of these storms, called the Big Red Spot, you can actually see through a telescope, though I have yet to see it through my humble Meade. I have, however, seen some of the cloud structure, but that’s not really what I’m hunting for this evening. As the sun’s light slips away and one by one more stars appear I finally strike backyard astronomy gold. Three little points of light appear around Jupiter. I was hoping for all four Galilean moons, but 3 out of four isn’t bad! If you can’t see all four of these moons its because one of more of the moons is either right in front or directly behind the gas giant. What you see will look something like this:
These four moons are actually fascinating to astronomers, both professional and the back yard variety such as myself. There is significant volcanic activity on Io. There are 400 active volcanoes on Io, making it the most geologically active object in our solar system. Of the four moons, it’s the closest to Jupiter and its proximity to the gas giant means that tremendous gravitational forces are at work inside of Io, causing all this activity. We see evidence of Jupiter’s gravitational power on the other moons as well. On Europa for instance, there are huge cracks on the surface thought to be caused by Jupiter tugging on the planet. What’s more fascinating about Europa’s surface is what is not there: Craters. Jupiter’s gravity means it and many comets and asteroids strike its moons, so we know Europa has been hit. The great Europa mystery – where are all those craters? Some astronomers believe that an ocean, possibly of water, which is frozen on the surface, covers Europa. They argue there might actually be liquid water underneath the surface of Europa! This makes Europa a prime candidate for colonization as we continue to expand our reach from Earth into other parts of the solar system.
I managed to capture these four Galilean Moons of Jupiter right in my own backyard. But they have also captured me, and my imagination. As the Sun’s light slipped away and I spotted these moons for the first time tonight, I imagined I was Galileo seeing these moons for the first time for all of humanity. I tried to put myself in his shoes, as history teachers often do, and imagine him puzzling over what these little dots of light were, and eventually coming to the realization that would change the world. I tried to channel from the past and over the centuries the excitement he must have felt, and it worked! I felt goose bumps as my mind began to race, moving now to all the possibilities of these moons in humanity’s future. Maybe one day a dorky history teaching backyard astronomer will be on one of these moons looking through his telescope at a tiny blue dot called Earth. It was a good hunt tonight, but now it is time for some more hot chocolate….