The Story of the Constellations

I hope you are enjoying your spring break but like so many spring breaks in Oregon, the clouds are what you see when you look toward the night sky. But it won't last for long. So I thought I'd take a moment and talk about the constellations.

In my last post on the Big Dipper, part of Ursa Major or the Great Bear, I pointed out what to look for when you do get to see it.

There is a story for every constellation in the sky. Before we had access to all of the information we now get from television and computers, ancient people (much older than me) told stories, watched the skies for changes in the seasons and marked their lives with the passing of these star formations in the night sky.

Here are just a couple of reasons why these stars were so important. In ancient times, when the months were the annual calendar, people studied astronomy to help them know when to plant and when to harvest. They knew when the rivers were likely to overflow...the Egyptians noted that the cycles of the Dog Star, Sirius, coincided with the rise and fall of the Nile River. They could accurately predict the Nile floods using just the stars in the sky!

Some of the Native American cultures here in North American had a different story. They noted that when the Big Dipper...they could see Ursa Major, the Great Bear...dipped low in the western sky, the leaves of the trees would turn red. Fall was here.

The story goes that three hunters were trailing the bear. The hunters were the three stars that we see as the handle of the Big Dipper. One of the hunters had shot the bear in the side, but the wound wasn't serious enough to stop the bear. The middle hunter carried a pot on his shoulder to cook the bear meat in, but the hunters never got close enough to kill the bear. He went crashing through the forests of the night, always managing to keep the same distance ahead of the three hunters. At the end of summer, the bear and the hunters grew tired, and they dipped lower and lower toward the horizon. When the bear got very close to the horizon, close enough for blood to drip from the wound in his side onto the trees, the people noticed that the leaves turned red. It was time to harvest and finish preparation for winter.

In ancient Greece, the people who lived there believed in a number of different gods that looked over them and, according to the stories, had regular lives with ups and downs, loves and fights, kids and occasionally, battles. The chief god was Zeus.

The story about the Big Dipper goes something like this: Zeus fell in love with Callisto, daughter of Lycaon and by her had a son, Arcas. In order to spare Callisto from the wrath of Hera (this was Zeus' wife - even the gods weren't perfect), Zeus changed her into a bear to hide her identity.

The Big Dipper

I had no idea how much time NCAA basketball would take to watch over the last four days - and how exhausting it was! But as I understand, the weather did not cooperate much for looking at the night sky over Bend.

Tonight promises to be different. Although I said we talk about Mars next, a constellation in tonight's sky might be worth catching. The Big Dipper is actually part of a larger constellation called Ursa Major. Sailors used the stars to guide their ships while ancient people - before the internet, before television, before written words, used these groups of stars in the night sky to tell stories.

The constellation Ursa Major contains the group of stars commonly called the Big Dipper. The handle of the Dipper is the Great Bear's tail and the Dipper's cup is the Bear's flank. The Big Dipper is not a constellation itself, but an asterism, which is a distinctive group of stars. Another famous asterism is the Little Dipper in the constellation Ursa Minor. More on Minor later on.

Can you find the North Star or Polaris?

First, you have to find the Big Dipper in the Northeast.

A Planetary Flyby

The morning sky this month is spectacular. And I know someone who is up that time on his way to school. And with the switch of daylight savings, it is still dark enough to see these events.

I've talked about Saturn (which you can still see in the evening sky looking east) and Venus (which you can still see looking west at about the same time). I mentioned that we probably wouldn't be here on earth if it were not for Jupiter blocking a lot of space junk that might get hurled into our blue planet.

And if you look southeast in the morning, you can see Jupiter. But here is something else exciting in that early sky: Mercury and Mars.

Mercury is in the southeast when Jupiter is at its brightest. Look just over the horizon and when you find Jupiter, look to the lower left and you should be able to see Mercury. At 51 million miles from Earth, it is the closest planet to the sun.

Even more fun, it is about to be orbited again by Messenger. On its 4.9 billion-mile journey to becoming the first spacecraft to orbit the planet Mercury, MESSENGER has flown by Earth once, Venus twice, and Mercury twice. Still to come is one more flyby of Mercury in late September 2009.

And even though Mercury is really close to the sun, it actually has water ice at the bottom of deep craters where the sun never shines. Mercury looks a lot like the moon but it has no moons of its own. It does have an atmosphere but because it is so close to the sun, the solar winds whip it out into space.

It would be hard to figure out what clothes to bring if you ever went there. The temperatures range from 450 degrees Celsius (840 degrees F) during the day as low as -170 degrees C (-275 degrees F) at night! Hotter than Venus and then colder than cold.

You have to look really close because the sun can be just bright enough to make it hard to see.

Tomorrow: Mars

Is Someone Looking at Us?

While the night sky over Bend is cloudy and there still isn't much to see, maybe we should talk for a minute about us.

There was time when we thought the Earth was the center of the universe. Nicolaus Copernicus's 1543 book, "On the Revolutions of the Heavenly Spheres", moved Earth from being the center of the Universe to just another planet orbiting the Sun. He was not popular because of this and told only a few people about what he thought. In fact, he was so sure that this idea was not going to get him any fans he decided to mention it - after he died.

If you fast forward to now, we know that we might not even be alone. Not only is the earth not the center of our solar system. but it isn't even near the center of our own galaxy, the Milky Way. We now know that the universe doesn't even have a center!

Science has determined that something like earth may exist in other places in the universe.

Here's why. We are located in a solar system and that system is in a galaxy. In order for a planet like ours to exist somewhere else, folks believe that we would need to be in a galactic habitable zone or GHZ. The Hubble Telescope has looked at 69 different galaxies within 30 million light years of where you are standing and do you know what they found? No galaxy is the same as another.

Looking even deeper into these galaxies (which can be made up of millions of solar systems (planets circling a star like our sun) we now know that planets have to be just the right distance from their sun to be worth living on.

Not only are we looking for water - which we think is the only way life could exist - but we are also looking for a moon around those planets. The moon pulls and tugs a planet and if we didn't have ours, we would be tilting in all sorts of directions. Sometimes the north pole would be tilted towards the sun; other times it would not. This would cause the temperature to change a lot. It might be hot in the summer and cold in the winter but without a steady tilt (the kind the moon gives us has been steady for billions of years), we wouldn't be able to survive the harshness.

Having a good position around the sun and a moon to make earth worth living on, it is possible that the sky might have as many as one million earths. Science figures that this is only about 10% (one in ten) of all of the planets in the universe. Once again, this is only a guess but a pretty good one.


Believe it or not, if it wasn't for earthquakes, we probably wouldn't be here. If it wasn't for Jupiter blocking large objects from banging into us, we wouldn't be here.

So the chances that someone may be looking for us the way we are looking for them is pretty good. As you look to the sky, somewhere, someone just like you might be looking back. Be sure to wave!

Don't say goodbye to Venus

It has been an incredible year to see the closet planet to the earth. Venus has been the showstopper in the evening sky all winter. But believe me, you wouldn't want to live there.

For one, it is hot. The nasty atmosphere is mostly carbon dioxide and it traps all of the heat from the sun (it is only 67 million miles away). While there are super-sized, hurricane force winds in the upper part of the sky on Venus, the surface has none. And if it did, because of how thick it is, a small breeze would knock you on your butt.

Of course you would have to survive the pressure first. Imagine being the guy on the bottom of a big pile-on. Hard to breath, weight crushing you and you can't move. That is what a vacation on Venus would be like. And the darned planet spins in the wrong direction with the sun rising in west, not the east.

The planet not only spins backwards, it takes 243 days for one day on Venus. If you were reading this on Venus, a couple of Earth days might have already passed. In fact, on Venus, one school day would last almost four months.

So it is much more fun to watch than to visit. Every day in March, Venus drops closer to the western horizon after sunset. But as it disappears from the evening sky, it enters the morning sky. It dims a bit toward the end of the month but brightens again as it assumes the title of Morning Star in April.

Looking Through the Clouds

I see the weather in Bend hasn't improved much since I last posted. Clouds can be a real problem when trying to look at the night sky. Even on a good day, the city of Bend makes it tough to see a lot of what is happening in your area.

The lights from the city are called ambient (am be ent). The sky, no matter how dark is not as dark as it could be because of these lights from buildings and street lamps. Did you know, that no matter where you go in the lower 48 states of America you can only see about two thousand stars. The darkest place (Death Valley) is impacted by the lights of a city hundreds of miles away (Las Vegas).

So when the clouds are out, they act as a reflector for those lights making seeing the sky even harder. Not impossible, just more difficult.

If you have a moment check this video out on what to expect when those clouds clear enough to get another look at what is happening above your head.

Saturn's March show

Note from Papa to Andre: This is a way to give you all of the information any young skywatcher should need to understand what he sees in the night sky. I'll include a weather forecast with each post, some directions and some background on the subject.

Last week, I sent your Mom an email about looking for Saturn in the early evening sky to the east of you. In it I told you about the first astronomer to see the rings around the planet. Only his telescope was so primitive - he made it himself even grinding the glass lens - that his view of the distant planet (746 million miles from earth) was rather crude.

It was so crude that Galileo assumed they were jug handles. In fact, this picture was taken using a replica of what Galileo saw. We now know that they are rings. It was two years before he was able to find the planet again and he was astonished that the rings had disappeared. Do you know why?

The next time Galileo was able to see the planet the tilt, or angle the planet was pointed at the astronomer had changed and the rings where nothing more than a straight line across the planet.

It is too bad that the weather in Bend will not be good for looking at this event but you might be able to catch it in the morning on the western horizon - perhaps underneath the clouds or in between snow showers.

Here is some other stuff about Saturn that you may not have known. It has sixty moons and is really cold. Try and imagine 170 degrees below zero cold! It also takes twenty nine and half years to get around the sun. If you were born on Saturn, you would only be a couple of months old!

Next up: some stuff you can look forward to when the clouds go away.