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Presenting the Sky from North Georgia Part 1 Video Transcipt

We're looking at the night sky from here in North Georgia on Friday, April 3rd. This is around 9:00 p.m.

Facing to the south we see a sky filled with stars. The stars form patterns on the sky that lead us to areas called constellations. Constellations are areas of the sky with defined borders. They're kind of like states on a map. Anywhere you point on a map of the United States, you point within the borders of a state and anywhere we point in the sky you point within the borders of constellation. These are the borders of the constellations that are up now. It's bright patterns of stars in each area that act as the landmarks so that we can find a constellation in the sky.

The first constellation that we'll look for is high in the sky to the south. We find it by looking for a pair of stars near the top center of your screen. They're called Castor and Pollux and they're the head of Gemini, the twins. I’ll put up the outlines of their bodies and a picture so we can see this a little bit better.

In Greek and Roman mythology the twins Castor and Pollux were actually half-brothers but they were such inseparable friends in life on earth that they wanted to be immortalized together in the sky. There's a very interesting object in the Gemini constellation. It's not one you'll see with your eyes but we'll mark where it is. It's called the Eskimo Nebula. It's a planetary nebula. Unfortunately planetary nebulas have nothing to do with planets. They're a small round cloud of gas. The word nebula just means cloud. They're actually from a dying star. Let's take a closer look at the Eskimo Nebula. We're going to zoom in on it which is kind of like looking at it through a telescope. At UNG we have telescopes and when the university is back up and running you can go out to the observatory. Hopefully by the summer or this fall we will have our brand new building finished as well with new bigger telescopes. So be sure to check that out later this year. But we're going to take a closer look at the Eskimo Nebula now here in the planetarium by zooming in on it. So here we're seeing a better view kind of like what you'd see through a telescope of this Eskimo Nebula. We can see why it's named the way it is. It kind of looks like a person wearing a furry parka hood but let's take a better look at this nebula by seeing a photograph taken with a camera through a telescope, a longer exposure, a high resolution photograph. We're going to bring up a picture taken with the hubble space telescope as well as a little bit of chandra x-ray telescope data. So this picture here is showing us the structures the filaments of gas. What's happening here is at the center we have a star that was once a very sun-like star but it started to run out of fuel in its core that it could fuse and so it has these strong winds material that's essentially drifting away. Eventually all the outer layers will be cast off and you'll be left with a dead dense core called a white dwarf star. Now this is what our sun will turn into someday when it starts to run out of fuel. Thankfully not for another five billion years.

Now this planetary nebula though might look a bit different than our own sun's will. It has a very interesting feature towards the center of the nebula. That pink area that you see, that's x-ray emission. That's where there's incredibly hot gas inside the inner shell of the nebula and what we think is happening there. What astronomers think is that there may be a companion star to this white dwarf and it basically has gases falling in onto it and that's heating up the material that gas is getting moving faster and faster and heating it up and when it gets really hot it gives off a lot of x-rays.

We'll zoom away from the eskimo nebula and look for some more objects in the sky. Our next constellation is a bit below gemini further to the west. Here it'll be more on the right side of your screen a very famous constellation called orion, the hunter. We look for orion by looking for three stars of his belt. Above it are two stars that are his shoulders and then beneath the belt are two stars that are his feet. I'll put up an outline so we can see this better as well as a picture of orion the hunter. In greek and roman mythology orion was a super strong giant when you see this constellation in the real sky. It'll look very large. We're going to look for another object. This one is in orion. It's hanging just off of orion's belt. Sometimes called the sword of orion. It's a hazy area in the sky where we have another nebula. This one's called orion's nebula and it's not a planetary nebula from a dying star. Instead it's a star-forming region where new stars are being born. Let's take a closer look at the orion `nebula. I’ll put up a marker here so we can see where it is and we're going to zoom in on it like we're looking at it through a telescope just like we did for the eskimo nebula. Now we see a better view of the orion nebula sort of what it might look like through - a telescope a hazy patch in the sky. This nebula is 1300 light years from earth. A light year is how far light travels in one year. So the light we see here from this nebula took 1300 years to travel to us. The eskimo nebula, by the way, was 6 500 light years away. Let's take a better look at the orion nebula by seeing another higher resolution photograph. This is going to be another picture taken with the hubble space telescope. So here we see a lot more detail in the cloud and you see a few colors across this picture. It's mostly showing us visible light and a little bit of lower energy infrared light. The pink color that you see is showing us where hydrogen gas is glowing. It's getting heated up by hot young stars that are in the nebula in the cloud. Now that hydrogen gas is glowing and most of the cloud is made out of hydrogen there's also some helium and trace amounts of heavier elements more complicated elements things like carbon and oxygen. That carbon and oxygen other heavier elements they are made in stars and sometimes they get repopulated into the cloud when stars are dying. When a lot of stellar winds a lot of material is thrown off of the stars and some of the stellar winds that you see here might carve out shapes in the clouds and even come off of the stars before they're dying as well. We're going to take a look at what happens though when you have a massive star. A very heavy star that dies is going to form a supernova instead of a planetary nebula.

Let's take a look at an artist's depiction of a supernova. Here we see a very massive heavy star and it's nearing the end of its life where it's starting to run out of fuel to fuse together in the center. It'll go supernova with a huge burst of energy and then the outer layers are cast off. But this is more quick and violent than what we see with the planetary nebulas from smaller more low mass stars. And that cast off cloud that was very round in shape that we saw there but they don't have to be sometimes the clouds can have sort of a lobed structure sort of two um opposing spheres coming off of the dying star and we actually see that in another star forming region we're going to bring up this picture of what is called the carina nebula. This can only be seen from the southern hemisphere of the earth and if you look in sort of the lower left corner very carefully there's a double lobe structure from a supernova or at least an imposter supernova. This is a pair of stars called era carina and one of the stars is incredibly massive over a hundred times as massive as the sun and it's had an outburst of material of energy that formed this little lobe structure that you see there, but most of the star is still intact and we think it was just some initial bursts and that this star hasn't gone through its final supernova yet.

Back in the mid 1800s is when we saw the star start to go through bursts where it became the second brightest star in the sky. When it finally goes supernova it'll be an incredible sight to see. We'll zoom away from the orion nebula and look for some more things in the sky you…

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