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The February 2021 Sky: Mars Part 1 Video Transcipt

We're looking at the sky on February 2nd, 2021. This is around 8:00 p.m., a bit after sunset. We're facing south. You'll see a curved line across the sides and bottom of the screen that's the horizon. So the bottom of our view here is the southern horizon, and we see the western horizon on the right, the eastern horizon on the left, and sort of the top towards the center of the view that's looking straight above your head, if you're outside looking at the night sky.

We want to look for some constellations. Constellations form a map across the sky kind of like a map of the United States. Anywhere you point in a map of the United States you point within the borders of a state and anywhere we point on the sky you point within the borders of constellation. These are the borders of the constellations that are up now, and it's bright patterns of stars in each constellation that act as the landmarks so that we can find them in the sky.

The first constellation we'll look for in the sky is between south and east. It's made of mostly bright stars and is easy to spot. We'll look for Orion the hunter we look for Orion by looking for the three stars of his belt. Above that are two stars are his shoulders, and beneath the belt are two stars that are his feet. I'll put up an outline so you can see Orion better as well as our artwork. In Greek and Roman mythology, Orion was a super strong giant. He'll look very large when you see this constellation in the real sky, and he's often seen fighting another constellation, a constellation that's right in front of him: Taurus the bull. We look for Taurus by looking for a v-shape of stars that's the head of the bull. It has one bright orange star you'll see there in the head of the bull that is the bull's eye, Aldebaran. There are stories from ancient Greece involving bulls, but Taurus might have even older origins. One of the oldest works of literature is the Babylonian Epic of Gilgamesh was written around 2100 BC, and it shows Taurus as the bull of heaven fighting a super strong tyrant king Gilgamesh, who may be represented by Orion here. Taurus could have even older origins than that. There is a cave in France called Lascaux covered in prehistoric paintings of large animals, one of which is a bull with dots around its eye that may represent the stars that we see with aldebaran there, the stars forming the head of Taurus the bull. If that's true, then Taurus would be coming to us from 17000 BC. Orion also has his hunting dogs accompanying him.

If we follow the belt of Orion down towards the horizon there, we'll come to the brightest star in the sky: Sirius, the dog star. That's the head of one of Orion's hunting dogs known as Canis Major. I'll put up a picture so we can see Orion with his hunting dog, and then he has another one just above Canis Major called Canis Minor, a little bit of a smaller dog. Right between the two dogs is a very elusive constellation. You'll notice that gap between them looks almost empty, but we do have a constellation in place there. It's known as Monoceros the unicorn. The unicorn is elusive. It's difficult to find in the sky, and its mythology is that it's very quiet and difficult to find in the forest. In fact, the unicorn is seen here sneaking up right behind Orion despite him being the great hunter. The unicorn here is a much more recent constellation compared to things like Orion that goes back to Greek and Roman mythology and Taurus which potentially goes back even further. Monoceros was added to our list of constellations only in the 1600s by Dutch and German astronomers. In Orion just off the belt, there is his sword. It's a hazy area on the sky. I'll mark where it is. It's hazy because there's gas there. The word nebula actually means cloud, and this nebula is a star-forming region that's just visible with the naked eye. You'll see it even better though through a small telescope or a pair of binoculars. We're going to zoom in on the Orion nebula so we can see it better and see what it looks like through a telescope or at least similar to what it would look like.

We have telescopes at UNG. They're at our observatory. We have a brand new building with new telescopes that we just finished last year. They are planning to open to the public this month but only for small groups that register in advance so check their Facebook page. It's under the North Georgia Astronomical Observatory, for updates and to find out about signing up if you want to visit that. Nonetheless, we're going to zoom in on the Orion nebula here in the planetarium. So now we have a much better view of the Orion nebula. This is one of the closest star-forming regions to earth but it's still over 1300 light years away. A light year is how far light travels in one year. So the light we're seeing here took 1300 years to travel to us. If we take photos of the Orion nebula, we can use a long exposure. We can look through a telescope. We can get higher resolution pictures to show more detail.

We're going to take a look at one of those photos this is going to be one taken by both the Hubble Space Telescope as well as the Spitzer Space Telescope.  So Hubble was a telescope in space, still there, but this is showing us more visible light like we see with our eyes. While the Spitzer Space Telescope is designed to show low energy infrared light that we wouldn't normally see with our eyes. What we're actually seeing in this picture is towards the center where it's very bright that's where we have four massive stars that are sort of dominating this nebula. They're shaping it. The blue and green colors we see are coming from Hubble. That's actually a little bit of UV as well as visible light, and it's showing us where there's hydrogen gas that's heated, trace amounts of sulfur as well. And then the more red and orange colors that we're seeing here is showing us where there's glowing dust and that's the infrared light.

The dust is made out of large molecules that are made of hydrogen and carbon. The carbon actually means they're organic molecules, and these molecules are really similar to smog that we might see on Earth. We're going to actually take a look at an animation that shows us what it might be like to dive through the Orion Nebula. So this is going to be an animation, an artist's depiction, but it's made very three-dimensional and using data from Hubble pictures of the Orion Nebula. And we can see here that there's sort of a cavity. These clouds are being sculpted and that's by those massive stars that are in the center of the nebula. They have stellar winds, material blowing off of them that are sculpting the clouds.

There's also new stars that can form in places where the clouds are more dense, where the gas is sort of compressing. As we fly through we'll start to see some very faint sort of bubble, sort of tadpole-ish bubble shapes towards the center of the view there, and those are actually brand new stars that are just formed. The Orion Nebula being close by means that it's inside our own galaxy called the Milky Way. It's close enough we can study it in detail and see stars forming, but we can actually observe star formation in distant galaxies, in other galaxies that are much further away. Some galaxies are actually referred to as starburst galaxies because they have higher rates of new stars forming than here in the Milky Way.

A recent study looked at a galaxy that was living a fast, hard life forming new stars at a rapid rate but also simultaneously losing gas, losing that material that you need to make new stars. Let's take a look at an artist's depiction of this galaxy. It's called ID 2299. It's not a very catchy name, and as I mentioned, this is actually an artist's depiction and not a photograph and that's because of how far away this galaxy is. It is about 9 billion light years away so it is much further away than the Orion Nebula, and so far that most telescopes aren't going to capture a clear view, not a pretty picture like we're used to seeing of the details across a galaxy or a nebula. And so here we're looking at an artist's depiction, but how do we know anything about what this galaxy looks like if it's so far away?

We can still collect some light from this galaxy, and in fact there were radio waves that were collected by a radio telescope array called ALMA. The radio waves are low energy type of light, very long wavelength. They travel very well over far distances. They don't get scattered as much. Those radio waves can tell us about how the gas that's inside this galaxy the gas where the radio waves come from is moving.

Essentially what scientists found is that about half the gas in this galaxy is moving much differently than the other half. Half of the gas is moving with a wide range of speeds that reach very fast velocities. In fact, they're moving fast enough that some of the gas is going to escape the galaxy. Most of that half of the gas will eventually leave the galaxy. It's leaving right now at a rate of 10,000 times the mass of our sun every year, and so that mass loss is huge. It means the gas is getting funneled out of this galaxy, and the remaining gas that's still there is rapidly being used to form new stars. So this galaxy is effectively dying. It's effectively going to stop making new stars entirely, and it's on a time scale we've never directly observed before maybe only tens of millions of years before this galaxy's done. And normally, we think of galaxies as taking billions of years to undergo this type of change. It was also really exciting when they looked at how the gas moves to realize that it's leaving in the form of a tidal tail you see that here in this picture, this sort of wisp tail that's flying out. And that's actually telling us that this galaxy is having the gas thrown out from a merger with another galaxy. It's not just like a wind being blown out but rather the material being thrown out from interactions. We'll zoom away from the Orion Nebula and look for another object in the sky.

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