Milky Way
“You are currently looking at the sky on November 6, the approximate midpoint of the fall season. But, before we zoom in, let’s zoom out - way out.”
Zoom out to plane-perpendicular view of the Milky Way Galaxy.
“This is the Milky Way, our host galaxy. All 90,000 light years of it! You may be surprised to learn that we’ve never taken a picture from outside The Milky Way. But with telescopes like the ESA’s Gaia Space Observatory1, we have been able to precisely measure distances and speeds of stars; giving us confidence that the galaxy is in the shape of a spiral. Current estimates put the number of stars in our galaxy alone between 100 and 400 billion.2 There are also believed to be 2 trillion galaxies we can see. That’s a lot of stars! With the exception of other galaxies, all the objects we are going to be looking at are contained within our galaxy. Let’s begin!”
Zoom Back in to Earth on November 6, at 11:30 P.M. facing due-north.
Constellations
Constellations and their respective names fade in.
“These are the constellations that you can see at night in the fall. Constellations were created by cultures across the globe. Each one had distinct shapes and stories behind them! The constellations we are familiar with are from the Greek tradition.”
“Here,”
Cassiopeia is circled
“we see Cassiopeia. The mother of neighboring Andromeda. Who was saved by Perseus riding a Pegasus.”
Perseus and Pegasus are circled respectively.
“Today, we don’t use constellations to immortalize mythological beings. Instead, we use them to map the sky. The stars that make the constellations are so far away that their incredible speeds in space reflect minimal change on Earth! If you were to stand in the same spot at the exact same time year after year, you would not see the constellations change all that much in your life time.”
Fade away constellations except for ursa minor.
Ursa Minor & Polaris
“A constellation you may already be familiar with is Ursa Minor: The Little Bear, more commonly called the little dipper. Ursa Minor contains a star called Polaris: The North Star.
Ping Polaris
It we bring up the celestial sphere, you’ll see that all the other stars in the sky rotate around it.”
Bring up the celestial sphere and rotate the stars around it. Making sure to return to 11:30 P.M. on November 6.
“The north star has been used for centuries to guide sailors across the seas. On September 13, 1492, Christopher Columbus wrote in his log-book that his and his ship pilots compasses did not point directly at the north star.”
Fade away Ursa Minor
“Another constellation you are probably familiar with is Orion: the hunter.”
Fade in Orion.
Orion Constellation & Orion Nebula
“Orion’s brightest star is Betelgeuse, a red supergiant.”
Ping Betelgeuse
“It is 400,000,000 times larger than our sun. Betelgeuse has been of particular interest to astronomers in the recent years. In 2020, Betelgeuse dimmed significantly in what is called ‘The Great Dimming’. This is a possible indicator of imminent death. If Betelgeuse does die, it will die in what we call a Supernova.3 A giant explosion. This explosion would be as bright as the full moon and possibly visible during the day.”
Unping Betelgeuse and ping the Orion Nebula.
“Tucked in under Orion’s Belt, we have the beautiful Orion Nebula.”
Expand Orion Nebula.
“This nebula is region of gas and dust where new stars are formed. Cocooned in the center is Orion’s Trapezium: a cluster of young hot stars.”
Expand or notice the trapezium.
“These young stars are actually blowing the nearby gas and dust away revealing a protoplanetary disk.”
Show image of protoplanetary disk.
“This is what our solar system looked like billions of years ago when our solar system was forming.” 4
Fade out Orion constellation.
“Next to Orion we have Taurus, the bull.”
Taurus Constellation & Crab Nebula
Highlight Taurus.
“Within Taurus, we have the Crab Nebula.”
Show the crab nebula.
“The crab nebula is an object called a supernova remnant. This is what Betelgeuse will look like once it dies. If you look very closely you can see a white dot in the center of it. This is a pulsar. Pulsars are the former cores of massive stars that, once the star died, collapsed into a super dense object. Think of an object that has the mass of 1-2 suns condensed into a ball only 10 miles wide. They are the densest objects in the universe next to black holes.”
“A thousand years ago, cultures across the globe noticed and wrote down their observations of the crab nebula.”
“The Natives of the White Mesa Ute tribe inscribed what they saw into rock.” 5
“The Chinese wrote of a ‘guest star’ that entered their skies.”
Your servant considers that, since the 5 th month of last year when the baleful star appeared, a full year has passed and until now its brilliance has not faded. This is what Gu Yong meant by ‘its rapid movement, the variations in the length of its flaming rays, and the asterisms on which it has trespassed successively,’ as a censorious anomaly it is greatly to be feared.
Fade out Taurus and Crab Nebula
Andromeda Constellation & Andromeda Galaxy
“In the constellation of Andromeda, we have the Andromeda galaxy.”
Fade in Andromeda Constellation and Andromeda Galaxy.
“The Andromeda galaxy is a spiral galaxy like the Milky Way. It is the next closest galaxy to us and and is on a collision course with our galaxy. In about 4 billion years the two will merge and create a new galaxy that astronomers have dubbed Milk-dromeda.6”
Show simulation while talking.
The Andromeda Galaxy is also the first galaxy identified to be outside the Milky Way. In 1923, Edwin Hubble was studying a type of star called a Cepheid Variable. Cepheid variables are what astronomers call a “Standard Candle” — objects that can be used to measure distances. Hubble found that the objects he was study in the “Andromeda Spiral Nebula” were giving distances much greater than previously estimated. He proved the existence of a separate galaxy.
Fade out Andromeda.
Pegasus Constellation & Pegasus Cluster
“In the constellation of Pegasus to the west we the Pegasus Cluster.”
Fade in pegasus cluster
“This object is called a Globular cluster: a volume with a super high concentration of stars. Thousands to potentially millions of stars are gravitationally bound to each other. Astronomers actually do not know definitively how these objects formed. The two competing theories are a. The clusters form from primordial gas clouds.
(document, p.1) We argue that the globular clusters may have originated as gravitationally bound gas clouds before the galaxies formed. This idea follows from the primeval-fireball picture, which suggests that the first bound systems to have formed in the expanding Universe were gas clouds with mass and shape quite similar to the globular star clusters. We present also a picture for the evolution from these assumed protoglobular gas clouds to globular star clusters
b. The clusters form from striping dwarf galaxies of stars just leaving the core.
This goes to show that there is still so much that we don’t know in astronomy. Scientific questioning never stops and we are discovering new things every day!”
Conclusion
“I hope you enjoyed this star tour. Again, if you have any questions on space and space science then don’t hesitate to ask a staff member! Thank you for visiting!