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(CNN) - In addition to the asteroid that annihilated dinosaurs 65 million years ago, there are not many connections between space and dinosaurs beyond imagination. But all that changed when NASA research scientist Jessie Christiansen brought the two together in a social media animation this month.
Over the past decade, Christiansen has studied the rates of occurrence of planets, or how often and what type of planets occur in the galaxy, while studying data from exoplanet hunters such as NASA's Kepler, K2 and TESS missions.
During a star-watching party at the California Institute of Technology, Christiansen was explaining how young the stars they observed were. Sky watchers looked at the Pleiades, a group of bright young stars that are some of the youngest in our sky.
They are 13 million years old, which sounds old. Christiansen wanted to convey that, astronomically, it is still an early age.
She told her fellow astronomers that before they went extinct, dinosaurs wouldn't even have seen these stars in the sky because they didn't exist until millions of years after the extinction event. And she told them that when dinosaurs like stegosaurus roamed the Earth, our entire solar neighborhood was on the opposite side of the Milky Way galaxy that it is now.
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Christiansen was not sharing new information, he said. But the fact called everyone's attention because the movement of our solar system while orbiting the galaxy is not something that most people think of.
"You don't think the sky changes," said Christiansen. "But the stars come and go, in tune with our time scales."
She had been hoping to create an animation of this intriguing idea for a while and the reaction of the star watchers inspired her one night after her children went to bed. Using the classic Milky Way illustration, as if viewed from above, by Caltech senior scientist Robert Hurt, Christiansen built the animation using timed slides in PowerPoint. Then he recorded the screen to create a video that he could share on Twitter.
I actually made a slightly updated version to address some of the critiques of the original (updated the period of rotation of the Galaxy, took out plesiosaurs since THEY'RE NOT ACTUALLY DINOSAURS JESSIE WHAT KIND OF NERD ARE YOU ANYWAY ?!) pic.twitter .com / LjLW6k5IGU
- Dr. Jessie Christiansen (@aussiastronomer) November 7, 2019
She wanted to share the idea that, although astronomical time scales seem very different from ours, they actually coincide quite well with archeological time scales.
The animation shows that the sun takes between 200 and 250 million years to orbit around the center of the galaxy, which is a large spiral, bordering the dangerous center that would be inhospitable for life.
According to our current position in the galaxy and the timescales shared in the animation, we have essentially completed an orbit.
The last time our solar neighborhood was in this part of the galaxy, relatively speaking, the first dinosaur began to appear on Earth during the Triassic period. After that, the Jurassic Period lasted 55 million years, followed by the Cretaceous Period, which lasted until the dinosaurs became extinct 65 million years ago.
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Dinosaurs such as stegosaurus, iguanodon and giganotosaurus lived during the early Cretaceous while Earth was on the other side of the galaxy. The long stretch of 79 million years of the Cretaceous period occurred largely there. To put things in perspective, the tyrannosaurus rex existed on Earth when it was in a part of the galaxy that is closer to our current position than many other dinosaurs.
The extinction event 65 million years ago was followed by the emergence of mammals and we are still in that "phase", so to speak. At the end of the animation, Christiansen proposes an intriguing question: what will be on the planet the next time we complete another orbit?
Christiansen used simplifications for its animation, but explained some of the most complex sciences behind this orbit.
While astronomers are still learning how the stars revolve around the center of the galaxy, ultimately, everything in our galaxy revolves around the black hole in its center. The stars closest to the center rotate faster, while those in the outer regions rotate more slowly. Our solar system is located in one of the spiral arms of the galaxy and everyone travels around the galaxy together, including the other stars in our "neighborhood," Christiansen said.
And the Milky Way galaxy is moving towards its great neighbor, the Andromeda galaxy. The two are in the process of collision and will join in about 4 billion years. While that sounds violent, galaxies are largely an empty space and the stars will not collide with each other, Christiansen said.
READ : The Milky Way swallowed another galaxy billions of years ago, according to a study
Then we returned to where we were between 200 and 250 million years ago. But based on our Milky Way orbit, which itself is moving and spiraling, we have never returned to the same absolute point in space because it is not possible.
“The simple idea I was trying to convey is that astronomy has certain time scales and archeology has them, and sometimes they coincide. Isn't it great?