How dinosaurs roamed the Earth on the other side of the Milky Way galaxy.
When dinosaurs ruled the Earth, the planet was on a compl ..
When dinosaurs ruled the Earth, the planet was on a completely different side of the galaxy.
A new animation by NASA scientist Jessie Christiansen shows just how long the dinosaurs' reign lasted, and how short the era
of humans has been in comparison, by tracing our solar system's movement
through the Milky Way.
Our sun orbits the galaxy's center,
completing its rotation every 250 million years or so. So Christiansen's
animation shows that last time our solar system was at its current
point in the galaxy, the Triassic Period was in full swing and dinosaurs
were just beginning to emerge. Many of the most iconic dinosaurs roamed
Earth when the planet was in a very different part of the Milky Way.
Christiansen got the idea to illustrate this
history when she was leading a stargazing party at California Institute
of Technology in Pasadena. Attendees were astonished when she mentioned
that our solar system had been across the galaxy when dinosaurs roamed.
"That was the first time I realized that those
time scales archaeological, fossil record time scales and astronomical
time scales actually kind of match along together," Christiansen told
Business Insider. "Then I had this idea that I could map out dinosaur
evolution through the galaxy's rotation."
The resulting video puts both timelines in perspective:
Christiansen said it took her about four hours to make the film using timed animations in PowerPoint.
'A spiral through space'
Galactic movement is more complicated than the
video shows, though. The other stars and planetary systems in the
galaxy are also moving, at different speeds and in different orbits. The
inner portions spin faster than the outer regions.
What's more, the galaxy itself is moving through space, slowly approaching the nearby Andromeda galaxy.
"The animation kind of makes it seem like
we've come back to the same spot, but in reality the whole galaxy has
moved a very long way," Christiansen said. "It's more like we're doing a
spiral through space. As the whole galaxy's moving and we're rotating
around the center, it kind of creates this spiral.
So in the solar system's rotation around the
galactic center, we're not returning to a fixed point. The neighborhood
is different from the last time we were here.
Earth, however, is not drastically different;
it still supports complex life. That's partially thanks to the path of
our sun's galactic orbit.
"Our solar system doesn't travel to the center of
the galaxy and then back again. We always stay about this distance
away," Christiansen said.
In other words, even as our solar system
travels through the Milky Way, it doesn't approach the inhospitable
center, where life probably wouldn't survive.
"There's a lot of stars, it's dynamically
unstable, there's a lot of radiation," Christiansen said. "Our solar
system certainly doesn't pass through that."
That's a huge part of why dinosaurs, mammals, or any other form of life can exist on Earth.
Our sun orbits the galaxy's center, so many dinosaurs roamed ..
Our sun orbits the galaxy's center, so many dinosaurs roamed ..
Our sun orbits the galaxy's center, so many dinosaurs roamed ..
No comments:
Post a Comment