Birth of a Planet

[Music]>>NARRATOR: We now know that the Earth and
the planets of our solar system are not alone in the universe. Over the past few decades,
the hunt for extrasolar planets has yielded incredible discoveries, and now planetary
researchers have a new tool. Simulated models of how planets are born. [Music]>>NARRATOR: It’s believed that most planets
form when a molecular cloud collapses into a young star. The leftover gas and dust form
a disk around the star, and the particulates inside the disk begin to collide and coalesce
over millions of years, forming larger and larger objects until a planet eventually takes
shape. Sally Dodson Robinson and her team of researchers are modeling and simulating
these protostellar disks, comparing their results to the Earth and the planets of our
own solar system.>>DODSON-ROBINSON: Any young star that’s,
you know, a few millions years old or less is surrounded by one of these disks, and it’s
like a Frisbee of gas and dust surrounding the star. And that’s the environment where
planets form. So we want to know what conditions are good for forming planets, what conditions
are bad for forming planets, etc. So getting really good detailed models of how these disks
work is important.>>LANDRY: The evolution of this disk greatly
impacts the way planets could be forming and that’s what we’re simulating. We’re
trying to simulate the global evolution of the disk over its entire lifetime.>>NARRATOR: The simulations model important
factors such as turbulence and temperature of the disk, which affect how and where planets
form. In a disk that’s too turbulent, the particles move too fast and bounce off each
other. Less turbulence means a greater chance for them to collide and stick together. The
temperature of the disk determines where ice forms, a phenomenon called the Ice Line.>>DODSON-ROBINSON: Ice is a good ingredient
for giant planets. You don’t really need it for Earth-like planets, terrestrial planets,
but for giant planets we think that you probably do need it. So our simulations will tell you:
well where do you expect to be giant planets forming and where do you expect there to be
small planets forming.>>NARRATOR: It was believed that the disk
would cool off as it expands, and the ice line would move closer to the star, making
it possible for giant planets to form. But the models showed that the opposite was true.
The disk heats up as it expands, and the ice line moves further away. Future theories of
planet formation can now consider this discovery, which marked a shift in their basic understanding
of disks. Discoveries like this are a result of the complexity of the models and simulations,
which cover a timescale of millions of years. The considerable computation involved was
facilitated by the Ranger supercomputer at the Texas Advanced Computing Center. But accurate,
two dimensional models were just the beginning. Sally and Russell have recently taken their
work a step further, collaborating with Greg Abram of TACC in order to create three dimensional
models of their data.>>ABRAM: Really, the challenge becomes figuring
out not what their data is, but what they want to convey from their data, and how they
can best convey that using visualization techniques.>>DODSON-ROBINSON: You know, with these 3D
renderings we’re able to see these are the correct proportions; this is what it really
looks like. We’re moving toward a better understanding of what this disk would actually
look like if you were to fly over it. It’s a way of looking that the problem before that
I never thought about, which is: how can you use your eyes to get information about this
disk and what can you leave, what can you cut out, and if you cut it out are you telling
the right story. So it’s kind of fun. You know TACC is incredibly well administered
so setting everything up so easy it was like boom, we were going.>>ABRAM: We do try to teach people to fish
rather than give them fish. So we have courses here that we teach at TACC which we hope enable
people to do as much of their own visualization as possible.>>LANDRY: He definitely made it look very
easy and he’s written a lot of the code that would take the data and turn it into
a fashion that can be easily visualized. And taking that forward, it seems that it would
be very doable to then start producing my own visualizations of the data.>>NARRATOR: In 1988, we knew of one solitary
extrasolar planet. In 2012, we know of almost 2,400 awaiting confirmation. Understanding
the conditions that are most favorable for planet formation will aid researchers like
Sally Dodson-Robinson in discovering more of them, and can also provide greater understanding
of the evolution of Earth and our own solar system.>>DODSON-ROBINSON: I love making new discoveries.
So sometimes I do it observationally, sometimes computationally, but either way it’s really
exciting to see something we haven’t seen before realize that’s important. That’s
a neat experience. So that’s my favorite thing. [Music, flourish]


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