Birth of a Planet

Uploaded by TACCutexas on 28.08.2012

>> 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.
>> 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
>> 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
[Music, flourish]