[ Sound Effects ]
Hi, I'm Maria and
this is NASA Now.
Recently, a team
of international astronomers
made a stunning announcement
after extensive research found
that our Milky Way
galaxy contains a minimum
of 100 billion planets.
That's right a hundred
with nine zeros after it.
Today, we have one of
the co-authors of a story
in the January 12th
issue of Nature
that announced this
amazing discovery.
That's ahead, first here's
what's happening at NASA Now.
[ Sound Effects ]
In an earlier program, we talked
about coronal mass
ejections, or CME's.
We also discussed how
the sun was entering
into the solar maximum period.
Well, in January, the Earth was
impacted by the largest wave
of plasma and electromagnetic
radiation since 2005.
The category M8.7 class solar
flare struck the Earth January
24th at 10:00 AM EST.
The result was one of the most
spectacular auroras sky watchers
have seen in a very long time.
You can keep track of the
solar flare activity by looking
for the space weather
link right here
at the NASA Explorer
Schools Virtual Campus.
[ Sound Effects ]
Everyday NASA scientists are
discovering something new
about our planet,
the solar system,
the Milky Way galaxy
and the universe.
Today, we are going to learn
more about the incredible study,
which revealed there are no
fewer than a 100 billion planets
in the Milky Way galaxy.
To help us grasp what
this means, we are joined
by research scientist
Stephen Kane,
from the NASA Exoplanet
Science Institute.
Hello Stephen, why is this
announcement about the number
of planets in our
galaxy so important?
The new discovery shows
that planets are very common
in our galaxy and
in the universe.
This is a very significant
result.
One of the main questions
we are trying to answer
at the moment is, how common
are planets in the universe,
and in particular, how common
are planets like the Earth?
The new result shows that
not only are planets common,
but that small planets are
more common than large planets.
And this is very good
news because we know
that life can occur
on small planets
where we have an atmosphere
and where we have liquid water.
So this is very good news
for finding habitable
planets like the Earth.
What type of research led you
to the conclusion that there are
as many as 100 billion planets
in the Milky Way galaxy?
The survey was all conducted
from the ground using fairly
small ground-based telescopes.
Only one meter in diameter,
which is fairly small these days
for those kinds of telescopes,
but we used a lot of them,
and the reason that
we used a lot
of them is we had them
spread all over the world
so that we could look at
these stars 24 hours a day.
So, that when the star
was setting somewhere,
it was rising somewhere else
and we could keep looking.
And over the course of these
10 to 15 years, we've been able
to tell how many of these
stars that we're looking
at have planets and
how many don't.
So, for the study you
used a large number
of ground-based telescopes, are
there other methods being used
to search for planets?
Another method that we can use
to find extra-solar planets
is called the transit method.
If you imagine that you
are looking at the disk
of another star and the
planet passes across the disk,
then it blocks out
some of the light.
We can measure how
much light is missing
by carefully monitoring the
light from the star and from
that we can tell not only
that there is a planet there,
but how big the planet is.
And it is now being used from
space by NASA's Kepler Mission.
Based on your findings, this
must mean there are a lot
of stars in the Milky
Way galaxy,
how many stars are there?
Our galaxy contains
over 100 million stars,
just like our sun.
And many of them
likely have planets.
But our galaxy is also only one
of many millions, and we can see
that there are many
more galaxies out there,
and that's when we start
to talk about the universe.
The universe is everything
that we can see around us.
[ Sound Effects ]
You heard that scientists
use different methods
to detect planets
orbiting around a star.
Here's a chance for
you to try one
of these techniques
using real data
from the Kepler Space Telescope.
In this activity, students will
investigate light curve data
gathered by Kepler
from ten planets.
They will use the data
to determine the period,
orbital distance and
size of the planet.
You can find the
link to this lesson
on the NASA Explorer
Schools Virtual Campus.
Well that's it for NASA Now,
be sure to visit our Facebook
page and leave a comment.
We'll see you next
time on NASA Now.
[ Sound Effects ]
NASA Now comes to you
from the Virtual Campus
at NASA Explorer Schools.
