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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.
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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.
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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.
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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.
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