So during a solar
eclipse, the sun, moon and earth are lined up
so that the sun shines on the moon, which then casts a shadow on the earth.
And so in the United States, in the contiguous United States,
everyone will have an opportunity to see at least a partial solar eclipse.
And so that's when the moon moves across
and partially blocks out the sun's disk.
There is also a narrow path that moves from Texas
up to New England, where you can experience totality.
So for a brief period of time as that shadow is moving across,
you will see the moon completely BLOCK the sun out.
And that then reveals the sun's outer atmosphere called the corona.
The rest of the time, it's still a partial eclipse,
but in that narrow time period, that's
when you can experience the full aspect of what is a total solar eclipse.
Well,
yeah, so there's a couple of ways we can do that.
So except for that narrow time, when you're in totality,
the rest of the time is what we call
a partial eclipse, where the sun is only partially blocked
and it's always, always too bright to look at just normally like the sun.
So what you want to do is if you want to look at it directly, you want to have safe
solar viewing glasses or eclipse glasses,
and then you're able to look up and safely see it.
Now, if you don't have solar viewing glasses,
then what you can do is you can create a projector which projects
the sun's image onto a piece of paper or the ground, or you can even take
a piece of paper with holes punched in it, which makes a pinhole camera
that allows you to see the sun the crescents cast onto the ground.
You can even take your hands, do them like this with the sun behind you.
And that creates a little pinholes.
And it's actually much like
what happens with the leaves in the trees, which is just an amazing thing to see.
Well,
I am really, really, really stoked to see the corona.
I mean, the corona, the outer part of the sun's atmosphere
is what I've been studying for 20 years, but I have always studied it from space.
When you can't actually see this part of the atmosphere
and the only time you can see it is when you're in totality on the ground.
So I will see the part of the sun I study with my own eyes.
But you know more than that, it's a really amazing experience.
Once I first saw a total solar eclipse, I was hooked.
And I'm really excited because I will get to experience this with my wife.
And this is just such an amazing opportunity
to share and with all of the people around you.
Well, this is a really amazing opportunity.
Nature is giving us a laboratory to study many aspects.
One, of course, is the corona, which is very, very important.
It's much, much hotter by 100 times than the surface of the sun.
And it is where solar activity and space weather
comes from huge explosions that send out solar material.
And so this is a really important opportunity to study that.
But also as we study that shadow moving across the country
and we see the change in light in the atmosphere,
it allows us to study the lower atmosphere, clouds and temperature,
and it also allows us to study the very important upper atmosphere
called the ionosphere, which is critical for our daily communications.
And this is giving scientists a really special opportunity
to do an experiment that can only be done during a total solar eclipse.
Well, the sun has an activity cycle.
It gets magnetically excited.
The magnets, the magnetism builds up in it
and it releases energy as it gets more and more twisted.
So we go from very low activity or solar min [minimum] to high activity.
Solar maximum back down to low.
We are currently either in or getting close to solar maximum.
So this is the most activity,
most space weather we could possibly see will be happening.
And this is a great time to study that because it has such a huge impact
on our society and scientists will take this opportunity
to learn more about our own star and how it affects our daily
lives.
It's an amazing achievement for humanity.
This is the fastest are totally autonomous spacecraft
it's ever been created, and it's already, since 2018,
been traveling, orbiting the sun, getting closer and closer.
It's already started flying through the sun's corona, this part
that we see during a total solar eclipse.
And on December 24th, it will make its closest approach.
It will be less than 4 million miles from the surface of the sun.
Now, this doesn't seem like that's very, very close.
But remember, the sun is 93 million miles away, so this is less than 4%
a distance, allowing us to study this really important
part of the sun's atmosphere.
Well, yeah.
So there's been a huge explosion in our ability
to make better predictions, which also includes making better maps.
And one of the keys to this is the data that we get
from the Lunar Reconnaissance Orbiter.
This is providing an incredibly detailed
profile of the edge of the moon,
which has a huge impact on how the shadow
is cast on earth and the structure of that shadow and the timing.
We've also used data about the Earth itself.
So combining the the the changes in the Earth
as well as the structure of the moon, has given us unprecedented abilities
to predict the timing, as well as the maps
that we use to know where and when the eclipse will be.
Yeah, so a transit is
when a planet, for example, moves in front of a star.
Now, of course, for the eclipses we're talking about,
the moon is moving in front of the sun and completely blocking it out.
But distant stars have little planets that are moving in front of them.
And by looking at how the light changes as the planet moves across it
very subtly, we can see the size of the planet.
The bigger the drop, the bigger the planet.
But we can also look at the different colors of light
that are coming through the edge of that planet, which is allowing us to
to study the atmospheres of those planets.
This is something that's happening with James Webb Space Telescope,
and we will be building even better instruments in the future
to help us figure out if life is possible or maybe even if life
exists on other planets outside of our own solar system.
Well, there are a lot of
great tips, participatory science opportunities.
Now, NASA has created a several apps that you can download for your phone.
One is called Globe Observer, which is a yearlong project,
but they have a special Eclipse app that during the eclipse
you can participate and take measurements of temperature and clouds.
There's also one called Sun Sketcher,
which is allowing you to sketch and to take images of the corona.
And Eclipse Soundscapes is allowing
people to take sounds to record sounds that are happening as the
the wildlife changes during the eclipse and bring back that data
to allow NASA's scientists, but also to have
the public participate as a scientist to help us gather more data
so that we can better understand
all of the amazing things that we can learn during a solar eclipse.
Well, it wasn't too long
after Einstein had proposed his theory of general relativity,
which basically says that a massive object
like the sun literally bends space.
And a consequence of that is this light travels through that bent space.
The light itself bends.
And so the gravity of the sun acts like a lens
and bends starlight when it travels around it.
So during a total solar eclipse, when the bright disk
is blocked out, we can see background stars.
But the positions of those stars are slightly shifted
because of the bending of the light going around the sun.
So we know exactly where they are.
We see them in a different location and that allows us to
confirm the results of what general relativity
predicts will happen when that star star's light passes the Sun.
Well, the viewers can go to
go that NASA dot gov slash eclipse 2024 [go.nasa.gov/eclipse2024].
And there you can find out about the citizen science.
You can participate in see live feeds across the country
and find out about all of the opportunities so that you can participate,
whether you're in the path or out of the path.
There are lots of things that people can enjoy
and take that experience and have it be something unique,
something that they can experience and share with all of the people around them.