Looking up the night sky on a clear night, you can see anywhere from a few hundred stars
to a few thousand without a telescope.
This massive dome of speckled darkness has been a giant game of connect the dots for
millennia.
These constellations have represented the gods, the changing of the seasons, and the
passage of time.
They even show up in our horoscopes.
These of course, are the constellations in the Zodiac, and to be specific,
these are 12 constellations that have held immense significance
throughout history.
And while they don't determine our personalities or fates, they do play an important role in astronomy
and understanding how Earth moves through space.
Before we dive into the role of zodiacs in astronomy.
Let's first clear up a few things about astrology.
It's not hard to imagine why ancient people placed a lot of value on certain constellations.
Finding relationships between the movement of the stars and what was happening on Earth,
likely helped make their world easier to predict and understand.
For the Babylonians the shape of a ram in the night sky meant spring was finally around
the corner.
You may be asking yourself, why are we talking about the zodiacs in a science video.
Well, actually the reason why they stood out among the rest to ancient stargazers is kind
of the same reason why they're pretty important for understanding basic astronomy today.
Here's how it works.
If you could see all of the stars during the day.
Over the course of a year, you'd be able to see the sun, slowly moving along a path from
one constellation to the next.
That imaginary path is called the ecliptic.
And it's arguably one of the most important coordinate systems in astronomy.
What makes the ecliptic line so useful is how it shows the plane of Earth's orbit around
the sun.
And our place in the solar system, because all of the major celestial bodies in the solar
system orbit the sun in a similar way.
They're on or near the same flat plane of the ecliptic.
That's all of the planets, and even the moon. While some differ by a few degrees from the line.
They're all essentially there.
Another reason Zodiac constellations became so famous throughout history, is that we always
see the moon planets and eclipses near them.
Eclipse... ecliptic.
You get the idea.
With all this action in one area of the night sky, it's easy to understand why ancient interpreters
placed immense value on these constellations, but it's also really important for modern
space work.
And it also turned out to be a good place to hunt for exoplanets during NASA's K2
mission, the Kepler mission was a space telescope that search for exoplanets by measuring brightness
dips in nearby stars.
And although the Kepler mission wasn't originally designed to search the ecliptic.
That part of the sky ended up being a good place to find exoplanets.
The whole purpose of Kepler was to find planets around other stars.
So originally we pointed Kepler near the constellation of Cygnus, and we picked that part of the
sky because we didn't know how common planets were.
But about four years into the mission, two wheels on the spacecraft failed, meaning
that it could no longer hold steady enough to observe near Cygnus, so they got creative and used the sun to keep
the telescope pointed in the same place.
Because the Kepler Space Telescope had symmetrical solar panels, the solar pressure was enough to keep it
oriented in one direction, and with the sun pushing it slightly, it meant that K2 was now pointed
directly at the ecliptic line.
But that was still great, we still found, oh, over 400 planets, looking at all these different parts of the sky
every few days. Some of us who work on K2 we think of the K2 mission as what may be one of NASA's
best hacks.
While astronomers continue to use the ecliptic line to learn about our solar system and exoplanets in the galaxy,
there's so much you can see right from where you are.
Depending on where you live, you should be able to see at least one Zodiac constellation every single night.
And my favorite part is that it's easy to find the planets, once you know where to look,
they're always going to be along the ecliptic.
It's pretty cool to be able to see where you are, relative to the rest of the solar system,
right from your backyard.
And one more thing that astrology doesn't get quite right when it comes to the Zodiac
constellations... astrology assumes that the zodiac signs are split evenly into the 12
slices of the year.
But in fact, the sun spends wildly different lengths of time in each Zodiac constellation.
Not to mention Ohiuchus, a 13th constellation, known as the serpent bearer, in which the
sun spends 18 days.
My name is Sarafina Nance, and this is Seeker Constellations.
If there's an astronomy topic or a favorite constellation you want us to cover.
Let us know in the comments.
Thanks for watching.