Imagine it's night time.
You're in an unfamiliar place and it's so dark you can't see anything
except for some distant lights.
Now imagine you had to map the area to find
out how far away those lights were.
If you've got nothing for reference, that's a tough ask.
You think: is that light fainter than the one next to it
because they're further away, or are they the same distance but coming
from different intensity light globes?
It would be a whole lot easier to measure distance
if you knew that light A, B and C are street lights, especially
if you know that all street lamps use the same type of light globe
and have an equation where the intensity of the street lights
you see helps calculate how far away they are.
This is kind of what it's like for an astrophysicist
like me exploring our galactic neighbourhood from earth.
This is 10 Minute Genius and I'm going to tell you all
about how I use the light emitted by stars to help us learn more
about our galactic neighbourhood in under 10 minutes.
While the archaeologist digs down to explore mysteries of our path,
a cosmic archaeologist like myself does my digging upwards
through space to illuminate the history of our universe.
When we look at stars, we're looking back in time.
The light we're seeing has spent a long time travelling unfathomable
distances through the cosmos to our eyes.
Even the light from our nearest star, the sun, takes over 8 minutes
to reach us from over 150 million kilometres away.
The relationship between time, light and space is second nature
to an astrophysicist, which is why we measure distance in space
as light years or the distance light travels in one earth year.
But not all stars are the same.
The light in our intergalactic street are
not only different distances away but come in different sizes,
chemical compositions and stages of evolution.
That's why we rely on measuring distances
in space using stars that we know have a consistent spectral fingerprint.
We call these 'standard candles' because they allow us
to measure distances in the same way as if they're cosmic street lights
with standard light globes in them.
We know all about the light they give off, its make up
and intensity and, therefore, we can more confidently
measure their distance.
My research is all about being able to tell our standard stellar candles
from the rest so we can use them to learn
about our neighbouring galaxies.
When everyone else is winding down for the night, my day
is just beginning.
My work involves pulling a lot of all nighters when it comes to time
to collect data.
It looks a bit sci fi.
I work in a room with a lot of computer screens, and when I log
on here in Sydney, I'm connecting remotely
with a telescope far from the city lights, in Coonabarabran.
I have a list of stars I'm targeting for my research.
I'm looking at two different types of stars: red clump stars
and red giant branch stars.
Red clump stars are standard candles, perfect for measuring distance,
but they can be hard to tell apart from red giant branch stars.
Both of them types of stars are at a similar stage of evolution
and appear similar on the surface but it's the inside that counts.
The structure of these stars' cores is where you can sort your red clumps
from your red giant branches.
It's like having to peel your fruit to tell apples from oranges.
Traditionally we've relied on a field called asteroseismology
to help tell these stars apart so that we can map the cosmos.
Asteroseismology uses the light emitted from stars to allow us
to tell the different types apart.
Just as you can tell that glass bottles are different by hearing the pitch
you get from blowing in them, you can also tell the difference
between different types of stars by studying the oscillation in the
light waves they produce over a long period of time.
The only problem?
This can take days, months or even years at a time to do
for each star.
I'm a PhD student so I don't have that kind of time.
Instead, I'm trying to forge a new faster path
to identifying our cosmic street lamps.
I spend all night every night collecting the
light from red clump stars and red giant branch stars our apples
and oranges so I can study their spectra,
which tells us the make up of the light these stars emit so
we can tell them apart.
If we can use this spectral signature as a fingerprint to tell us what type
of star we're looking at, we could speed
up our process so that it takes minutes, not years.
That would also be a giant leap forward in finding our way
around our galactic neighbourhood without even leaving home.
And if my research makes that leap forward possible for the field,
that would be a dream come true.
And possibly a few less all nighters.