To look up at the sky on a dark, clear night is a jaw-dropping and humbling experience.
It makes you wonder where we fit in in all of this.
I'm Laylan from ESA Education and today we're going to speak to an
ESA astronomer to find out more about our place in the universe.
Tereza Jerabkova, did I say that right? Yes, you said it perfectly.
Welcome. Thank you for joining us today.
Thank you for having me, I'm really happy to be here.
So what do you do at ESA? I work at ESA as a research fellow
which means a hundred percent of my time is dedicated to doing research.
And I work on star formation. So I'm trying to understand how
stars form, how they evolved, and in which groups they are forming.
If we, for example, can see some star clusters, how they evolve.
How did you understand our place in the universe, like where the Earth is in the solar system?
If we look at the solar system, we live on Earth but there are other planets as well.
Some of them are closer, some of them are bigger. Some of them have a moon.
Some of them have actually have many more moons. And with all this we orbit around the Sun.
There are also smaller objects called asteroids. The minor planets.
And they are all over the system. There are also very distant objects
in the Kuiper Belt that actually are on very different orbits and can
become a comet when they come close to the Sun. So in order to understand the scales a bit better.
As a ruler we can use the speed of light and how long it would take the light to travel
from different parts of the Solar System. So if we are on Earth it would take
us one second to reach the Moon. It takes eight minutes to get to the Sun.
And it would take more than four hours to reach the outer parts of the solar system.
So maybe in a more common analogy we could say that our solar system fits into one house.
Then the outer parts of it would be the garden. And then we would like to visit our closest
neighbour which would be the closest star to the Sun.
So this would take us, with the same velocity as the speed of light, around four years.
And that's the closest star to us. And then there are billions of other stars.
Billions of other houses that actually create a galaxy.
And they are not randomly distributed, but there are villages.
This can be small star clusters but there are also really big cities.
And these would be more massive and more dense star clusters.
And the centres are the densest. You can see it as the downtown
area of big cities, with the high tower houses with lots of apartments in them.
And then these different cities, they would form states and countries.
These would be galaxies? Yeah exactly.
So if a city would be a star cluster, then indeed we could distinguish the galaxy
from a star cluster in a way as we have cities and states because they are different objects.
Typically astronomers use telescopes to take pictures that also give us measurements.
But how is it that we can understand how heavy a star is or how fast it's moving
from an object that we can't actually put on a scale and weigh?
This is a very good question and maybe I can come up with another analogy in this way.
So the thing is. How actually we study stars.
Stars are born, then they evolve, they age in a similar way as we do and then they die.
But we can just take pictures so how does this work?
So the way we can study stars would be similar in Earthly matters, if we would get a task.
Imagine you are at school and the teacher tells you "okay you now have one hour to learn
about dogs, everything you can" "But you cannot use the internet or anything,
you have just one hour and I want you to figure out what dogs they are, how can you determine how
much they weigh and what's their age." So you can then quickly take your bike
and a camera and run all over the city and take as many pictures of dogs as possible.
Then you come back to the classroom and then you can have a look at the pictures.
And then there will be pictures of a number of dogs playing in groups,
like stars and star clusters, and then some of these dogs will be alone.
And some of them are big. And some of them are small.
But you face all of the same problems that for example you have two small dogs.
One is a puppy. Because puppies are small,
because when a dog is born it's small. But there are also a small breed,
so it can be an older chihuahua for example. And then you need to come up with the features,
how to actually distinguish whether it's a puppy or a chihuahua.
So then your estimate of the mass just based on the information would be different.
And this is the type of research that actually we do in astronomy.
We take all of these pictures and then we try to see okay this star is similar like the Sun.
It has a similar light. So probably it will weigh the same as the Sun.
Tereza why do we care about the size of a star, about its weight, about how fast it spins
in a galaxy that's billions of light years away from us?
That's a great question and actually when I now think about it, we did always care.
I would say that we can define astronomy as a field that is studying
every object that we can see in the sky. So it can be the Sun, it can be planets,
but also other stars and galaxies. It was actually crucial for our survival.
So for example when we started to travel on the sea and the ocean,
in between the continents, we needed stars for navigation otherwise we would always get lost.
In addition, the knowledge of seasons and tides and the weather in general
was crucial to harvest and create food. So actually, all of astronomy in general
and the knowledge of celestial bodies helped us to create a society that we have today.
Now is astronomy something you were always inspired by as a kid?
What was your path to astronomy? I was actually born in a small village
in the mountains. I did lots of sports.
I did skiing. I played football.
And I was not really thinking about any scientific career or anything for a very long time.
Only just before when I had to decide what high school I'm going to go I realized oh wow.
I need to do something else than just running around in the forest.
So I was thinking what I should do. I vividly remember one moment when I
was just looking at the books and I was thinking where to start and the one book that I opened was
problems in mathematics And I said okay so I will sit
down and try to focus on this one problem that I thought is probably difficult.
But I sat down and I read the problem and I thought about it a but and then
suddenly I knew how to solve it. And I solved it and I checked
and the answer was correct. And it felt really satisfying.
So I thought okay maybe this is something I want to do.
Thank you so much Tereza for speaking to us about our place in the universe.
Thank you for having me.
If you're looking for more astronomy educational resources check out ESA Education's Teach with
Astronomy webpage and keep an eye out for more videos coming from ESA Education.