Translator: Dina Ismail
Reviewer: Peter van de Ven Star dust. Think about it. Evidence suggests that life happened
from cosmic processes. The iron in our bodies, and the water in our bodies as well, came from the stars. Therefore, every matter we know,
of course, comes from the stars. So, I remember when I was 13 years old, and I became interested in astronomy. I saw the picture of Buzz Aldrin standing in front of
the American flag on the moon, and I decided that I wanted
to become an astronomer one day. Just because I saw that picture. And I told myself that I'm going to
find life in the universe one day. And today I am an astronomer
and soon an aerospace engineer, and I have the same goal
as I had when I was 13 years old. Which takes me to the next topic: What is life ? We know the meaning of the word, but how are we going to define what it is? We know what is meant when we say
that something is alive. But remember that you and I have different visions
of what life might be. In science, however, life can be anything. Everything from small
microscopic bacteria to huge animals. It doesn't have to be intelligent
or as intelligent as us. And remember that even if we find small fossils
or remains of life somewhere else, that means that we
are not alone in the universe, and we are automatically insignificant. So, think about it. So, what does it take for life
to exist somewhere? There are actually
many factors that decide whether a planet can have life or not. For instance, why isn't Mercury or Pluto
full of creatures, like here on Earth? Well, one of the things is that our planet
is on the habitable zone, and the habitable zone
is a great position in the solar system because it will permit a planet or body to sustain an atmosphere and liquid water. So, Earth is in that zone, Mercury is not and Pluto is not. And this distance depends on
the size of the star. So if the stars are really big, of course the distance between them
has to increase as well, obviously. So we are lucky enough
to be in the habitable zone. Another important thing
that astronomers have told us is that a planet or a solar system
needs to have a huge planet. And why is that? Well, we can take Jupiter as an example. Jupiter works as
a vacuum cleaner, basically. It attracts all big asteroids
and other dangerous bodies that might collide with us
and destroy everything here. So these are the two things,
among some other factors, that decide whether or not
we can have life on a planet. So, I am really interested in one body, particularly this one,
as you can see in the photo here. And this one is very special because as you can see,
it has ice on it. But there are other things
that make this one very special. It has liquid water, a global liquid ocean. It also has many active geysers
that are spraying out water. Well, it is a Saturn moon,
by the way, Enceladus. It is spraying out water
to its outer rings, and it is a really active body
in the solar system. And it is more active
than, for instance, Mars. I mean, why are we interested in Mars ? (Laughter) There is, like, a small percentage
of liquid water on Mars, but why are we still investigating
that planet when we have this one? I don't have an answer to that, actually. So, this one might be
a perfect place for life. Who knows? What if we find it one day? I want to do it, by the way. I hope so. So, I am really interested in this topic, to find life in the universe
and the solar system. So, sometimes I like to design
my own projects and space missions, and I had a chance to present two of them on the European Planetary Science Congress
in France, couple of months ago. And I am just going to tell you
a little about it. First of all, it was my first poster session,
I mean, I was so scared because all of the attendants
were actually astronomers, they were basically experts in this. I was afraid that they would
criticize me for everything in detail, and they were actually kind, of course, and we brainstormed a little, and I got some new ideas after that day. So, what I learned so far is that a space mission
is quite complicated. And they asked me, "You want to find life on Enceladus.
How are you going to do it?" And I told them, "Well, I want to send
an underwater robot to that moon." And they were like, why?
Why Enceladus? Why are you going to do it? Well, I told them, "Imagine this, there is life on Enceladus
beneath the ice surface. How would it feel if we actually had footage
of this life swimming in the water. Wouldn't it be groundbreaking
and paradigm shifting? I mean, it would change us completely." They were, of course, skeptical and told me, "Why not use the old method? Send satellites through the geysers, and let the satellites collect
the samples instead." Well, of course, they are always
in these comfort zones, astronomers. I understand them, but you have to try a little harder, or else, how are you going to succeed? So after that day, I realized how much work
and how much energy there is behind a space mission. You don't know
a percentage of it, actually. We don't read a percentage of it
in the newspapers. And I believe that we will,
someday, find something, very soon actually: 10, 20, 50 years. I mean, it sounds like it is many years, but in astronomical terms,
it is nothing, basically. So, let us take a look
at something different. It is a silly question, but let us presume
that we have this spacecraft, a lander that is, on a planet, and it finds something one day. How do we know that that life
is from the planet it is observing and not from Earth? Well, it is a huge problem, actually, and it seems like there always
is a passenger that survives this even though we're building the spacecrafts
in clean rooms and disinfect them. They seem to survive for some reason. And the astronomers have found
life, evidence of life, about 16 kilometers above our surface
in the atmosphere, actually. And also one specific one, the tardigrade, that I can't pronounce, but I can show it to you,
this one right here - you may have read about it. Imagine these ones being
in the waters of Enceladus. Why not? I mean,
it will be possible for it since it is alien, it can survive
in harsh environments, it can be exposed to radiation
about 100 times necessary to kill us, and one-sixth of its DNA
is alien, basically. So there is a possibility. Who knows? So now, let us step further
to advanced life. What stands in our way when it comes to finding something
in the solar system or somewhere else? The two main reasons
to why we haven't found anything is the distance between the bodies and the technology we are having today. Let us look at the distance. The closest star system to us,
Alpha Centauri, is 4.3 light years away from us. Okay, it sounds a little, but it takes 4.3 years
for the light to reach our eyes. So let us presume
that we have a space shuttle, and we are sitting in this space shuttle
and travelling towards that system. It would take us
more than 150 thousand years to reach that system. So it is impossible for us, unfortunately, but what we will do in the future when we want to examine a body
or observe a body will be to send a robot
to that planet or moon or whatever we are interested in. Because a robot has the ability
to travel in great distances without any problem. And if it is intelligent,
it can fix itself and so on. So, what happens
if we don't receive anything? Not a single signal from somewhere. Does it mean that we are alone? No, actually not. Well, this is what I believe in, actually. The human factor
is always there, of course. Maybe our measurements
haven't been sensitive enough, maybe we have missed
the signal from an alien life. Or maybe something different:
We're contacting a planet that has life, but it is not evolved enough,
and it cannot contact us back. Of course, whatever it might be,
we should continue with the search. If we really want to find out
if we are alone or not in the universe. So for now, we don't have the ability to send
something, a robot, to a distant planet. So what we are dong right now
is to use instruments instead. One example is the radio telescope. A radio telescope can send
radio signals to a distant planet, and hopefully get an answer back. And these signals can travel
in great distances, and carry a lot of information. Another thing that we are using
right now that is really great is the telescope. For now, we have found
more than a thousand exoplanets, that is planets outside
our own solar system, and many of them have been due to size. So, does this mean that it is
only due to size planets outside our solar system? No, it is just much easier to find
bigger planets than smaller. But we have found
about 20 so-called super Earths, that is planets that are almost
as big as our own planet. And they can have life,
we don't know. So, before we learn
how to travel to space and time - I don't know if it will happen,
maybe it will - this is the only thing
we can do right now: to hope for an answer back
and to send signals to planets. I want you to take a look
at this animation. This is Hubble's Deep Field image. And what you are seeing here
are not stars, these are single galaxies, and each of them has some
millions or even billions of stars. And since astronomy
is nothing without numbers, I am going to tell you a little
about the numbers we know so far. So, for now, we know
that there is approximately between 200 to 400 billion stars
in our own galaxy, and there is an equal number
of galaxies in the universe. So what does it mean? It means that about 10 to the power of 22. So these are the stars we have. Yes, huge number,
I can't even say it. There are many stars, actually, and about one percent of these
can have an Earth-like planet, which is not so much, basically. So, to guess the total number
of planets in the Milky way is easy for astronomers. It is about 160 billion planets,
just in our own galaxy. So imagine, multiplying this with the amount of galaxies
there are in our universe. I mean, it is impossible, right? (Laughter) My head hurts, of course. So before I leave the stage,
I just want to tell you something. I remember when I was 14 years old, and I saw the craters of the moon
for the first time with my own telescope. And the things that I felt that day
was just incredible. I was actually scared
to look at the craters because they were so strange. I had never seen
something like this before, and I want you all to go
to an observatory or even buy your own telescope
and just observe the night sky, because I will promise you that you will feel the same thing
that I felt the first time. When you see the rings of Saturn or the moons of Jupiter
or even a galaxy, I'll promise you that you will never
forget that feeling, because I have seen these
more than hundreds of times, and they still amaze me. And that is maybe why
I continue with astronomy. Thank you. (Applause)
