Humans spent thousands of years gazing  at the night sky and wondering about  
Humans spent thousands of years gazing  at the night sky and wondering about  

the presence of life elsewhere. Could it be in our solar system?  
the presence of life elsewhere. Could it be in our solar system?  

Could it be on some other blue planet around  another star? Nobody ever knew. But such  
Could it be on some other blue planet around  another star? Nobody ever knew. But such  

thoughts have found their expression in fiction,  scientific missions and religions worldwide.  
thoughts have found their expression in fiction,  scientific missions and religions worldwide.  

Pondering the rise of life on our planet  was not only a philosopher's but also  
Pondering the rise of life on our planet  was not only a philosopher's but also  

an ordinary people job. Creation myths have been  
an ordinary people job. Creation myths have been  

fundamental to every civilization and  culture and reflected the profound  
fundamental to every civilization and  culture and reflected the profound  

resonance of the question of our origins.  What about today? Did we make some steps forward? 
resonance of the question of our origins.  What about today? Did we make some steps forward? 

Today, astronomers have pushed back  our understanding of the origins of  
Today, astronomers have pushed back  our understanding of the origins of  

the universe to tiny tiny fractions  of microseconds of the big bang. 
the universe to tiny tiny fractions  of microseconds of the big bang. 

However, we can't yet give any  satisfying definition of life,  
However, we can't yet give any  satisfying definition of life,  

nor yet point to the exact time and conditions  when the organic matter first went from unanimated  
nor yet point to the exact time and conditions  when the organic matter first went from unanimated  

to animated, from nonliving to living. It was about 50 years ago when humanity  
to animated, from nonliving to living. It was about 50 years ago when humanity  

began to extend its presence into space,  first with robots and then with humans.  
began to extend its presence into space,  first with robots and then with humans.  

As this tentative expansion of our species into  other worlds continues, basic questions remain  
As this tentative expansion of our species into  other worlds continues, basic questions remain  

unanswered about the long-term adaptation  of living organisms to other environments.  
unanswered about the long-term adaptation  of living organisms to other environments.  

For example, we often think about  Mars as our second possible home,  
For example, we often think about  Mars as our second possible home,  

but we do not know what the effect  will be of living for years on Mars  
but we do not know what the effect  will be of living for years on Mars  

(in fact, the pull of gravity on Mars  is about one-third that of Earth). 
(in fact, the pull of gravity on Mars  is about one-third that of Earth). 

Astrobiologists try to answer  this type of questions. 
Astrobiologists try to answer  this type of questions. 

But what is exactly astrobiology?  
But what is exactly astrobiology?  

Follow me to get to know more  about it: you won't regret it!
Follow me to get to know more  about it: you won't regret it!

Let's start by simply answering  the question: What's astrobiology?
Let's start by simply answering  the question: What's astrobiology?

As it's easy to imagine, Astrobiology  is the study of life in the universe.  
As it's easy to imagine, Astrobiology  is the study of life in the universe.  

Do you think it is an easy task?  Well, I'm sorry to disappoint you,  
Do you think it is an easy task?  Well, I'm sorry to disappoint you,  

but life in the universe is actually  one of the hardest things we can study.  
but life in the universe is actually  one of the hardest things we can study.  

But let's go back for a moment to when  the term Astrobiology was invented. 
But let's go back for a moment to when  the term Astrobiology was invented. 

It was only in the 50s in the 1950s space-age  that the term Astrobiology was coined. 
It was only in the 50s in the 1950s space-age  that the term Astrobiology was coined. 

It was used to define the study of the  biological impact of space missions  
It was used to define the study of the  biological impact of space missions  

and to define the study of the  search for extraterrestrial life. 
and to define the study of the  search for extraterrestrial life. 

Later, famous scientist Carl Sagan  brought Astrobiology to the public  
Later, famous scientist Carl Sagan  brought Astrobiology to the public  

and to the scientific community, and  the field began to gain recognition.  
and to the scientific community, and  the field began to gain recognition.  

So nowadays astrobiology is defined as the  science that studies the origin, distribution and  
So nowadays astrobiology is defined as the  science that studies the origin, distribution and  

evolution of life in the universe, and it takes  several branches of science: biology, geology,  
evolution of life in the universe, and it takes  several branches of science: biology, geology,  

astronomy, physics, chemistry, but also  engineering and sociology and together.
astronomy, physics, chemistry, but also  engineering and sociology and together.

Astrobiologists can work alone on  particular scientific questions,  
Astrobiologists can work alone on  particular scientific questions,  

but often astrobiologists from  different scientific disciplines  
but often astrobiologists from  different scientific disciplines  

work together to examine complex questions  that no one field can answer alone. 
work together to examine complex questions  that no one field can answer alone. 

When we think about life in other words, what we  immediately start to imagine is little green men  
When we think about life in other words, what we  immediately start to imagine is little green men  

or maybe tall intelligent species that invade  our home earth on their technologic spaceships. 
or maybe tall intelligent species that invade  our home earth on their technologic spaceships. 

But this is science fiction. Do you want to know what we  
But this is science fiction. Do you want to know what we  

really know about life in the universe? Well if we want to speculate about life,  
really know about life in the universe? Well if we want to speculate about life,  

in other words, what it could be?  One of the logical starting points  
in other words, what it could be?  One of the logical starting points  

(and maybe the only one!) is to  start by looking at our own planet. 
(and maybe the only one!) is to  start by looking at our own planet. 

In fact, for now, the only known  planet-hosting life is Earth! 
In fact, for now, the only known  planet-hosting life is Earth! 

You'd say this is pretty obvious, right? So what astrobiologist do next? 
You'd say this is pretty obvious, right? So what astrobiologist do next? 

They use a method called “the great analogy”.  In short terms, they use the knowledge that  
They use a method called “the great analogy”.  In short terms, they use the knowledge that  

they have from life on Earth,  how it originated and evolved. 
they have from life on Earth,  how it originated and evolved. 

Then they try to understand how to extrapolate  that knowledge to other environments in the  
Then they try to understand how to extrapolate  that knowledge to other environments in the  

universe, such as our solar system. That's why the understanding of the  
universe, such as our solar system. That's why the understanding of the  

origin of life on Earth is the main key  in order to give a push to astrobiology.
origin of life on Earth is the main key  in order to give a push to astrobiology.

The question now is...what do  we know about life on Earth? 
The question now is...what do  we know about life on Earth? 

We know that here on Earth life emerged around 3.8  billion years ago, probably in the deep oceans. 
We know that here on Earth life emerged around 3.8  billion years ago, probably in the deep oceans. 

Why? Well, we know that back then the  
Why? Well, we know that back then the  

earth was not the same as today. What do we mean? We mean that if you were here, you could have  
earth was not the same as today. What do we mean? We mean that if you were here, you could have  

not been able to breathe. Because there was no oxygen  
not been able to breathe. Because there was no oxygen  

at all, and there was no ozone layer! This means that we had a lot of radiation,  
at all, and there was no ozone layer! This means that we had a lot of radiation,  

and it brings us to the conclusion that  the first forms of life would have to be  
and it brings us to the conclusion that  the first forms of life would have to be  

anaerobic: they would have to avoid  radiations and to grow up without oxygen. 
anaerobic: they would have to avoid  radiations and to grow up without oxygen. 

That's why we think it originated in deep  oceans: there the radiation doesn't hit.
That's why we think it originated in deep  oceans: there the radiation doesn't hit.

These are our first clues about  what it takes for life to emerge:  
These are our first clues about  what it takes for life to emerge:  

liquid water and organic molecules. What we think is that the oceans  
liquid water and organic molecules. What we think is that the oceans  

brought the molecules around and  eventually the right molecules  
brought the molecules around and  eventually the right molecules  

met at the right time, and at the right place. That's how astrobiologists think life emerged. 
met at the right time, and at the right place. That's how astrobiologists think life emerged. 

Also, by looking at the different  life forms we study every day,  
Also, by looking at the different  life forms we study every day,  

we realize that biodiversity is amazingly big!  Every day we find a new variety of organisms  
we realize that biodiversity is amazingly big!  Every day we find a new variety of organisms  

that live in places that we  thought no life could ever exist. 
that live in places that we  thought no life could ever exist. 

They are called extremophiles. An extremophile (from Latin "extremus"  
They are called extremophiles. An extremophile (from Latin "extremus"  

meaning "extreme" and Greek philiā (φιλία) meaning  "love") is an organism with optimal growth in  
meaning "extreme" and Greek philiā (φιλία) meaning  "love") is an organism with optimal growth in  

environmental conditions considered extreme in  that it is challenging for a carbon-based life  
environmental conditions considered extreme in  that it is challenging for a carbon-based life  

form, such as all known life on Earth, to survive. These organisms are dominants in the evolutionary  
form, such as all known life on Earth, to survive. These organisms are dominants in the evolutionary  

history of the planet. Dating back to more than 40  million years ago, extremophiles have continued to  
history of the planet. Dating back to more than 40  million years ago, extremophiles have continued to  

thrive in the most extreme conditions, making  them one of the most abundant lifeforms. 
thrive in the most extreme conditions, making  them one of the most abundant lifeforms. 

These microorganisms can live  at temperatures above 100°C! 
These microorganisms can live  at temperatures above 100°C! 

Also, they live in acid rivers or very salty  lakes, and they help us set the limits of life. 
Also, they live in acid rivers or very salty  lakes, and they help us set the limits of life. 

Since one of the most extreme environment is  actually space, astrobiologists asked themselves:  
Since one of the most extreme environment is  actually space, astrobiologists asked themselves:  

can life survive in space?  That's why they have done a  
can life survive in space?  That's why they have done a  

lot of experiments in situ: they actually have  sent bacteria and other microorganisms to space,  
lot of experiments in situ: they actually have  sent bacteria and other microorganisms to space,  

put them on the outside of the  International Space Station,  
put them on the outside of the  International Space Station,  

where they are exposed to the real space  vacuum and the real space radiation,  
where they are exposed to the real space  vacuum and the real space radiation,  

so they stood there for months and what they  found out is that many of them actually survived.
so they stood there for months and what they  found out is that many of them actually survived.

This is a sort of revolution  because it makes us wonder where  
This is a sort of revolution  because it makes us wonder where  

else in the universe can life survive!
else in the universe can life survive!

so the first place we actually look,  of course, is our own solar system.  
so the first place we actually look,  of course, is our own solar system.  

We begin by looking at the moon, we went there.  There are not these teams, there is no life there,  
We begin by looking at the moon, we went there.  There are not these teams, there is no life there,  

but then we focus on other things. 
but then we focus on other things. 

“Before finding out what we found  about life in our solar system,  
“Before finding out what we found  about life in our solar system,  

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Europa, Jupiter's moon. Did you know that the  
Europa, Jupiter's moon. Did you know that the  

surface of Europa is made of water ice? Many scientists think that beneath the frozen  
surface of Europa is made of water ice? Many scientists think that beneath the frozen  

surface is a layer of liquid water, literally  an ocean! which is prevented from freezing by  
surface is a layer of liquid water, literally  an ocean! which is prevented from freezing by  

the heat from flexing.  How do we know it? 
the heat from flexing.  How do we know it? 

Evidence for this ocean includes geysers  erupting through cracks in the surface ice,  
Evidence for this ocean includes geysers  erupting through cracks in the surface ice,  

a weak magnetic field and chaotic terrain on  the surface, which could have been deformed  
a weak magnetic field and chaotic terrain on  the surface, which could have been deformed  

by ocean currents swirling beneath.  At the bottom of this ocean world, it is  
by ocean currents swirling beneath.  At the bottom of this ocean world, it is  

conceivable that we might find hydrothermal vents  and ocean floor volcanoes. On Earth, such features  
conceivable that we might find hydrothermal vents  and ocean floor volcanoes. On Earth, such features  

often support very rich and diverse ecosystems.  Could therefore Europa host (or have hosted) life?
often support very rich and diverse ecosystems.  Could therefore Europa host (or have hosted) life?

Titan, Saturn' moon. Titan is the only moon in the  
Titan, Saturn' moon. Titan is the only moon in the  

solar system with a substantial atmosphere. The atmosphere consists mostly of nitrogen,  
solar system with a substantial atmosphere. The atmosphere consists mostly of nitrogen,  

which is an important chemical element  used in the construction of proteins  
which is an important chemical element  used in the construction of proteins  

in all known forms of life.  Recently, radar observations have detected the  
in all known forms of life.  Recently, radar observations have detected the  

presence of rivers and lakes of liquid methane and  ethane and possibly the presence of cryovolcanoes. 
presence of rivers and lakes of liquid methane and  ethane and possibly the presence of cryovolcanoes. 

Cryovolcanoes are...volcanoes that  erupt liquid water rather than lava! 
Cryovolcanoes are...volcanoes that  erupt liquid water rather than lava! 

This suggests that Titan, like Europa,  has a subsurface reserve of liquid water. 
This suggests that Titan, like Europa,  has a subsurface reserve of liquid water. 

Although its distance from the sun (it's  very cold on Titan for liquid water!),  
Although its distance from the sun (it's  very cold on Titan for liquid water!),  

the bountiful chemicals available on Titan have  raised speculation that lifeforms – potentially  
the bountiful chemicals available on Titan have  raised speculation that lifeforms – potentially  

with fundamentally different chemistry from  terrestrial organisms – could exist there.
with fundamentally different chemistry from  terrestrial organisms – could exist there.

Mars. Mars is one of the most Earth-like worlds  
Mars. Mars is one of the most Earth-like worlds  

in the solar system. It has a 24.5-hour day, polar  ice caps that expand and contract with the seasons  
in the solar system. It has a 24.5-hour day, polar  ice caps that expand and contract with the seasons  

and a large array of surface features that were  sculpted by water during the planet’s history. 
and a large array of surface features that were  sculpted by water during the planet’s history. 

Scientists detected the presence of a lake beneath  the southern polar ice cap, which makes Mars a  
Scientists detected the presence of a lake beneath  the southern polar ice cap, which makes Mars a  

very interesting candidate for life.  They also found methane. 
very interesting candidate for life.  They also found methane. 

This is amazing because it could be produced  by biological processes, even though the actual  
This is amazing because it could be produced  by biological processes, even though the actual  

source for Mars' methane is not yet known.  We just have to keep hoping and bringing  
source for Mars' methane is not yet known.  We just have to keep hoping and bringing  

information from the Martian soil, maybe with  the fantastic help of Perseverance and Ingenuity!
information from the Martian soil, maybe with  the fantastic help of Perseverance and Ingenuity!

As one can imagine, while astrobiology  is a relatively young field,  
As one can imagine, while astrobiology  is a relatively young field,  

it has a secure and promising future. Astrobiology  research has a significant impact on how agencies  
it has a secure and promising future. Astrobiology  research has a significant impact on how agencies  

such as NASA and the European Space Agency  plan for current and future space missions.  
such as NASA and the European Space Agency  plan for current and future space missions.  

Many recent missions were launched with the  aim of exploring worlds in our own solar  
Many recent missions were launched with the  aim of exploring worlds in our own solar  

system, and find signs of past, present  or the precursors of life, including Mars. 
system, and find signs of past, present  or the precursors of life, including Mars. 

One of the most famous missions  was the Cassini mission,  
One of the most famous missions  was the Cassini mission,  

which gave us a better understanding of  Saturn and its moons (such as Titan). 
which gave us a better understanding of  Saturn and its moons (such as Titan). 

Today, we are waiting for the launch  of the James Webb Space Telescope,  
Today, we are waiting for the launch  of the James Webb Space Telescope,  

which will allow us to begin searching for  habitable planets outside our solar system.
which will allow us to begin searching for  habitable planets outside our solar system.

Communicating the discoveries and excitement  of astrobiology has been understood  
Communicating the discoveries and excitement  of astrobiology has been understood  

as a fundamental requirement since  the early development of the field.  
as a fundamental requirement since  the early development of the field.  

Meeting this objective has taken various forms.  One element was a common forum, embodied in the  
Meeting this objective has taken various forms.  One element was a common forum, embodied in the  

Astrobiology Science Conference held biennially,  that today attracts over 800 scientists from  
Astrobiology Science Conference held biennially,  that today attracts over 800 scientists from  

over 30 fields. With meetings in 2000, 2002,  2004 and 2006 that have continued to grow in  
over 30 fields. With meetings in 2000, 2002,  2004 and 2006 that have continued to grow in  

attendance, the conference remains a forum where  scientists are encouraged to push the boundaries.
attendance, the conference remains a forum where  scientists are encouraged to push the boundaries.

What about the future of astrobiology? On NASA's website we can read: 
What about the future of astrobiology? On NASA's website we can read: 

<
<<The first decade of astrobiology has laid  significant groundwork for the understanding  

of the genesis and evolution of life in the  universe. Fieldwork has provided fossils,  
of the genesis and evolution of life in the  universe. Fieldwork has provided fossils,  

organisms, and ecosystems that have all led  to significant insight into the early Earth,  
organisms, and ecosystems that have all led  to significant insight into the early Earth,  

possible models for origins and a huge expansion  of the recognized environmental limits of life.  
possible models for origins and a huge expansion  of the recognized environmental limits of life.  

Laboratory work, coupled with astronomical  observation, has added another significant  
Laboratory work, coupled with astronomical  observation, has added another significant  

piece of the puzzle and continues to provide clues  and refine models. Missions are just beginning  
piece of the puzzle and continues to provide clues  and refine models. Missions are just beginning  

to take astrobiology to entirely new levels of  understanding. Given the timeless fascination with  
to take astrobiology to entirely new levels of  understanding. Given the timeless fascination with  

questions of the origins and prevalence of life,  astrobiology will endure long into the future.>>
questions of the origins and prevalence of life,  astrobiology will endure long into the future.>>

"This video ends here! Thanks for watching  everyone! Is there something more you want  
"This video ends here! Thanks for watching  everyone! Is there something more you want  

to hear about astrobiology? Let  us know in the comments below! 
to hear about astrobiology? Let  us know in the comments below! 

See you next time on the channel!
See you next time on the channel!