it is a lark winter night and the city
is getting ready to go to sleep in a big
apartment building a kitchen window is
lit on the other side a young woman and
her daughter are looking into the
darkness and pointing at the Stars
the woman is telling stories feeding the
growing curiosity of her daughter but
questions keep coming if I had to look
back that would be the first time I
recall looking up at the sky we all
share similar memories stargazing nights
with family or friends
hoping to see a shooting star to make a
wish and I wonder how many of you tried
to count stars how many of you felt
intimidated by the size of the universe
and how many of you have fallen asleep
while stargazing over time I managed to
answer some of the questions that
intrigued me back then but I’m still
working on others this is a bit
embarrassing but up until I was four or
five I was convinced at the sky with the
Sun during the day and the moon and the
stars during the night were just theater
curtains that someone was in charge of
changing I was not sad though when I
learned the truth because it opened me
the door to all of possibilities
according to the oxford dictionary
astronomy is the scientist Sally’s
celestial objects the space and the
universe as a whole is that clear
perhaps not much what do we understand a
celestial objects the definition can be
used all the way from meteorites which
can be as small as a grain of Sun up to
planets or stars or even whole galaxies
so pretty much everything that lies
beyond our atmosphere
nowadays we the astronomers prefer to be
called astrophysicists in order to
respect the professional feel of the
astrologist trust me
I’ve lost count of the number of times
that I’ve been asked to read a hand or
to do a horoscope
yes we study the Stars no we don’t
predict people’s fortunes and what does
astronomy have in particular that has
made us wonder for generations questions
about where we come from or whether we
are alone in the universe have filled
our imaginations for centuries producing
cultures rich in myth but that’s not
what Falls mine don’t get me wrong we
all like a bit of alien debate over a
veer from time to time but that’s not my
thing
what makes me wonder are the scales or
the sizes I remember a visit I did to
the Sequoia National Park a couple of
years ago I was walking through the
forest and I saw the sign that said how
big is big and I was extending next to
the sign which was already taller than
me next to one of those immense sequoias
and it made me feel small and
insignificant and I had the same feeling
in astronomy the time over which
processes happened the masses of the
objects and the distances between them
there are all in normal skills and
they’re almost impossible to imagine I
know you’ve heard comparisons to
thousands of millions of stadiums but I
know that doing those comparisons with
everyday objects does not help to better
understand the concepts so the question
is how big is weak even in astronomy
that is a tough question what we call a
small and large will depend on our fill
of a study if you are someone that is
working with planets they will tell you
that a star is quite large but if you
are someone that is working with the
structure of the universe they will tell
you the rest are is like me next to the
Sequoia just insignificant but it is not
all about the size or so they say
what really makes me wonder is the
interplay between those scales how the
large scales determine what the small
ones can do how the small scale
processes work together to shape the big
picture here is an image of the
Andromeda galaxy also known as an 31
among the galaxies that surround us this
is a brightest one to the extent that it
can be seen with a clear with your naked
eye on a clear night do you see it’s
this cloud shape by developing an
observational II testing theories of
galaxy formation we have learned that
galaxies form from the contraction of a
big halo of gas and the only reason why
this gas can collapse is because it can
lose energy thanks to the interactions
among the atomic on the atomic level so
it is those interactions among the atoms
that compose the gas where allows the
gas to collapse and settle into the disk
of the galaxy this constant interplay of
scales might seem difficult to
understand at first but we have a tool
to shed light on it and it’s called the
scientific method this method allows us
to learn from nature with just five
steps first one formulation of a
question we observe a phenomena in
nature
that we want to learn about and so we
formulate a simple question about it
second hypothesis from what we already
know we can touch her what the answer
can be third prediction this one is
especially relevant scientific models
and theories not only are capable of
describing nature but they’re also
capable of predicting events for the
testing this is the most well known
because here is where the actual
experiments are being performed and five
analysis with this we can evaluate
whether our hypothesis is correct or not
different Sciences may refer on the way
they do the testing a step but they are
all use the scientific method to bill
knowledge
for example if you ask biologists how do
they face research that will tell you
how the most important thing is to be
able to control all the variables that
may play a role in whatever it is that
you want to study and then they will
start talking about also experiments
that can be done in which they can
replicate over and over the exact same
conditions in order to investigate what
are the most relevant variables in
astronomy we cannot do that imagine you
want to study how a galaxy like
Andromeda here forms what can we do in
the same way that paleontologists can
reconstruct the evolutionary trajectory
of a given species using only fossils
which are fragments of that history we
must construct the formation history of
OVA galaxies using only examples similar
to that galaxy and sometimes actual
glimpses into the past with that we can
put forward theories to try to explain
these processes and then we try to prove
those theories wrong once we’ve proven
them wrong because that will happen you
have to test the theory and try again
these theories are never set in stone
but they are constantly developing to
better describe what we observe there’s
another solution and that is to put all
our knowledge into a computer to create
a beautiful galaxy in a simulation to
actually replicate how the birth of that
galaxy has been numerical simulations
are very important in astronomy because
they allows us to change the properties
of the universe and so to build a bridge
between observations and the models like
in the real universe our simulated
galaxies are made of particles but
because we do not have the computational
power available to treat each star in
your galaxy individually what we call
particles actually correspond to chunks
of mass that can correspond up to
several millions of stars like the Sun
there is not what one things by the word
particle right
to design these big numerical
simulations we first need to think how
different physical processes will affect
one of our particles and then we grow a
code in which we simulate all those
different physical processes for several
millions of particles once we’ve run the
simulation we can compare the results
with the observations to see whether the
physical ingredients that we have
implemented in our simulation correctly
describe the observed properties of the
galaxies or not designing one of these
big numerical simulations is not a
trivial problem because there’s many
many physical mechanisms and need to be
accounted for another very important
issue is the number of particles that we
use to describe these galaxies the
smaller the number of particles the
faster we can run our simulation but the
less information we’re going to obtain
out of it so we have to constantly
trade-off between computational speed
and precision I am a PhD student at the
University of Heidelberg and I’m not
interested interested as much in these
objects but actually in these dollars
which are called stellar clusters a
stellar cluster is a group of stars that
has formed at the same time in the same
place of the galaxy and there is held
together by the gravitational
interaction among each other here is
another image of the Andromeda galaxy do
you see that in the bottom right corner
there is a blue circle that circle
corresponds to its brightest a stellar
cluster in that galaxy and you can see
that there’s quite a difference between
a stellar cluster and a galaxy my field
has developed mainly from observations
and over the years people have found
many different types of a stellar
clusters being the two most well-known
these two which are called
open clusters or globular clusters the
first time they’re heard about these
objects I was on my second year of uni
back in Barcelona and the finger I most
clearly remember about that lecture is
how much they emphasized on the
differences between them open clusters
are young the
have very few stars and some diffuse gas
whereas chloral clusters are old they
have up to several thousands of a stars
and they have no guys at all
so the question is how did these objects
form here there’s a bit of debate as
usual seeing how different the
properties are some people suggest that
these objects form following two
complete different physical processes
and that you cannot compare them in any
way on the other hand there are some
other people who suggest that these
objects form following the same physical
process but because these objects are
orbiting in the galaxies and so they’re
evolving inside of that galaxy what
happens throughout the life will modify
their aspect and so will change how we
see them nowadays I’m working with that
second hypothesis and it is not a
trivial problem because we have to work
from the largest scales of how does the
galaxies form and evolve through cosmic
time down to the smaller scales of how
the the clusters form from the gas
sitting in the galaxies and how they
evolve inside of that galaxy and how
they keep interacting with that gas
throughout their lifetimes in order to
work with certain interplay of scales I
have to use numerical simulations which
allow me to replicate how galaxies and
clusters form evolve and interact
through our LED throughout their
lifetimes
I will end up comparing my simulations
with observations those are which will
allow me to evaluate our hypothesis on
the stellar cluster formation thus
fulfilling the last step of the
scientific method the complexity of
interplays of scales may obscure the way
to the truth behind it but armed with a
scientific method and some Efrain
dedication I know I can light my way out
from the darkness thank you
you
is getting ready to go to sleep in a big
apartment building a kitchen window is
lit on the other side a young woman and
her daughter are looking into the
darkness and pointing at the Stars
the woman is telling stories feeding the
growing curiosity of her daughter but
questions keep coming if I had to look
back that would be the first time I
recall looking up at the sky we all
share similar memories stargazing nights
with family or friends
hoping to see a shooting star to make a
wish and I wonder how many of you tried
to count stars how many of you felt
intimidated by the size of the universe
and how many of you have fallen asleep
while stargazing over time I managed to
answer some of the questions that
intrigued me back then but I’m still
working on others this is a bit
embarrassing but up until I was four or
five I was convinced at the sky with the
Sun during the day and the moon and the
stars during the night were just theater
curtains that someone was in charge of
changing I was not sad though when I
learned the truth because it opened me
the door to all of possibilities
according to the oxford dictionary
astronomy is the scientist Sally’s
celestial objects the space and the
universe as a whole is that clear
perhaps not much what do we understand a
celestial objects the definition can be
used all the way from meteorites which
can be as small as a grain of Sun up to
planets or stars or even whole galaxies
so pretty much everything that lies
beyond our atmosphere
nowadays we the astronomers prefer to be
called astrophysicists in order to
respect the professional feel of the
astrologist trust me
I’ve lost count of the number of times
that I’ve been asked to read a hand or
to do a horoscope
yes we study the Stars no we don’t
predict people’s fortunes and what does
astronomy have in particular that has
made us wonder for generations questions
about where we come from or whether we
are alone in the universe have filled
our imaginations for centuries producing
cultures rich in myth but that’s not
what Falls mine don’t get me wrong we
all like a bit of alien debate over a
veer from time to time but that’s not my
thing
what makes me wonder are the scales or
the sizes I remember a visit I did to
the Sequoia National Park a couple of
years ago I was walking through the
forest and I saw the sign that said how
big is big and I was extending next to
the sign which was already taller than
me next to one of those immense sequoias
and it made me feel small and
insignificant and I had the same feeling
in astronomy the time over which
processes happened the masses of the
objects and the distances between them
there are all in normal skills and
they’re almost impossible to imagine I
know you’ve heard comparisons to
thousands of millions of stadiums but I
know that doing those comparisons with
everyday objects does not help to better
understand the concepts so the question
is how big is weak even in astronomy
that is a tough question what we call a
small and large will depend on our fill
of a study if you are someone that is
working with planets they will tell you
that a star is quite large but if you
are someone that is working with the
structure of the universe they will tell
you the rest are is like me next to the
Sequoia just insignificant but it is not
all about the size or so they say
what really makes me wonder is the
interplay between those scales how the
large scales determine what the small
ones can do how the small scale
processes work together to shape the big
picture here is an image of the
Andromeda galaxy also known as an 31
among the galaxies that surround us this
is a brightest one to the extent that it
can be seen with a clear with your naked
eye on a clear night do you see it’s
this cloud shape by developing an
observational II testing theories of
galaxy formation we have learned that
galaxies form from the contraction of a
big halo of gas and the only reason why
this gas can collapse is because it can
lose energy thanks to the interactions
among the atomic on the atomic level so
it is those interactions among the atoms
that compose the gas where allows the
gas to collapse and settle into the disk
of the galaxy this constant interplay of
scales might seem difficult to
understand at first but we have a tool
to shed light on it and it’s called the
scientific method this method allows us
to learn from nature with just five
steps first one formulation of a
question we observe a phenomena in
nature
that we want to learn about and so we
formulate a simple question about it
second hypothesis from what we already
know we can touch her what the answer
can be third prediction this one is
especially relevant scientific models
and theories not only are capable of
describing nature but they’re also
capable of predicting events for the
testing this is the most well known
because here is where the actual
experiments are being performed and five
analysis with this we can evaluate
whether our hypothesis is correct or not
different Sciences may refer on the way
they do the testing a step but they are
all use the scientific method to bill
knowledge
for example if you ask biologists how do
they face research that will tell you
how the most important thing is to be
able to control all the variables that
may play a role in whatever it is that
you want to study and then they will
start talking about also experiments
that can be done in which they can
replicate over and over the exact same
conditions in order to investigate what
are the most relevant variables in
astronomy we cannot do that imagine you
want to study how a galaxy like
Andromeda here forms what can we do in
the same way that paleontologists can
reconstruct the evolutionary trajectory
of a given species using only fossils
which are fragments of that history we
must construct the formation history of
OVA galaxies using only examples similar
to that galaxy and sometimes actual
glimpses into the past with that we can
put forward theories to try to explain
these processes and then we try to prove
those theories wrong once we’ve proven
them wrong because that will happen you
have to test the theory and try again
these theories are never set in stone
but they are constantly developing to
better describe what we observe there’s
another solution and that is to put all
our knowledge into a computer to create
a beautiful galaxy in a simulation to
actually replicate how the birth of that
galaxy has been numerical simulations
are very important in astronomy because
they allows us to change the properties
of the universe and so to build a bridge
between observations and the models like
in the real universe our simulated
galaxies are made of particles but
because we do not have the computational
power available to treat each star in
your galaxy individually what we call
particles actually correspond to chunks
of mass that can correspond up to
several millions of stars like the Sun
there is not what one things by the word
particle right
to design these big numerical
simulations we first need to think how
different physical processes will affect
one of our particles and then we grow a
code in which we simulate all those
different physical processes for several
millions of particles once we’ve run the
simulation we can compare the results
with the observations to see whether the
physical ingredients that we have
implemented in our simulation correctly
describe the observed properties of the
galaxies or not designing one of these
big numerical simulations is not a
trivial problem because there’s many
many physical mechanisms and need to be
accounted for another very important
issue is the number of particles that we
use to describe these galaxies the
smaller the number of particles the
faster we can run our simulation but the
less information we’re going to obtain
out of it so we have to constantly
trade-off between computational speed
and precision I am a PhD student at the
University of Heidelberg and I’m not
interested interested as much in these
objects but actually in these dollars
which are called stellar clusters a
stellar cluster is a group of stars that
has formed at the same time in the same
place of the galaxy and there is held
together by the gravitational
interaction among each other here is
another image of the Andromeda galaxy do
you see that in the bottom right corner
there is a blue circle that circle
corresponds to its brightest a stellar
cluster in that galaxy and you can see
that there’s quite a difference between
a stellar cluster and a galaxy my field
has developed mainly from observations
and over the years people have found
many different types of a stellar
clusters being the two most well-known
these two which are called
open clusters or globular clusters the
first time they’re heard about these
objects I was on my second year of uni
back in Barcelona and the finger I most
clearly remember about that lecture is
how much they emphasized on the
differences between them open clusters
are young the
have very few stars and some diffuse gas
whereas chloral clusters are old they
have up to several thousands of a stars
and they have no guys at all
so the question is how did these objects
form here there’s a bit of debate as
usual seeing how different the
properties are some people suggest that
these objects form following two
complete different physical processes
and that you cannot compare them in any
way on the other hand there are some
other people who suggest that these
objects form following the same physical
process but because these objects are
orbiting in the galaxies and so they’re
evolving inside of that galaxy what
happens throughout the life will modify
their aspect and so will change how we
see them nowadays I’m working with that
second hypothesis and it is not a
trivial problem because we have to work
from the largest scales of how does the
galaxies form and evolve through cosmic
time down to the smaller scales of how
the the clusters form from the gas
sitting in the galaxies and how they
evolve inside of that galaxy and how
they keep interacting with that gas
throughout their lifetimes in order to
work with certain interplay of scales I
have to use numerical simulations which
allow me to replicate how galaxies and
clusters form evolve and interact
through our LED throughout their
lifetimes
I will end up comparing my simulations
with observations those are which will
allow me to evaluate our hypothesis on
the stellar cluster formation thus
fulfilling the last step of the
scientific method the complexity of
interplays of scales may obscure the way
to the truth behind it but armed with a
scientific method and some Efrain
dedication I know I can light my way out
from the darkness thank you
you
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