OPTI’mag is the scientiﬁc PhD students’ newletter from Caen, members
of
OPTIC
association.
EDITO
In this issue :
– Article about Fermi’s paradox
– Article about the PhD...
OPTIC
Organisation for PhD sTudents
Interdisciplinary
in
Caen is an association for all
PhD students in scientiﬁc subjects, in Caen. PhD students
are considered members
if they are in the following
laboratories :
CIMAP, CRISMAT, ESITC, GANIL, GREYC, M2C, LMNO, LCS,
LPC and LUSAC.
OPTIC Ofﬁce hours
Tuesday and Thursday,
from 1:00 p.m. to 2:00 p.m.
Place : ENSICAEN, Campus 2
The Doctoral School Days (DSD) is an event for all PhD students
of the SIMEM Doctoral School. DSD are organized by the DSD
Committee, and consist exclusively of volunteer PhD students
from SIMEM. It is an opportunity for you to discover other PhD
student’s work and learn about their subjects. Like the past DSD,
students can present their work in the form of an oral or poster
presentation, which should be understandable by any scientiﬁc
PhD students.
1. Discover other PhD topics !
2. Have a break from your damn PhD subject !
3. Meet people at the coffee breaks
4. The social dinner
1. Train yourself to present your subject
2. Improve your English !
3. Tell us why your subject is fabulous !
4. Try to win amazing awards ;)
1. Learn to organize scientiﬁc events
2. Choose the guest lecturers, the menu, the awards, the special activities, etc...
3. Bring your own ideas in order to make DSD better and funnier !
4. We are nice and we make cookies ;)
Local OPTIC
The next DSD will be around the 25th of June. Information will
come soon.
In charge of the newsletter : L. Augey
Newsletter committee : F. V. Ferrari
Contact : [email protected] [email protected]
Website : http ://assoc-optic.fr/ https ://www.facebook.com/orga.optic
Thanks : B. Dechenaux, H. Ben-Ammar, G. Jolly
Fermi’s paradox : « Where is everybody ? »
Scientiﬁc Culture
Fermi’s paradox originates from the apparent contradiction between a high probability
of existence of one or more extraterrestrial
civilization and humanity’s lack of evidence for
such civilization. Indeed, despite the colossal
distances involved when talking about interstellar travels, physicist Enrico Fermi realized
that the entire colonization of our Milky Way
by an advanced civilization could happen very
fast.
In 1950, while working at Los Alamos, Fermi
had a casual conversation during lunch with
some colleagues about the recent spate of
UFO reports and the chances of observation
of extraterrestrial civilizations in a close future. The conversation shifted to other subjects, until Fermi suddenly exclaimed « Where
is everybody ?».
Fermi was known for his ability to make accurate estimates from basic principles and minimal amount of data (a.k.a Fermi estimates). We
will here follow Fermi’s original thought experiment.
Let’s suppose the existence of an advanced
civilization willing to explore and colonize our
galaxy. For this noble purpose, two spaceships
are built, each capable of enduring the tough
conditions of long interstellar travels and with
enough space to welcome an entire colony
that will live, die and reproduce during the trip.
Once constructed, the spaceships are sent to
the two closest stars (for the sake of brevity,
we’ll suppose that each solar system in the galaxy has an habitable planet...) in order to colonize thas sytem. Once they’re settled, each
colony has the mission to build two spaceships,
that will colonize two other systems, etc...
Let’s now do a bit of maths. We will suppose
that the extraterrestrial civilization considered
can build spaceships going at a speed of 0,01c
(with c being the speed of light : c = 300 000
km/s. Apollo 11 top speed was something like
0,0001c but it wasn’t designed for long trips. If
you can manage to keep a steady acceleration of let’s say 1g during 6 years, it’ll be enough
to reach 0,01c). The average distance between
stars in the Milky Way is about 5 light years.
So each spaceship will take something like 500
years to reach the closest star.
Let’s suppose that each colony needs 500 supplementary years once settled to achieve the
construction of their two brand new spaceships. The total time between two launches of
spaceships is therefore 1000 years.
There are about 1011 stars in the galaxy. How
long would it take for the civilization to visit all
of them ? The answer is easy : the number of
spaceships is doubled at each generation. After k generations, the number N of visited stars
is therefore :
N=
k
X
2i
i=1
A basic calculation shows
that the humongous amount
of stars in the galaxy would
be explored in about ... 40
generations ! ! With 1000 years
per generation, our galaxy
would have been entirely
colonized by the extraterrestrial civilization in a
’ridiculous’ 40 000 years ! So,
like Fermi we can ask ourselves : Where is everybody ?
Benjamin DECHENAUX
LPC, Post-Doc
Ref. : www.xkcd.com
OPTI’mag #2 - May/June 2015
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Do not be afraid : everything will be alright
PhD Students’ life
Raiders of the Lost Ark
Without really knowing where we are going,
a thesis topic is deﬁned within a scientiﬁc ﬁeld
more or less related to our previous studies.
A "supervisor" (a word still unclear at this time)
is going to trust us and allow us to begin research work. Some time later, it is time to
present our thesis subject and research, more
or less relevant, done on the ﬁeld. This is when
we realize they do not understand us. Worse,
we do not even understand ourselves. Tedious
work will then begin to assemble a mountain
of knowledge and position ourselves versus
existing work. A bit of motivation later, we are
not far from communicating about our work.
If you don’t ﬁnd anything, keep
looking
Regardless of the form of communication,
we are ﬁnally understood and we feel like a
"padawan" scientist, ready to improve science
and to represent our research team in front
of a group of students or an audience during a conference. However, new issues are
incoming. As we begin to become clear to ourselves, people are still confused about our me-
OPTI’mag #2 - May/June 2015
thod. This is the time to ask ourselves the right
questions. Perseverance and working capacity are to be proven again. The time seems
long, but it ﬂies, and it ﬂies rather quickly. Some
complementary activities of research work, although time consuming, place us on the front of
the stage : teacher, communicator at a conference or scientiﬁc mediation workshop. Then
we make notice of our large range of skills.
A light at the end of the tunnel
In hard times, the student can count, or not,
on the support of his supervisor, colleagues
or family. The exercise of synthesis begins. We
have few months to write the manuscript. We
have to summarize three years of work and
link the various works done. Tedious work begin again. We will our tear his hair for months
to prepare the ﬁnal defense, still and still writing in order to achieve a complete and accurate document. Finally, the student becomes a
doctor, a "master of the science".
Germain JOLLY
GREYC, 3rd year PhD
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Fête de la Science
Games and Events
Game : Killer Sudoku
You have standard squares that
you will need to ﬁll with the usual
rules. But, if you look closer, you’ll
notice regions circled with dashed
lines ! OMG !
In each one, you have a number,
each number has to be the sum of
the numbers inside each region.
The ﬁrst PhD student who come
during OPTIC ofﬁce hours with
the grid completed will receive
an award !
the
longest
possible solar
eclipse is 7.31
minutes
Fête de la Science
This year, the Fête de la
Science will take place from 7
to 11 October 2015. It is a national event that aims to popularize science among the general public.
Like last year, the association OPTIC wants to provide
an opportunity for PhD students to contribute with their
own stand / project, regardless of what their laboratories present.
If you have ideas or want to help organize this event, we
encourage you to come and talk to the Bureau of OPTIC.
OPTIC must send the list of projects before the 22nd of May
2015. If you want to suggest something or if you have questions, contact us now !
OPTI’mag #2 - May/June 2015
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