Week 1 :

I. a) Our view from the garden

"From now on, we live in a world where man has walked on the moon. It wasn't a miracle, we just decided to go."

Jim Lovell, Apollo 13

Texte 01 - Our view from the garden

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♦ Notes :

Our Milky Way galaxy (100.000 AL diameter, 200/400 billions stars) is then part of what's referred to as a Local Group of galaxies, which is a group of about 40 galaxies. The other largest member of the local group is the Andromeda galaxy. The Local Group is then embedded in what's called the Local Supercluster, which contains about 1,000 galaxies in a relatively small volume of space.

► Three conditions for a celestial object to be considered as a "planet" :

An object that orbits its star,
has enough mass for gravity to make it round-ish,
and has cleared other objects from its path.

Pluto hasn't got the third condition, it's situated in the Kuiper belt, so it's considered as a dwarf-planet.

We see Pluto as it was approximately about one light hour ago.

◄ solar system < star system < star cluster < galaxy < galaxy supercluster ◄

1 UA = 150.000.000 km Rotation ≠ Révolution

1 AL = 10¹⁶ m = 9 460,730 milliards de km = 10 trillion km

I. b) One to a Trillion

"The universe is a big place, perhaps the biggest."

Kurt Vonnegut.

Texte 03 - One to a trillion

text02_One_to_A_Trillion.pdf

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♦ Notes :

Proxima Centauri : nearest star from the sun; 4 light-years away

I. c) Space station Earth

Spaceship Earth: The problem for the passengers is that there is no manual to identify all the parts, and no instructions on how to operate the spaceship.

Richard Buckminster Fuller

Texte 03 - Space station Earth

text03_Space_Station_Earth_Final.pdf

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♦ Notes :

Inclinaison de la Terre : 23,5° en rapport au plan de l'écliptique

Rotation autour du centre de la galaxie : 230 millions d'années

Distance entre système solaire et centre : 28.000 AL

II. Patterns in the night sky

II. a) Sky dances

We had the sky, up there, all speckled with stars, and we used to lay on our backs and look up at them, and discuss about whether they was made, or only just happened.

Mark Twain, Huckleberry Finn

Texte 04 - Sky Dances

text04_Sky_Dances_Final.pdf

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♦ Notes :

6.000 étoiles visible max de nuit, 88 constellations et 13 dans le zodiaque

Ophiuchus est le 13e signe.

Elles traversent le ciel d'Est en Ouest de manière droite en suivant la forme d'un cercle. Il y a un pôle Nord sur cette sphère. Les étoiles qui se situent près du pôles sont les circumpolaires et sont visible dans tout l'hémisphère Nord.

A chaque instant, on peut voir qu'une seule moitié de la sphère céleste depuis la Terre.

Planets don't go around the earth like regular stars, they are the seven wanderers with an irregular motion.

Friday = Freyda's day Via Lactea = Voie Lactée

Les babyloniens comptaient sur des bases de 12. Ainsi, il y a 360° dans un cercle, car c'est divisible par 12 et proche de 365. 12 mois, 24 heures...

▬> Olber's paradox : Why is the sky dark at night ?

We should see a lot of stars evrywhere if the universe is infinite in space and in time...

▬> Edgar Allan Poe's answer : The universer might not be infinite at all !

II. b)Reason for the season

"All people everywhere should have free energy sources. Electric power is everywhere present in unlimited quantities, and can drive the world's machinery without coal, oil, or gas."

Nikola Tesla