international astronomical union / office of astronomy for development kevin govender –...
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International Astronomical Union / Office of Astronomy for Development
Kevin Govender – [email protected]
J.-C. Mauduit – [email protected]
OAD
www.astro4dev.org
IAU: International Astronomical Union
NRF: National Research Foundation
Dr. Jean-Christophe MauduitIAU Office of Astronomy for Development
From planets to superclusters of galaxies
The different scales of the Universe
National Research Foundation
From the Solar system to the Milky Way…
The blue planet: Earth
Radius ~ 6 378 km Atmosphere < 600 km
Troposphere < 15 km
From the Earth to the Moon
Earth-Moon distance: 384 401 km
30 Earth planets one after the other
~ 2 months of high speed train
Apollo missions : less than 2 days
(Speed of ~ 8000 km/h to ~ 40 000 km/h)
Space shuttle take-off
The crescent Earth from the Moon
You are here !
As imaged from the red planet, Mars
Our star, the Sun
Characteristics:
Radius~ 695,000 km
Mass = 1.9891×1030 kg
Volume = 1.41×1018 km³
Luminosity = 3.827×1026 W
Comparison to Earth:
109 × Earth
332 950 × Earth
1 300 000 × Earth
9.15 × 1016 tons of TNT / s
Distances in the Solar system
The astronomical unit (A.U.) is the Earth-Sun distance :
1 A.U. = 149 597 871 km
Voyager,The furthest probe sent by humans is at 12,5 billion kilometres of the Earth, hence 82 A.U. of us…
Sun 0 109
Mercury 0,39 0,38
Venus 0,72 0,95
Earth 1,0 1,00
Mars 1,5 0,53
Jupiter 5,2 11
Saturn 9,5 9
Uranus 19,2 4
Neptune 30,1 4
Pluto 39,5 0,18
MassDistance
The Solar system, as seen from the Voyager probe
Credits : Sonde Voyager
The speed of light
The Sun is at~ 8 light-minutes
The Voyager probe is at ~ 12 light-hours
c ~ 300 000 km/s
Light-minutes Astronomical Units
Average planet distances to the Sun
1 Light-year = 63240 Astronomical Units = 9,46 x 1012 km
The stars in the sky are similar to our Sun
But so far away that we see them as points of light
• Located at 4.22 Light-year from the Sun.
• Its light takes about 4 years to reach us
Proxima Centaurus,The closest star from our Sun
Stars sometimes form clusters
Messier 3 (M3) Star cluster
D (Sun– M3) ~ 34 000 light years
Before AfterThe Milky Way
The city sky
A little geography of our Milky Way
Magellanic cloudsGalactic bulbSpiral arms
The Milky Way, as seen from the inside
Two satellite galaxies of the Milky Way
The extragalactic domain
The extragalactic « nebulae »
M75
Star clusters belong to our
Galaxy
M32 M101
But these other diffuse objects are
galaxies
Voie LactéeVoie Lactée
Petit nuage de Magellan
Grand nuage de Magellan
Voie Lactée
Petit nuage de Magellan
Grand nuage de Magellan
Voie Lactée~ 160 000 l.y.~ 2.5 million l.y..
~ 200 000 l.y.
Our greatest neighbor, the “Andromeda” galaxy
D (Milky Way – M31) ~ 2.5 million l.y.r ~
50000 l.y.
M31 fait partie du groupe “ Local ” de galaxies …
1 Million Light Years
Our Galaxy
From Earth…
To the Local Group of galaxies
M74 : 30 million l.y.
Sombrero : 40 million l.y.
A compact group
500 000 l.y.
Hickson compact group 79
Virgo cluster
At ~ 60 Million Light Years
10 million l.y.
The large-scale structure of the Universe
Abell cluster 1689
10 million l.y.
Hubble Ultra-Deep Field
How many galaxies on this image?
!
2D view of galaxies in the sky as observed in infrared
… to the large-scale structure of the Universe
From the Perseus cluster…
~ 1 B
illion l.y
.
Large galaxy surveys generally focus on small portions of the sky
3D Diagram
~ 163 million l.y.
Scale:
100 Million l.y.
~ 26
0 M
illion
s l.y
.
The local group of galaxies within the local supercluster
The most distant galaxies ever observed
~ 11 Billion years
The “most distant” picture of the Universe at its “youngest”
The “beginning” of the Universe
Thank you!
Vidéos et Images d’astronomie
Loi de Hubble (1929)
v= H0 d
Edwin Hubble
Galaxie proche :
Galaxie distante :
From the ground
From space
M51 and its companion
Pairs of galaxies
In this computer simulation, one can see the formation of the large scale structures of the Universe
Groupe de galaxies : des galaxies en intéraction ?
Du visible … à la radio !
Elliptiques
Spirales
Les différents types de galaxies
simples
barrées