How BIG is the Universe?

A Photographic Tour

Apollo 17 Lunar Rover(scale: a few metres)

Space Shuttle, Columbia(scale: 100 metres)

Barringer Crater, Arizona(1.2 km diam, 200 m deep - 50 m diam asteroid at 11 km/s)

Earth(diam 12,756 km)

Cloud covered Venus(0.95 Earth diameters)

Mercury(0.38 Earth diameters)

The Moon(0.27 Earth diameters)

The Sun(diam 1 392 000 km or 109 Earth diameters,

distance 150 000 000 km or 1 astronomical unit - 1 AU)

Eclipse of the Sun by the Moon as seen from Antarctica(both subtend almost exactly the same angle

of half a degree at the Earth)

Mars - the Red Planet(0.53 Earth diam)

Surface of Mars

Phobos and Deimos(max lengths 28 and 16 km)

Orbits of the planets to scale

Asteroid Gaspra(20 km long)

Jupiter and its Great Red Spot (11.2 Earth diam,distance 5.2 AU)

Jupiter’s cloud belts as seen by the Cassini spacecraft

Jupiter with (top to bottom)Io, Europa, Ganymede and

Callisto

Io and its sulphur volcanoes(0.28 Earth diam, 1.04

Moon diam)

Ganymede, largest moon

in the Solar System (0.41 Earth diam,1.51 Moon diam)

Not all Jupiter’s moons are large:Thebe (100 km), Amalthea (270 km max) and Metis (40 km)

Saturn and its beautiful rings(9.4 Earth diam at 9.6 AU)

Orbits of the planets to scale

Uranus, the tilted planet(4.0 Earth diam

at 19.2 AU)

Neptune(3.9 Earth diam

at 30.1 AU)

Pluto and Charon - double planet(0.18 and 0.09 Earth diam

1.54 Earth diam apartat 29.7 to 49.4 AU from Sun)

Comet Hale-Bopp in March 1997

A comet tail can be over 1 AU long,but its nucleus measures only a few km across

Comet Halley and the Milky Way

Southern Pinwheel Galaxy

15 million light years away and similar to the Milky Way

How the Milky Way might look seen edge-on

160 million light years

Sun

Size of the Milky Way Galaxy

Sombrero Galaxy

Whirlpool Galaxy

Andromeda Galaxy(2.5 million light years away -

most distant naked eye object)

Giant Elliptical Galaxy M87in Virgo Cluster

50 million light years away

Virgo Cluster of Galaxies1500 galaxies

9 million light years across50 million light years away

ComaCluster

Hubble Deep Field showing galaxies over 10 billion light years away (looking back in time to near the

beginning of the universe)

How the Milky Way might look seen edge-on

160 million light years

Sun

The Milky Way as seen from Australia

(Notice the pink nebulae where new stars are forming)

Milky Way with Faulkes Telescope in Australia in foreground

The constellation of Orionand the Milky Way

(The bright stars we see here are no more than a few hundred light years away)

Betelgeuse

Rigel

OrionNebula

Orion Nebulaa small star forming region about 1 light year across

New solar systems forming in Orion

New stars forming in pillars of molecular hydrogen and dust that are light years in length (in Eagle Nebula)

Pleiades and Hyadesstar clusters

(with Jupiter and Saturn)

Betelgeuse - a Red Supergiant star(big enough to reach the orbit of Jupiter)

Life Cyclesof Stars in Outline

The Life Cycles of Stars in Outline

Cloud of dust and gas

Main Sequence star

Low mass star High mass star Very high mass star< 4 solar masses 4 to 25(?) solar masses > 25 (?) solar masses

Red giant Red supergiant Red supergiant

White dwarf and

planetary nebula

Neutron star and

supernova remnant

Black hole and

supernova remnant

< 1.4 solar masses > 3 to 5 (?) solar masses

Contracts under gravity andheats up until eventually

thermonuclear reactions start

Expands Expands

Explodes as asupernova

Explodes as asupernova

Loses outer layers

Expands

(Most of a star's life)

Helix Planetary Nebula (1.5 light years across)

White dwarf star(remains of core of star and about size of the Earth)

Planetary nebula(remains of outer layers of star)

Cat’s Eye Planetary Nebula and white dwarf(A solar mass white dwarf would be only as big as the Earth)

Cocoon Planetary Nebula

Ring Planetary Nebula

Abell Planetary Nebula

Crab Nebula a supernova remnant - remains of a star that exploded

10 light years across

neutron star about 10 kmacross is at centre (not visible)

Vela or GumNebula

A Black Hole

(“Radius” of a 10 solar mass black hole would be only 30 km)

A black hole a few million times the mass of the Sun lurks at the centre of our galaxy and causes nearby stars to orbit very

rapidly

How Orion would look if you were near a black hole (computer simulation)

Gravitational lensing by a galaxy cluster 2 billion light years away bends light from a galaxy so far away that its light has been travelling for 95% of the age of the Universe

The End