Transcript Modern Telescopes and Ancient Skies

Modern Telescopes
and Ancient Skies
New Views of the Universe
An IU Lifelong Learning Class
Tuesdays, May 10, 17, 24
Size and
Scale
Surveying
the Universe
from the
Earth to the
farthest
reaches of
the visible
Universe
Our
closest
neighbor
Galileo Galilei's "The Phases of the Moon"
Image courtesy of Biblioteca Nazionale
Florence, Italy
Visualizing the
Earth from Space
• What do you see?
– Earth
– Moon
– Sun
– Stars
Copyright 1980 by DC Comics Inc.
Welcome to
Outer Space!
Moon
Radius: ¼ Earth’s radius
Distance from Earth:
384,000 km
Earth
Radius: 6400 km
Distance from Sun: 150,000,000 km
1 AU, 8 light minutes
Sizes of planets NOT to scale
Solar Distance to Pluto: about 40 AU
(about 320 light minutes)
System
The
Nearest
Stars
The closest star to our Sun is
Proxima Centauri, about 4 light
years distant.
Most of the stars
we see in the
sky are within
250 light years
Our Sector of the
Galaxy
The Sun lies along one of
our Galaxy’s spiral arms,
known as the Orion Arm
View of the
Milky Way
Galaxy
Our Milky Way galaxy
contains two hundred
billion stars.
The Sun is
about 26,000
light years
from the
center.
Our Milky Way
Galaxy is part of
a small cluster of
galaxies.
Our Local Group of
galaxies is part of a
larger supercluster
of galaxy groups.
Virgo
Supercluster
Galaxies and
clusters of galaxies
collect into vast
streams, sheets and
walls of galaxies.
The Visible
Universe
On the largest
scales, the
universe seems
to be more or
less uniform
With thanks to Bill Watterson, 1990
What will we cover?????
How telescopes work
Modern telescopes
Space telescopes
Future
Visiting
the Gemini
Observatory
telescopes
Kirkwood Obs
Sky viewing
This sketch of a telescope
was included in a letter
written by Giovanpattista
della Porta in August 1609
Beginnings…
Thomas Harriet’s
Drawings of the
Moon and Sun
Telescopes
and
how they
work
to
mirrors
from
lenses…
Technology
moves forward…
The 3.5-meter WIYN telescope
Kitt Peak, Arizona
New Telescope
Technology
 “Fast” mirror
 Lightweight mirror
 Mirror shape controlled
 Mechanically simpler
mount
 Temperature control
Casting
the WIYN
Mirror
Polishing
the WIYN
Mirror
The WIYN New Technology “Dome”




Compact telescope chamber
Open for ventilation
Insulated to keep cool
Heated spaces kept separate
Breaking the “cost curve”
New technology
provides better
performance at
lower cost
WIYN
WIYN TECHNOLOGY
in 6-8 meter telescopes
The importance
of image quality
text
typical groundbased image
Hubble image
WIYN image
The Ring Nebula
Connecting the First Nanoseconds to the Origin of Life
How is the Universe put together?
 The Wilkinson Microwave Anisotropy
Probe tells us about the state of the
Universe 400,000 years after the Big
Bang.
How did the Universe
evolve from this…
…to this?
Observing the assembly of galaxies
Intergalactic
gas
Galaxy
building blocks
observed with
Hubble
Clumps
concentrated
by dark
matter
lead to
galaxies
Simulation
The cosmic web of intergalactic gas
and galaxies in a young universe
WMAP also provides
evidence of the first stars
 Tiny fluctuations in
polarization
 About 200 million
years after the Big Bang
We can almost see the first stars
Green=hot gas
yellow=stars
What we might see with
a 30-meter telescope
(Barton et al., 2004)
Simulation
4 million LY
hydrogen emission
from hot stars
What is the Universe made of?
The composition of stars and gas:
90% hydrogen atoms
10% helium atoms
Less than 1%
everything else
everything
else
But ordinary matter is
only part of the story…
96% of the Universe is something else
Galaxy interactions require more
mass than we can see
Computer
simulation
The real
thing
Antennae Galaxy (HST)
Dark Matter
 The universe contains additional matter
we cannot see
 Dark matter interacts with normal
matter through gravity
 Dark matter does NOT interact with light
the way the normal matter does
 The Universe contains 5 or 6 times
MORE dark matter than normal matter
All galaxies are embedded in clouds of
dark matter
 We do not know what it is!
“Redshift”
of Galaxies
The spectra of galaxies are shifted to the
red: galaxies are moving away from us.
The farther away a galaxy is, the faster it
recedes from us!
Hubble’s Law
Distance (LY)
3000
2000
1000
Distance - Velocity Relation
0
0
20000
Velocity (km/sec)
40000
The brightness of stellar
explosions tells us how
far away galaxies are
The speeds of very distant
galaxies tell us the Universe
is expanding faster today
than in the past
The Universe is speeding up!
The universe is expanding faster
today than it did in early times
This expansion cannot be caused
by ordinary or dark matter,
which slows expansion.
The acceleration suggests a new
repulsive force (anti-gravity)
acting on very large scales
The New Force Is Called
“Dark Energy”
Dark energy accounts for 73% of the
content of the universe
Dark matter accounts for 23%
The content we’re familiar with is only 4%
What is Dark Energy?
We don’t know
Identifying what dark
energy is requires bigger
telescopes and new
techniques
Connecting the First Nanoseconds to the Origin of Life
Kirkwood Observatory Viewing
Tuesday evenings, weather permitting
Night Sky
Viewing
• Scheduled nights
–Tuesday, May 17
–Tuesday, May 24
• Roof of Swain West
Next Week
• Telescopes in Space,
including the Hubble Space
Telescope
• New Views of the Universe
– Planets around other Suns
• Kirkwood Obs and Rooftop,
weather permitting
Is there life elsewhere?
More than 150
planets found
around other
stars
Most are vastly
different from
our Solar System
Artist’s conception of 55 Cancri’s planetary system
Detecting
Planets
detecting planets directly is hard
planets are small and dim
planets are near much brighter stars
detecting planets directly requires
large telescopes (30-meters) and/or
special instruments
Imaging planets around other stars
Gemini/Keck AO detection
by Michael Liu (IfA), 2002
“Brown Dwarf”
orbiting a star
at the same
distance as
Saturn from
our Sun
Simulation of the spectra of 55 Cancri’s planets
With a 30-meter
telescope we can
obtain the spectra
of planets around
other stars to search
for the signatures
of life
Simulation by Sudarsky
et al. 2003