Transcript Lecture 2: ppt, 5 MB

Modern Telescopes
and Ancient Skies
New Views of the Universe
II. Space Telescopes
An IU Lifelong Learning Class
Tuesdays, May 10, 17, 24
Space
Telescopes
NASA’s four Great Observatories
Visible – Hubble Space Telescope
Gamma rays - Compton Gamma Ray Obs.
X-rays - Chandra X-ray Observatory
Infrared - Spitzer Space Telescope
Electromagnetic Spectrum
Hubble
Trivia
Launched April 24, 1990, by
Space Shuttle Discovery
First space-based visiblelight telescope
Also ultraviolet and nearinfrared
Orbits about 380 miles (611
km) above Earth
Named after astronomer
Edwin Hubble
discovered galaxies beyond
our Milky Way
determined that space is
expanding
More
Hubble
Trivia
The size of a school
bus
43.5 feet (13.3 m)
long
“weighs” more than
12 tons (11,000 kg)
Primary mirror 94.5
inches wide (2.4 m)
The wings are solar
panels that power the
Keeping track
of Hubble
Where is Hubble now?
hubblesite.org/fun_.and._games
When can I see Hubble?
www.heavens-above.com
Hubble’s greatest
achievements
Dark Energy
Age of the Universe
Baby galaxies
Chemical makekup
of extra-solar
planets
Black holes in
galaxies
Powerful stellar
explosions
 Source of quasar
light
Forming Planets
Comet impact on
Jupiter
Deaths of stars
Beginning
with
Dark Energy
What is the Universe made of?
Ordinary matter is only part of
the story…
96% of the Universe is something else
“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
Space and
Ground in
Partnership
 Supernova brightness
measure with Hubble
Velocities measured
from the ground
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
The Age
of the
Universe
 One of Hubble's key observations
 Cepheid variable stars in the Virgo cluster
 Hubble narrowed the age to 13 - 14 billion years
Baby Galaxies
Hubble Deep Fields
Great Observatories Origins Deep Survey
Hubble Ultra Deep Field
 Deepest images of the most distant galaxies
 A scrapbook of the early universe
 Hubble images reveal "toddler" galaxies 400 to
800 million years after the Big Bang
 Unlike the Milky Way, baby galaxies take many
shapes
 toothpicks
 links on a bracelet
 Hubble lets us witness how galaxies form
 By studying galaxies at different eras, we can
see how galaxies change over time.
Planets around
other stars
 Ground-based telescopes find planets
 Hubble can measure their chemical makeup
 sodium, hydrogen, carbon, and oxygen in the atmosphere
of a Jupiter-sized planet
 Does life exist on extra-solar planets?
 Hubble also measured the masses of two distant
worlds
 One is the oldest known planet - 13 billion years
Monster
Black
Holes
The centers of galaxies contain black holes
with masses millions to billions times that of
our Sun
Big galaxies contain big black holes, small
galaxies have mall black holes
Black holes may grow with their galaxies,
feasting on gas and stars swirling around the
hearts of those galaxies.
Biggest
Booms
Gamma ray bursts
are the most
powerful explosions
in the universe
 Hubble showed that these brief, bright flashes
come from distant galaxies forming stars at
enormously high rates
 The "bursts“ are the collapse of massive stars
 A nearby gamma ray burst would burn away the
ozone in Earth's atmosphere
Quasar
Light
Quasars are no larger
than our solar system
but outshine galaxies
of hundreds of billions
of stars.
 Hubble tracked down the "homes" of quasars,
proving that these dynamos reside in the
centers of galaxies
 Quasars are massive black holes swallowing
stars and has from their host galaxies
Building Planets
 Hubble discovered that many young stars are surrounded by
flattened disks of gas and dust
 These disks, now known as "proplyds" (short for
protoplanetary disks), are the likely birthplaces of new
planetary system
 Hubble provided visual proof that pancake-shaped dust disks
around young stars are common, suggesting that the
building blocks for planet formation are in place.
Comet Impact
 In 1994, two dozen chunks of Comet ShoemakerLevy 9 smashed into Jupiter
 Hubble captured the massive explosions that sent
towering mushroom-shaped fireballs of hot gas
into the Jovian sky
 Each impact left temporary black sooty scars in
Jupiter's planetary clouds.
Planetary Nebulae: A Sun-like star's death is a
colorful event. Such stars die gracefully by
ejecting their outer gaseous layers into space.
The outer layers glow in vibrant colors of red,
blue, and green. Hubble revealed the details of
this process, showing that the shapes of
planetary nebulae are quite complex.
Stellar Deaths
Supernovae: Massive stars end in glorious
explosions. Hubble found three mysterious
rings of material encircling a doomed star
that exploded as a supernova in 1987.
During the years since the eruption,
Hubble spied brightened spots on the
middle ring caused by material ejected
from the explosion slamming into it.
Even More Hubble Trivia
 Hubble has taken more than 700,000
exposures and probed more than 22,000
celestial objects.
 Hubble has whirled around Earth nearly
88,000 times, racking up 2.3 billion miles.
 The telescope's observations have produced
23 terabytes of data, equal to the amount of
text in 23 million novels. The Hubble data
would fill two Library of Congress book
collections.
 In Hubble's 15-year lifetime, about 3,900
astronomers from all over the world have used
the telescope to probe the universe.
 Astronomers have published more than 4,000
scientific papers on Hubble
The Hubble Space Telescope
The
Chandra X-Ray
Telescope
How Do X-Ray Telescopes Work?
 X-rays do not reflect off mirrors the same way that visible
light does
 X-ray photons penetrate into the mirror in much the same
way that bullets slam into a wall
 X-rays ricochet off mirrors like bullets off a wall
 X-ray telescopes are very different from optical telescopes.
X-ray mirrors are
precisely shaped
and aligned to
incoming x-rays.
They look more
like barrels than
the familiar dish
mirrors of optical
telescopes.
Chandra Factoids
 Chandra flies 200 times higher than Hubble - more than 1/3 of the
way to the moon!
 Chandra can observe X-rays from clouds of gas so vast that it takes
light five million years to go from one side to the other!
 During maneuvers from one target to the next, Chandra slews more
slowly than the minute hand on a clock.
 At 45 feet long, Chandra is the largest satellite the shuttle has ever
launched!
 If Colorado were as smooth as Chandra's mirrors, Pikes Peak would
be less than one inch tall!
 Chandra's resolving power is equivalent to the ability to read a stop
sign at a distance of twelve miles.
 The electrical power required to operate the Chandra spacecraft and
instruments is 2 kilowatts, about the same power as a hair
dryer.
 Chandra can observe X-rays from particles up to the last second
before they fall into a black hole!!!
X-Rays from Young Suns
Chandra studies x-ray flares in Orion solar
mass stars
Early solar flares ionized protoplanetary disk,
induced turbulence that may have “saved”
the Earth from migrating into the Sun
X-Rays from Black Holes
A spinning
black hole
drags space
around with it
 X-rays from Cygnus X-1 come from as close as 20100 miles from the black hole, but it does not seem
to be spinning
 Chandra observations of another stellar black hole,
GX 339-4, indicate that it is spinning rapidly
The Center of the Milky Way
in X-Rays
Chandra observed
matter falling toward
the black hole at the
center of the Milky Way
X-Ray flare from
material close to the
black hole
The
Spitzer
Infrared
Space
Telescope
Spitzer
Trivia
 Launched 25 August 2003
 Delta rocket from Cape Canaveral
 Estimated Lifetime:2.5 – 5 years
 Orbits the Sun, Earth-trailing, heliocentric
 Wavelength Coverage: 3 - 180 microns
 Telescope - 85 cm diameter (33.5”)
 f/12 lightweight beryllium mirror, cooled to less 5.5 K
Infrared Views of
Familiar Objects
Spitzer
Studies
Star
Formation
Spitzer Teachers
Compton Gamma
Ray Observatory
 1991 – 2000
 solar flares
 gamma-ray bursts
 pulsars
 nova
 supernova explosions
 black holes
 quasar emission
Kirkwood Observatory Viewing
Tuesday evenings, weather permitting
Night Sky
Viewing
• Scheduled nights
–Tuesday, May 17
–Tuesday, May 24
• Roof of Swain West
Next Week
• Giant Telescopes
• New Views of the Universe
– Planets around other Suns
• Kirkwood Obs and Rooftop,
weather permitting