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by taking our sense of sight far beyond the realm of our forebears imagination
these wonderful instruments the telescopes open the way to a deeper and
more perfect understanding of nature for millennia mankind gazed out into the
mesmerizing night sky without recognizing the stars of our own Milky
Way galaxy as other Suns or the billions of sister galaxies making up the rest of
our universe
or that we are merely punctuation in the universe is 13.7 billion year life story
with only our eyes as observing tools we had no means of finding solar systems
around other stars or of determining whether life exists elsewhere in the
universe
today we are well on our way to unraveling many of the mysteries of the
universe living in what may be the most remarkable age of astronomical discovery
I'm dr. J and I will be your guide to the telescope that amazing instrument
that proved to be mankind's gateway to the universe
four centuries ago in 1609 a man walked out into the fields near his home he
pointed his homemade telescope at the moon the planets and the stars
his name was Galileo Galilei astronomy would never be the same again
today 400 years after Galileo first pointed a telescope to the skies
astronomers use giant mirrors on remote mountaintops to survey the heavens the
telescope's collect faint chirps and whispers from outer space scientists
have even launched telescopes into earth orbit high above the disturbing effects
of our atmosphere
view has been breathtaking
however Galileo did not in fact invent the telescope that credit goes to hunt
slipper hey a slightly obscure Dutch German spectacle maker but hans
lipperhey never used this telescope to look at the Stars
instead he thought his new invention would mainly benefit seafarers and
soldiers lipeh hey came from Middleburg then a large trading city in the
fledgling Dutch Republic in 1608 lipperhey found that when viewing a
distant object through a convex and a concave lens the object would be
magnified if the two lenses were placed at just the right distance from one
another the telescope was born in September 1608 lipperhey revealed his
new invention to prince mal wreaths of the Netherlands he could not have chosen
a more advantageous moment because at that time the Netherlands were embroiled
in the eighty years war with Spain
the new spyglass could magnify objects and so it could reveal enemy ships and
troops that were too distant to be seen by the unaided eye a very useful
invention indeed but the Dutch government never granted lipperhey a
patent for his telescope the reason was that other merchants also claimed the
invention especially Lipper his competitor zacharias janssen the dispute
was never resolved and to this day the true origins of the telescope remain
shrouded in mystery Italian astronomer Galileo Galilei the father of modern
physics heard about the telescope and decided to build his own about 10 months
ago I reported to reached my ears that the certain flamming had constructed the
spyglass by means of which visible objects though very distance from the
eye of the observer were distinctly seen as if nearby Galileo was the greatest
scientist of his time he was also a strong supporter of the new worldview
advocated by the Polish astronomer Nicolaus Copernicus who proposed that
the earth orbited the Sun instead of the other way round based on what he had
heard of the Dutch telescope Galileo constructed his own instruments they
were of much better quality
finally sparing neither labor nor expenses I succeeded in constructing for
myself so excellent an instrument that objects seen by means of it appeared
nearly 1,000 times larger than when regarded with our natural vision it was
time to train the telescope on the heavens I have been led to the opinion
and conviction that the surface of the Moon is not smooth uniform and precisely
spherical as a great number of philosophers believed it to be but is an
even graph and full of cavities and prominences being nothing like the face
of the earth a landscape of craters mountains and
valleys a world like our own a few weeks later in January 1610 Galileo looked at
Jupiter close to the planet he saw four pricks of light but changed their
position on the sky night after night along with Jupiter it was like a slow
cosmic ballet of satellites orbiting the planet these four pricks of light would
come to be known as the Galilean moons of Jupiter
what else did Galileo discover the phases of Venus just like the Moon Venus
waxes and wanes from Crescent to full and back again
strange appendages on either side of Saturn dark spots on the face of the Sun
and of course stars thousands of them maybe even millions each too faint to be
seen by the naked eye It was as if mankind had suddenly thrown off its
blindfold there was a whole universe to discover out there
news about the telescope spread across Europe like wildfire in Prague at the
court of emperor rudolf ii Johannes Kepler improved the design of the
instrument in antwerp dutch cartographer michelle phan Langer and produced the
first reliable maps of the moon showing what he believed to be continents and
oceans and johannes hevelius a wealthy brewer in poland built huge telescopes
at his observatory in Danzig this Observatory was so large that it covered
three rooftops but the best instruments of the time were probably constructed by
Christian Hurons in the Netherlands in 1655 here hims discovered Titan the
largest moon of Saturn a few years later his observations revealed Saturn's ring
system something Galileo had never understood and last but not least hood
hem saw dark markings and bright polar caps on Mars could there be life on this
remote alien world the question occupies astronomers to this day the earliest
telescopes were refracting telescopes that used lenses to collect and bring
together the Starlight later the lenses were replaced with mirrors this
reflecting telescope was first built by Nikola Zuki and later refined by Zack
Newton now in the late 18th century the largest mirrors in the world were cast
by William Herschel an organist turned astronomer who worked with his sister
Caroline in the house in Bath in England the Herschel's poured red-hot molten
metal into a mold and when the whole thing had cooled off they would polish
the surface so that it would reflect starlight
during the course of his life Herschel built more than 400 telescopes
the largest of these was so huge that he needed four servants to operate all the
various ropes wheels and pulleys that were required to track the motions of
the stars across the night sky which is of course caused by the Earth's rotation
now Herschel was like a surveyor he scanned the heavens and catalogued
hundreds of new nebulae and binary stars he also discovered that the Milky Way
must be a flat disk and he even measured the motion of the solar system through
that disk by observing the relative motions of the stars and the planets and
then on the 13th of March in 1781 he discovered the new planet Uranus it was
over 200 years until NASA's Voyager 2 spacecraft gave astronomers their first
close-up look of this distant world in the lush and fertile countryside of
central island William Parsons the third Earl of Rosse built the largest
telescope of the 19th century with a metal mirror a whopping 1.8 metres
across the giant telescope became known as the Leviathan of Parsons town on
occasional clear moonless nights the Earl sat at the eyepiece and sailed on a
journey through the universe
to the Orion Nebula now known to be a stellar nursery on to the mysterious
Crab Nebula the remnant of a supernova explosion the Whirlpool Nebula Lord Ross
was the first to note its majestic spiral shape a galaxy like our own with
intricate clouds of dark dust and glowing gas billions of individual stars
and who knows maybe even planets like Earth
the telescope had become our vessel to explore the universe at night your eyes
adapt to the dark your pupils widen to let more light into
your eyes as a result you can see dimmer objects and fainter stars now imagine
you had pupils one meter across you'd look pretty strange but you'd also have
supernatural eyesight and that's what telescopes do for you a telescope is
like a funnel its main lens a mirror collects a star light and brings it all
together into your eye the bigger the lens or the mirror of a telescope the
fainter the objects you can see so size really is everything but how big can you
make a telescope well actually not too big if it's a refractor the Starlight
has to pass through the main lens and so you can only support it around its edge
now if you make the lens too big it becomes too heavy and it starts
deforming under its own weight that means that the image will be
distorted the largest refractor in history was completed in 1897 at Yerkes
Observatory outside Chicago its main lens was just over one meter across but
it's tube was an incredible 18 meters long with a completion of the Yerkes
telescope the builders of refracting telescopes had pretty much reached their
limit you want bigger telescopes think mirrors
in a reflecting telescope the star light bounces off the mirror instead of
passing through a lens that means that you can make the mirror a lot thinner
then a lens and you can support it from the back the result is that you can
build a lot larger mirrors than lenses big mirrors came to Southern California
or a century ago back then Mount Wilson was a remote peak in the wilderness of
the San Gabriel Mountains the sky was clear in the nights were dark here
George Ellery Hale first built a 1.5 meter telescope smaller than lord Ross's
retired Leviathan it was of much better quality and at a much better sight - hey
old talked local businessman John *** into financing a two point five meter
instrument tons of glass and riveted steel were hauled up Mount Wilson the
*** telescope was completed in 1970 it would remain the largest telescope in
the world for 30 years a big piece of cosmic artillery ready to attack the
universe and attack it did along with the incredible size of the new telescope
came transformations in the way the image was viewed astronomers no longer
peered through the eyepiece of the new giant but instead collected the light on
photographic plates for hours on end never before had anyone peeled so far
into the cosmos spiral nebulae turned out to be brimming with individual stars
could they be sprawling stellar systems like our own Milky Way in the Andromeda
nebula Edwin Hubble discovered a particular type of star that changes its
brightness with clock-like precision from his observations Hubble was able to
deduce the distance to Andromeda almost a million light years
spiral nebulae like Andromeda were clearly individual galaxies in their own
right but that wasn't the only incredible thing most of these galaxies
were found to be moving away from the Milky Way at Mount Wilson Hubble
discovered that the nearby galaxies were receiving at small velocities whereas
the distant galaxies were moving away at a much faster pace the conclusion the
universe was expanding the *** telescope had given scientists the most
profound astronomical discovery of the 20th century thanks to the telescope we
have traced the history of the universe a little less than 14 billion years ago
the universe was born in a huge explosion of time and space matter and
energy called the Big *** tiny quantum ripples grew into dense patches in the
primordial brew from these galaxies condensed a stunning variety of sizes
and shapes
nuclear fusion in the cause of stars produced new atoms carbon oxygen iron
gold supernova explosions blew these heavy elements back into space raw
material for the formation of new stars and planets someday somewhere somehow
simple organic molecules evolved into living organisms life is one miracle in
an ever evolving universe we are Stardust it's a grand vision and a
sweeping story brought to us through telescopic observations imagine without
the telescope we would know about just six planets one moon and a few thousand
stars astronomy would still be in its infancy like buried treasures the
outposts of the universe have beckoned to the adventurous from immemorial times
princes and potentates political or industrial equally with men of science
have felt the lure of the Uncharted Seas of space and through their provision of
instrumental means the sphere of exploration has rapidly widened
which Ellery Hale had one final dream to build a telescope twice as large as the
previous record-holder meet the grand old lady of 20th century astronomy the
5-metre Hale telescope at Palomar Mountain over 500 tons of moving weight
yet so precisely balanced that it moves as gracefully as a ballerina its 40-ton
mirror reveals stars 40 million times fainter than the eye can see
completed in 1948 the Hale telescope gave us unsurpassed views of planets
star clusters nebulae and galaxies giant Jupiter with its many moons the stunning
flame nebula faint wisps of gas in the Orion Nebula
but could we go bigger still well Soviet astronomers tried in the
late 1970s I up in the caucasus mountains they built the Bolshoi
telescope as in mutiny sporting a primary mirror six meters in diameter
but it never really lived up to its expectations it was simply too big too
expensive and too difficult so did telescope builders have to give
up at that point did they have to bury their dreams of even bigger instruments
at the history of the telescope come to a premature end well of course not today
we have 10 meter telescopes in operation and even bigger ones are on the drawing
board what was the solution new technologies
just as modern cars don't look like a Model T Ford anymore so our present-day
telescopes radically different from the classic predecessors like the 5-metre
Hale telescope but one thing their mounts are much smaller the old-style
mount is an equatorial one where one of the axes is always mounted parallel to
the Earth's rotation axis in order to keep track of the sky's motion the
telescope simply has to rotate around this axis at the same speed with which
the Earth rotates easy but space hungry the modern day altitude azimuth mounts
are much more compact with a mount like that the telescope is pointed much like
a cannon one simply chooses the bearing chooses the altitude and off you go the
problem is to keep track of the sky's motion the telescope pretty much has to
rotate around both axes and at varying speeds essentially this only became
possible once telescopes were computer-controlled
a small amount is cheaper to build moreover it fits into a smaller dome
which reduces the cost even further and it improves the image quality
take the twin Keck telescopes on Hawai for example although they're 10 meter
mirrors are twice as large as the one of the Hale telescope they nevertheless fit
into smaller domes and the one on Palomar Mountain telescope mirrors have
evolved too they use to be thick and heavy now they're thin and lightweight
mirror shells that can be many meters wide are cast in giant rotating ovens
and they are still less than 20 centimeters thick
an intricate support structure prevents the thin mirror from cracking under its
own weight computer-controlled Pistons and
actuators also help to keep the mirror in perfect shape this system is called
active optics the idea is to compensate and to correct any deformations of the
main mirror caused by gravity the wind or temperature changes now a thin mirror
also weighs much less that means that its whole supporting structure including
the mount can also be a lot trimmer and lighter and cheaper now here's the 3.6
meter new technology telescope built by european astronomers in the late 1980s
it served as a testbed for many of the new technologies in
telescope building and even its enclosure has nothing in common with
traditional telescope domes the new technology telescope was a great success
it was time to break the 6-metre barrier Mauna Kea Observatory sits on the
highest point in the Pacific 4200 meters above sea level
on the beaches of Hawaii tourists enjoy the Sun and the surf but high above them
astronomers face chilling temperatures and altitude sickness in their quest to
unravel the mysteries of the universe the Keck telescopes are among the
largest in the world their mirrors are 10 metres across and
wafer-thin tiled like a bathroom floor they consist of 36 hexagonal segments
each controlled to nanometre precision these are true giants devoted to
observing the heavens the cathedrals of science nightfall on Mauna Kea the Keck
telescopes begin collecting photons from the far reaches of the cosmos their twin
mirrors combining to be effectively larger than all earlier telescopes what
will be tonight's catch
a pair of colliding galaxies billions of light-years away a dying star gasp in
its last breath into a planetary nebula or maybe an extrasolar planet that might
harbor life
on Cerro Paranal in the Chilean Atacama Desert the driest place on earth we find
by far the biggest astronomy machine ever built the European Very Large
Telescope
the VLT is really for telescopes in one each sporting an eight point two meter
mirror hantum clear Mele par yet one native Mapuche names for the Sun the
Moon the Southern Cross and Venus the huge mirrors were cast in Germany
polished in France shipped to Chile and then slowly transported across the
desert at sunset the telescope enclosures open up starlight rains down
on the VLT mirrors new discoveries are made a laser pierces the night sky the
projects an artificial star into the atmosphere 90 kilometres above our heads
wavefront sensors measure how the Stars image is distorted by the atmospheric
turbulence then fast computers tell a flexible mirror of how it has to deform
itself in order to correct the distortion in effect and twinkling the
Stars this is called adaptive optics and it's the big magic trick of present-day
astronomy without it our view of the universe would look blurred by the
atmosphere but with it our images are razor sharp
the other piece of optical wizardry is known as interferometry the idea is to
take the light from two separate telescopes and to bring it together in a
single point on preserving the relative shifts between the light waves if it is
done precisely enough result is that the two telescopes act as if they were a
part of a single colossal mirror as large as the distance between them in
effect interferometry gives you telescope eagle-eyed vision it allows
smaller telescopes to reveal a level of detail that would otherwise only be
visible with a much larger telescope the twin Keck telescopes on Mauna Kea
regularly team up as an interferometer in the case of the VLT or four
telescopes can work together in addition several smaller auxiliary telescopes can
also join the ranks in order to sharpen up the view even more other big
telescopes can be found all over the globe Subaru and Gemini north on Mauna
Kea Gemini's south and the Magellan telescopes in Chile
the large binocular telescope in Arizona they are constructed at the best
available sights high and dry clear and dark their eyes are as large as swimming
pools all kitted out with adaptive optics to counteract the blurring
effects of the atmosphere and sometimes they can have the resolution of a
virtual Bowerman thanks to interferometry
actual sizes and squash shapes of some stars a cool planet orbiting a brown
dwarf giant stars whirling around the core of our Milky Way galaxy governed by
the gravity of a supermassive black hole we've come quite a ways since Galileo's
day 400 years ago when Galileo Galilei wanted to show others what he saw
through his telescope he had to make drawings the pockmarked face of the moon
the dance of the Jovian satellites
sunspots all the stars in Orion he took his drawings and published them
in a small book the starry messenger that was the only way he could share his
discoveries with others for well over two centuries astronomers also had to be
artists peering through their eyepieces they made detailed drawings of what they
saw the stark landscape of the Moon a storm in the atmosphere of Jupiter the
subtle veil of gas in a distant nebula and sometimes they over interpreted what
they saw dark linear features on the surface of Mars were thought to be
canals suggesting civilized life on the surface of the Red Planet we now know
that the canals were an optical illusion what astronomers really needed was an
objective way to record the light collected by the telescopes without the
information first having to pass through their brains and their drawing pens
photography came to the rescue the first agario type of the moon it was
made in 1840 by Henry Draper Photography was less than 15 years old but
astronomers had already seized on his revolutionary possibilities so how did
photography work well the sensitive emulsion of the
photographic plate contained small grains of silver halide expose them to
light and they turned dark so the result was a negative image of the sky with
dark stars on a light background but the real bonus was that the photographic
plate can be exposed for hours on end when you take in the night
sky with your own eyes once they're dark adapted you don't see more and more
stars just by looking longer but with a photographic plate you can do just that
you can collect and add up the light over hours on end so a longer exposure
reveals more and more stars and more and more and then some in the 1950s the
Schmidt telescope at the Palomar Observatory was used to photograph the
entire northern sky almost 2,000 photographic plates each exposed for
nearly an hour a treasure trove of discovery photography had turned
observational astronomy into a true science objective measurable and
reproducible but silver was slow you have to be patient the digital
revolution changed all that silicon replaced silver pixels replace
grains
even in consumer cameras we no longer use photographic film instead images are
recorded on a light-sensitive chip a charged coupled device or CCD for short
professional C CDs are extremely efficient and to make them even more
sensitive they are cooled down to well below freezing using liquid nitrogen
almost every photon is registered as a result exposure times can be much
shorter what the Palomar Observatory Sky Survey achieved in an hour a CCD can now
do in a few short minutes using a smaller telescope the silicon revolution
is far from over astronomers have built huge CCD cameras
with hundreds of millions of pixels and there's more to come
the big advantage of digital images is that they're well digital they're all
set and ready to be worked on with computers astronomers use specialized
software to process their observations of the sky stretching or contrast
enhancing reveals the faintest features of nebulae or galaxies color coding
enhances and brings out the structures that would otherwise be difficult to see
moreover by combining multiple images of the same object that were taken through
different color filters one can produce spectacular composites that blur the
boundary between science and art you too can benefit from digital astronomy it
has never been so easy to dig up and enjoy the amazing images of the cosmos
pictures of the universe are always just a mouse-click away
robotic telescopes equipped with sensitive electronic detectors are
keeping watch over the sky right now the Sloan telescope in New Mexico has
photographed and catalogued over a hundred million celestial objects
measured distances to a million galaxies and
discovered a hundred thousand new quasars but one survey is not enough
the universe is an ever-changing place I see comments come and go leaving
scattered debris in their way asteroid zip bye
distant planets orbit their mother stars temporarily blocking part of the star's
light supernovas explode while elsewhere new stars are born pulsars flash
gamma-ray bursts detonate black holes are creeped to keep track of
these grand plays of nature astronomers want to carry out all sky surveys every
year or every month or twice a week at least that's the ambitious goal of the
large synoptic survey telescope if completed in 2015 it's three Giga pixel
camera will open up a webcam window on the universe more than fulfilling
astronomers dreams this reflecting telescope will photograph almost the
entire sky every three nights
when you listen to your favorite piece of music your ears pick up on a very
wide range of frequencies from the deepest rumblings of the bass to the
very highest pitched vibrations now imagine your ears were only sensitive to
a very limited range of frequencies you'd miss out on most of the good stuff
but that's essentially the situations that astronomers are in our eyes are
only sensitive to a very narrow range of light frequencies visible light but we
are completely blind to all other forms of electromagnetic radiation however
there are many objects in the universe that do emit radiation at other parts of
the electromagnetic spectrum for example in the 1930s it was discovered by
accident that there are radio waves coming from the depths of space some of
these ways have the same frequency as your favorite radio station but there
are much weaker and of course there's nothing to listen to in order to tune in
to the radio universe you need some sort of receiver a radio telescope a fall but
the longest wavelengths a radio telescope is just a dish much like the
main mirror of an optical telescope but because radio waves are so much longer
than visible light waves the surface of a dish doesn't have to be nearly as
smooth as the surface of a mirror and that's the reason why it's so much
easier to build a large radio telescope than it is to build a large optical
telescope also at radio wavelengths it is much easier to do interferometry that
is to increase the level of detail that can be seen by combining the light from
two separate telescopes as if they were part of a single giant dish the Very
Large Array in New Mexico for example consists of 27 separate antennas each
measuring 25 metres across now each antenna can be moved around
individually and in its most extended configuration the virtual dish mimicked
by the array measures 36 kilometres across
so what does the universe look like in the radio well for start our Sun shines
very brightly at radio wavelengths so does the center of our Milky Way galaxy
but there's more pulse ours are very dense stellar
corpses that emit radio waves only into a very narrow beam in addition they
rotate at speeds of up to several hundred revolutions per second so in
effect a pulsar looks like a rotating radio lighthouse and what we see from
them is a very regular and fast sequence of very short radio pulses hence the
name the radio source known as Cassiopeia A is in fact the remnant of a
supernova that exploded in the 17th century
Centaurus a Cygnus a and Virgo a are all giant galaxies that pour out huge
amounts of radio waves each galaxy is powered by a massive black hole at its
center some of these radio galaxies and quasars are so powerful that their
signals can still be detected from a distance of 10 billion light years and
then there's the faint relatively short wavelength radio hiss that fills the
entire universe this is known as the Cosmic Microwave Background and it is
the echo of the Big *** the very afterglow of the hot beginnings of the
universe each and every part of the spectrum has its own story to tell at
millimetre and submillimetre wavelengths astronomers study the formation of
galaxies in the early universe and the origin of stars and planets in our own
Milky Way but most of this radiation is blocked by water vapour in our
atmosphere to observe it you need to go high and dry to Llano - at night or for
example at five kilometres above sea level this surrealistic plateau in
northern Chile is the construction site of Alma the Atacama Large millimeter are
a when completed in 2014 Alma will be the largest astronomical observatory
ever built sixty-four antennas each weighing 100
tons will work in unison giant trucks will spread them out over an area as
large as London to increase the detail of the image or bring them close
together to provide a wider view each move will be made with millimeter
precision many objects in the universe also glow in the infrared discovered by
William Herschel infrared radiation is often also called heat radiation because
it is emitted by all relatively warm objects including humans
you may be more familiar with infrared radiation than you think because on
earth this kind of radiation is used by night-vision goggles and cameras but to
detect the faint infrared glow from distant objects astronomers need very
sensitive detectors cool down to just a few degrees above absolute zero in order
to suppress their own heat radiation
today most big optical telescopes are also equipped with infrared cameras they
allow you to see right through a cosmic dust cloud revealing the newborn stars
inside something that just cannot be seen in the optical for example take
this optical image of the famous stellar nursery in Orion but look how different
it is when seen through the eyes of an infrared camera being able to see me
infrared is also very helpful when studying the most distant galaxies the
newborn stars in a young galaxy shine very brightly in the ultraviolet
but then this ultraviolet light has to travel for billions of years across the
expanding universe the expansion stretches the light ways so that when
they are received by us they've been shifted all the way into the
near-infrared this stylish instrument is the magic telescope on La Palma it
searches the sky for cosmic gamma rays the most energetic form of radiation in
nature
lucky for us the lethal gamma rays are blocked by the Earth's atmosphere but
they do leave behind footprints for astronomers to study after hitting the
atmosphere they produce cascades of energetic particles these in turn caused
a faint glow that magic can see and here's the Piero CA Observatory in
Argentina it doesn't even look like a telescope PLJ consists of 1,600
detectors spread over 3,000 square kilometers they catch the particle
fallout of cosmic rays from distant supernovas and black holes
and what about neutrino detectors built in deep mines or beneath the surface of
the ocean or in the Antarctic ice could you call those telescopes well why not
after all they do observe the universe even if they don't capture data from the
electromagnetic spectrum neutrinos are elusive particles that are produced in
the Sun and supernova explosions they were even produced in the Big ***
itself unlike other elementary particles neutrinos can pass through regular
matter travel near the speed of light and have no electric charge
although these particles may be difficult to study they are plentiful
each second more than 50 trillion electron neutrinos from the Sun passed
through you finally astronomers and physicists have joined forces to build
gravitational wave detectors these telescopes do not observe radiation or
catch particles instead they measure tiny ripples in the very structure of
space-time a concept predicted by Albert Einstein's theory of relativity
with a stunning variety of instruments astronomers have opened up the full
spectrum of electromagnetic radiation and have even ventured beyond but some
observations simply can't be done from the ground the answer space telescopes
the Hubble Space Telescope is by far the most famous telescope in history and for
good reason Hubble has revolutionised so many fields
in astronomy by modern standards Hubble's mirror is actually quite small
it only measures about 2.4 meters across but its location is literally out of
this world high above the blurring effects of the atmosphere it has an
exceptionally sharp view of the universe and what's more Hubble can see
ultraviolet and me infrared light this light just cannot be seen by
ground-based telescopes because it is blocked by the atmosphere cameras and
spectrographs summers big as a telephone booth dissect and register the light
from distant cosmic Shores just like any ground-based telescope Hubble is
upgraded from time-to-time spacewalking astronauts carry out servicing missions
broken parts get refurbished and all the instruments get replaced with newer and
state-of-the-art technology Hubble has become the powerhouse of observational
astronomy and it has transformed our understanding of the cosmos with its
keen eyesight Hubble observed seasonal changes on Mars
a cometary impact on Jupiter an edge-on viewer Saturn's rings
and even the surface of tiny *** it revealed the life cycle of stars from
their very birth and baby days in the nursery of dust-laden clouds of gas all
the way to their final farewell as delicate nebulae slowly blown into space
by dying stars or as Titanic supernova explosions that almost outshine their
home galaxy deep in the Orion Nebula Hubble even saw
the breeding ground of new solar systems dusty discs around newborn stars that
may soon condense into planets the Space Telescope studied thousands of
individual stars in giant globular clusters the oldest stellar families in
the universe and galaxies of course never before had astronomers seen so
much detail majestic spirals absorbing dust legs
violent collisions
extremely long exposures of blank regions of sky even revealed thousands
of faint galaxies billions of light-years away photons that were
emitted when the universe was still young a window into the distant past
shedding new light on the ever-evolving cosmos Hubble is not the only telescope
in space this is NASA's Spitzer Space Telescope launched in August 2003 in a
way it is Hubble's equivalent for the infrared Spitzer has a mirror that is
only 85 centimeters across but the telescope is hiding behind a
heat shield that protects it from the Sun and it's detectors are tucked away
in a Dewar filled with liquid helium here the detectors are cooled down to
just a few degrees above absolute zero making them very very sensitive Spitzer
has revealed a dusty universe dark opaque clouds of dust glow in the
infrared when heated from within shockwaves from galaxy collisions sweep
up dust in telltale rings and tidal features new sites for ubiquitous star
formation
dust is also produced in the aftermath of a star's death splits are found that
planetary nebulae and supernova remnants are laden with dust particles the
prerequisite building blocks of future planets and other infrared wavelengths
Spitzer can also see right through a dust cloud revealing the stars inside
hidden in the dark cause finally the space telescope's spectrographs have
studied the atmospheres of extrasolar planets gas giants like Jupiter that
raced around their parent stars in just a few days so what about x-rays and
gamma rays well they are completely blocked by the Earth's atmosphere and so
without space telescopes astronomers would be totally blind to these
energetic forms of radiation x-ray and gamma-ray Space Telescope's
reveal the hot energetic and violent universe of galaxies clusters black
holes supernova explosions and galaxy collisions
they're very hard to build though energetic radiation passes right through
a conventional mirror x-rays can only be focused with nested mirror shells made
of pure gold and gamma rays are studied with sophisticated pinhole cameras of
stacked scintillators that give off brief flashes of normal light when
struck by a gamma ray photon in the 1990s NASA operated the Compton gamma
ray Observatory at the time it was the largest and most massive scientific
satellite ever launched a fully fledged physics lab in space in 2008 Compton was
succeeded by glassed the gamma ray large area space telescope it will study
everything in the high-energy universe from dark matter to pulsars
meanwhile astronomers have to x-ray telescopes in space NASA's Chandra x-ray
observatory and ESA's xmm-newton Observatory are both studying the
hottest places in the universe this is what the sky looks like with x-ray
vision extended features are clouds of gas heated to millions of degrees by
shockwaves in supernova remnants the bright point sources are x-ray binaries
neutron stars or black holes that suck in matter from a companion star this hot
infalling gas emits x-rays likewise x-ray telescopes reveal
supermassive black holes in the cause of distant galaxies
that spirals inward gets hot enough to glow in x-rays just before it plunges
into the black hole and out of sight hot but tenuous gas also fills the space
between individual galaxies in a cluster sometimes this intra cluster gas is
shocked and heated even more by colliding and merging galaxy clusters
even more exciting are gamma-ray bursts the most energetic events in the
universe these are catastrophic terminal
explosions of very massive rapidly spinning stars in less than a second
they release more energy than the Sun does in 10 billion years Hubble Spitzer
Chandra xmm-newton and glass are all versatile giants but some space
telescopes are much smaller and have much more focused missions take a row
for example this French satellite is devoted to stellar seismology and the
study of extrasolar planets or NASA's Swift satellite a combined x-ray and
gamma-ray Observatory designed to unravel the mysteries of gamma-ray
bursts and then there's w map the Wilkinson microwave anisotropy probe in
just over two years in space it had already mapped the cosmic background
radiation to unprecedented detail w map gave cosmologists the best view yet of
one of the earliest phases of the universe more than 13 billion years ago
opening up the space frontier has been one of the most exciting developments in
the history of the telescope so what's next
in Arizona the first mirror has been cast for the giant Magellan telescope
this huge instrument will be built at the Las Campanas Observatory in Chile
it's seven mirrors each well over eight meters across will be arranged like the
petals of a flower and together they will capture more than four times the
amount of light any current telescope can catch the Californian thirty meter
telescope planned for 2015 is more like a giant version of Keck hundreds of
individual segments make up one enormous mirror as tall as a six-story apartment
in Europe plans are ready for a European extremely large telescope at 42 meters
in diameter its mirror will be as large as an Olympic swimming pool twice the
surface area of the thirty meter telescope these future monsters
optimized for infrared observations will all be outfitted with sensitive
instruments and adaptive optics they should reveal the very first generation
of galaxies and stars in the history of the universe moreover they may provide
us with the first true picture of a planet in another solar system for radio
astronomers 42 metres is peanuts they hook up many smaller instruments to
synthesize a much larger receiver in the Netherlands the low-frequency array
LOFAR is under construction fiber optics will connect 30,000 antennas to a
central supercomputer novel design has no moving parts but it can observe in
eight different directions simultaneously loaf' our technology will
probably find its way into the Square Kilometre Array which is now topping the
wish list of radio astronomers the International array will be built in
Australia or South Africa large dish antennas and small receivers
will team up to provide incredibly detailed views of the radio sky and with
a total collecting area of one square kilometer the new array will be by far
the most sensitive radio instrument ever constructed evolving galaxies powerful
quasars blinking pulsars no single source of radio waves will be safe from
the spying eyes of the Square Kilometre Array the instrument will even look for
possible radio signals from extraterrestrial civilizations and what
about space well after its fifth and final servicing mission the Hubble Space
Telescope will be on active duty until 2013 around that time its successor will
be launched meet the James Webb Space Telescope a space infrared Observatory
named after a former NASA Administrator once in space it's six point five meter
segmented mirror unfolds like a blooming flower 1/7 times as sensitive as
Hubble's a large sunshade keeps the optics on the low-temperature
instruments in permanent shadow allowing them to operate near a whopping minus
233 degrees Celsius a James Webb Space Telescope won't orbit the Earth instead
it will be parked 1.5 million kilometres from our planet in a wide orbit around
the Sun half a century ago the Hale telescope on Palomar Mountain was the
largest in history now an even bigger one will be flying into the depths of
space we can only speculate about the exciting discoveries it will make stay
tuned meanwhile creative engineers come up with revolutionary designs for new
telescopes all the time in Canada scientists have built the so called
liquid mirror telescope in this kind of telescope the star light is reflected
not by a solid mirror but rather by the curved surface of a
rotating reservoir of liquid mercury because of their design mercury
telescopes can only look straight up but their advantages is that better
relatively cheap and easy to build radio astronomers want to put a loafer like
array of small antennas onto the surface of the moon as far away as possible from
terrestrial sources of interference who knows one day there might even be a big
optical telescope on the far side of the moon using space telescopes and
occulting disks x-ray astronomers hope to improve their eyesight tremendously
in the future they may even succeed in imaging the very edge of a black hole
interferometers launched into the darkness of space may provide a novel
answer right now NASA is considering a project called the terrestrial planet
finder and in Europe scientists are designing the Darwin
array six space telescopes orbit the Sun in formation lasers control their mutual
distances to the nearest nanometer together they have incredible resolving
power cancelling out the light from overbearing stars so scientists can
actually see earth-like planets around other stars next astronomers must study
the light reflected by the planet it carries the spectroscopic fingerprint of
the planet's atmosphere who knows in 15 years time we may detect the signatures
of oxygen methane and ozone the signposts of life the universe is full
of surprises the sky never ceases to impress no wonder that hundreds of
thousands of amateur astronomers across the globe go out every clear night to
marvel at the cosmos their telescopes are much better than the instruments
used by Galileo the digital images even surpass the photographic images taken by
professionals just a few decades ago astronomers quest for cosmic
understanding a telescopic exploration of the universe is only 400 years old
there's still a lot of uncharted territory out there we've come a long
way since Galileo began charting the heavens with his telescope four
centuries ago today we still observe the universe with
telescopes from earth but in the limitless regions of space the seed of
humanity lies in our seemingly endless supply of ingenuity and curiosity we
have just begun answering some of the greatest questions conceived
we have charted over 300 planets around other stars in our own Milky Way and
located organic molecules on planets around far-flung stars these incredible
discoveries may seem like the zenith of human exploration but the best is
undoubtedly yet to come you too can join the discoverers look up and one