Download Exploring the cosmos

Key
1a Thomas Harriot’s Moon drawing (facsimile)
1b Thomas Harriot’s Moon map
1c
Thomas Harriot’s drawing of Jupiter’s moons
1d Thomas Harriot’s sunspot drawings
2
Telescope by Galileo (replica)
3
Galileo’s Sidereus nuncius
Isaac Newton’s reflecting telescope (replica)
4
Representation of E-ELT mirror segment
5
Hubble Space Telescope (1:10 model)
6
Stjerneborg Observatory
7
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Islamic astrolabe
9
European astrolabe
10 Norman Lockyer’s seven-prism spectroscope
11ISO long-wavelength spectrometer
12Japanese star map
13 William Herschel’s galaxy maps (facsimiles)
Front cover Pioneer plaque image: NASA
14Hubble’s classification of ‘nebulae’
15Hipparcos scale model (1:6)
16Sloan Digital Sky Survey plate
17Parts from the Cambridge ‘pulsar’ array
18 Model of a pulsar
19 Kew Photoheliograph
20aKew sunspot photographs
20bKew Photoheliograph diapositives
21 William Herschel’s ‘infrared’ prism
22Model of the Jodrell Bank Lovell Telescope
23 XMM-Newton grazing mirror (flight spare)
24Mirror segment for FUSE satellite
25Scale model (1:30) of HESS telescope
26Spare mirror segment for HESS
27Scale model of Swift satellite
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1b
1c
1d
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Exploring
the cosmos
The cosmos
and us
Exploring the cosmos
The sky is a source of endless
discovery. Four hundred years ago, a
simple spyglass took us on a journey
to the Moon and planets. Today, giant
telescopes let us explore faraway
galaxies – and reveal new wonders.
The first telescopic observations
Thomas Harriot’s Moon drawing (facsimile)
1609
At about 9pm on 26 July 1609, just outside
London, Thomas Harriot turned his new
‘Dutch trunke’ to the Moon. His drawing
of what he saw is the first recorded
astronomical observation with a telescope.
The drawing, made five days after the new
moon, shows the terminator line separating
light and dark areas. The written notes prove
that Harriot’s observations pre-date Galileo’s.
But he never published his work, so did not
become as famous as the Italian astronomer.
Source: By permission of Lord Egremont/West Sussex Record Office
Object 1a
Mapping the Moon
Thomas Harriot’s Moon map (facsimile)
1610–13
As Thomas Harriot gained access to more
powerful telescopes, he made increasingly
sophisticated maps of the Moon. This one,
probably made with a telescope of around
30 times magnification, precisely details
the Moon’s ‘seas’ or ‘maria’.
Harriot regularly corresponded with friends
who were also trying out telescopes. One wrote
to him saying that the full moon ‘appears like a
tarte that my cooke made me the last week’.
Object 1b
Source: By permission of Lord Egremont/West Sussex Record Office
In Galileo’s footsteps
Thomas Harriot’s drawing of Jupiter’s moons (facsimile)
1610
This drawing shows Thomas Harriot’s first
observations of Jupiter’s moons in autumn 1610.
Harriot probably saw a copy of Galileo’s book
describing the moons around July, but by then
Jupiter was too near the Sun for him to see
for himself.
On the first night, 17 October, Harriot notes,
‘I saw but one, and that above.’ Over the next
year he made 98 further observations and
tracked all four of the Galilean satellites.
Source: By permission of Lord Egremont/West Sussex Record Office
Object 1c
Spots on the Sun
Thomas Harriot’s sunspot drawings (facsimile)
1610
The top drawing on this page records Thomas
Harriot’s first view of sunspots. He was one of
several astronomers to independently discover
them around the same time. Harriot risked
blindness by using his telescope to view the Sun
directly with only mist to shield its fierce glare.
We now know that these dark spots moving
across the Sun’s face are caused by strong
magnetic fields that keep some areas slightly
cooler than their surroundings.
Object 1d
Source: By permission of Lord Egremont/West Sussex Record Office
Galileo’s spyglass
Telescope by Galileo (replica)
Original c. 1610
This is a replica of one of only two surviving
telescopes made by Galileo. He made his first
telescope after hearing descriptions of a new
device that had begun circulating around
Europe in late 1608. He refined the design into
a powerful tool for astronomy.
The ornate decoration on the wood and leather
tube suggests that Galileo made this telescope
for demonstration to his patron Cosimo de
Medici, rather than for regular use.
Source: Purchased Inv. No: 1923-668
Object 2
The starry messenger
Sidereus nuncius
1610
In this book Galileo reported the astronomical
capabilities of his new spyglass. His drawings
of the pitted lunar surface and Jupiter’s moons
provided evidence to support theories of a
Sun-centred Solar System.
Sidereus nuncius could also be considered
Galileo’s job application for a position at court
in Florence. He called his newly discovered
satellites of Jupiter ‘Medicean stars’ to
impress the Grand Duke Cosimo II de Medici.
Object 3
Source: Science Museum Library (O.B. GAL)
Newton does it with mirrors
Isaac Newton’s reflecting telescope (replica)
Original 1668–71
This is a replica of the first successful reflecting
telescope, built by Isaac Newton. It used mirrors
instead of lenses to focus light, giving a better
performance for a smaller instrument.
The circular mark near the front of the telescope
tube shows that Newton tried out where the
eyepiece would go, but filled in his first attempt
and made a new one.
Source: Purchased Inv. No: 1924-209
Object 4
The world’s biggest telescope?
Representation of E-ELT mirror segment
2009
The world’s largest optical telescope, the
European Extremely Large Telescope, is due to
begin operations in 2018. It will consist of 984
hexagonal segments of this size, fitted together
to make a mirror 42 metres across – around
the length of five London buses.
A telescope this big could examine the oldest
stars and galaxies, and search for Earth-like
planets that might harbour life.
Object 5
Source: Science Museum
Image: European Southern Observatory
The world’s most famous telescope
Hubble Space Telescope (1:10 model)
Original 1985–90
Hubble is one of the most successful space
missions of all time. The quality and quantity
of data and images collected by its visible and
infrared instruments have delighted scientists
and the public alike.
Hubble is about the size of a single-decker
bus – the largest it could be and still fit inside
the Space Shuttle.
Source: European Space Agency Inv. No: L2009-4041
Object 6
Studying the stars
People have stargazed for centuries,
first with the naked eye, then with
increasingly complex instruments.
We now know that our Sun is just one
star in the galaxy, and our galaxy is
one of many billions.
Tycho Brahe’s star castle
Stjerneborg Observatory
1634
Nobleman Tycho Brahe was one of the foremost
astronomers of the pre-telescopic age. His
underground observatory on the Danish island
of Hvaena was shielded from the wind, allowing
him and his assistants to measure the stars
accurately using a variety of instruments.
Tycho called the observatory Stjerneborg, or
‘star castle’. Data from his observations were
later used to develop the laws of planetary
motion that supported Copernicus’s theory of
a Sun-centred universe.
Source: Purchased Inv. No: 1937-615
Object 7
A vital tool
Islamic astrolabe
AD 901–1100
Knowing the time for prayer and locating the
direction of the holy city of Mecca is a key part of
Islam. Medieval Islamic scholars developed the
original Ancient Greek design for an astrolabe
to create a highly sophisticated instrument.
Many 11th-century mosques employed their
own muwaqqit or astronomer-timekeeper
who was responsible for using an astrolabe
like this one to determine the essential prayer
times and directions.
Object 8
Source: Purchased Inv. No: 1981-1380
Star catcher
European astrolabe
1607–18
The astrolabe was the main astronomical
instrument before the telescope. It could be
used to tell the time, determine star positions
at particular latitudes and predict future
astronomical events.
Each curly pointer corresponds to a bright star.
On this astrolabe you can see a tulip shape in the
framework – the signature style of the renowned
Arsenius family workshop in Flanders.
Source: Purchased Inv. No: 1878-11
Object 9
Analysing light
Norman Lockyer’s seven-prism spectroscope
1868
This seven-prism spectroscope was designed
to bend light into its different colours, allowing
Norman Lockyer to identify different elements
in stars.
When observing the Sun he noticed the
signature of a mystery element unknown on
Earth. He named it ‘helium’ after the Greek
word for Sun, helios. This element was only
found on Earth decades later.
Object 10
Source: Purchased Inv. No: 1987-1162
Seeing through cosmic dust
Long-wavelength spectrometer from the Infrared Space Observatory (identical spare model)
1990s
Cosmic dust between the stars blocks out visible
light, but it can be penetrated by infrared.
Scientists study the infrared radiation emitted by
gas molecules to find out more about cooler
areas of space where stars have yet to form, or
have died.
This instrument is identical to one flown on the
Infrared Space Observatory, launched in 1995.
This satellite revealed the presence of water in
many parts of our galaxy.
Source: Rutherford Appleton Laboratory Inv. No: L2009-4033
Object 11
Japanese star map
Tenmon Bun’ya no zu (map showing divisions of the heavens and regions they govern)
1677
This star map was made by Harumi Shibukawa,
official astronomer to the Japanese Edo court.
He was one of the first people to use a
telescope in Japan after the instrument was
introduced by European traders.
The map combines Shibukawa’s systematic
observations with concepts from Chinese
astrology, so that the stars could be used to
predict events in different regions of Japan.
Object 12
Source: Purchased Inv. No: 2007-1
Mapping the Milky Way
William Herschel’s galaxy maps (facsimiles)
Originals 1784–85
William Herschel and his sister Caroline made
the first maps of the structure of our galaxy.
For two years they painstakingly surveyed
thousands of stars, using their brightness to
estimate distance from Earth.
Herschel rushed to publish the first attempt
(left) to prove the capabilities of his new 20-foot
telescope. A later, more detailed study (right)
shows a more familiar bulging disc. The Sun is
shown at the centre, although Herschel was not
sure exactly where it was in the galaxy.
Source: By permission of the Royal Astronomical Society
Object 13a, b
Sorting galaxies
Glass positive of Hubble’s classification of ‘nebulae’
1930
The famous astronomer Edwin Hubble showed
that ‘spiral nebulae’ were actually galaxies of
stars beyond our own galaxy, the Milky Way.
He devised a system of galaxy classification
that is still widely used today.
These galaxy images were taken at the Mount
Wilson Observatory in California and show
some of the different types of spiral galaxy.
Object 14
Source: Science Museum Inv. No: 1930-682
Star-mapping spacecraft
Scale model (1:6) of the Hipparcos (High Precision Parallax Collecting Satellite)
astrometry spacecraft
c. 1985
Hipparcos was the first space mission designed
to map stars. It measured the positions, distances
and motion of over 2 million stars to new degrees
of precision.
The satellite’s name acknowledges the Greek
astronomer Hipparchus, who systematically
mapped over a thousand stars with the naked eye
around 150 BC. In 2010 a new mission called Gaia
will launch, aiming to map over a billion stars.
Source: European Space Agency Inv. No: 1986-850
Object 15
Mapping the cosmos
Aluminium spectroscopic plate from the Sloan Digital Sky Survey (SDSS)
c. 2000
The Sloan Digital Sky Survey is the largest
astronomical survey ever completed. Between
2000 and 2008 it created a 3D map of over a
million stars and galaxies, covering a quarter of
the night sky.
This plate is one of about 4000 custom-built to fit
the telescope. Each plate carries a unique pattern
of 640 holes, used to select hundreds of stars and
galaxies for each exposure. The circled guide
stars marked on the plate help astronomers align
it to the sky.
Object 16
Source: Sloan Digital Sky Survey Inv. No: E2008.173.1
Discovering pulsars
Parts from the Cambridge Interplanetary Scintillation Array
1967
This is part of the four-acre radio telescope used
in one of astronomy’s most famous chance
discoveries. In 1967, student Jocelyn Bell noticed
a ‘bit of scruff’ on the telescope’s data charts.
Astronomers realised that the unusual signal,
which repeated regularly, came from a new class
of cosmic object.
Initially, these objects were nicknamed LGM, for
‘little green men’. But rather than aliens, they are
rapidly spinning dense stars. They are called
pulsars and over 1800 are now known.
Source: University of Cambridge, Department of Physics Inv. No: 2009-43
Image: Jocelyn Bell Burnell
Object 17
A new kind of star
Model of a pulsar
c. 1969
Antony Hewish used this model to teach
people about pulsars – the new kind of star
he and Jocelyn Bell discovered in 1967.
The orange ball at the centre represents a
neutron star, the incredibly dense remnant
of a supernova explosion.
The curved wires show magnetic field lines. The
foil tubes represent beams of radiation from the
neutron star. As the star rotates, the beam turns
in the direction of the Earth, and astronomers
detect radio pulses. Hewish’s first version of the
model was driven by a gramophone motor.
Object 18
Source: University of Cambridge, Department of Physics Inv. No: L2009-4026
Looking with light
Light is the real measure of the
universe. It comes in many forms,
most of them invisible to the human
eye. But with the right instruments,
astronomers can illuminate some of
the darkest mysteries of the cosmos.
Photography comes to astronomy
Kew Photoheliograph
1857
This is the first instrument that was purpose
built for astronomical photography. It was
used at Kew and Greenwich to take daily
photographs of the Sun.
Warren de la Rue took this instrument to
Rivabellosa in Spain to photograph the solar
eclipse of 18 July 1860. The photographs were
compared with ones taken 500 km away and
proved that the prominences visible during an
eclipse are part of the Sun, rather than an
effect of the Earth’s atmosphere.
Source: The Royal Society Inv. No: 1927-124
Object 19
Tracking sunspots
Photographs of sunspots taken with the Kew Photoheliograph
September 1870
These photographs are from a series taken in
September 1870 with the Kew Photoheliograph,
the large instrument at the very right of this
showcase. Astronomers used it to take daily
photographs of the Sun.
Comparing the photographs day by day showed
how features such as sunspots moved. We now
know these dark spots are caused by magnetic
activity on the Sun’s surface.
Object 20a
Source: Mrs E Whipple Inv. No: 1982-684
Observing the Sun and Moon
Diapositives of photographs taken with the Kew Photoheliograph
1860–62
These photographs of the Sun and Moon were
taken with the Kew Photoheliograph, the large
instrument in the corner of this showcase.
The Moon image, on the right, was taken at
Kew Observatory. The Sun image, on the left,
was taken during an expedition to north Spain
to observe the solar eclipse of July 1860. It
shows a partial eclipse as the Moon crosses
the Sun before blocking it out completely.
Source: Mr Warren de la Rue Inv. Nos: 1862-122/1, 1862-122/4
Object 20b
Discovering invisible light
William Herschel’s ‘infrared’ prism
1795–1805
This may be the prism used by William
Herschel when he accidentally discovered
invisible radiation in 1800. Using the prism,
he split sunlight into its different colours and
measured their temperatures. He noticed that
the temperature was highest beyond the red
light, in a region now known as infrared.
Object 21
Source: Mr John Herschel-Shorland Inv. No: 1876-951
Stars on the radio
Model (scale 1:200) of the Jodrell Bank Lovell Telescope
1961
The 76-metre Lovell Telescope is the third
largest steerable radio telescope in the world.
It was originally built to track cosmic rays,
high-energy particles from space, with radio
waves. Designer Bernard Lovell drew on
expertise he had developed for radar systems
during the Second World War.
The telescope has been used for a wide range
of astronomical and space work, including the
tracking of Sputnik 1, the world’s first artificial
satellite. It is now a Grade I listed building.
Source: United Steel Companies Ltd Inv. No: 1961-159
Object 22
Skimming X-rays
XMM-Newton grazing mirror (flight spare)
Mid 1990s
This is one of 58 cylindrical mirrors that nest
together in each of the three telescopes aboard
the XMM-Newton spacecraft. Incoming X-rays
skim the inside of each mirror and come to a
focus at the telescope’s detector.
The mirror array helps make XMM-Newton the
most sensitive X-ray observatory ever launched.
It sends back huge amounts of data on a range of
cosmic phenomena, including X-rays emitted by
hot gas falling into black holes.
Object 23
Source: University of Leicester Inv. No: L2009-4035
Catching UV rays
Mirror segment for FUSE (Far Ultraviolet Spectroscopic Explorer) satellite
Mid 1990s
This mirror segment has been left without its
reflective coating to reveal its lightweight
glass-ceramic structure. It was used in
developing NASA’s FUSE satellite. During its
eight-year run, each of FUSE’s four mirrors
collected ultraviolet light emitted by gas
atoms in deep space and focused them onto
the spacecraft’s detector.
FUSE mapped the distribution of deuterium,
a heavy type of hydrogen formed during the
Big Bang. By measuring how much deuterium
still exists, scientists can learn more about
how the young universe evolved.
Source: Johns Hopkins University Inv. No: L2009-4028
Object 24
Viewing the violent cosmos
Scale model (1:30) of a single telescope from the High Energy Stereoscopic System (HESS)
Namibia’s HESS observatory studies some of
the most violent events in the universe,
including exploding stars and supermassive
black holes. Its four identical telescopes detect
high-energy cosmic gamma rays produced by
these objects. Gamma rays are the most
energetic form of light known.
This model is one-thirtieth life size. Each of the
four telescope dishes is actually 12 metres
wide – 11/2 times the length of this showcase.
Object 25
Source: Purchased Inv. No: 2009-60
Detecting cosmic violence
Spare mirror segment for the High Energy Stereoscopic System (HESS)
c. 2002
This is a spare mirror segment for one of
HESS’s four gamma-ray telescopes. Gamma
rays are given off in violent cosmic events,
such as a star exploding. When these rays
are absorbed by the Earth’s atmosphere they
produce flashes of blue light. The telescope’s
mirror focuses this light onto a huge camera
to be recorded.
The scale model in front of this mirror shows
you how 382 segments like this would be
arranged on each telescope.
Source: University of Durham, Department of Physics Inv. No: 2009-44
Object 26
Catching cosmic explosions
Scale model (1:10) of Swift gamma-ray burst satellite
c. 2000
The Swift spacecraft responds to gamma-ray
bursts – unimaginably large explosions that
originate from all points of the cosmos.
Scientists are not sure exactly what causes
them. Within minutes of a gamma-ray burst
being detected, Swift can turn towards the
source and catch the associated visible and
X-ray light that is emitted, before it fades.
Swift is named after the bird because of its
ability to turn rapidly.
Object 27
Source: University of Leicester Inv. No: L2009-4034