ALMA
In Search of Our Cosmic Origins
High on the desolate Chajnantor Plateau in the Chilean Andes.
One of the harshest environments on Earth.
Amid volcanoes ...
Desert plains ...
And bitter winds ...
ALMA — the Atacama Large Millimeter/sub-millimeter Array — is ready.
Astronomers and scientists all over the globe
have been eagerly anticipating this moment for decades.
ALMA is the world’s largest astronomical project.
But it is not a conventional telescope.
Instead of collecting and analysing visible light
it looks in a different and largely unmapped part of the spectrum.
By opening a new window on the cosmos,
ALMA explores one of the last frontiers of astronomy — the cold and distant Universe.
All in search of answers to some of the deepest questions about our cosmic origins.
How do stars and planets form?
How did the first galaxies form?
The Chajnantor Plateau in North Chile.
Despite the — literally! — breath-taking altitude of 5000 metres above sea level,
ALMA has flourished.
Over the last few years,
more than 50 antennas have been installed across the high desert plain.
ALMA is a unique, giant telescope built in a partnership
between Europe, North America and East Asia, in cooperation with Chile.
Sixty-six state-of-the-art antennas will observe the Universe
at millimetre and submillimetre wavelengths
— one thousand times longer than visible wavelengths.
This light reaches us from some of the coldest
and most distant objects in the Universe.
Water vapour in the atmosphere blocks
these faint whispers from the hidden Universe,
so to collect them we have to go to to an extremely high and dry site
— like Chajnantor.
The Birth of ALMA
The origin of the ALMA project dates back decades.
Scientists from Europe, North America and East Asia
developed three individual concepts for new, large telescopes
for millimetre and submillimetre observations.
Eventually these concepts were merged into one.
Big science takes big global collaborations.
Together countries can achieve what they cannot do alone.
The whole is greater than the sum of its parts.
The ALMA project was born!
Finding the Right Site
This new telescope needed a home,
and eyes turned to Chajnantor.
Every aspect of the site, from the astronomical to the meteorological,
was thoroughly tested and the atmosphere monitored daily.
The conclusion: Chajnantor was the perfect place for ALMA.
Breaking Ground
Construction began in 2003 with the groundbreaking
for ALMA’s Array Operations Site.
Conditions here at an altitude of 5000 metres above sea level
are harsh and very challenging.
Strong winds.
Low temperatures.
Intense ultraviolet radiation.
And a desperately thin atmosphere.
So thin that to work here people need supplementary oxygen
and have to undergo rigorous health checks.
Forging the tools
The production of ALMA’s antennas has been shared
between the three ALMA partners.
Three prototypes were put through their paces at the ALMA Test Facility,
on the Very Large Array site, in the USA.
The 66 antennas on the high plateau are a critical part of ALMA.
Their big dishes collect the faint millimetre waves from space.
These antennas are truly the state-of-the-art.
Their surfaces are accurate to much less than the thickness of a sheet of paper.
They can move precisely enough to pick out a golf ball at a distance of 15 kilometres.
And they must survive, exposed to the elements, on Chajnantor!
Twenty-five antennas have been provided by the European Southern Observatory,
25 by the US National Radio Astronomy Observatory,
and 16 by the National Astronomical Observatory of Japan.
In a truly global endeavour,
the antenna components were constructed in several locations around the world,
sent to Chile to be assembled
and then tested at the Operations Support Facility,
in readiness for their first time observing the sky.
Linking the First Antennas
The first ALMA antenna was accepted and shortly thereafter
two antennas were successfully linked together.
Detectors in each antenna register the finest nuances
of the faint signals collected by the dishes.
These detectors are the most sensitive of their kind
and are cooled using helium gas
to just four degrees above absolute zero.
Reaching New Heights
The first completed antenna makes its way
up to the Array Operations Site.
Two custom-built transporter vehicles — Otto and Lore —
move the 100-tonne antennas around.
Otto carefully climbs the winding road,
carrying the high-tech antenna up
to its final home on the high plateau.
This first antenna was soon joined by many more.
Beating Expectations
The first observations using two, and then three
antennas in unison were made.
Key tests for the ALMA array.
And all passed with flying colours!
Millimetre and submillimetre wavelengths
give astronomers a unique window on the Universe.
But to see them with the sharpness astronomers need,
a single-dish telescope would have to be
kilometres across (and impossible to build)!
Instead, ALMA uses 66 separate antennas
which can be spread out over the plain
with separations of up to 16 kilometres.
The antennas are linked and their signals combined.
The result: one giant telescope as wide as the whole array,
observing with unprecedented sensitivity and resolution.
Making sense of these intertwined signals
takes the highest-altitude supercomputer in the world.
With 134 million processors,
performing 17 quadrillion operations per second
— as many as the fastest supercomputer in the world —
the ALMA correlator, on Chajnantor,
combines and compares the signals from every antenna.
As more and more antennas arrive at Chajnantor,
the Operations Support Facility, the control centre of the observatory,
takes shape at the slightly more hospitable altitude of 2900 metres.
The site is busy around the clock.
Operating the telescope.
Testing and maintaining antennas and other equipment.
And home for the ALMA staff
during their day- and night-shifts at the observatory.
Santiago Central Offices
In the capital of the host nation, Chile,
the ALMA Santiago Central Offices were built.
Here the technical, scientific and administrative staff
of the Joint ALMA Office is working.
Proving Excellence
Even before the construction stage was complete,
the first scientific observations began
with a partial array of antennas.
ALMA had opened its eyes!
Thousands of scientists from around the world
competed to be among the lucky few to use the facilities first.
Even with just 16 antennas
ALMA was already the most powerful telescope of its kind.
The first scientific observations fulfilled everyone’s hopes.
The Antennae Galaxies,
a pair of colliding galaxies with dramatically distorted shapes.
Visible light can show us the stars in the galaxies,
but ALMA reveals the clouds of cold, dense gas
from which new stars are born.
The heart of the distinctive galaxy Centaurus A.
ALMA peers through the opaque dust lanes that obscure its centre.
A view of the nearby star Fomalhaut provides clues
as to how planetary systems form and evolve.
Cosmic dust grains found around a brown dwarf
suggest that rocky planets
might even be more common in our Universe than we thought.
Sugar molecules, spotted around a young,
Sun-like star for the first time:
the building blocks of life in the right place, at the right time,
to be part of new planets forming around the star.
An unexpected spiral structure in the material around the old star R Sculptoris
revealed the secrets of this dying star.
Vast streams of gas
flowing across a gap
in the disc of material around a young star.
A key stage in the birth of giant planets,
observed for the first time.
And all this before the array was fully complete!
Towards New Horizons
ALMA’s inauguration celebrates its coming of age.
The journey has been a long one.
ALMA has grown from an idea,
to a construction project,
to a fully operational observatory,
and to a truly global scientific partnership.
In the serene and lonely beauty of the Chilean Atacama desert,
ALMA is ready for the future.
By using this marvellous telescope,
the world’s astronomers will peer deep
into the hidden secrets of the cosmos.
In search of our own cosmic origins!
ALMA
To all those whose curiosity drives them to ask the biggest questions
Transcription by ESO; translation by —