ALMA – the birth of a giant telescope

Every time we see an image taken by a space or ground telescope, we mostly hear about the image itself and not the tool that took it, and which “opened” our eyes to the Universe. What do we know about these eyes on the sky, which can see much farther and sharper than our own physical eyes, and the people who built them? Usually nothing. In this four-page special feature, Sandra Kropa, science journalist with Latvian Public Radio, tells the incredible story behind one of them.

Sandra Kropa at the 5,000-metre high ALMA observatory in Chile. She clutches a can of oxygen because the air is twice as thin as at sea level. Credit: Sandra Kropa

Changing skies

For thousands of years, mankind has looked at the sky and asked itself some of the most challenging questions: Are we alone in the Universe? Where do we come from?

Isn’t it interesting that after 3000 years, we have achieved such technological progress that we can send robots to Mars and spacecrafts to the confines of the Solar System, and yet, we still ask ourselves the same questions? Are we closer to the answers now, having built huge telescopes on Earth and even in space?

While we don’t have one indisputable answer to the question of our cosmic origin yet, we know much more than our ancestors did – we can look much deeper in the Universe to understand the book of astronomy. But not only thanks to better instruments.

The night sky we have access to is also very different from the one ancient Greeks and Babylonians saw. For more than 50 years now, Europeans and others have moved far beyond their geographical borders to the southern hemisphere where the sky offers much better conditions to observe the Universe.

This is the place where the world’s most powerful telescopes are being built! Why? Because the southern skies are clearer – with less light pollution than in Europe – and also give astronomers access to two very special features of the sky: a view of the centre of our galaxy, the Milky Way, and of the Magellanic Clouds – two little dwarf galaxies orbiting our own.

It’s better together

Like astronauts who can’t travel to space without the cooperation of hundreds, even thousands, of other people who provide technical, scientific and financial support, astronomers alone cannot observe the Universe without the help of many others. Today, to remain competitive and achieve groundbreaking science, many European countries have come together to create the largest and one of the most powerful astronomy organisations in the world – the European Southern Observatory (ESO).

Cooperation is the key that enabled Europe to expand its sky and reach the other hemisphere. The world’s most advanced optical instrument in the world – the Very Large Telescope (VLT), was built between nine ESO countries and is located very far away from Europe indeed – in Chile.

Chile also hosts one of the largest astronomical projects in existence: the Atacama Large Millimetre/submillimetre Array (ALMA), a radio telescope made up of 66 antennas so powerful it can detect molecules in distant interstellar clouds of dust and gas. To achieve this, the Europeans worked with the Americans and the Japanese – involving some 20 countries in total in the project.

ALMA is a large project with many partners who could have different interests but as Richard Kurz, who was overall ALMA Project Manager at the Joint ALMA Observatory reveals, the cooperation within the European side was easiest due to the existence of ESO. He says: “It provided an established common framework for cooperation between the member countries. It was necessary to reach out and enlist the involvement of the relevant scientific organisations in the ESO member states because that is where most of the European scientific/technical expertise essential to building ALMA was located.”

The VLT and ALMA have already shown their power, providing exciting results about the formation and evolution of nearby planetary systems and seeing through dark and cold regions of the Universe, telling us ever more about our cosmic origin. But Galileo’s telescope and the most powerful telescopes on Earth such as the VLT and ALMA have at least one thing in common – they all started from an idea. Page 2 >>

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