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Read the Inspiring ‘Questions of Existence’ Letter from the World’s Greatest Thinkers

6 minute read

On July 20, a consortium of scientists funded by billionaire investor Yuri Milner announced a $100 million project to scan the universe for signs of intelligent life. Milner, 53, a prescient technology investor, is also a former physicist. The endeavor, named Breakthrough Listen, is being supported by some of the world’s most well-known scientists and thinkers. As part of the announcement, the group release a letter explaining why the search matters and why it must continue. Here is the document in full.

Are we alone? Now is the time to find out

Who are we?

A mature civilization, like a mature individual, must ask itself this question. Is humanity defined by its divisions, its problems, its passing needs and trends? Or do we have a shared face, turned outward to the Universe?

In 1990, Voyager 1 swiveled its camera and captured the ‘Pale Blue Dot’ – an image of Earth from six billion kilometers away. It was a mirror held up to our planet – home of water, life, and minds. A reminder that we share something precious and rare.

But how rare, exactly? The only life? The only minds?

For the last half-century, small groups of scientists have listened valiantly for signs of life in the vast silence. But for government, academia, and industry, cosmic questions are astronomically far down the list of priorities. And that lengthens the odds of finding answers. It is hard enough to comb the Universe from the edge of the Milky Way; harder still from the edge of the public consciousness.

Yet millions are inspired by these ideas, whether they meet them in science or science fiction. Because the biggest questions of our existence are at stake. Are we the Universe’s only child – our thoughts its only thoughts? Or do we have cosmic siblings – an interstellar family of intelligence? As Arthur C. Clarke said, “In either case the idea is quite staggering.”

That means the search for life is the ultimate ‘win-win’ endeavor. All we have to do is take part.

Today we have search tools far surpassing those of previous generations. Telescopes can pick out planets across thousands of light years. The magic of Moore’s law lets our computers sift data orders of magnitude faster than older mainframes – and ever quicker each year.

These tools are now reaping a harvest of discoveries. In the last few years, astronomers and the Kepler Mission have discovered thousands of planets beyond our solar system. It now appears that most stars host a planetary system. Many of them have a planet similar in size to our own, basking in the ‘habitable zone’ where the temperature permits liquid water. There are likely billions of earth-like worlds in our galaxy alone. And with instruments now or soon available, we have a chance of finding out if any of these planets are true Pale Blue Dots – home to water, life, even minds.

There has never been a better moment for a large-scale international effort to find life in the Universe. As a civilization, we owe it to ourselves to commit time, resources, and passion to this quest.

But as well as a call to action, this is a call to thought. When we find the nearest exo-Earth, should we send a probe? Do we try to make contact with advanced civilizations? Who decides? Individuals, institutions, corporations, or states? Or can we as species – as a planet – think together?

Three years ago, Voyager 1 broke the sun’s embrace and entered interstellar space. The 20th century will be remembered for our travels within the solar system. With cooperation and commitment, the present century will be the time when we graduate to the galactic scale, seek other forms of life, and so know more deeply who we are.

Yuri Milner –

Founder, Breakthrough Prize; Founder, DST Global

Cori Bargmann –

Investigator, Howard Hughes Medical Institute; Torsten N. Wiesel Professor, The Rockefeller University

Sarah Brightman –


Magnus Carlsen –

World Chess Champion

Ding Chen –

Professor and Principle Investigator of the Search for Terrestrial Exo-Planets Mission, Chinese Academy of Sciences

Frank Drake –

Chairman Emeritus, SETI Institute; Professor Emeritus of Astronomy and Astrophysics, University of California, Santa Cruz; Founding Director, National Astronomy and Ionosphere Center; Former Goldwin Smith Professor of Astronomy, Cornell University

Ann Druyan –

Creative Director of the Interstellar Message, NASA Voyager; Co-Founder and CEO, Cosmos Studios; Emmy and Peabody award winning Writer and Producer

Stephen Hawking –

Professor, Dennis Stanton Avery and Sally Tsui Wong-Avery Director of Research, University of Cambridge

Paul Horowitz –

Professor of Physics and of Electrical Engineering, Emeritus, Harvard University

Garik Israelian –

Professor and Staff Astrophysicist, Institute of Astrophysics of Canary Islands

Lisa Kaltenegger –

Director, Carl Sagan Institute; Associate Professor of Astronomy, Cornell University

Nikolay Kardashev –

Deputy Director, Russian Space Research Institute, Russian Academy of Sciences

Mark Kelly –


Eric Lander –

President and Founding Director of the Broad Institute of MIT and Harvard; Professor of Biology, MIT; Professor of Systems Biology, Harvard Medical School

Alexey Leonov –


Avi Loeb –

Frank B. Baird Jr. Professor of Science, Chair of the Astronomy Department and Director of the Institute for Theory and Computation, Harvard University

Seth MacFarlane –

Writer, Director and Actor

Geoff Marcy –

Professor of Astronomy, University of California, Berkeley

Lord Martin Rees –

Astronomer Royal, Fellow of Trinity College; Emeritus Professor of Cosmology and Astrophysics, University of Cambridge

Kenneth Rogoff –

Thomas D. Cabot Professor of Public Policy and Professor of Economics, Harvard University; International Grandmaster of Chess

Dimitar Sasselov –

Phillips Professor of Astronomy, Harvard University; Founding Director, Harvard Origins of Life Initiative

Sarah Seager –

Professor of Planetary Sciences and Professor of Physics, MIT

Sujan Sengupta –

Associate Professor, Indian Institute of Astrophysics, Ministry of Science and Technology

Seth Shostak –

Professor, Senior Astronomer and Director, Center for SETI research

Thomas Stafford –

Jill Tarter –

Astronomer; Bernard M. Oliver Chair for SETI Research, SETI Institute

Kip Thorne –

Feynman Professor of Theoretical Physics Emeritus, California Institute of Technology; Scientific consultant and an executive producer, Interstellar

James Watson –

Chancellor Emeritus, Cold Spring Harbor Laboratory; Nobel Prize Laureate

Steven Weinberg –

Professor of Physics and Astronomy, University of Texas at Austin; Nobel Prize Laureate

Edward Witten –

Professor, School of Natural Sciences, Institute for Advanced Study

Pete Worden –

Chairman, Breakthrough Prize Foundation

Shinya Yamanaka –

Professor and Director of the Center for iPS Cell Research and Application, Kyoto University; Nobel Prize Laureate

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