The Rest Is Science: Arecibo, SETI and The Paradox of Extraterrestrial Life

Overview

The Rest Is Science explores the Arecibo message, how it was crafted, and what it reveals about humanity when decoded from space. The episode also dives into the Fermi paradox, the Drake equation, SETI, and various explanations for why we have not yet detected intelligent life beyond Earth. Juxtaposed with lighthearted side discussions on lab grown diamonds and breakthrough technologies, the hosts reflect on what it means to describe ourselves to potential extraterrestrials and what we hope the future of science might hold.

What to expect

Readers will encounter a detailed walkthrough of the Arecibo message, critiques of its components, and a thoughtful conversation about the likelihood of life elsewhere in the cosmos, including the possibility that we are among the first intelligent civilizations. The episode also features listener questions on topics such as CRISPR and fusion energy, tying together astronomy with cutting edge biology and energy research.

Introduction and Scope

The Rest Is Science uses Field Notes as a platform to explore discoveries and riddles in science. In this episode, the conversation centers on humanity's attempts to communicate across interstellar distances, beginning with a close look at the Arecibo message that was transmitted in 1974 from Puerto Rico. The message was aimed at the M13 star cluster and encoded using a binary pattern that can be arranged into a 23 by 73 grid. The discussion explains that 1,679 is a semi-prime, the product of two primes, which allows the creators to design a reproducible decoding puzzle that must be arranged correctly to reveal any meaningful image or information.

The Arecibo Message: Structure and Decoding

The posters shown by the hosts illustrate the binary pulses that form the message, including a representation of numbers, atomic numbers, DNA, the human form, and the solar system. The episode delves into the complexity of decoding such a message, noting the need for shared numerical systems, understanding of bullet point conventions, and the bottom-to-top arrangement of certain binary components. It highlights how the message includes references to hydrogen, carbon, nitrogen, oxygen, and phosphorus, as well as the nucleotides and the double helix of DNA, and even a rough estimate of Earth's population in 1974. The discussion emphasizes that the planetoid Pluto is included, reflecting the 1970s view of the solar system, and acknowledges that later discoveries would alter some of this information.

Limitations and Critique

The hosts critique the execution of the Arecibo message, arguing that its practical decodability depends on several assumptions about receiving civilization's math, astronomy, and biology. They point out that the message was aimed at a moving cluster of stars, which means by the time the signal arrives, the target stars will have shifted position. They also note that the message carries some incorrect information by today’s standards, such as estimates of human base pairs and population, but that these mistakes are a product of the era in which it was created. The episode uses this example to explore broader questions about how we present ourselves to potential extraterrestrial intelligences and how to improve our methods of communication.

Fermi Paradox and Theories of Silence

The conversation shifts to the Fermi paradox and the Drake equation, exploring why we have not yet observed intelligent life despite the vastness of the universe. They discuss possible explanations, including the great filter, the zoo hypothesis, and the idea that civilizations might not last long enough to overlap in time. They consider the possibility that life is indeed plentiful, but perhaps we are not yet listening in the right way or at the right wavelengths, or that alien signals are beyond our current understanding.

Personal Theories and Outlook

The hosts offer personal reflections on whether we are truly alone, the long timescales of cosmic evolution, and the potential for humanity to become a more capable civilizational species through future technologies such as fusion energy and CRISPR gene editing. They acknowledge that predicting the trajectory of intelligent life is fraught with uncertainty, but they maintain a sense of optimism about scientific progress and the ongoing quest to understand our place in the cosmos.

Listener Interaction and Closing

The episode closes with questions from listeners about real world science topics like lab grown diamonds, the potential impact of fusion power, and how CRISPR has transformed medicine. The hosts discuss the role of science communication in shaping public understanding and invite listeners to engage further through email and newsletters.