The Washington PostDemocracy Dies in Darkness

Intelligent life probably exists on distant planets — even if we can’t make contact, astrophysicist says

Hakeem Oluseyi: “I have gone on to spend much of my career working with other astrophysicists to develop telescopes and detectors that peer into the remote reaches of space and measure the structure and evolution of our universe.” (Freddie Claire)

Recently released Navy videos of what the U.S. government now classifies as “unidentified aerial phenomena” have set off another round of speculative musings on the possibility of aliens visiting our planet. Like other astrophysicists who have weighed in on these sightings, I’m skeptical of their extraterrestrial origins. I am confident, however, that intelligent life-forms inhabit planets elsewhere in the universe. Math and physics point to this likely conclusion. But I think we’re unlikely to be able to communicate or interact with them — at least in our lifetimes.

Wanting to understand what’s “out there” is a timeless human drive, one that I understand well. Growing up in poorer and rougher neighborhoods of Watts, Houston’s Third Ward and the Ninth Ward of New Orleans, I was always intrigued by the night sky even if I couldn’t see it very easily given big-city lights and smog. And for the sake of my survival, I didn’t want to be caught staring off into space. Celestial navigation wasn’t going to help me find my way home without getting beaten up or shaken down.

From early childhood, I compulsively and continuously counted the objects in my environment — partly to soothe my anxieties and partly to unlock the mysteries inside things by enumerating them. This habit earned me nothing but taunts and bullying in my hood where, as a bookish kid, I was already a soft target. But whenever I looked up at a moonless night sky, I wondered how I might one day count the stars.

By age 10, I’d become fascinated, even obsessed, with Einstein’s theory of relativity and the quantum possibilities for the multiple dimensions of the universe it opened up in my mind. By high school, I was winning statewide science fairs by plotting the effects of special relativity on a first-generation desktop computer.

So perhaps it’s not surprising that I have gone on to spend much of my career working with other astrophysicists to develop telescopes and detectors that peer into the remote reaches of space and measure the structure and evolution of our universe. The international Dark Energy Survey collaboration has been mapping hundreds of millions of galaxies, detecting thousands of supernovae, and finding patterns of cosmic structure that reveal the nature of dark energy that is accelerating the expansion of our universe. Meanwhile, the Legacy Survey of Space and Time will make trillions of observations of 20 billion stars in the Milky Way.

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What we’re discovering is that the cosmos is much vaster than we ever imagined. According to our best estimate, the universe is home to a hundred billion trillion stars — most of which have planets revolving around them. This newly revealed trove of orbiting exoplanets greatly improves the odds of our discovering advanced extraterrestrial life.

Scientific evidence from astrobiology suggests that simple life — composed of individual cells, or small multicellular organisms — is ubiquitous in the universe. It has probably occurred multiple times in our own solar system. But the presence of humanlike, technologically advanced life-forms is a much tougher proposition to prove. It’s all a matter of solar energy. The first simple life on Earth probably began underwater and in the absence of oxygen and light — conditions that are not that difficult to achieve. But what enabled the evolution of advanced, complex life on Earth was its adaptation to the energy of the sun’s light for photosynthesis. Photosynthesis created the abundant oxygen on which high life-forms rely.

It helps that Earth’s atmosphere is transparent to visible light. On most planets, atmospheres are thick, absorbing light before it reaches the surface — like on Venus. Or, like Mercury, they have no atmosphere at all. Earth maintains its thin atmosphere because it spins quickly and has a liquid iron core, conditions that lead to our strong and protective magnetic field. This magnetosphere, in the region above the ionosphere, shields all life on Earth, and its atmosphere, from damaging solar winds and the corrosive effects of solar radiation. That combination of planetary conditions is difficult to replicate.

Still, I’m optimistic that there have been Cambrian explosions of life on other planets similar to what occurred on Earth some 541 million years ago, spawning a cornucopia of biodiversity that is preserved in the fossil record. The more expert we become in observing and calculating the outer reaches of the cosmos, and the more we understand about how many galaxies, stars and exoplanets exist, the greater the possibility of there being intelligent life on one of those planets.

For millennia, humans have gazed in wonder at the stars, trying to understand their nature and import. We developed telescopes only a few hundred years ago, and since then the dimensions of our observable universe have expanded exponentially with technological advances and the insights of quantum physics and relativity. Beginning in the early 1960s, scientists have tried to calculate the odds of advanced extraterrestrial life. In 1961, researchers at the NASA-funded search for extraterrestrial intelligence (SETI) developed the “Drake Equation” to estimate how many civilizations in the Milky Way might evolve to develop the technology to emit detectable radio waves.

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Those estimates have been updated over the decades, most recently by Sara Seager’s group at MIT, based on observations of exoplanets outside our solar system by successive generations of advanced space-based telescopes — such as the Kepler Space Telescope, launched in 2009, and NASA’s MIT-led Transiting Exoplanet Survey Satellite, launched in 2018. Detecting the presence of life on exoplanets requires large telescopes outfitted with advanced spectroscopy instruments, which is what the James Webb Space Telescope will deliver when it launches in November.

In 1995 the first exoplanet was discovered orbiting Pegasus 51, 50 light-years distant from Earth. Since then, there have been more than 4,000 confirmed discoveries of exoplanets in our galaxy. More important, astronomers agree that almost all stars have planets, which radically improves the odds of our discovering intelligent life in the universe.

At the low end of consensus estimates among astrophysicists, there may be only one or two planets hospitable to the evolution of technologically advanced civilizations in a typical galaxy of hundreds of billions of stars. But with 2 trillion galaxies in the observable universe, that adds up to a lot of possible intelligent, although distant, neighbors.

If only one in a hundred billion stars can support advanced life, that means that our own Milky Way galaxy — home to 400 billion stars — would have four likely candidates. Of course, the likelihood of intelligent life in the universe is much greater if you multiply by the 2 trillion galaxies beyond the Milky Way.

Unfortunately, we’re unlikely to ever make contact with life in other galaxies. Travel by spaceship to our closest intergalactic neighbor, the Canis Major Dwarf, would take almost 750,000,000 years with current technology. Even a radio signal, which moves at close to the speed of light, would take 25,000 years.

The enormity of the cosmos confronts us with an existential dilemma: There’s a high statistical likelihood of intelligent life-forms having evolved elsewhere in the universe, but a very low probability that we’ll be able to communicate or interact with them.

Regardless of the odds, the existence of intelligent life in the universe matters deeply to me, and to most other humans on this planet. Why? I believe it’s because we humans are fundamentally social creatures who thrive on connection and wither in isolation. In the past year, many of us felt the hardship of isolation as deeply as the threat of a potentially fatal infectious disease. Enforced seclusion during the pandemic tested the limits of our tolerance for separation and made us acutely aware of our interdependence with all life on Earth. So, it’s no wonder that the idea of a trackless universe devoid of intelligent life fills us with the dread of cosmic solitary confinement.

For a hundred years, we’ve been emitting radio signals into space. For the past 60 years, we’ve been listening — and so far, in vain — for the beginning of a celestial conversation. The prospect of life on other planets remains a profound one, regardless of our ability to contact and interact with them. As we await evidence of extraterrestrial intelligence, I draw comfort from the knowledge that there are many powerful forces in the universe more abstract than the idea of alien intelligence. Love, friendship and faith, for example, are impossible to measure or calculate, yet they remain central to our fulfillment and sense of purpose.

As I head into my mid-50s, I look forward with an infinity of hope to the moment when humans will finally make contact with extraterrestrial intelligence — in whatever far-flung star system they may live, and in whatever century or millennium moment that momentous meeting may occur. Until that day, I have no doubt that generations of young humans around the globe will continue to stand watch, looking skyward with the same sense of amazement and wonder that intoxicated me as a young boy.

Hakeem Oluseyi, president-elect of the National Society of Black Physicists, has taught and conducted research at MIT, University of California at Berkeley and the University of Cape Town. His memoir, “A Quantum Life: My Unlikely Journey from the Street to the Stars,” co-written with Joshua Horwitz, was published last week.

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