When we imagine contact with extraterrestrial intelligence, we tend to picture messages: radio signals, mathematical codes, or perhaps a universal language waiting to be discovered. But what if alien beings don’t “speak” in any sense we understand? What if the bridge between our worlds isn’t language at all, but physics?
In a recent episode of SETI Live, theoretical physicist Dr. Daniel Whiteson, co-author of Do Aliens Speak Physics?: And Other Questions about Science and the Nature of Reality (2025), joined SETI Institute communications specialist Beth Johnson to explore how the laws of the universe themselves might form the foundation for contact with other civilizations.
Communication Without Words
Interstellar communication is often envisioned through symbols such as mathematical progressions or encoded radio pulses. SETI science has long assumed that intelligent beings might send structured signals to demonstrate intent. But as Dr. Whiteson asks, “Even if we receive something that looks structured, how do we know what it means? How do we know they’re trying to say anything at all?”
Human language evolved through shared experience and biology. Alien minds might perceive reality through entirely different senses or dimensions. For such beings, our concepts of “signal” or “pattern” might be meaningless. Yet there’s one thing that all intelligent life would share: the same physical universe.
Physics as a Universal Grammar
While languages are unique to each species, physics may be the only true universal grammar. The laws that govern gravity, electromagnetism, and atomic structure apply everywhere from Earth to the most distant galaxy. For scientists at the SETI Institute, this universality provides a foundation for imagining how communication might transcend biology and culture.
A hydrogen atom behaves the same way no matter who observes it. The wavelengths of light it emits are constants of nature. Any civilization capable of doing science would encounter those same patterns. Physics is what reality tells us, whether we’re listening in English, Mandarin, or electromagnetic waves.
Still, interpretation remains a human act. Another civilization might understand the same laws through entirely different sensory or conceptual frameworks. Their equations may be unrecognizable to us, yet they are rooted in the same truths. That shared reality may be the only true common ground between species separated by light-years.
Signals Written in the Stars
If physics forms the basis for communication, what might that look like in practice?
Researchers at the SETI Institute search for structured signals that reveal deliberate intent—sequences of pulses, prime numbers, or patterns unlikely to occur naturally. Such transmissions could represent an attempt by another civilization to announce its presence using the logic of the physical world.
But recognition is only the first step. Even if a signal clearly shows signs of intelligence, its meaning may remain elusive. Dr. Whiteson likens the challenge to interpreting ancient cave paintings: we recognize their creators as thinking beings, but the meanings of the symbols are often lost to time.
The question, then, isn’t only whether we can detect a message, but whether we can comprehend its intent.
Listening to the Universe
Dr. Whiteson’s reflections reach beyond alien contact. Physics itself, he suggests, is a kind of ongoing dialogue between humanity and the cosmos. Every experiment is a question posed to the universe, and every observation is an answer. This spirit of inquiry underlies both science and the SETI Institute’s search for intelligence beyond Earth: a humble acknowledgment that meaning begins with listening.
“We’re constantly in conversation with the universe,” Dr. Whiteson says. “Each time we measure, we’re learning how reality speaks.”
A Shared Reality
So, do aliens speak physics? Perhaps the question isn’t about extraterrestrials at all, but about what connects us to the cosmos. The laws of physics form a shared reality that unites all matter and energy, whether on Earth or in distant galaxies. By grounding our search for life in these universal principles, SETI science is not only seeking out others but also refining humanity’s understanding of its own place in the universe.
“If we ever make contact,” Whiteson concludes, “it won’t be because we spoke the same language. It’ll be because we lived in the same reality.”
Watch the full SETI Live conversation with Dr. Daniel Whiteson here.
Read more about Dr. Whiteson’s book Do Aliens Speak Physics?: And Other Questions about Science and the Nature of Reality (2025).