NASA Detects a 10-Second Signal Sent More Than 13 Billion Years Ago — And It Changes Everything We Thought We Knew About the Early Universe
There are moments in science that stop you cold. Not because they are loud or dramatic, but because the scale of what has just been discovered takes a few seconds to fully land. This is one of those moments.
NASA has detected a 10-second radio signal that left its source more than 13 billion years ago. To put that in context — the Earth itself is only about 4.5 billion years old. This signal was already ancient before our planet existed. Before our sun existed. Before almost anything in our corner of the universe existed at all.
And somehow, it reached us.
What Was Actually Detected and How
The signal was picked up by NASA’s Hydrogen Epoch of Reionization Array — known as HERA — a radio telescope located in the remote Karoo region of South Africa. HERA is not your average telescope. It was designed specifically for one purpose: to peer into one of the least understood chapters in the history of the universe, a period scientists call the cosmic dark ages.
The telescope uses extraordinarily sensitive receivers and advanced data processing systems to detect fluctuations in the faint background radiation that permeates the entire universe. This background radiation — known as the cosmic microwave background — is essentially the afterglow of the Big Bang, still faintly glowing across all of space more than 13 billion years later.
Within that faint glow, HERA found something that did not belong to the background noise. A 10-second signal, faint but distinct, originating from a time just a few hundred million years after the Big Bang itself.
What the Cosmic Dark Ages Actually Were
To understand why this discovery matters, you need to understand what the universe was like when this signal was sent.
The Big Bang happened approximately 13.8 billion years ago. For the first few hundred thousand years, the universe was so hot and dense that light could not travel freely — it was essentially a thick, opaque fog of energy and matter. When things cooled enough for hydrogen atoms to form, the fog cleared and the universe became transparent for the first time. This is the point from which the cosmic microwave background radiation originates.
But then something strange happened. The universe went dark.
There were no stars yet. No galaxies. Just vast clouds of hydrogen gas slowly drifting and clumping together under the pull of gravity and dark matter. This period — lasting hundreds of millions of years — is what astronomers call the cosmic dark ages. No light. No heat sources. Just cold gas and the slow, invisible work of gravity drawing matter together.
Eventually, the first stars ignited. The first galaxies began to form. Their radiation began to ionise the surrounding hydrogen, gradually lighting up the universe in a process called reionisation. It is from this exact transitional period — right at the edge of the dark ages ending — that this signal appears to originate.
Why a 10-Second Signal From 13 Billion Years Ago Is So Significant
Scientists have been trying to study the cosmic dark ages for decades. The problem is that you cannot see darkness. There is nothing to photograph. No visible light to capture. Conventional optical telescopes are essentially useless for this period of cosmic history.
Radio telescopes like HERA work differently. They detect radio waves rather than visible light, and hydrogen gas — the dominant material of the early universe — emits a specific radio frequency known as the 21-centimetre line. By detecting fluctuations in this signal across the sky, astronomers can essentially map where hydrogen gas was concentrated in the early universe and infer what was happening to it.
What makes this particular detection remarkable is its age and clarity. Signals from this era are incredibly faint by the time they reach us, having travelled across billions of light years and billions of years of time. The fact that HERA was able to isolate and identify this signal against the background noise is itself a significant technological achievement.
More importantly, what the signal appears to show is a galaxy in the earliest stages of formation — hydrogen gas beginning to organise itself into something coherent, under conditions that existed nowhere in the modern universe.
What This Tells Us About How Galaxies Are Born
One of the biggest open questions in cosmology is how the first galaxies actually formed. We know roughly when it happened. We have theoretical models that predict how it should have happened. But direct observational evidence from that period has been extraordinarily difficult to gather.
This signal offers something rare — a direct data point from the formation era itself.
By analysing the frequency, intensity, and duration of the signal, researchers can begin to probe the physical conditions inside this early galaxy. How dense was the gas? How hot? What role was dark matter playing in pulling it together? Were the first generation of stars — known as Population III stars — already beginning to ignite within it?
Population III stars are of particular interest to astronomers because they were unlike anything that exists today. Formed from pure hydrogen and helium with essentially no heavier elements present, these stars are thought to have been enormous — potentially hundreds of times more massive than our sun — burning intensely hot and dying young in massive explosions that seeded the surrounding space with heavier elements for the first time.
Everything we see in the universe today — every rock, every ocean, every human body — contains atoms forged in the hearts of stars. The first generation of those stars set the entire chain in motion. This signal may be our closest look yet at the environment in which they first appeared.
The Technology That Made This Possible
A discovery like this does not happen by accident. It is the result of years of careful instrument design, data collection, and analysis by teams of scientists across multiple countries.
HERA is a remarkable piece of engineering. Situated in one of the most radio-quiet locations on Earth — the South African Karoo desert, far from the interference of cities and electronics — it consists of hundreds of dish antennas working together to create an extraordinarily sensitive detector. The array is specifically tuned to the frequencies associated with hydrogen emission from the epoch of reionisation, making it uniquely suited to exactly this kind of detection.
The data processing required to pull a genuine signal out of the background noise is also a significant undertaking. Cosmic microwave background radiation, interference from the Earth’s ionosphere, and the radio emissions of our own galaxy all have to be carefully modelled and subtracted before the faint traces of a 13-billion-year-old signal can be identified with confidence.
The fact that this has now been achieved represents a genuine step forward in observational cosmology — not just a scientific result, but a demonstration that this kind of detection is possible.
What Comes Next for Deep Universe Research
This detection is not the end of something. It is the beginning of a new chapter in how we study the early universe.
With the James Webb Space Telescope already returning extraordinary images of the earliest galaxies, and next-generation radio arrays being planned and built around the world, the tools available to cosmologists are becoming more powerful every year. The Square Kilometre Array — a massive international radio telescope project with components in both South Africa and Australia — will dwarf HERA in sensitivity when fully operational, and is expected to produce detections like this one routinely rather than as rare events.
For Australian scientists and institutions, this is particularly relevant. Australia is a co-host of the SKA project, meaning the country will be at the physical heart of the next generation of deep universe research. Discoveries that currently make global headlines will become part of a regular stream of findings emerging from facilities built on Australian soil.
The 10-second signal NASA has now detected is a glimpse through a narrow window. What is coming will throw those windows wide open.
What It Means for Our Understanding of Where We Came From
There is a question that sits beneath all of this science, one that is not strictly technical but is nonetheless deeply human: why does it matter?
The honest answer is that understanding the early universe is understanding our own origins at the most fundamental level possible. The atoms in your body were forged in stars. Those stars formed from gas clouds shaped by conditions set in place in the first billion years of cosmic history. The signal HERA detected is not just a piece of astronomical data. It is, in a very real sense, a record of the processes that eventually led to everything — including us.
That 10 seconds of radio signal, faint as a whisper across 13 billion years of space and time, is the universe leaving us a message about how it began. Scientists are only just starting to read it.
Key Facts
| Signal duration | 10 seconds |
| Signal age | More than 13 billion years |
| Detected by | NASA’s HERA telescope, South Africa |
| Period of origin | Cosmic dark ages — shortly after the Big Bang |
| Key implication | Direct evidence of early galaxy formation |
Frequently Asked Questions
How did NASA detect a signal from 13 billion years ago? Using the HERA radio telescope in South Africa, which is specifically designed to detect faint radio emissions from the early universe. The telescope picks up hydrogen gas signals from the period when the first galaxies were forming.
What is the cosmic dark ages? It is the period of several hundred million years after the Big Bang when no stars existed yet. The universe was filled with cold hydrogen gas and dark matter, with no light sources present.
What is so special about a 10-second signal? Its age and origin. Signals from this era of cosmic history are extraordinarily faint and difficult to isolate from background noise. Detecting one this clearly is a significant technological and scientific achievement.
What are Population III stars? The first generation of stars in the universe, formed from pure hydrogen and helium. They are thought to have been massive and short-lived, and their deaths seeded the universe with the heavier elements that make all later chemistry — and life — possible.
Does this discovery change what we know about the Big Bang? It does not challenge the Big Bang model, but it provides direct observational evidence that supports and refines our understanding of what happened in the hundreds of millions of years that followed it.
What is the Square Kilometre Array and why is Australia involved? The SKA is the world’s largest planned radio telescope, with components in South Africa and Western Australia. When complete, it will be far more sensitive than any existing radio observatory and is expected to transform our ability to study the early universe.
