{"id":314792,"date":"2025-08-03T14:41:10","date_gmt":"2025-08-03T14:41:10","guid":{"rendered":"https:\/\/www.europesays.com\/uk\/314792\/"},"modified":"2025-08-03T14:41:10","modified_gmt":"2025-08-03T14:41:10","slug":"its-deeper-than-darkness-cosmic-dawn-signal-reveals-13-billion-year-echo","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/uk\/314792\/","title":{"rendered":"It\u2019s deeper than darkness \u2014 Cosmic dawn signal reveals 13\u202fbillion-year echo"},"content":{"rendered":"

Have you ever thought about hearing a whisper from 13 billion years ago<\/strong>? Besides being almost poetic, we thought it impossible, but that\u2019s exactly what happened. For the first time, telescopes here on Earth have managed to capture the silent echo of the universe\u2019s first stars, born shortly after the Big Bang, in a period known as the cosmic dawn. Until then, this type of signal could only be observed with equipment in space, but scientists have broken that barrier. And the feat isn\u2019t just technical; in fact, it could change the way we understand the birth of light in the universe.<\/p>\n

What erased the universe\u2019s fog? Mysterious dawn that reshaped light itself<\/p>\n

We must remember that in the first moments after the Big Bang, the universe was a dense soup of charged particles\u2014electrons everywhere, so tightly packed that light simply couldn\u2019t pass through. It was like an endless cosmic fog. However, over time, the universe cooled, and protons began capturing electrons, forming neutral hydrogen atoms. And only then was light able to break free. This light is what we know today as the cosmic microwave background<\/strong>, a kind of fossil glow from the birth of the universe.<\/p>\n

However, this light didn\u2019t remain untouched. When the first stars appeared (during the cosmic dawn), they changed everything. This is because, with their power, they ripped electrons from hydrogen atoms, disrupting the path of light traveling through them. This process is called reionization; understanding how it happened is essential to deciphering cosmic history.<\/p>\n

Can we hear the universe whisper? Cosmic signal buried in Earth\u2019s noise<\/p>\n

The problem is that detecting this type of light, specifically the polarized microwaves coming from the cosmic aurora, is a nearly impossible task.<\/strong> That\u2019s because the signal is weak, about a million times more subtle than the interference we experience here on Earth, such as radio, radar, satellites, even weather. To put it mildly, it was like trying to hear a cricket whispering in the middle of a rock concert.<\/p>\n

Until the US National Science Foundation\u2019s CLASS project telescopes (different from, but just as important as, the James Webb)<\/a> arrived, installed at an altitude of over 5,000 meters in the Chilean Andes. They were built precisely for this challenge. With extreme precision, they managed to isolate this cosmic whisper and, most importantly, confirmed its reality by comparing it with data from space missions like Planck and WMAP.<\/p>\n

Their idea was to search for a \u201ccommon signal\u201d,<\/strong> a kind of signature that could only come from the cosmic aurora. Just as polarized sunglasses eliminate annoying reflections, the researchers used technological filters (and a lot of calculations) to eliminate noise and focus only on the light that matters.<\/p>\n

\n

\u201cUsing the new common signal, we can determine how much of what we\u2019re seeing is cosmic glare from light bouncing off the hood of the cosmic dawn, so to speak\u201d, said first author Yunyang Li.<\/p>\n<\/blockquote>\n

Ground-based telescopes just did the impossible: Universe\u2019s oldest secrets are next<\/p>\n

We must keep in mind that this advance is not just a technical feat; on the contrary, it has enormous implications. First, it helps us understand how light behaved in the first billions of years.<\/strong> This helps us refine models about the birth of the first galaxies, stars, dark matter itself, and neutrinos, the particles that are ubiquitous but remain a mystery in many ways.<\/p>\n

We now know it\u2019s possible to take this deep reading without leaving the planet<\/strong>, which opens up new possibilities for terrestrial astrophysics. In other words, what was previously only possible with space telescopes is now being done by instruments down here, with greater flexibility and lower cost\u2026 It\u2019s no wonder other signals from nearly 10 billion years ago have recently been detected.<\/a><\/p>\n

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