Scientists Detect 13-Billion-Year-Old Light Signal from Earth for the First Time

Scientists appear to have used Earth-based telescopes to identify a signal that is 13 billion years old. This achievement is considered a very exceptional achievement for humans. Through this achievement, they were able to observe the effects of the first stars on the light released by the Big Bang. 

Measurements of polarized microwave light helped astronomers better understand what is referred to as Cosmic Dawn. Using telescopes located high in the northern Chilean Andes, they were able to trace this. The term "Cosmic Dawn" describes the time frame of 50 million to one billion years following the Big Bang, when the first galaxies, stars, and black holes are said to have formed.

First-Ever Ground-Based Detection of Cosmic Dawn Signals

For the first time, scientists have successfully recorded signals from the Cosmic Dawn using ground-based telescopes. This breakthrough was led by Professor Tobias Marriage of Johns Hopkins University (JHU). Until now, many experts believed this was impossible to achieve from Earth.
“Microwave signals from the Cosmic Dawn are famously difficult to measure, and astronomy is a technology-limited field,” Marriage stated on the JHU website. He added, “This measurement is a major accomplishment because those challenges have been overcome.”

Why Cosmic Dawn Signals Are Hard to Detect

Cosmic microwave signals have a wavelength of only a few millimeters, making them extremely hard to detect. The signal from polarized microwave light is about a million times weaker than ordinary signals.
On Earth, these faint signals face several disturbances like:

• Broadcast radio waves

• Radar and satellites

• Weather and atmospheric changes

• Fluctuations in ground temperature

According to the researchers, even under perfect conditions, measuring these microwaves requires extremely sensitive instruments.

Special Telescopes Used to Detect Early Star Light

To make this discovery, the scientists used specially built ground-based telescopes from the Cosmology Large Angular Scale Surveyor (CLASS) project by the US National Science Foundation. These instruments were specifically designed to detect light from the first stars in the Big Bang’s leftover glow.

Until now, only space-based telescopes—like the European Space Agency’s Planck and NASA’s WMAP—could detect such signals.