The Oldest Light Observed in the Universe!

Right after the Big Bang, everything was super hot and dense. Fast forward to today, the universe is much cooler and everything is spread way out. But here's the mind-blowing fact: there's still a faint echo of that hot, early universe floating around everywhere – it's called the Cosmic Microwave Background Radiation (CMBR). CMBR is the leftover heat from the Big Bang. After about 380 million years, as the universe expanded, things started to cool down. The particles rearranged, and instead of a mix of everything, most of the universe became neutral hydrogen gas (the simplest form of hydrogen). This change was crucial as it allowed light to travel freely, forming the oldest light we have observed in the universe.

CMBR isn't our average light. It's actually made up of super low-energy light particles called photons, mostly in the microwave range (like the ones that heat our food in a microwave). Our eyes can only see a certain range of light, called the visible spectrum. CMBR is mostly in the microwave range, which is invisible to us. A special kind of radio telescopes are used to detect it.

CMBR is like a fossil record of the early universe. It tells us a lot about what happened earlier in our univese and things like the temperature and composition of the universe. It's is an importance evidence for the Bib Bang. Scientists call it relic radiation because it's a leftover signal from a very distant past. The discovery of this important relic radiation was completely accidental! In the 1960s, two astronomers named Arno Allan Penzias and Robert Woodrow Wilson were trying to improve their radio telescope when they noticed this faint microwave signal coming from everywhere.

By studying the CMBR in even greater detail, scientists hope to unlock even more secrets about the universe's origin and its ultimate fate.