The universe is approximately 13.8 billion years old.
We know this through scientific methods, most notably radiometric dating. Radiometric dating measures the radioactive decay of isotopes in a sample to determine its age. While this method is often applied to Earth rocks, it also plays a crucial role in understanding the age of the universe by dating very old stars and other celestial objects. As the reference states, the Earth itself is much younger than the universe, estimated to be around 4.5 billion years old.
Here's a summary table:
| Object | Estimated Age | Method Used |
|---|---|---|
| Universe | 13.8 Billion Years | Radiometric Dating of old stars/celestial objects, measuring the expansion rate of the universe |
| Earth | 4.5 Billion Years | Radiometric Dating |
In summary, radiometric dating and other astronomical observations provide strong evidence supporting the age of the universe being approximately 13.8 billion years.
