Final answer:
Evidence for early universe inflation includes the uniformity of the cosmic microwave background (CMB) and the flatness of the universe, which align with predictions by Grand Unified Theories. Current technology is still seeking definitive proof, such as gravitational wave imprints on the CMB.
Step-by-step explanation:
The evidence that supports the theory of inflation in the early universe includes the flatness and uniformity of the cosmos, the cosmic microwave background (CMB), and the consistency with Grand Unified Theories (GUTs). The CMB is particularly significant as it provides a snapshot of the universe when it was around 380,000 years old, which shows uniformity across the sky. This uniformity, along with the very flat large-scale geometry of the universe, cannot be easily explained by the standard Big Bang model alone. The concept of inflation proposes a rapid expansion of the universe that occurred shortly after the Big Bang, resolving these puzzles. Potential evidence such as variations in density and produced gravitational waves might have left a detectable imprint on the CMB, which could support the inflation theory, though current technology has not yet definitively confirmed this. Still, these observations and the alignment with theoretical predictions provide the best indirect evidence of inflation that we have today.