Cosmic Expansion: Universe Stretches, We don't

Physicists believe that we exist in an expanding universe. But what does that mean? Do our habitats, bodies, and atoms "blow up" as the spacetime fabric stretches?

In the early 20th century, scientists, including famed astronomer Edwin Hubble, concluded that our universe is expanding based on Hubble's observation that distant galaxies are receding from the Earth. This idea is built on the redshifted light emitted from these remote objects, a seemingly showcase of the Doppler effect.

But it's worth noting that the redshift in this backdrop isn't truly a Doppler effect of electromagnetic waves. Instead, it's due to the expansion of space (also known as cosmological redshift). In other words, while the fabric of spacetime gets stretched by the dark energy, every atom inside of our body and planet are still bound together by gravitational force and electromagnetism. Therefore, the cosmic expansion won't cause our world to go puff.

Source: Veritasium via Youtube