Because I move your watch slows down.
Or as Alan Lightman said on a PBS documentary about Einstein, "different clocks in motion relative to each other tick at different rates."
We've been lead to believe this...it just makes sense, amirite???
Ed McQuarrie talks the REAL History of Stocks and Bond performance.
https://www.morningstar.com/funds/vanguard-wellesley-income-is-top-choice
Could be a great fund to start with starting in retirement and cash. Or use Vanguard Wellington and cash if you want to be more aggresive