# Fine Tuning of the Universe

I'm an A level student looking into the fine tuning of various constants. Physicists explain the extensive effects that would happen if these constants were to be changed/different and hence, how this affects the probability of life existing. What I fail to understand is why, if these constants were to be different, life wouldn't adapt to these changes. If gravity was stronger, then wouldn't the general muscle mass/stability of life be greater through evolution in order to withstand a greater force? Or am I looking at it from the wrong perspective? Some clarification on this would be appreciated.

• It's more fundamental than that: if certain constants were different, it could prevent stars and planets from forming, much less allow liquid water to exist, and then allow for organic chemistry as we know it. – Dmitry Brant Mar 27 at 20:22

• also look at the triple $\alpha$ process (en.wikipedia.org/wiki/Triple-alpha_process) which appears terribly fine tuned, and is the only way to make lots of carbon and oxygen, which are life's favorite elements. – JEB Mar 27 at 22:16
• The proton-proton chain does start by making a diproton (aka $^2_2\mathrm{He}$), which by the weak force can turn into a deuteron, but normally the diproton just falls apart instead. According to Ben's answer here the number of times a solar core proton makes a diproton before it suceeds in making a deuteron is on the order of $10^{23}$. So stars would have very short lifespans if the diproton were stable. – PM 2Ring Mar 28 at 8:13