Life in Vastly Different Universes

[Krunchyman]

I have two questions: I have often heard physicists such as Victor J. Stenger argue that life could evolve and thrive in universes with physical constants vastly different than our own. I am curious to know what kind of universes these physicists propose. Can physical constants counterbalance each other to form stable universes i.e. weak gravity being countered by a stronger value of other forces?

Secondly, are stars necessary for the creation of complex elements which will form the backbone of life? Consider a universe where instead of stars forming, the only structure that forms is a molecular cloud filled with gas or plasma. Here, gravity is strong enough for molecules to bind but stars do not form or are very weak. The only molecules that exist are hydrogen, helium and perhaps a few other elements such as carbon. Despite this, self-replicating molecules form from the sheer number of atoms interacting with each other over time. Are life-harboring universes such as this conceivable?

 

[soothsayer]

Hi Krunchyman!

Two really good questions. It's hard to give a definite answer, because we are talking about a completely new universe we have no experience with, but I'll give it a try

I think it's entirely possible that a universe with slightly different physical constants could still harbor life. No doubt, this life would be significantly different. If you alter the strength of the electromagnetic force, or nuclear force, for example, the atoms in this universe will look completely different from those in our universe, but there is no reason to think that these new atoms and elements would necessarily be incapable of creating life like the ones in our universe did. Certainly, one relationship between constants that should be most important to life is the balance between gravity and the nuclear force. I feel as though nuclear fusing stars are essential to life, as they are the power plants of energy in the universe, and also responsible for the diversity of elements. It's hard to imagine life arising in a universe where stars cannot ignite.

This brings me to the second question, I don't think what you're proposing is possible. In our own universe, the heaviest element created in the Big Bang was Lithium. We had Hydrogen (its isotope Deuterium), Helium and Lithium, but no Carbon. These elements certainly collected in molecular clouds to form the first stars, but in a universe where ignition is not possible, no other elements would be formed. There are really very few chemical possibilites, as helium is inert, and hydrogen and lithium can form Lithium hydrite, LiH, and we can get Dihydrogen, H₂, but that's about it. No other elements will ever form. Now, the creation of this other universe could be very different, in that its formation could have resulted in the creation of many more, heavier elements that could bond to create life, but as I mentioned before, without energy from stars, it's doubtful anything could have arose. Imagine how planets and atmospheres would also be different. If there were life, it would be vastly different from what we have on Earth.

 

[Chronos]

The question does not generate much interest so long as there is no evidence other universes actually exist. It is, of course, interesting to discuss possible ways to detect other universes. A paper to this effect shows up on arxiv once in a great while. This, however, may turn out to be impossible.