Re: How tall would someone be if the they grew up on Mars?

Hello Gareth,

     That's an interesting question...one not so easily answered with 
something like "7 feet 8 inches using the following formula..."

     I can give you several considerations that would go into some good 
answers, mostly because there is no one good answer to this.

     The first thing that must have prompted your question is that when 
you look at the most obvious characteristic of Mars, compared to the 
earth, is that Mars is a smaller planet with less gravity exerted on its 
would-be inhabitants.  Specifically, the gravitational pull of Mars on 
this individual would be 37.5% what it is on you and me.  Thus, it is a 
very astute observation to say that with less pulling us down, could we 
conceivably grow taller.  For instance, we need only look to our own 
planet for some examples such as the people living in Tibet or other high 
altitude locations like in the Andes mountain range, who are somewhat 
taller and have larger lung capacities.  So, this is correct to a point, 
since gravity is not the only factor deciding how tall this mars 
inhabitant could get...

     A person growing up on Mars would also experience another result of 
a lower gravity environment.  Imagine that the vertebrae in your back 
form a giant spring. Pushing down on the spring keeps it coiled tightly. 
When this force is released, the spring stretches out. In the same way, 
the spine elongates under less gravity.  So, a lower grav environment 
like Mars would also let the spine "spring" be less tightly coiled, 
adding potentially another few centimeters to the person's height.  We 
have actually observed this in all of the astronauts that we send up into 
space.  Matter of fact, they engineer their spacesuits with a little 
extra room just for this change.  Even here on earth, lying down to sleep 
takes pressure off the "coil" and thus you might actually be a tad taller 
when you wake up in the morning!

     Another determining factor that would still apply on Mars as it does 
here on Earth would be the instructions that the person carries in their 
DNA...Conceivably after many generations of humans inhabiting Mars, we 
might see taller and taller people as a result of evolutionary tweaking 
from the new environment... assuming that taller people are healthier on Mars
than shorter people.

In addition to this genetic determination there is also the affect 
of nutrition.  Some studies have indicated that nutritional deficiencies 
can result in decreased height potential.  

     So, to bring it all together, you have a few factors that would most 
likely lead to a taller human growing up on the planet Mars.

     Just as a side thought for you to think about, a lower grav 
environment also makes it easier for the body to pump blood (e.g., up 
from the legs to the heart) and puts less stress on the bones, muscles, 
and blood vessels.     

I hope this helped.  Let us know if this sparked any new questions...

Tye "A Tall Mad Scientist"