Explain why scientists think that Ganymede's interior includes ice

Ganymede has a very thin atmosphere and its average surface temperature is -171 degrees F. so it would obviously require an external suit for protection from the elements and to store, filter and convert oxygen to a form breathable by humans, as Ganymede has a largely oxygen composed atmosphere but not in the form or density humans need. For a size comparison, here is a picture of Earth, our moon and Ganymede all side by side. Ganymede is the medium sized of the three in the bottom left-hand corner.

It has a liquid-iron core which provides a small magnetosphere for protection from radiation but Jupiter’s magnetosphere substantially over powers it. The surface gravity is slightly more than a tenth of Earth’s, so I’d personally enjoy the lesser effort required to move my big bones around. As with most moons, Ganymede is tidally-locked, meaning that one side always faces Jupiter and one side always faces outward. This means a few things but most importantly to your question, it means that Jupiter’s gravity pulls hard enough, continuously on the same side to provide some geothermal activity. Those warm spots would provide opportunities for energy gathering and further scientific study.

Maybe the most important part of Ganymede’s potential habitability is that we believe it has a huge underground salt-water ocean which could be used in many ways to sustain a colony. The only obstacle is that much and/or all of the technology we are talking about that would be required, is not yet in existence.

the african cheetah.

this species has a relatively low level of genetic

variation because the population was reduced to a small size approxi-

mately 10,000 to 12,000 years ago.

chapter   outline

24.1

genes in populations and the hardy-

weinberg equation

24.2

factors that change allele and genotype

frequencies in populations

24.3     sources of new genetic variation

population   genetics

24

until   now,   we   have   primarily   focused   our   attention   on   genes  

within   individuals   and   their   related   family   members.   in   this  

chapter   and   chapters   25   and   26   ,   we   turn   to   the   study   of   genes   in  

a   population   or   species.   the   field   of

population   genetics

  is   con-

cerned   with   changes   in   genetic   variation   within   a   group   of   indi-

viduals   over   time.   population   geneticists   want   to   know   the   extent  

of   genetic   variation   within   populations,   why   it   exists,   and   how   it  

changes   over   the   course   of   many   generations.   the   field   of   popu-

lation   genetics   emerged   as   a   branch   of   genetics   in   the   1920s   and  

1930s.   its   mathematical   foundations   were   developed   by   theoreti-

cians   who   extended   the   principles   of   gregor   mendel   and   charles  

darwin   by   deriving   formulas   to   explain   the   occurrence   of   geno-

types   within   populations.   these   foundations   can   be   largely   attrib-

uted to three scientists: sir ronald fisher, sewall wright, and j. b. s.

haldane.   as   we   will   see,   support   for   their   mathematical   theories  

was provided by several researchers who analyzed the genetic com-

position   of   natural   and   experimental   populations.   more   recently,  

population   geneticists   have   used   techniques   to   probe   genetic  

variation   at   the   molecular   level.   in   addition,   staggering   advances  

in   computer   technology   have   aided   population   geneticists   in   the  

analysis   of   their   genetic   theories   and   data.   in   this   chapter,   we   will  

explore   the   genetic   variation   that   occurs   in   populations   and   con-

sider   the   reasons   why   the   genetic   composition   of   populations   may  

change over the course of several generations