Author Question: Why didn't the Big Bang produce many heavier elements than helium? What will be an ideal ... (Read 90 times)

xroflmao · **on:** Jul 27, 2018

Why didn't the Big Bang produce many heavier elements than helium?

What will be an ideal response?

Question 2

What is the most intriguing piece of evidence that suggests that the Martian meteorite ALH84001 may have once contained life?

A) molecules of DNA were found inside
B) oxygen gas was found trapped inside the meteorite
C) amino acids were found inside
D) highly magnified images of carbonate grains found inside reveal rod-shaped structures that look much like terrestrial nanobacteria

amandalm · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

By the time helium nuclei could exist in large numbers without being destroyed by the intense radiation field, the universe was about a minute old and the temperature and density were rapidly decreasing. Nuclear fusion reactions to produce heavier elements were possible, but the combination of two helium nuclei or a hydrogen nucleus and helium nucleus produces unstable nuclei. The combination of three helium nuclei produce carbon, but by this time the density of the universe was too low for many three-body collisions to occur. Thus the production of heavier elements had to wait until stellar nucleosynthesis.

Answer to Question 2

D