Tuesday, December 12, 2023
Thursday, November 2, 2023
Life on Earth
We saw that the universe was born in the Big Bang about 14 billion years ago. After the initial hot, dense fireball of creation cooled sufficiently for atoms to exist, all matter consisted of hydrogen and helium (with a very small amount of lithium). As the universe aged, processes within stars created the other elements, including those that make up Earth (such as iron, silicon, magnesium, and oxygen) and those required for life as we know it, such as carbon, oxygen, and nitrogen. These and other elements combined in space to produce a wide variety of compounds that form the basis of life on Earth. In particular, life on Earth is based on the presence of a key unit known as an organic molecule, a molecule that contains carbon. Especially important are the hydrocarbons, chemical compounds made up entirely of hydrogen and carbon, which serve as the basis for our biological chemistry, or biochemistry. While we do not understand the details of how life on Earth began, it is clear that to make creatures like us possible, events like the ones we described must have occurred, resulting in what is called the chemical evolution of the universe.
Saturday, June 24, 2023
Subscribe to:
Posts (Atom)
-
angular momentum the measure of the motion of a rotating object in terms of its speed and how widely the object’s mass is distributed arou...
-
Gravity is a “built-in” property of mass. Whenever there are masses in the universe, they will interact via the force of gravitational attra...
-
Kepler initially assumed that the orbits of planets were circles, but doing so did not allow him to find orbits that were consistent with Br...
