January 2: Contemplating Black Holes, Quasars, and the Fine-Tuning of Water
Especially the fine tuning of water
Today we contemplate the 800 million year timespan from 12.94 to 12.14 billion years ago. By now the universe was on its second generation of stars, most of the first generation having exploded as supernovae, or else collapsed into neutron stars or black holes. The black holes often gave rise to quasars (or QSOs – quasi-stellar objects), which are the brightest objects in the universe, although not visible to the naked eye since they are billions of light years away.
Obviously, the universe would not be the same without black holes; the one at the center of the Milky Way (whose birthday we will celebrate on January 7) is what holds the Milky Way together. So maybe we can be thankful for them, and marvel at the brilliance of the people who predicted that they must exist well before we were capable of detecting them.
This period might also have marked the first appearance of water molecules. And we should definitely be thankful for water. In fact, the amazing properties of water are just one more example of how the universe is fine-tuned to support us.
Here are some of the ways that water is unique among molecules, and uniquely life-promoting:
Water is a universal solvent, thereby facilitating all the chemical reactions necessary for life.
Water’s high specific heat capacity enables it to absorb large amounts of heat without significant change in temperature. This promotes life by regulating not just the Earth's climate, but also the temperatures of living organisms and ecosystems.
Water’s high heat of vaporization means that takes a lot of energy to go from liquid to gas, which facilitates efficient cooling mechanisms (e.g. sweating) in living organisms, and is crucial for the water cycle, which is crucial for the Earth’s climate and for life.
Water is transparent to visible light, allowing sunlight to penetrate deep into oceans and lakes, enabling photosynthesis in aquatic plants and algae, which oxygenated the Earth’s atmosphere, giving rise to more complex forms of life — our ancestors.
Water expands when it freezes, with the result that bodies of water freeze from the top down as opposed to from the bottom up, which in turn allows life to survive under the ice. Some of our ancestors most certainly survived this way; if they hadn’t, we wouldn’t be here.
That’s it for today, stay hydrated and be thankful for water!
Notes:
There does not seem to be a clear consensus on all of the dates about the early universe. ChatGPT 4o insists that supernovae of massive, short-lived hydrogen stars (millions of times bigger than our sun) that appeared within first few hundred million years of the Big Bang produced oxygen, some of which combined with hydrogen in interstellar space to form water. But the chart I’ve been working from puts the creation of water at 12.2 billion years ago, citing a paper I don’t have access to. So since water is worthy of its own holiday, let’s just assume it was created in today’s period, until more definitive evidence comes in.
Similarly, ChatGPT believes that SagittariusA*, the massive black hole the center of the Milky Way, is well over 13 billion years old, whereas a recent scientific estimate puts it at 9 billion. For now, we’ll go with nine billion and celebrate the birthday on January 7.