Short answers, pulled from the story.
The observable universe is about 93 billion light-years in diameter. The distance from Earth to its edge is approximately 46 billion light-years. This is larger than the age of the universe times the speed of light because space has been expanding the whole time light was traveling.
Dark matter is a form of matter that is invisible to the entire electromagnetic spectrum. It accounts for about 26.8 percent of the total mass-energy of the universe. Its existence is inferred from its gravitational effects on visible matter and on the large-scale structure of the cosmos. It has never been directly detected, making it one of the greatest mysteries in astrophysics.
Dark energy accounts for approximately 68.3 percent of the total mass-energy of the universe. It is a form of energy that is uniformly distributed through space and is responsible for the accelerating expansion of the universe. Its density is roughly 7 times 10 to the minus 30 grams per cubic centimeter. Its underlying nature is unknown.
Using the Lambda-CDM model and measurements from numerous experiments, the best estimate for the age of the universe is 13.799 plus or minus 0.021 billion years, as of 2015.
Aristarchus of Samos proposed a heliocentric model in ancient times. His original text has been lost, but Archimedes described the model in his book The Sand Reckoner. Seleucus of Seleucia, who lived a century after Aristarchus, was the only other ancient astronomer known by name to support this view.
Big Bang nucleosynthesis lasted about 17 minutes and ended approximately 20 minutes after the Big Bang. During this period, about 25 percent of all protons and all neutrons fused into helium, with small amounts of deuterium and traces of lithium also formed. The remaining 75 percent of protons stayed as hydrogen. No heavier elements like carbon were produced.