Short answers, pulled from the story.
The first astronomical objects began to emerge thirteen point six billion years ago. This event occurred roughly two hundred million years after the Big Bang formed the cosmos.
Nicolaus Copernicus published his heliocentric model in 1543. This work shifted human understanding of our place in the solar system.
Irregular, elliptical, and disk-like shapes define galaxy morphologies based on formation history. Spiral arms and distinct halos characterize disc galaxies while most galactic cores contain a supermassive black hole creating an active nucleus.
Ejnar Hertzsprung and Henry Norris Russell developed this tool independently in 1913. Stars follow evolutionary tracks across this chart throughout their lives.
The International Astronomical Union requires Sun-orbiting bodies to reach hydrostatic equilibrium for planet status. This process creates a roughly spherical shape seen on Mars and Jupiter.