Our universe is estimated to be around 13.8 billion years old. It began with the Big Bang, an incredibly hot and dense state that expanded and cooled over time to form the galaxies, stars, and other structures we see today. The universe is thought to be made up of approximately 68% dark energy, 27% dark matter, and only 5% ordinary matter (the matter that makes up stars, planets, and other visible objects).
Dark energy is a mysterious force that is causing the expansion of the universe to accelerate. Dark matter is also not directly observable, but its effects can be seen through its gravitational influence on visible matter.
The universe is divided into galaxies, which are vast systems of stars, gas, dust, and dark matter. Galaxies come in various shapes and sizes, including spiral, elliptical, and irregular galaxies. Our own Milky Way galaxy is a spiral galaxy that contains billions of stars, including our Sun.
Within galaxies, stars are the main sources of light and energy. Stars come in different sizes and temperatures, and they undergo various stages of evolution throughout their lifetimes. The Sun is a yellow dwarf star that is about halfway through its life cycle.
Planets are solid bodies that orbit stars. Planets in our solar system include Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Some planets have moons orbiting them, while others have rings of dust and particles.
The universe is also filled with other objects, such as asteroids, comets, and nebulae. Asteroids are small rocky bodies that orbit the Sun, while comets are icy bodies that have a long, streaming tail when they approach the Sun. Nebulae are vast clouds of gas and dust where new stars are born.
The universe is constantly evolving and expanding, and scientists are constantly exploring and learning more about its mysteries. Advances in technology and astronomical instruments have allowed us to probe deeper into space and gain a better understanding of the universe's vastness and complexity.