Two things are infinite: the universe and human stupidity; and I’m not sure about the universe, Albert Einstein.
Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space, Douglas Adams, The Hitchhiker’s Guide to the Galaxy.
Astronomy is the study of the universe. It includes Earth and everything that lies outside of its atmosphere, such as planets, stars, galaxies, comets, and black holes.
The Earth is the fourth planet away from the Sun . The Solar System is the sun and everything that orbits or moves around it due to its gravity. It is a collection of planets, moons, asteroids, comets, dust and gas. It is situated within the Orion-Cygnus Arm of the Milky Way galaxy.
The Sun is a 4.5 billion-year-old yellow dwarf star made mainly out of hydrogen and helium. It is, by far, the biggest and heaviest celestial body in the Solar System. It contains more than 99.8% of the total mass of the Solar System.
The Milky Way is a barred spiral galaxy around 13.6 billon years old. To be more specific, the Milky Way is a spiral galaxy with a central bar-shaped structure composed of stars and large pivoting arms stretching out across the cosmos. The Milky Way galaxy is a huge collection of dust, gas, and stars, including our Sun. It is composed of between 100 to 400 billion stars. We know by the orbits of stars in the center of our galaxy that there is a supermassive black hole in its center.
Galaxies are vast collections of stars, gas, dust, and, possibly, mysterious dark matter brought together by gravity.
The Milky Way is one galaxy among billions of galaxies in the Universe.
The universe is a huge wide-open space that holds everything from the smallest particle to the biggest galaxy. No one knows just how big the Universe is, StarChild, a learning centre for young astronomers.
Some believe (string theory) that our universe is one bubble in an infinite and inaccessible foam and the number of possible types of universes that can bubble up in a multiverse is around 10500, Scientific American, by Natalie Wolchover, Quanta Magazine on June 1, 2013.
According to NASA, the new estimate of dark matter content in the universe is 26.8 percent, while dark energy is 68.3 percent. Normal matter accounts for only 4.6 percent. Scientists have no idea what it is, but Dark Matter and Dark Energy make up almost 96% of the Universe.
Furthermore, the universe and everything in it is mostly empty space. Atoms make up all matter in the universe. They contain almost all of their mass in a tiny nucleus at the center of the atom. Nuclei are around 100,000 times smaller than the atoms they’re housed in.
Do you like astronomy? Read our article Astronomy Free Software that compiles a list of free, educational apps that may help you to enjoy and learn more about the Solar System, the Milky Way, and the Universe.