Astronomy is the oldest natural science. The Sumerians, Ancient Egyptians, and Indus Valley Civilization all understood that the objects in the sky moved since before 3000 BC. This is because they worshiped the objects in the sky as gods. Their understanding wasn't scientific, but their observations influenced later astronomy. A significant amount of astronomy came from Mesopotamia, Babylonia, Ancient Egypt, and Ancient Greece. Astronomers from Egypt built monuments that showed how objects in the sky moved, and most of the names for the constellations in the Northern hemisphere came from Greek astronomers.
Natural philosophy started in Greece around 650 BC when a movement of philosophers replaced superstition with naturalism, which refuted the spiritual. Leucippus and his student Democritus suggested the idea of the atom around this period.
Physics in the medieval Islamic world
Islamic scholars continued to study
Aristotelian physics during the Islamic Golden Age. They also developed an early form of the scientific method. Scientists like
Ibn Sahl, Al-Kindi, Ibn al-Haytham,
Al-Farisi and Avicenna worked extensively on optics and vision. In The Book of Optics, Ibn al-Haytham rejected previous Greek ideas concerning vision and proposed a new theory. He studied how light enters the eye and then developed the camera obscura. European scientists later built eyeglasses, magnifying glasses, telescopes, and cameras from this book.
Physics became a separate field of study after the scientific revolution. Galileo's experiments helped to create classical physics. Although he did not invent the telescope, he used it when he looked into the night sky. He discovered that the stars and planets were not perfect. He also investigated gravity. Isaac Newton used Galileo's ideas to create his three laws of motion. He also developed calculus to help understand problems in mechanics, such as how celestial bodies moved around the Sun.
In a couple centuries, the Industrial Revolution was in full swing and many more discoveries were made in many fields of science. The laws of classical physics are good enough to study objects that move much slower than the speed of light, and are not microscopic. When scientists first studied quantum mechanics, they had to create a new set of laws, which was the start of Modern Physics.
As scientists researched particles, they discovered what classical mechanics could not explain. Classical mechanics predicted that the speed of light varied, but experiments showed the speed of light stayed the same. This was predicted by Albert Einstein's theory of special relativity. Einstein predicted that the speed of electromagnetic radiation through empty space would always be the same. His view of space-time replaced the ancient idea that space and time were quite separate things.
Max Planck came up with quantum mechanics to explain why metal releases electrons when you shine a light at it, and why matter emits radiation. Quantum mechanics applies for very small things like the electrons, protons, and neutrons that make up an atom. People like Werner Heisenberg, Erwin Schrödinger, and Paul Dirac continued to work on quantum mechanics and eventually we got the Standard Model.