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240 BCE
Discoveries of Eratosthenes (276 BCE-195 BCE)
Around 240 BC, Eratosthenes used the Sun to measure the circumference of the Earth. His measurements were very close to accurate as they were only about 211 miles off. His discovery is important because we now understand the size of the Earth in relation to other celestial bodies. -
150
Discoveries of Ptolemy (100-170 AD)
In 150 AD, Ptolemy combined the star's movements with mathematics and geometry to predict the movement of planets. He felt that planets moved in small circles. Ptolemy's work is important because although planets do not move in circles, his discovery led to the ellipse shape of orbit that we have today. -
1514
Discoveries of Nicolaus Copernicus (1473-1543)
At around 1514, Nicolaus Copernicus discovered that the solar system did not orbit around the Earth. Instead, the solar system, including Earth, orbited around the Sun. This important discovery completely changes the way we view our solar system today. For example, we now know that the Sun's gravity keeps the planets in orbit. -
1577
Discoveries of Tycho Brahe (1546-1601)
After observing our solar system in the year 1577, Tycho Brahe disproved many previous beliefs about the world. It had been previously thought that our solar system was unchanging. However, after witnessing a Supernova, Brahe understood that our solar system is constantly changing and the life cycle is just one example. This discovery not only changes the way we study stars, but it also changed the way we understand our Sun, an important life-giving star. -
Discoveries of Johannes Kepler (1571-1630)
Between the years 1609-1619, Johannes Kepler published his Three Laws of Motion. The first of these three laws is that planets orbit the sun in elliptical orbits. Secondly, any radius vector that is connected from a planet to the Sun will sweep out equal areas of equal lengths of time. And lastly, the squares of the revolutions of these planets are directly proportional. These laws are important because they eventually led to later discoveries, like Newton's Laws. -
Discoveries of Sir Isaac Newton (1643-1727)
In the year 1687,Sir Isaac Newton created three groundbreaking laws of motion.The first is the law of inertia saying that an object at rest will remain at rest unless acted upon by another force.Secondly, acceleration occurs when a force acts upon an object.Newton's third law states that for every action there is an equal and opposite reaction.These laws are important because they increase our understanding of gravity.Gravity doesn't just exist on Earth but it makes our solar system functional. -
Discoveries of Albert Einstein (1879-1955)
One of the biggest discoveries Einstein made was space-time. This suggested that space and time are forever linked to one another and are sometimes distorted by gravity. Einstein's important discovery proved that events in the universe don't always happen at the same time for every observer. With this information, we are able to understand how far away a star or celestial object is because the events that occurred there do not happen at the same time they are being observed.
