IOA

By Jakecrichardson
  • 250 BCE

    Eratosthenes Astronomical Discovery?

    Eratosthenes measured Earth's circumference mathematically using two surface points to make the calculation. He noted that the Sun's rays fall vertically at noon in Syene, Egypt, at the summer solstice.
  • 250 BCE

    Why is Eratosthenes Important?

    In mathematics, the sieve of Eratosthenes is an ancient algorithm for finding all prime numbers up to any given limit. It does so by iteratively marking as composite (i.e., not prime) the multiples of each prime, starting with the first prime number, 2.
  • 163 BCE

    Johannes Kepler Astronomical Discovery?

    Eratosthenes was an ancient Greek astronomer, geographer, and mathematician. He lived from 276 to 194 B.C. Eratosthenes is most famous for making the first accurate measurement of the circumference of the Earth. He lived and worked for most of his life in the city of Alexandria in Egypt.
  • 163 BCE

    Why is Johannes Kepler Important?

    Tycho's data let Kepler refine his model for planetary motion. It led him to create what we today call Kepler's three laws of planetary motion. The first law of planetary motion states: Planets move around the sun in an elliptical orbit, where the sun is one of the foci.
  • 150 BCE

    Claudius Ptolemy Astronomical Discovery?

    Ptolemy made contributions to astronomy, mathematics, geography, musical theory, and optics. He compiled a star catalog and the earliest surviving table of a trigonometric function and established mathematically that an object and its mirror image must make equal angles to a mirror.
  • 150 BCE

    Why is Claudius Ptolemy Important?

    Claudius Ptolemy was a Greek mathematician, astronomer and geographer. Much of medieval astronomy and geography were built on his ideas: his world map, published as part of his treatise Geography in the 2nd century, was the first to use longitudinal and latitudinal lines.
  • 1497

    Nicolaus Copernicus Astronomical Discovery?

    Nicolaus Copernicus was an astronomer who proposed a heliocentric system, that the planets orbit around the Sun; that Earth is a planet which, besides orbiting the Sun annually, also turns once daily on its own axis; and that very slow changes in the direction of this axis account for the precession of the equinoxes.
  • 1497

    Why is Nicolaus Copernicus Important?

    The Copernican Revolution gives us an important framework for understanding the Universe. We do not occupy a special or privileged place in the Universe. The Universe and everything in it can be understood and predicted using a set of basic physical laws.
  • 1572

    Tycho Brahe Astronomical Discovery?

    Tycho Brahe’s study of the “new star” showed that it was farther away than the Moon and was among the fixed stars, which were regarded as perfect and unchanging.
  • 1572

    Why is Tycho Brahe Important?

    His use of astronomical instrumentation showed its worth in combination with systematic record keeping, as a basis for astronomical research, and also as a justification for the rewriting of the speculative understanding of the cosmos of antiquity which had prevailed hitherto.

  • Sir Isaac Newton Astronomical Discovery?

    Newton was one of the first to make a reflecting telescope. However, his most profound contribution to science is the formulation of three Laws of Motion, described in Philosophiae Naturalis Principia Mathematica in 1687, which also lays the foundation for the principle of universal gravitation.

  • Why is Sir Isaac Newton Important?

    Isaac Newton changed the way we understand the Universe. Revered in his own lifetime, he discovered the laws of gravity and motion and invented calculus. He helped to shape our rational world view.

  • Albert Einstein Astronomical Discovery?

    Einstein's many visionary scientific contributions include the equivalence of mass and energy (E=mc^2), how the maximum speed limit of light affects measurements of time and space (special relativity), and a more accurate theory of gravity based on simple geometric concepts (general relativity).

  • Why is Albert Einstein Important?

    Albert Einstein's greatest contribution to the world was his theory of relativity in which he described new ways of looking at time, space, matter, energy and gravity.