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Using the angles of shadows in two different locations, he estimated Earth’s size with remarkable accuracy, proving that Earth is a sphere.
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In his book Almagest, he proposed that Earth was the center of the universe, a belief that dominated astronomy for over 1,400 years.
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In De revolutionibus orbium coelestium, he argued that the Sun, not Earth, was at the center of the universe, challenging Ptolemy’s model. -
His detailed astronomical observations proved that the heavens were not perfect and unchanging, contradicting Aristotelian ideas.
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Kepler’s laws described how planets move in elliptical orbits rather than perfect circles and that they speed up when closer to the Sun. -
He observed Jupiter’s four largest moons, proving that not everything orbits Earth, and saw the phases of Venus, which supported heliocentrism. -
Newton’s work explained gravity as the force that governs planetary motion, unifying celestial and earthly physics under the same laws. -
Using a telescope he built himself, Herschel found Uranus, the first new planet discovered in modern times, expanding the known solar system.
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Le Verrier mathematically predicted Neptune’s existence based on Uranus’ orbital irregularities, and Galle confirmed its location with a telescope.
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His theory revolutionized our understanding of space, time, and gravity, laying the foundation for modern cosmology. -
Using Einstein’s equations, he proposed the existence of black holes, objects so dense that even light cannot escape their gravity.
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By observing redshifts in distant galaxies, he found that the universe is expanding, leading to the development of the Big Bang Theory. -
While searching for a ninth planet, Tombaugh found Pluto, though it was later reclassified as a dwarf planet in 2006.
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During the Apollo 11 mission, Armstrong famously declared, “That’s one small step for man, one giant leap for mankind.” -
Voyager 1 and 2 were designed to explore the outer planets and continue to send data from interstellar space today. -
They detected 51 Pegasi b, proving that planets exist outside our solar system, revolutionizing astronomy.
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The International Astronomical Union (IAU) redefined what it means to be a planet, downgrading Pluto and classifying it as a dwarf planet.
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A global network of telescopes created a groundbreaking image of the black hole at the center of the galaxy M87. -
As the most powerful space telescope ever built, JWST is designed to study the earliest galaxies and search for habitable exoplanets. -
Elon musk perfects the first completely reusable spaceship