Every milestone across the calendar — 60 space & 60 astronomy events.
The Dog Star reaches its highest culmination on winter evenings in the Northern Hemisphere. At magnitude −1.46 it outshines every other star; the ancient Egyptians used its heliacal rising to predict the Nile flood.
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The Soviet Luna 1 became the first spacecraft to reach the vicinity of the Moon and the first to escape Earth's gravity, opening the interplanetary era.
SOURCEOne of the strongest annual showers, producing up to 120 meteors per hour at peak. Radiates from the defunct constellation Quadrans Muralis, in the northern sky between Boötes and Draco. Source body: asteroid 2003 EH1.
SOURCEEvery January, Earth swings to its closest point to the Sun — about 147.1 million km. Counterintuitive to Northern Hemisphere winter, but the seasons are driven by axial tilt, not distance.
SOURCENASA's Mars Exploration Rover Spirit bounced to a stop in Gusev Crater on airbags. Designed for 90 days, it survived over six years, discovering evidence of ancient hot springs and past water on Mars.
SOURCEPointing his crude telescope at Jupiter, Galileo saw four 'stars' that shifted position nightly. Within a week he realised they orbited the planet — the first moons found beyond Earth, and hard evidence against a geocentric universe.
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ESA's Huygens descended through the thick atmosphere of Saturn's moon Titan — the first (and only) landing on a body in the outer Solar System.
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Astronauts Grissom, White and Chaffee died in a cabin fire during a pre-flight test at Cape Kennedy, forcing a total redesign of the Apollo command module.
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Challenger broke apart 73 seconds after launch, killing all seven crew including teacher Christa McAuliffe. Root cause: O-ring failure in cold conditions.
SOURCEGerman astronomer Max Wolf identified the faint red dwarf Wolf 359 during proper-motion surveys. At just 7.86 light-years away, it remains one of Earth's closest stellar neighbours — later made famous by Star Trek.
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Columbia disintegrated during atmospheric re-entry, killing all seven crew. A piece of foam had damaged the wing's heat shield during launch.
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Explorer 1 reached orbit and discovered the Van Allen radiation belts — the first major scientific discovery of the Space Age.
SOURCEX-ray observations of the binary system Cygnus X-1 revealed a compact object too massive to be a neutron star. Stephen Hawking famously bet Kip Thorne it wasn't a black hole — and conceded the bet in 1990.
SOURCEAt Carl Sagan's request, Voyager 1 turned back at 6 billion km from the Sun and photographed Earth as a single pale blue pixel. Sagan's essay 'A Pale Blue Dot' remains a defining meditation on our place in the cosmos.
SOURCEThe Italian philosopher argued the stars were distant suns, orbited by their own planets — some possibly inhabited. The Roman Inquisition burned him at the stake for heresy. Modern exoplanet counts have vindicated him.
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Clyde Tombaugh spotted Pluto at Lowell Observatory using a blink comparator — the first Kuiper Belt object identified, later reclassified as a dwarf planet in 2006.
SOURCEThe IAU formally defined the boundaries of the 88 modern constellations, including the Great Bear (Ursa Major) which contains the Big Dipper asterism. Boundaries drawn by Eugène Delporte, following straight lines of RA and declination.
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Aboard Friendship 7, John Glenn became the first American to orbit Earth, completing three revolutions and closing the orbital gap with the Soviets.
SOURCEIn the Large Magellanic Cloud, a blue supergiant detonated as the closest naked-eye supernova in nearly 400 years. Neutrino detectors on Earth caught the blast three hours before the light arrived — the first observation of a supernova by particle astronomy.
SOURCEJocelyn Bell Burnell and Antony Hewish published the discovery of a strange, precisely-repeating radio source. Initially nicknamed 'LGM-1' (Little Green Men), it turned out to be a rapidly spinning neutron star — a pulsar.
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The first spacecraft to cross the asteroid belt and to make direct observations of Jupiter. Pioneer 10 carried a plaque with a message from humanity.
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Voyager 1 made its closest approach to Jupiter, discovering active volcanoes on Io and returning stunning images of the giant planet's atmosphere.
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Kepler stared at a single patch of sky for years, confirming over 2,600 exoplanets and revealing that small rocky worlds are common in our galaxy.
SOURCEWilliam Herschel spotted what he thought was a comet during a routine sky survey from his Bath garden. It turned out to be the first planet discovered by telescope — and the first new planet since antiquity.
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During Voskhod 2, Leonov exited the spacecraft for 12 minutes, becoming the first human to walk in space. His suit ballooned dangerously — he barely got back inside.
SOURCEThe Sun crosses the celestial equator moving north, giving both hemispheres roughly equal day and night. Astronomically the start of northern spring — and the reference point (0°) for right ascension.
SOURCEChristiaan Huygens spotted Saturn's largest moon using a telescope of his own design. Titan is the only moon in the Solar System with a substantial atmosphere and stable liquid on its surface (methane and ethane).
SOURCEThe first spacecraft to visit Mercury, and the first to use a gravity assist (from Venus). Mariner 10 revealed a Moon-like, heavily cratered world with a surprising internal magnetic field.
SOURCEHenrietta Swan Leavitt published the period-luminosity relation for Cepheid variables, giving astronomers their first reliable way to measure galactic distances. Without it, Edwin Hubble couldn't have proved galaxies exist beyond the Milky Way.
SOURCEDiscovered in 1995 by Alan Hale and Thomas Bopp, comet C/1995 O1 became one of the most-observed comets of the 20th century. Visible to the naked eye for a record 18 months.
SOURCEThe Event Horizon Telescope collaboration released the first direct image of a supermassive black hole's shadow at the centre of galaxy M87 — a glowing orange donut 55 million light-years away.
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Vostok 1 carried the 27-year-old cosmonaut on a single 108-minute orbit of Earth, making Gagarin the first person ever to leave the planet.
SOURCEColumbia lifted off exactly 20 years after Gagarin's flight, piloted by John Young and Robert Crippen. The first (and last, until Shenzhou) reusable crewed spacecraft to reach orbit and be flown home.
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The cosmos began as an unimaginably hot, dense state and expanded rapidly. Georges Lemaître proposed the 'primeval atom' hypothesis in April 1927, laying the foundation of modern cosmology.
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An oxygen tank exploded en route to the Moon. Lovell, Swigert and Haise used the lunar module as a lifeboat and returned safely — a successful failure.
SOURCENASA confirmed the discovery of an Earth-sized exoplanet orbiting within its star's habitable zone. Kepler-186f is about 500 light-years away and could potentially harbour liquid water.
SOURCEOne of the oldest recorded showers — Chinese astronomers noted it in 687 BCE. Debris from comet C/1861 G1 Thatcher produces ~15 meteors per hour, occasionally with brilliant fireballs.
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Deployed from Space Shuttle Discovery, Hubble has since become one of the most productive scientific instruments ever built, redefining astronomy.
SOURCEA stellar explosion 7,200 light-years away outshone every star in the sky, reaching a peak apparent magnitude of about −7.5. Observed by astronomers across the world; visible in daylight for weeks.
SOURCECourt astronomers of the Song dynasty logged a brilliant new star in Taurus, visible in daylight for 23 days and at night for nearly two years. Modern astronomers identify it as SN 1054 — the origin of the Crab Nebula.
SOURCEFollowing its discovery in February, the newly-found ninth planet needed a name. Venetia Burney, an 11-year-old English schoolgirl, suggested 'Pluto' — Roman god of the underworld. Adopted by the Lowell Observatory on May 1, 1930.
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Aboard Freedom 7, Shepard flew a 15-minute suborbital flight, making him the second person in space (after Gagarin) and America's first astronaut.
SOURCEDebris from Halley's Comet produces one of the most reliable annual showers, with up to 60 meteors per hour visible from the Southern Hemisphere and tropics. Radiates from the constellation Aquarius.
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Launched aboard the final Saturn V, Skylab hosted three crews between 1973–1974 and pioneered long-duration living and working in orbit.
SOURCEThe Soviet Union's third satellite carried 12 scientific instruments — cosmic ray detectors, ion traps, magnetometers — becoming the first true orbital laboratory.
SOURCEHalley's 1910 apparition brought Earth within 0.15 AU of the comet. Some newspapers spread fear about cyanogen gas in the tail; astronomers documented the closest approach in modern times.
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Before a joint session of Congress, President Kennedy declared the United States would land a man on the Moon and return him safely before the decade was out.
SOURCEDuring a total solar eclipse, Arthur Eddington measured the deflection of starlight passing near the Sun. The result matched Einstein's General Relativity, not Newtonian gravity — instantly making Einstein a global celebrity.
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SpaceX's Crew Dragon carried NASA astronauts Behnken and Hurley to the ISS, ending nine years of US reliance on Russian Soyuz launches.
SOURCERadio astronomers began mapping the compact radio source at the centre of the Milky Way. Decades later, the object was confirmed as a supermassive black hole 4 million times the mass of the Sun.
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During Gemini 4, Ed White floated outside the capsule for 23 minutes attached by a golden tether — America's first EVA.
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Vostok 6 carried the 26-year-old textile worker on a solo three-day flight of 48 orbits — more time in space than all US astronauts combined at that point.
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Aboard Shuttle Challenger STS-7, physicist Sally Ride broke a barrier that had stood for 22 years since Tereshkova's flight.
SOURCEThe Sun reaches its highest point in the northern sky, delivering the longest day of the year above the equator. Marks the astronomical start of northern summer and the origin of solstice-aligned monuments like Stonehenge.
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Scaled Composites' SpaceShipOne reached the edge of space with pilot Mike Melvill aboard — the first non-government crewed spaceflight, winning the Ansari X Prize months later.
SOURCEJames Christy noticed a bulge on Pluto's image that shifted with time. Charon turned out to be so large relative to Pluto that the two form a double dwarf-planet system, tidally locked to each other.
SOURCEThe Roman Inquisition convicted Galileo of heresy for defending the Copernican model. Under threat of torture, he abjured his views — reportedly muttering 'E pur si muove' ('and yet it moves') as he left.
SOURCEAfter the first crewed stay aboard a space station (Salyut 1), cosmonauts Dobrovolski, Patsayev and Volkov were killed when a vent valve opened during re-entry. The only humans to die in space beyond the Kármán line.
SOURCEA 12-megaton airburst over Siberia flattened 2,000 km² of forest — likely a small asteroid or comet fragment exploding at altitude. The largest impact event in recorded history, and a stark reminder of Earth's cosmic neighbourhood.
SOURCEAn Earth-mass planet was found orbiting Proxima Centauri, just 4.24 light-years away. Located in the star's habitable zone, it remains the closest known potentially habitable world — a plausible first destination for interstellar probes.
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After a seven-year journey, Cassini became Saturn's first artificial satellite. It would go on to reveal geysers on Enceladus, methane lakes on Titan, and Saturn's braided rings.
SOURCESix months after perihelion, Earth swings out to its farthest point from the Sun — about 152.1 million km. Despite the added distance, the Northern Hemisphere is in high summer thanks to axial tilt.
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The first successful Mars landing in 21 years delivered the tiny Sojourner rover — the first wheeled vehicle to operate on another planet.
SOURCESN 1054 exploded 6,500 light-years away in Taurus, briefly reaching apparent magnitude −6 — bright enough to see in daylight for 23 days. The expanding remnant is now the Crab Nebula (M1), a laboratory for high-energy astrophysics.
SOURCEAfter nine years and 5 billion km, the spacecraft returned the first sharp images of Pluto — revealing the heart-shaped Tombaugh Regio, water-ice mountains, and a surprisingly active surface.
SOURCEFragments of a fragmented comet slammed into Jupiter over 6 days, leaving Earth-sized dark scars visible in amateur telescopes. The first solar-system impact humans directly observed — a wake-up call about the threat of comets and asteroids.
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US and Soviet crews docked their spacecraft and shook hands 220 km above Earth — the first international crewed spaceflight and a symbolic thaw of the space race.
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Armstrong and Aldrin walked on the Sea of Tranquility while Collins orbited above. "That's one small step for man, one giant leap for mankind."
SOURCEBest viewed from the Southern Hemisphere and low northern latitudes, this shower delivers up to 20 meteors per hour. Debris trail believed to come from comet 96P/Machholz.
SOURCENASA's Mars 2020 mission delivered the Perseverance rover and Ingenuity helicopter — the first aircraft to fly on another planet. Perseverance is caching Mars samples for a future return mission.
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NASA's car-sized rover survived the '7 minutes of terror' Sky Crane descent to touch down in Gale Crater. Still active over a decade later.
SOURCEThe most beloved shower of the year, delivering up to 100 meteors per hour on warm summer nights. Debris from Comet Swift-Tuttle; radiant lies in Perseus, high in the northern sky after midnight.
SOURCEOhio State's Big Ear radio telescope detected a strong, narrowband signal from Sagittarius lasting 72 seconds. Astronomer Jerry Ehman circled the printout and wrote 'Wow!' Never repeated, never explained — the tantalising outlier of SETI history.
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Six weeks after landing, Viking 1 delivered humanity's first sharp colour view of the Martian surface — reddish soil, pink sky, alien and familiar at once.
SOURCEThe only spacecraft to have visited all four gas giants — Jupiter, Saturn, Uranus and Neptune. Still transmitting from interstellar space today.
SOURCEA total solar eclipse crossed the continental United States from Oregon to South Carolina — the first coast-to-coast US totality since 1918. Peak totality lasted 2 minutes 40 seconds; ~215 million viewers.
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The IAU adopted a new definition of 'planet,' demoting Pluto and creating the dwarf planet category — a controversial decision that continues to be debated.
SOURCEThe International Astronomical Union created the 'dwarf planet' category. Pluto no longer met the third criterion (clearing its orbital neighbourhood) and was reclassified. The decision remains contested by many planetary scientists.
SOURCEThe first human to walk on another world passed away at age 82. Notoriously private after Apollo 11, Armstrong spent his post-NASA years teaching engineering. He described himself as 'a white-socks, pocket-protector, nerdy engineer.'
SOURCEHumanity's only close-up look at the ice giant. Voyager 2 revealed the Great Dark Spot, supersonic winds (2,100 km/h), and geysers of nitrogen on the moon Triton.
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A collapsing molecular cloud fragment gave birth to the Sun and its planets. Meteorite dating pins this event to within a few million years, with September marking it in Sagan's Cosmic Calendar.
SOURCEThe most distant human-made object, now over 24 billion km from Earth in interstellar space. Carries the Golden Record — a message to any who might find it.
SOURCEMichel Mayor and Didier Queloz announced the first confirmed planet orbiting a normal star other than our Sun. A 'hot Jupiter' completing an orbit every 4.2 days, it overturned assumptions about planetary formation and won them the 2019 Nobel Prize.
SOURCENASA confirmed the probe had crossed the heliopause the previous August, becoming the first human-made object to enter the space between stars.
SOURCELIGO detected the merger of two black holes 1.3 billion light-years away — the first direct observation of gravitational waves, exactly a century after Einstein predicted them. Announced Feb 2016; the discovery signal remains dated Sep 14, 2015.
SOURCEAfter 13 years exploring the Saturn system, Cassini deliberately dove into the planet's atmosphere to protect its potentially habitable moons from contamination. It transmitted science data until it burned up.
SOURCEWilliam Cranch Bond and George Phillips Bond, along with William Lassell independently, discovered Hyperion — later revealed to have chaotic rotation and a peculiar sponge-like appearance.
SOURCEThe Sun crosses the celestial equator moving south. Day and night are approximately equal worldwide, and northern autumn (or southern spring) officially begins. Also marks the start of Libra in the astronomical zodiac.
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Johann Galle found Neptune within 1° of where Urbain Le Verrier had calculated it should be, based on perturbations in Uranus' orbit — a triumph of Newtonian physics.
SOURCENASA's Double Asteroid Redirection Test intentionally rammed a 570 kg spacecraft into the moonlet Dimorphos at 22,530 km/h, successfully changing its orbit — the first practical test of planetary defense.
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The National Aeronautics and Space Administration officially opened for business, replacing the NACA and consolidating US civilian space efforts.
SOURCEScaled Composites' SpaceShipOne completed two suborbital flights within two weeks, taking home the $10M Ansari X Prize. The proof-of-concept for private crewed spaceflight that would inspire Virgin Galactic.
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The Soviet Union launched a 58-cm aluminium sphere into orbit. Its steady 'beep-beep' shocked the world and started the space race.
SOURCEEdwin Hubble identified Cepheid variables in the 'Andromeda Nebula' — using Leavitt's Law, he calculated the object was over 900,000 light-years away, far outside our galaxy. Andromeda was another galaxy, not a nebula. Our universe suddenly got much bigger.
SOURCEThe last confirmed naked-eye supernova in the Milky Way, blazing in Ophiuchus for 18 months. Johannes Kepler observed and wrote about it extensively; visible in daylight for over three weeks.
SOURCEThe largest interplanetary spacecraft ever launched at the time began a 7-year cruise to Saturn — and delivered 13 years of world-changing science on arrival.
SOURCEThe Pan-STARRS telescope in Hawaii spotted an elongated object on a hyperbolic trajectory through the Solar System. Its extreme shape and non-gravitational acceleration sparked debate about its origin — comet, asteroid, or something stranger.
SOURCEThe second annual visit from Halley's Comet debris — this time producing up to 20 fast meteors per hour, radiating from the club of Orion. Best viewed after midnight in dark skies.
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India's first Moon mission confirmed water ice at the lunar poles and put ISRO on the global scientific map.
SOURCEA series of massive X-class flares and coronal mass ejections erupted from the Sun. Auroras were seen as far south as Texas; satellites failed, Mars orbiters lost communications, and airline routes over the poles were rerouted.
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The Soviet dog Laika became the first living creature to orbit the planet aboard Sputnik 2. She died within hours from overheating, but proved life could survive launch.
SOURCETycho Brahe observed a new star as bright as Venus in Cassiopeia and wrote 'De Nova Stella' — the origin of the term 'nova'. The apparition shattered the Aristotelian belief that the heavens were unchanging.
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ESA's Rosetta mission dropped the Philae lander onto Comet 67P/Churyumov-Gerasimenko — the first controlled landing on a comet nucleus.
SOURCEThe 305m Arecibo radio telescope transmitted a 1,679-bit message toward globular cluster M13, 25,000 light-years away. Encoded: numbers, DNA structure, human silhouette, Solar System diagram. The first intentional interstellar message.
SOURCEEvery 33 years the Leonids produce spectacular storms (up to 100,000 meteors/hour, as in 1833 and 1966). In non-storm years, expect ~10-15 per hour. Debris trail from Comet 55P/Tempel-Tuttle.
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The Russian Zarya module reached orbit, becoming the first piece of the International Space Station — now continuously inhabited for over 25 years.
SOURCEChina's ambitious mission collected 1.7 kg of lunar regolith from Mons Rümker and returned it to Earth on Dec 16. The first lunar samples brought home since the Soviet Luna 24 mission 44 years earlier.
SOURCEThe Mars Science Laboratory began its 254-day trip to Mars, carrying an instrument suite designed to search for the chemical building blocks of life.
SOURCEThe English clergyman John Michell proposed that a star sufficiently massive would have an escape velocity exceeding the speed of light — making it invisible. A prescient description of black holes, 150 years before Einstein.
SOURCERadio astronomers pinpointed a compact source at the very centre of the Milky Way. Decades of observation would confirm it as a supermassive black hole — winning Ghez and Genzel the 2020 Nobel Prize.
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Cernan and Schmitt spent 22 hours on the lunar surface. As of today, no one has returned. Cernan's footprints are still there.
SOURCEWidely considered the best annual shower — up to 150 slow, bright, multicoloured meteors per hour. Uniquely, the parent body is not a comet but the asteroid 3200 Phaethon.
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Orville flew 12 seconds and 37 metres over Kitty Hawk, North Carolina. Just 66 years later, humans would walk on the Moon.
SOURCEHubble stared at a seemingly-empty patch of sky in Ursa Major for 10 consecutive days. The resulting image revealed nearly 3,000 galaxies — proof that the universe is teeming with structure across billions of light-years.
SOURCEThe Sun reaches its lowest point in the northern sky — the shortest day of the year. Marks the astronomical start of winter and the origin of many midwinter festivals from Yule to Sol Invictus.
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Borman, Lovell and Anders became the first humans to leave low Earth orbit, circle the Moon, and see the whole Earth as a fragile blue marble ('Earthrise').
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For the first time in history, an orbital-class rocket landed vertically on solid ground after delivering payloads to space — cracking the door open on cheap reusable spaceflight.
SOURCEEdmond Halley died in 1742 without seeing his prediction confirmed. On Christmas Day 1758 — 76 years after its previous passage — the comet reappeared exactly where he'd calculated, cementing his name in history and Newtonian mechanics.
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The largest and most powerful space telescope ever built began its journey to the L2 Lagrange point, where it now peers back over 13 billion years into the early universe.
SOURCEVenus showed a full range of phases like the Moon — impossible in the Ptolemaic model, but perfectly explained if Venus orbited the Sun. One of the strongest early proofs of heliocentrism.
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