Great American Eclipse of 2017

2017Notable

On August 21, 2017, a total solar eclipse crosses the United States from Oregon to South Carolina, the first coast to coast since 1918. Tens of millions watch from the path and online.

Longest chain: The Big Bang → First atomic nuclei form → First stars ignite → First galaxies assemble → Milky Way takes shape → The Sun forms → Earth forms → First oceans → First life → Photosynthesis evolves → Great Oxidation Event → Complex cells (eukaryotes) → Multicellular life → First animals → Cambrian Explosion → First vertebrates → Jawed fish → Lobe-finned fish → Fish walk onto land → The amniotic egg → The Great Dying → Dinosaurs appear → End-Triassic extinction → Pangaea breaks apart → Paleocene-Eocene Thermal Maximum → Early primates → First anthropoid primates → Apes split from monkeys → Great apes split from gibbons → Human line splits from chimpanzees → Walking upright → First stone tools → Genus Homo appears → Homo erectus → Control of fire → Habitual fire and cooking → Homo sapiens appears → Complex language → Natufian villages → Oldest known bread → Agriculture begins → Irrigation → Uruk and the first cities → Cylinder seals → Writing (cuneiform) → Egyptian hieroglyphs → The alphabet → Phoenician alphabet → Greek alphabet → Solon's reforms → Athenian democracy → Trial and death of Socrates → Plato's Academy → Aristotle's Lyceum → Alexander's conquests → Death of Alexander and the Hellenistic kingdoms → Seleucid Empire founded → Parthian Empire founded → Sasanian Empire → Birth of Muhammad → Muhammad's first revelations → The Hijra → Conquest of Mecca → Death of Muhammad and the Rashidun caliphate → Arab conquests → Abbasid Caliphate → Battle of Talas → Paper reaches the Islamic world → House of Wisdom → Al-Khwarizmi and algebra → Fibonacci's Liber Abaci → Bills of exchange → Medici Bank → Double-entry bookkeeping → Muscovy Company → English East India Company → Seven Years' War → Stamp Act → Boston Tea Party → American Revolution → Declaration of Independence → Articles of Confederation ratified → Shays' Rebellion → U.S. Constitution → Louisiana Purchase → Austin's colony in Mexican Texas → Texas Revolution → United States annexes Texas → Mexican-American War → Compromise of 1850 → Kansas-Nebraska Act → Lincoln elected president → Fort Sumter → U.S. Civil War → National Banking Act → Federal Reserve → Great Depression → Nazis take power → Munich Agreement → Nazi-Soviet Pact → Invasion of Poland → World War II → Atomic bomb → Soviet atomic bomb → Baikonur Cosmodrome built → Sputnik → NASA → Great American Eclipse of 2017

The story

On August 21, 2017, the Moon's shadow swept across the United States from Oregon to South Carolina, about 115 kilometers wide. Around 12 million people lived in the path of totality, and millions more traveled to see it. It was the first total solar eclipse to cross the whole width of the contiguous United States since 1918. Totality lasted at most about 2 minutes 40 seconds, near Hopkinsville, Kentucky, and Carbondale, Illinois.

The eclipse was predicted years ahead with great accuracy, based on knowledge of lunar motion going back to Babylonian cycles. NASA and universities used it for science, from studying the Sun's corona to watching how animals and weather respond. Local officials and the public prepared for crowds, with eclipse glasses in huge demand. The eclipse also gave students and teachers a rare classroom lesson. Seven years later, on April 8, 2024, another total eclipse crossed the country from Texas to Maine.

Why it mattered

Brought a rare astronomical event to tens of millions of people at once, boosting public interest in astronomy.
Produced new data on the solar corona and on atmospheric and animal responses to totality.
Showed how long-range prediction and mass preparation allowed safe viewing for huge crowds.