1. Spaceship Earth An Ever Changing World

2. The half-Earth as seen by Mars Global Surveyor. An overlay shows the continents North and South America at the time of the exposure. Credit: NASA/JPL The Earth and Moon Viewed from Mars (May 8, 2003)

3. Cosmic Calendar Imagine that the entire history of the universe is compressed into one year - with the Big Bang corresponding to the first second of the New Year's Day, and the present time to the last second of December 31st (midnight). Using this scale of time, each month would equal about 1.1 billion years.

4. Details Big Bang January 1 Big Bang January 1 Origin of Milky Way Galaxy May 1O Origin of Milky Way Galaxy May 1O Origin of the solar systemSeptember 9 Origin of the solar systemSeptember 9 Formation of the EarthSeptember 14 Formation of the EarthSeptember 14 Origin of life on Earth~ September 25 Origin of life on Earth~ September 25 Formation of the oldest rocks known on Earth October 2 Formation of the oldest rocks known on Earth October 2 Date of oldest fossils (bacteria and blue-green algae) October 9 Date of oldest fossils (bacteria and blue-green algae) October 9 Invention of sex (by microorganisms) ~ November 1 Invention of sex (by microorganisms) ~ November 1 Oldest fossil photosynthetic plantsNovember 12 Oldest fossil photosynthetic plantsNovember 12 Eukaryotes (first cells with nuclei) flourish Eukaryotes (first cells with nuclei) flourish November 15

5. SundayMondayTuesdayWednesdayThursdayFridaySaturday 1 Significant oxygen atmosphere begins to develop on Earth. 2345 Extensive vulcanism and channel formation on Mars. 6 7 8910111213 14 1516 First Worms. 17 Precambrian ends. Paleozoic Era and Cambrian Period begin. Invertebrates flourish. 18 First oceanic plankton. Trilobites flourish. 19 Ordovician Period. First fish, first vertebrates. 20 Silurian Period. First vascular plants. Plants begin colonization of land. 21 Devonian Period begins. First insects. Animals begin colonization of land. 22 First amphibians. First winged insects. 23 Carboniferous Period. First trees. First reptiles. 24 Permian Period begins. First dinosaurs. 25 Paleozoic Era ends. Mesozoic Era Begins. 26 Triassic Period. First mammals. 27 Jurassic Period. First birds. 28 Cretaceous Period. First flowers. Dinosaurs become extinct. 29 Mesozoic Era ends. Cenozoic Era and Tertiary Period begin. First cetaceans. First primates. 30 First evolution of frontal lobes in the brains of primates. First hominids. Giant mammals flourish. 31 End of Pliocene Period. Quaternary (Pleistocene and Holocene) Period. First humans. December One day = 37 million years

6. Origin of Proconsul and Ramapithecus, probable ancestors of apes and men ~ 1:30 p.m. First humans ~ 10:30 p.m. Widespread use of stone tools 11:00 p.m. Domestication of fire by Peking man 11:46 p.m. Beginning of most recent glacial period 11:56 p.m. Seafarers settle Australia 11:58 p.m. Extensive cave painting in Europe 11:59 p.m. Invention of agriculture 11:59:20 p.m. Neolithic civilization; first cities 11:59:35 p.m. First dynasties in Sumer, Ebla and Egypt; development of astronomy 11:59:50 p.m. Invention of the alphabet; Akkadian Empire 11:59:51 p.m. Hammurabic legal codes in Babylon; Middle Kingdom in Egypt 11:59:52 p.m. December 31 One minute = 26 thousand years One hour = 1.6 million years One second = 431 years

7. Bronze metallurgy; Mycenaean culture; Trojan War; Olmec culture; invention of the compass 11:59:53 p.m. Iron metallurgy; First Assyrian Empire; Kingdom of Israel; founding of Carthage by Phoenicia 11:59:54 p.m. Asokan India; Ch'in Dynasty China; Periclean Athens; birth of Buddha 11:59:55 p.m. Euclidean geometry; Archimedean physics; Ptolemaic astronomy; Roman Empire; birth of Christ 11:59:56 p.m. Zero and decimals invented in Indian arithmetic; Rome falls; Birth of Islam and the Islamic Civilization 11:59:57 p.m. Mayan civilization; Sung Dynasty China; Byzantine empire; Mongol invasion; Crusades 11:59:58 p.m. Renaissance in Europe; voyages of discovery from Europe and from Ming Dynasty China; emergence of the experimental method in science 11:59:59 p.m. Widespread development of science and technology; emergence of global culture; acquisition of the means of self-destruction of the human species; first steps in spacecraft planetary exploration and the search of extraterrestrial intelligence Now: The first second of New Year's Day December 31 One minute = 26 thousand years One hour = 1.6 million years One second = 431 years

8. 1.1 billion years ago (late pre-Cambrian)

9. Animals with hard-shells appeared in great numbers for the first time during the Cambrian. The continents were flooded by shallow seas. The supercontinent of Gondwana had just formed and was located near the South Pole. Cambrian: the beginning of the Paleozoic Era

10. During the Ordovician ancient oceans separated the barren continents of Laurentia, Baltica, Siberia and Gondwana. The end of the Ordovician was one of the coldest times in Earth history. Ice covered much of the southern region of Gondwana. Ancient Oceans Separate the Continents

11. By the Devonian the early Paleozoic oceans were closing, forming a "pre- Pangea". Freshwater fish were able to migrate from the southern hemisphere continents to North America and Europe. Forests grew for the first time in the equatorial regions of Artic Canada. The Devonian Was the Age of Fish!

12. During the Early Carboniferous the Paleozoic oceans between Euramerica and Gondwana began to close, forming the Appalachian and Variscan mountains. An ice cap grew at the South Pole as four-legged vertebrates evolved in the coal swamps near the Equator. During the Early Carboniferous Pangea Begins to Form.

13. By the Late Carboniferous the continents that make up modern North America and Europe had collided with the southern continents of Gondwana to form the western half of Pangea. Ice covered much of the southern hemisphere and vast coal swamps formed along the equator. The Late Carboniferous a Time of Great Coal Swamps

14. Vast deserts covered western Pangea during the Permian as reptiles spread across the face of the supercontinent. 99% of all life perished during the extinction event that marked the end of the Paleozoic Era. At the end of the Permian was Greatest Extinction of All Time

15. The supercontinent of Pangea, mostly assembled by the Triassic, allowed land animals to migrate from the South Pole to the North Pole. Life began to rediversify after the great Permo-Triassic extinction and warm-water faunas spread across Tethys. At the end of the Triassic, Pangea began to rift apart.

16. By the Early Jurassic, south-central Asia had assembled. A wide Tethys ocean separated the northern continents from Gondwana. Though Pangea was intact, the first rumblings of continental break up could be heard. Early Jurassic, the Dinosaurs spread across Pangea

17. Pangea Begins to Rift Apart The supercontinent of Pangea began to break apart in the Middle Jurassic. In the Late Jurassic the Central Atlantic Ocean was a narrow ocean separating Africa from eastern North America. Eastern Gondwana had begun to separate form Western Gondwana.

18. New Oceans Begin to Open During the Cretaceous the South Atlantic Ocean opened. India separated from Madagascar and raced northward on a collision course with Eurasia. Notice that North America was connected to Europe, and that Australia was still joined to Antarctica.

19. The World Assumes a Modern Configuration 20 million years ago, Antarctica was coverd by ice and the northern continents were cooling rapidly. The world has taken on a "modern" look, but notice that Florida and parts of Asia were flooded by the sea.

20. The Earth has been in an Ice House Climate for the last 30 million years When the Earth is in its "Ice House" climate mode, there is ice at the poles. The polar ice sheet expands and contacts because of variations in the Earth's orbit (Milankovitch cycles). The last expansion of the polar ice sheets took place about 18,000 years ago.

22. The Atlantic Ocean begins to Close New subduction zones along the eastern coasts of North America and South America will begin to consume the ocean floor separating North America from Africa. About 100 million years from now the present-day Mid-Atlantic Ridge will be subducted and the continents will come closer together.

23. "Pangea Ultima" will form 250 million years in the Future

24. Earth’s Climate Throughout History