1. In 1906, the seismologist Henry Reid developed the “elastic rebound theory” to explain earthquakes. When rocks begin to press against each other, they initially bend, like a spring, to accommodate the opposing forces. Eventually, when the rocks reach a point where they cannot bend further, they break. The bent rocks snap back, or rebound, to their original shape. The break is the fault itself, and the shock waves emanating from the rebound are the earthquake. The shock waves vibrate through the Earth, making it “ring” like a bell.

    A fault is a rock fracture along which movement occurs. Normal faults develop where the crust stretches apart, as in the East African Rift Valley. In thrust faults, which are found at subduction zones, the rocks on one side of the fault are pushed up and over those on the other side. A third type of fault is the strike-slip fault, where the rocks on either side of the fault slip by each other horizontally. The San Andreas Fault is a strike-slip fault.

    Learn more about earthquakes in the Gottesman Hall of Planet Earth

  2. In partnership with Khan Academy, the American Natural History Museum is excited to present two online educational series.
Khan Academy provides a free world-class education for anyone anywhere. After working together for several months, we have developed engaging learning experiences around topics that everyone can get excited about: Dinosaurs and The Universe!
Get started learning.

    In partnership with Khan Academy, the American Natural History Museum is excited to present two online educational series.

    Khan Academy provides a free world-class education for anyone anywhere. After working together for several months, we have developed engaging learning experiences around topics that everyone can get excited about: Dinosaurs and The Universe!

    Get started learning.

  3. The material of stars is recycled over billions of years. Interstellar gas clouds collapse to make stars. Stars forge heavy elements and return their gas to space. This material enriches gas clouds from which new stars are formed, and the cycle continues. Each generation of stars is made in part from the ashes of previous generations.
Click to enlarge this diagram, and learn more about stars on our website.

    The material of stars is recycled over billions of years. Interstellar gas clouds collapse to make stars. Stars forge heavy elements and return their gas to space. This material enriches gas clouds from which new stars are formed, and the cycle continues. Each generation of stars is made in part from the ashes of previous generations.

    Click to enlarge this diagram, and learn more about stars on our website.

  4. Curious about what a day in the life of a paleontologist is really like? Jack Tseng, a postdoctoral fellow in the Division of Paleontology at the Museum, is blogging from a fossil-finding expedition in Inner Mongolia. In his most recent post he covers many topics. 

    Breakfast:

    "A typical day in Inner Mongolia begins with a hearty breakfast…a feast of freshly boiled sheep parts at the crack of dawn, usually accompanied by sheep cheese and milk tea."

    Water:

    "We also make sure we have enough water (both potable and non-potable) to drink and to make plaster casings with, in case we find something worth excavating."

    Revisiting old dig sites:

    "Even at the most surveyed fossil sites, nature works its wonder through wind, rain, snow, and tectonic activities. Existing rock layers at the surface (where most of previous fossil discoveries are located) are slowly weathered away each year, exposing fresh surfaces that have not been studied before."

    The necessity of binoculars:

    "For surveying rock outcrops in the distance, or for bird-watching when no other paleontologists are around!"

    Read much more in his Fieldwork Journal on the Museum blog

  5. Headed to the beach this weekend? You might spot a Tiger Cowrie! 
See archival images of the Museum’s Shell Hall in the Digital Special Collections. 

    Headed to the beach this weekend? You might spot a Tiger Cowrie! 

    See archival images of the Museum’s Shell Hall in the Digital Special Collections. 

  6. The weekend has arrived! Arachnophobes and ’philes alike will get a kick out the live animal exhibition Spiders Alive! See 20 species of live arachnids, get a close up view in the live spider presentations, and hop up on the climbable trapdoor spider. Learn more. 

    This week you may have missed:

    Have a great weekend!

  7. Look, #FossilFriday is smiling at you!
This fossil is Diadectes phaseolinus, and it lived in the Early Permian, about 280 million years ago. The anthracosaurs that gave rise to the amniotes—true land animals with watertight eggs—probably looked something like Diadectes. Diadectes shows the general form of early amniote relatives: well developed limbs clearly capable of terrestrial locomotion, but a posture that is sprawling, not erect, like that of many later amniotes. What Diadectes ate is unknown, but it had complex, molarlike teeth and may have been a plant-eater. 
This fossil is located in the Museum’s Hall of Vertebrate Origins. 

    Look, #FossilFriday is smiling at you!

    This fossil is Diadectes phaseolinus, and it lived in the Early Permian, about 280 million years ago. The anthracosaurs that gave rise to the amniotes—true land animals with watertight eggs—probably looked something like Diadectes. Diadectes shows the general form of early amniote relatives: well developed limbs clearly capable of terrestrial locomotion, but a posture that is sprawling, not erect, like that of many later amniotes. What Diadectes ate is unknown, but it had complex, molarlike teeth and may have been a plant-eater. 

    This fossil is located in the Museum’s Hall of Vertebrate Origins

  8. Two-toed Sloth
Albert Seba’s (1665-1736) four volume Thesaurus (Locupletissimi rerum naturalium thesauri accurata descriptio…) illustrated the Dutch apothecary’s enormous collection of animal and plant specimens amassed over the years. Using preserved specimens, Seba’s artists could depict anatomy accurately—but not behavior. For example, this two-toed sloth is shown climbing upright, even though in nature, sloths hang upside down.
See this and other illustrations from the Museum’s Rare Book Collection in Natural Histories: 400 Years of Scientific Illustration from the Museum’s Library.

    Two-toed Sloth

    Albert Seba’s (1665-1736) four volume Thesaurus (Locupletissimi rerum naturalium thesauri accurata descriptio…) illustrated the Dutch apothecary’s enormous collection of animal and plant specimens amassed over the years. Using preserved specimens, Seba’s artists could depict anatomy accurately—but not behavior. For example, this two-toed sloth is shown climbing upright, even though in nature, sloths hang upside down.

    See this and other illustrations from the Museum’s Rare Book Collection in Natural Histories: 400 Years of Scientific Illustration from the Museum’s Library.

  9. Today’s peek into the archives takes us back to the Museum in 1910. “Sigurd Neandross painting figure in Haida ceremonial canoe, North Pacific Hall” was photographed by Thomas Lunt. 
The Great Canoe has since been moved to the Museum’s Grand Gallery. At 63 feet long, the seaworthy Great Canoe is one of the Museum’s most popular artifacts. It was carved in the 1870s from the trunk of a single cedar tree, and features design elements from different Native American peoples of the Northwest Coast, notably Haida and Heiltsuk. 
Learn more about the history of the Great Canoe.
AMNH/33006

    Today’s peek into the archives takes us back to the Museum in 1910. “Sigurd Neandross painting figure in Haida ceremonial canoe, North Pacific Hall” was photographed by Thomas Lunt.

    The Great Canoe has since been moved to the Museum’s Grand Gallery. At 63 feet long, the seaworthy Great Canoe is one of the Museum’s most popular artifacts. It was carved in the 1870s from the trunk of a single cedar tree, and features design elements from different Native American peoples of the Northwest Coast, notably Haida and Heiltsuk.

    Learn more about the history of the Great Canoe.

    AMNH/33006

  10. Fieldwork Journal: Reporting from Inner Mongolia

    Jack Tseng and Camille Grohe, postdoctoral fellows in the Division of Paleontology at the American Museum of Natural History, are blogging from the field during an expedition to Inner Mongolia. Their expedition aims to find fossils of extinct mammals that lived between 20 and 6 million years ago.

    In Jack’s first blog post, he discusses the area of Inner Mongolia (not to be confused with Mongolia) where the expedition is taking place and Museum’s historic Central Asiatic Expeditions of the 1920’s. 

    Read the full Fieldwork Journal on the Museum blog. 

  11. A time-lapse Vine, taken over the course of five minutes in the Theodore Roosevelt Rotunda. 

    Check out more Museum Vine Videos!

  12. Golden Orb-Web Spider - Nephila pilipes
Walking through the Southeast Asian rainforest, you might glimpse this large spider, with its bright yellow markings and its large orb web. The spider sits in this strong web day and night, feeding whenever prey gets caught.
Check me out: My first pair of legs is long—reaching roughly twice the length of my body.
Species range: From northern Australia through Southeast Asia, eastern India and parts of China and Japan.
Habitat: Terrestrial; from rainforest trees to gardens, with webs even attached to buildings at times.
Should you worry? No. This spider is not aggressive and very rarely bites humans. Even if it did, the venom is harmless.
Fun fact: Spiders of the genus Nephila, like the one on display here, are sometimes called “golden orb spiders,” for their giant webs tend to gleam yellow in the sun. Why? Females of some Nephila species use silks containing yellow pigments in their constructions. Because flowers and new leaves are often yellow, some scientists think the color in a web may help attract insects that either pollinate or feed on plants. 
See this and other arachnid species in the exhibition, Spiders Alive! open now. 

    Golden Orb-Web SpiderNephila pilipes

    Walking through the Southeast Asian rainforest, you might glimpse this large spider, with its bright yellow markings and its large orb web. The spider sits in this strong web day and night, feeding whenever prey gets caught.

    Check me out: My first pair of legs is long—reaching roughly twice the length of my body.

    Species range: From northern Australia through Southeast Asia, eastern India and parts of China and Japan.

    Habitat: Terrestrial; from rainforest trees to gardens, with webs even attached to buildings at times.

    Should you worry? No. This spider is not aggressive and very rarely bites humans. Even if it did, the venom is harmless.

    Fun fact: Spiders of the genus Nephila, like the one on display here, are sometimes called “golden orb spiders,” for their giant webs tend to gleam yellow in the sun. Why? Females of some Nephila species use silks containing yellow pigments in their constructions. Because flowers and new leaves are often yellow, some scientists think the color in a web may help attract insects that either pollinate or feed on plants. 

    See this and other arachnid species in the exhibition, Spiders Alive! open now. 

  13. This #MuseumMonday, we’re featuring the Ellsworth Corridor. 
This area on the Museum’s first floor just off the Grand Gallery celebrates a relatively unsung hero of polar exploration: the American Lincoln Ellsworth. His bust graces the back wall of the narrow hallway, while the display cases on either side contain artifacts detailing Ellsworth’s efforts to become the first man to fly across both polar continents, a feat he accomplished in 1935 when he crossed the Antarctic in his plane Polar Star. Ten years earlier, Ellsworth’s first attempt to fly over the North Pole teamed him with Norwegian Roald Amundsen, whose earlier overland competition with British Royal Navy Captain Robert Falcon Scott to reach the South Pole is chronicled in the Museum’s traveling exhibition Race to the End of the Earth. Through the special relationship between Amundsen and Ellsworth, the Museum Library’s Memorabilia Collection came to possess items the Norwegian explorer carried with him on his quest to reach the South Pole, including a sledge, chronometer, binoculars, shotgun, and a tin cup from the ship Fram, which are featured in the corridor.
Explore other halls on this #MuseumMonday!

    This #MuseumMonday, we’re featuring the Ellsworth Corridor. 

    This area on the Museum’s first floor just off the Grand Gallery celebrates a relatively unsung hero of polar exploration: the American Lincoln Ellsworth. His bust graces the back wall of the narrow hallway, while the display cases on either side contain artifacts detailing Ellsworth’s efforts to become the first man to fly across both polar continents, a feat he accomplished in 1935 when he crossed the Antarctic in his plane Polar Star. Ten years earlier, Ellsworth’s first attempt to fly over the North Pole teamed him with Norwegian Roald Amundsen, whose earlier overland competition with British Royal Navy Captain Robert Falcon Scott to reach the South Pole is chronicled in the Museum’s traveling exhibition Race to the End of the Earth. Through the special relationship between Amundsen and Ellsworth, the Museum Library’s Memorabilia Collection came to possess items the Norwegian explorer carried with him on his quest to reach the South Pole, including a sledge, chronometer, binoculars, shotgun, and a tin cup from the ship Fram, which are featured in the corridor.

    Explore other halls on this #MuseumMonday!

  14. In celebration of our new film Great White Shark, now playing daily in 3D and IMAX, here are some spectacular shark facts:

    • Sharks began evolving about 450 million years ago. Of the roughly 340 living species some have changed little in the past 100 million years.
    • Sharks were the first vertebrates to develop an immune system and may have a greater immunity to cancer than humans.
    • Shark teeth are made of hard enamel, which may explain why ancient shark teeth are the most commonly found vertebrate fossils today.
    • Some living shark species replace old and broken teeth as frequently as every ten days. There are 12,000 bull-shark fossil teeth on view in the Museum’s Hall of Vertebrate Origins—approximately the number of teeth a bull-shark will have during its lifetime. 
    • Shark bones are made of light, tough cartilage, which is rarely fossilized.
    • Like other cartilaginous fishes, sharks do not have a gas bladder to keep them afloat so many species (but not all) must move constantly to keep from sinking. Many sharks have large, oil-filled livers that make them more buoyant.
    • Most sharks bear live young. Some species can remain pregnant for over two yea­rs, longer than any other vertebrate.
    • Sharks typically bear three to 12 pups and many do not reproduce until age 30, making it hard for them to recover when large numbers are killed by humans.

  15. Sewellel (Mountain Beaver) - August Morning, Mount Rainier, Washington
Neither a beaver nor a high-mountain dweller, the sewellel is a rather singular animal. It’s the last living member of a once-successful family of rodents called the Aplodontiidae. The sewellel is a “living fossil,” showing primitive skeletal features that other rodents have lost. Its kidneys are also unusual: they are inefficient at maintaining the body’s water balance. Thus the sewellel needs to live close to water so it can drink a lot—a third of its weight in water per day. 
This diorama is located in the Bernard Family Hall of North American Mammals.

    Sewellel (Mountain Beaver)August Morning, Mount Rainier, Washington

    Neither a beaver nor a high-mountain dweller, the sewellel is a rather singular animal. It’s the last living member of a once-successful family of rodents called the Aplodontiidae. The sewellel is a “living fossil,” showing primitive skeletal features that other rodents have lost. Its kidneys are also unusual: they are inefficient at maintaining the body’s water balance. Thus the sewellel needs to live close to water so it can drink a lot—a third of its weight in water per day. 

    This diorama is located in the Bernard Family Hall of North American Mammals.