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History of Earth - in brief - Paleozoo. How old is the Earth? When did life first appear upon it? How did we come to be here? Questions as old as humankind. History of Earth - in brief - an outline of the evolution of the planet from its Hadean origins to its Anthropocene present. A timeline of the history of life on Earth. The Earth has undergone constant change in its 4.54 billion year history, with life evolving in response to those changes - in particular to the changing atmospheric compositions of carbon dioxide and oxygen. Species extinctions have been a natural part of the evolutionary processes of the planet throughout its long history, however there are now thought to have been at least 8 mass extinction events in the history of the Earth - each of major consequence to life on the planet and of import to our modern understandings of climate change. There have been many extinction events, both great and small, but the most profound of these would be the End-Permian Extinction that closed the Palaeozoic era (~252 Ma). Also known as the Great Dying, it is thought that over 90% of all marine species and 70% of all terrestrial species became extinct. A rapid increase in surface temperatures towards the end of this period brought about a collapse in the carbon cycle - starving life on land and subsequently suffocating life in the oceans. No environmental niche was left unchanged by the Permian Extinction. From the earliest ages of the planet - when microbial blooms spread around the globe - up to the radiation of Homo sapiens, life has repeatedly colonized every viable location on the planet. Life is nothing if not resilient and great extinctions serve to highlight this. Even if only a few isolated pockets of single-celled organisms survived a global extinction event - an event even more destructive than the Great Permian Extinction - life would continue on, evolving, adapting and radiating back across the world as soon as conditions allow. ~ This 5 minute animation was written and animated by Bruce Currie More information can be found at https://www.paleozoo.com.au KEY REFERENCE: Ward and Kirschvink, 2015 ‘A New History of Life’ https://www.amazon.com.au New-History-Life-Discoveries-Evolution/dp/1408835525 International Commission on Stratigraphy. https://stratigraphy.org NASA - Visible Earth catalogue https://visibleearth.nasa.gov/collect... British Geological Society. https://www.bgs.ac.uk Geological Society of America https://www.geosociety.org Gplates - Earthbytes https://www.earthbyte.org/gplates Paleomap Project - Christopher Scotese. http://www.scotese.com Algol - History of the Earth • History of the Earth Researchgate.net https://www.researchgate.net Other Paleozoo videos include: • Video • Placoderms of the Devo... • Video

From year to year, the moon never seems to change. Craters and other formations appear to be permanent now, but the moon didn't always look like this. Thanks to NASA's Lunar Reconnaissance Orbiter, we now have a better look at some of the moon's history. Learn more in this video! This video is public domain and can be downloaded at: http://svs.gsfc.nasa.gov/goto?10930

This artist’s rendering illustrates new findings about a star shredded by a black hole. When a star wanders too close to a black hole, intense tidal forces rip the star apart. In these events, called “tidal disruptions,” some of the stellar debris is flung outward at high speed while the rest falls toward the black hole. This causes a distinct X-ray flare that can last for a few years. NASA’s Chandra X-ray Observatory, Swift Gamma-ray Burst Explorer, and ESA/NASA’s XMM-Newton collected different pieces of this astronomical puzzle in a tidal disruption event called ASASSN-14li, which was found in an optical search by the All-Sky Automated Survey for Supernovae (ASAS-SN) in November 2014. The event occurred near a supermassive black hole estimated to weigh a few million times the mass of the sun in the center of PGC 043234, a galaxy that lies about 290 million light-years away. Astronomers hope to find more events like ASASSN-14li to test theoretical models about how black holes affect their environments. During the tidal disruption event, filaments containing much of the star's mass fall toward the black hole. Eventually these gaseous filaments merge into a smooth, hot disk glowing brightly in X-rays. As the disk forms, its central region heats up tremendously, which drives a flow of material, called a wind, away from the disk. Music credit: Encompass by Mark Petrie from Killer Tracks. This video is public domain and can be downloaded at: http://svs.gsfc.nasa.gov/goto?12005 You can read more about this at: http://www.nasa.gov/mission_pages/cha... Like our videos? Subscribe to NASA's Goddard Shorts HD podcast: http://svs.gsfc.nasa.gov/vis/iTunes/f... Or find NASA Goddard Space Flight Center on Facebook: / nasa.gsfc Or find us on Twitter: / nasagoddard

2013-04-09 - To better understand how vision is impacted in the space environment, astronauts use onboard medical instruments like the tonometer to examine the health of eyes. Commander Chris Hadfield gives us an inside look at these instruments and demonstrates how they work. Credits: Canadian Space Agency and NASA Expedition 34-35 Web page: http://www.asc-csa.gc.ca/eng/missions... Living in space Web page: http://www.asc-csa.gc.ca/eng/astronau... Find out more about this video: http://www.asc-csa.gc.ca/eng/search/v...

Expedition 33 Commander Suni Williams concludes her tour of the International Space Station with a visit to the Russian segment, which includes Zarya, the first segment of the station launched in 1998, and Zvezda, the central command post. She also takes a look at the Poisk and Rassvet modules where Soyuz spacecraft are

We’ve taken giant leaps and left our mark in the heavens. Now we’re building the next chapter, returning to the Moon to stay, and preparing to go beyond. We are NASA – and after 60 years, we’re just getting started. Special thanks to Mike Rowe for the voiceover work. This video is available for download from NASA's Image and Video Library: https://images.nasa.gov/details/NHQ_2...