4.6 billion years old How do we know? Scientists think that Earth probably formed at about the same time as the rest of the solar system. They have determined that some chondrite meteorites, the unaltered remains from the formation of the solar system, are up to 4.6 billion years old. Scientists believe that Earth and other planets are probably that old. They can determine the ages of rocks by measuring the amounts of natural radioactive materials, such as uranium, in them. Radioactive elements decay (change into other elements) at a known rate. For example, uranium gives off radiation and decays into lead. Scientists know the time it takes for uranium to change to lead. They can determine the age of a rock by comparing the amount of uranium to the amount of lead. Source: NASA
The Earth changes over time http://www.youtube.com/watch?v=Cm5giPd5Uro
What is the circumference of the Earth at the equator?
24,901.55 miles How long would it take you to walk around the Equator of the Earth?
The 7 Continents Asia Europe Africa North America South America Australia Antarctica
The Continents, Oceans, and borders
Where is Rhode Island? Latitude 41 degrees North Longitude 71 degrees West
Rhode Island in the World
Ocean floor maps show continental shelves, the true edge of the continents
Mount Everest, 29,035 feet
Mid Atlantic Ridge
Gobi desert in Mongolia
Greenland, Iceland, Madagascar, Borneo, Japan, and New Zealand.
7 billion people on Earth? World population clock
Population in 2050
The Human Footprint http://www.wcs.org/humanfootprint/
World air traffic
The Age of Humans - Anthropocene http://www.globaia.org/en/anthropocene/
Environmental Change Over billions of years, earth systems change. Humans have been on earth for about 1 or 2 million years About 12,000 years ago, with end of Ice Age, humans migrated into North & South America About 10,000 years ago, agriculture was developed in the Middle East Since then, the human footprint has expanded rapidly … I = P A T Sustainability – what does it mean?
Environmental movement http://www.nytimes.com/interactive/2010/04/22/science/earth/20100422_environment_timeline.html?ref=science
Today We live on a changing planet… change is the norm. The human interaction with natural systems is complex – we are part of nature, not apart from nature. The future will be what we make it to be … all things are possible.
Next week - Water What is a watershed? What watershed do you live in? Where does your water come from? What is the quality of the water? What environmental factors affect that quality? Who controls the water? Who oversees its quality? How much do you use? How much does it cost?
For Next Week Explore your town via Google maps. Find out what watershed you live in. Find out where your water comes from and anything else you can find out about it. Read the short article about water posted on the course Web site. Come to class prepared to discuss what you learned and also hand in a written report (1 or 2 pages). Include in that a summary of what you learned from the article plus one or two questions about water.