Earth Engine from Google

" Google Earth Engine brings together the world’s satellite imagery — trillions of scientific measurements dating back almost 40 years — and makes it available online with tools for scientists, independent researchers, and nations to mine this massive warehouse of data to detect changes, map trends and quantify differences on the Earth’s surface. Applications include: detecting deforestation, classifying land cover, estimating forest biomass and carbon, and mapping the world’s roadless areas. "

• Earth Engine

see also,

• Google Blog post, http://googleblog.blogspot.com/2013/05/a-picture-of-earth-through-time.html
• Time magazine article, http://world.time.com/timelapse/