Atmosphere of Earth development of animals. Today's atmosphere contains 21% oxygen, which is great enough for this rapid development of animals. "Air pollution" is the introduction into the atmosphere of chemicals, particulate matter or biological materials that cause harm or discomfort to organisms. Stratospheric ozone depletion is caused by air pollution, chiefly from chlorofluorocarbons and other ozone-depleting substances. The scientific consensus is that the anthropogenic greenhouse gases currently accumulating in the atmosphere are the main cause of global warming. On October 19, 2015 NASA started a website containing daily images of the full sunlit side of Earth on http://epic.gsfc.nasa.gov/. The images are taken
Atmosphere of Titan within Titan itself, released via eruptions from cryovolcanoes. A possible biological origin for the methane has not been discounted (see Life on Titan). There is also a pattern of air circulation found flowing in the direction of Titan's rotation, from west to east. Observations by "Cassini" of the atmosphere made in 2004 also suggest that Titan is a "super rotator", like Venus, with an atmosphere that rotates much faster than its surface. Titan's ionosphere is also more complex than Earth's, with the main ionosphere at an altitude of 1,200 km but with an additional layer of charged particles at 63