Glaciers are melting faster than expected due to global warming, depleting ice around the world. The human genome was fully mapped between 2000-2003 in a massive scientific effort. In 2008, the Phoenix lander confirmed the presence of water ice on Mars, fueling hopes of microbial life. Stem cells were found in new sources like adult skin cells in 2007, avoiding ethical issues with embryonic stem cells. Direct evidence in 2006 confirmed the long-inferred existence of dark matter through observations of the Bullet Cluster collision.