Vast regions of dark dunes also extend across Titan's exotic landscape, especially around its equatorial regions. Unlike Earth's sand, the "sand" that creates Titan's dunes is composed of dark grains of hydrocarbon that resemble coffee grounds. The tall linear dunes of this misty moisty moon-world appear to be quite similar to those seen in the desert of Namibia in Africa. Because Titan's surface is pockmarked by relatively few impact craters, its surface is considered to be quite young. Older surfaces display heavier cratering than more youthful surfaces, whose craters have been "erased" by resurfacing. This resurfacing is caused by processes that cover the scars left by old impacts as time goes by. Our own planet is similar to Titan in this respect. The craters of Earth are erased by the ongoing processes of flowing liquid (water on Earth), powerful winds, and the recycling of Earth's crust as a result of plate-tectonics. These processes also occur on Titan, but in modified forms. In particular, the shifting of the ground resulting from pressures coming from beneath (plate tectonics), also appear to be at work on this veiled moon-world. However, planetary scientists have not seen signs of plates on Titan that are analogous to those of our own planet. When we learn these influences that the moon holds over us and astrological phenomena, we can use this information to our advantage. For example, during the new moon most people are not capable of rational thought. Knowing this can help you to avoid major decision making during the time of the full moon. Life as we know it depends on the presence of three ingredients: liquid water; a source of energy for metabolism; and the right chemical ingredients, mainly carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. With this new discovery of the existence of hydrogen, in the tattle-tale plume shooting out from the surface of Enceladus, Cassini has revealed to the prying eyes of curious astronomers, that this small, icy moon has almost all of these ingredients important for habitability. At this point, Cassini has not detected the presence of phosphorus and sulfur in the hidden subsurface ocean of this distant small world, but many planetary scientists suspect that they will eventually be detected because the rocky core of Enceladus is believed to be similar to certain meteorities that contain these two critical elements.