1 Drainage basin-the area of land drained by a river. 2  Catchment area-the area within the drainage basin. 3  Watershed-the edge of highland surrounding a drainage basin.4  It marks the boundary between two drainage basins. 5  Source-The beginning or start of a river. 6  Confluence-the point at which two rivers or streams join. Watershed-the edge of highland surrounding a drainage basin. 2  It marks the boundary between two drainage basins. 3  Source-The beginning or start of a river. 4  Confluence-the point at which two rivers or streams join.
Dangerous levels of radiation in space could bar astronauts from a mission to Mars and limit prolonged activity on the moon, experts now caution.However, more research could reveal ways to handle the risks that radiation poses to space missions.The magnetic field of Earth protects humanity from radiation in space that can damage or kill cells. Once beyond this shield, people become far more vulnerable.owever, more research could reveal ways to handle the risks that radiation poses to space missions. The magnetic field of Earth protects humanity from radiation in space that can damage or kill cells. Once beyond this shield, people become far more vulnerable.
The Moon's average radius is 1,080 miles, and assuming generously that the astronauts held the camera 5 feet, or 0.000947 miles above the surface (the cameras are shown in photographs as having no viewfinder, and the astronauts seem to hold them in the centre of their chest, so five feet is generous).