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.
1 escape the Moon entirely if the particle is moving at or above the lunar escape velocity of 2.38 km/s; 2  be lost to space either by solar radiation pressure or, if the gases are ionized, by being swept away in the solar wind's magnetic field.