41.   There are also enormous erosion channels demonstrating that water really did carve the martian surface.

42.   These impacts fractured the Martian surface, causing carbonate globules to form in the crevices.

43.   There is no liquid water on the Martian surface now, but scientists figure that the planet is water-rich.

44.   They also want instruments that can locate geothermal sources, which could maintain liquid water nearer the frigid Martian surface.

45.   They have received a signal from the Pathfinder spacecraft on the Martian surface confirming that it is successfully receiving the to-do list being transmitted from Earth.

46.   There, Lowell claimed to see long, thin lines on the Martian surface.

47.   Transmissions to Earth were to resume after the probe reached the Martian surface, deploying power-generating solar arrays and a communications antenna.

48.   Water cannot exist on the Martian surface now because the atmosphere is too thin, and it would immediately evaporate.

49.   While liquid water cannot exist on the Martian surface because of its low air pressure, water could flow just below the surface.

50.   Another instrument called the Pressure Modulator Infrared Radiometer will measure temperatures, dust, water vapor and clouds from the Martian surface to above the horizon.