NABARD Grade A (Assistant Manager) 2021 · Question 18 of 113

According to the passage, what is the theory behind the presence of water on moon’s surface? Read the following passage and answer the give questions accordingly. Lunar water is water that is present on the Moon. It was first discovered by ISRO through its Chandrayaan mission. Diffused water molecules can persist at the Moon's sunlit surface, as discovered by NASA's SOFIA observatory in 2020. Gradually water vapor is decomposed by sunlight, leaving hydrogen and oxygen lost to outer space. Scientists have found water ice in the cold, permanently shadowed craters at the Moon's poles. Water molecules are also in the extremely thin lunar atmosphere. Water (H2O), and the chemically related hydroxyl group (-OH), exist in forms chemically bound as hydrates and hydroxides to lunar minerals (rather than free water), and evidence strongly suggests that this is the case in low concentrations as for much of the Moon's surface. In fact, of surface matter, adsorbed water is calculated to exist at trace concentrations of 10 to 1000 parts per million. Inconclusive evidence of free water ice at the lunar poles had accumulated during the second half of the 20th century from a variety of observations suggesting the presence of bound hydrogen. On 18 August 1976, the Soviet Luna 24 probe landed at Mare Crisium, took samples from the depths of 118, 143, and 184 cm of the lunar regolith, and then took them to Earth. In February 1978, it was published that laboratory analysis of these samples shown they contained 0.1% water by mass. Spectral measurements shown minima near 3, 5, and 6 km, distinctive valence-vibration bands for water molecules, with intensities two or three times larger than the noise level. On 24 September 2009, it was reported that the NASA's Moon Mineralogy Mapper (M3) spectrometer onboard India's ISRO Chandrayaan-1 probe had detected absorption features near 2.8—3.0 km on the surface of the Moon. But about 10 months before, on 14 November 2008, India's made Moon Impact Probe onboard Chandrayaan-1 orbiter landed into Shackleton crater and confirmed the presence of water ice. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. In August 2018, NASA confirmed that M3 showed water ice is present on the surface at the Moon poles. Water was confirmed to be on the sunlit surface of the Moon by ISRO on October 26, 2020. Water may have been delivered to the Moon over geological timescales by the regular bombard ment of water-bearing comets, asteroids, and meteoroids or continuously produced in situ by the hydrogen ions (protons) of the solar wind impacting oxygen-bearing minerals. The search for the presence of lunar water has attracted considerable attention and motivated several recent lunar missions, largely because of water's usefulness in rendering long-term lunar habitation feasible. The presence of large quantities of water on the Moon would be an important factor in rendering lunar habitation cost- effective since transporting water (or hydrogen and oxygen) from Earth would be prohibitively expensive. If future investigations find the quantities to be particularly large, water ice could be mined to provide liquid water for drinking and plant propagation, and the water could also be split into hydrogen and oxygen by solar panel- equipped electric power stations or a nuclear generator, providing breathable oxygen as well as the components of rocket fuel. The hydrogen component of the water ice could also be used to draw out the oxides in the lunar soil and harvest even more oxygen.

Reading Comprehension - Lunar Water

1. AWater may have been delivered to the moon over geological timescales by the regular bombardment of water-bearing comets, asteroids, and meteoroids.Correct
2. BWater may have been delivered to the moon over geological timescales by the regular bombardment of planets.
3. CWater may have been delivered to the moon over geological timescales by the regular bombardment of spaceships.
4. DWater is stored within glasses or in voids between grains sheltered from the harsh lunar environment, thus allowing the water to remain on the lunar surface.
5. EThe surface of that crater is covered in glacier.