‘Like a bomb had exploded in our hands’ – the scientist who found water on Moon
When early astronomers gazed up at the Moon, they mistook its dark patches for seas. By the time Neil Armstrong stepped on to the Sea of Tranquility in 1969, scientists knew it was nothing but terra firma.
Most researchers concluded that the Moon was ‘‘bone dry’’, a celestial desert devoid of water or ice. But in a set of papers published beginning in 2008, geochemist Erik Hauri, who has died from cancer, aged 52, helped demonstrate that water existed on the Moon after all – and that its interior might contain as much water as the Mediterranean Sea.
Hauri helped usher in a new era in our understanding of the Moon, an astronomical object now known to have ice on its poles and water deep inside its mantle.
A longtime researcher at Washington’s Carnegie Institution for Science, Hauri was first recognised for his work with highly sensitive instruments called ion microprobes, which he pushed ‘‘to their absolute technical limits’’, said Larry Nittler, a cosmochemist and Carnegie colleague.
Using techniques he developed in the 1990s, Hauri used the instruments to examine slivers of shards, portions of rock the width of a human hair or smaller. He detected trace amounts of elements such as hydrogen and carbon, down to a few parts per million – work that enabled him to obtain key insights on the Earth and Moon.
A former marine biology student, he began studying rocks after deciding marine animals were fickle and unco-operative. But he spent much of his career outside the lab, collecting volcanic samples from Hawaii, Iceland, Alaska and Polynesia that shed light on the movement of elements and minerals deep inside the Earth.
He was focusing on water, which has a broad impact on volcanic eruptions and the movement of tectonic plates, when his friend Alberto Saal suggested they conduct measurements for hydrogen, water and other volatile substances using the lunar samples of the Apollo programme.
‘‘When people measured these Moon rocks they never found anything,’’ Saal said. ‘‘We had a good technique. Nothing had been done on hydrogen for a long time. We said, ‘Why not try?’ ’’
It took three years for the researchers to obtain their samples from Nasa, which twice rejected their research proposal, Saal said. But when he and Hauri reviewed their findings, ‘‘it was like a bomb had exploded in our hands’’.
Their work centred on a thimble’s worth of orange-tinted soil, which included tiny beads of volcanic glass collected by astronaut and geologist Harrison Schmitt in 1972. The beads were formed when the Moon was relatively young, when lava was ejected from volcanoes and cooled so fast that it turned to glass before falling to the ground.
In a 2008 article in Nature, the scientists reported that some of the beads contained trace amounts of water – about 50 parts per million. Three years later, in an article in Science, Hauri and his colleagues reported finding far more – about 100 times more water than had previously been believed. Their research indicated that the mantle of the Moon, just below the surface, contained about as much water as the upper mantle of Earth.
‘‘If you take our measurements and use them to estimate the water content of the interior of the Moon, you arrive at a volume of water that’s equivalent to the Mediterranean Sea. Now that’s a fair bit of water,’’ Hauri said in 2011.
Erik Harold Hauri was born near Chicago, to a mother who was a homemaker and a father who was an car mechanic and avid fisherman, taking Erik on trips that spawned a lifelong interest in the outdoors.
Neither parent had attended college. But Hauri studied geology and marine science at the University of Miami, where he received a bachelor’s degree in 1988 and acquired a level of self-confidence unusual for a student his age. While interviewing for the doctoral programme at MIT, his future adviser, Stanley Hart, told him that he might be leaving the school in two years. ‘‘Oh, that’s OK,’’ Hauri replied. ‘‘I think I can learn all you have to teach in two years.’’
Outside the lab, he played guitar – worship music at church, and progressive metal at home. He also became a self-taught luthier, making more than a dozen guitars and bass guitars by hand after finding himself unable to acquire a 12-string Fender Stratocaster in a store.
In addition to wife Tracy, survivors include three children, plus his father, sister and brother.
Hauri and Saal continued their lunar work in recent years, finding that water on the Moon and on Earth appeared to originate from the same source, a class of meteorites known as carbonaceous chondrites.
Others took up the hunt for lunar water In August, a new study found ‘‘direct and definitive evidence’’ for water ice on the surface of the Moon’s poles. It might some day be possible, scientists noted, for that ice to be used as a resource for a station or colony on the Moon. – Washington Post