Russian scientists opened a frontier miles under the Antarctic ice, after drilling down and finally reaching the surface of 20-million-year-old Lake Vostok, an achievement the mission chief likened to placing a man on the moon. The gigantic buried freshwater reservoir could harbor life from Earth's distant past. The event is a major scientific achievement: "In the simplest sense, it can transform the way we think about life," NASA's chief scientist, Waleed Abdalati, told The Associated Press.
The scientific commuity anticaptes that Lake Vostok could host living organisms that have been locked in frigid darkness for some 20 million years, as well as clues to the search for life elsewhere in the solar system such as Jupiter's "Ocean Moon," Europa, under the ice crust on Mars, and Saturn's moon Enceladus, also believed to harbor a vast buried ocean. Penetrating the surface of the lakecame after more than two decades of drilling when the Russian team made contact with the lake water Sunday at a depth of 12,366 feet (3,769 meters), about 800 miles (1,300 kilometers) east of the South Pole in the central part of the continent.
Valery Lukin, the head of Russia's Arctic and Antarctic Research Institute, said reaching the lake was akin to the Americans winning the space race in 1969.
"I think it's fair to compare this project to flying to the moon," said Lukin, who oversaw the mission and announced its success.American and British teams are drilling to reach their own subglacial Antarctic lakes, but Columbia University glaciologist Robin Bell said those are smaller and younger than Vostok, which is the big scientific prize."It's like exploring another planet, except this one is ours," she said.
Lake Vostok is kept from freezing into a solid block by the more than two-mile-thick crust of ice that acts like a blanket, keeping in heat generated by the Earth's geothermal energy. Lukin said he expects the lake to contain chemotroph bacteria that feed on chemical reactions in pitch darkness, probably similar to those existing deep on the ocean floor but dating back millions of years.
"They followed different laws of evolution that are yet unknown to us," he said.Studying Lake Vostok will also yield insights about the origins of Antarctica, which is believed by many to have been part of a broader continent in the distant past.
Lake Vostok might also provide an Earth-bound preview of Jupiter's Europa. "Europa, I think, is the premier place to go for extant life," said JPL's Kevin Hand, Europa really does give us this opportunity to look for living life in the ocean that is there today, and has been there for much of the history of the solar system."
But Jupiter's Europa might not only sustain, but foster life, according to the research of University of Arizona's Richard Greenberg, a professor of planetary sciences and member of the Imaging Team for NASA's Galileo Jupiter-orbiter spacecraft.
Europa, similar in size to Earth's moon, and has been imaged by the Galileo Jupiter-orbiter spacecraft. Its surface, a frozen crust of water, was previously thought to be tens of kilometers thick, denying the oceans below any exposure. The combination of tidal processes, warm waters and periodic surface exposure may be enough not only to warrant life, but also to encourage evolution.
With Jupiter being the largest planet in the solar system, its tidal stresses on Europa create enough heat to keep the water on Europa in a liquid state. More than just water is needed to support life. Tides also play a role in providing for life. Ocean tides on Europa are much greater in size than Earth's with heights reaching 500 meters (more than 1,600 feet). Even the shape of the moon is stretched along the equator due to Jupiter's pull on the waters below the icy surface.
The mixing of substances needed to support life is also driven by tides. Stable environments are also necessary for life to flourish. Europa, whose orbit around Jupiter is in-sync with its rotation, is able to keep the same face towards the gas giant for thousands of years. The ocean is interacting with the surface, according to Greenberg, and "there is a possible that extends from way below the surface to just above the crust."
"The real key to life on Europa," Greenburg adds, "is the permeability of the ice crust. There is strong evidence that the ocean below the ice is connected to the surface through cracks and melting, at various times and places. As a result, the , if there is one, includes not just the liquid water ocean, but it extends through the ice up to the surface where there is access to oxidants, organic compounds, and light for photosynthesis. The physical setting provides a variety of potentially habitable and evolving niches. If there is life there, it would not necessarily be restricted to microorganisms."
Tides have created the two types of surface features seen on Europa: cracks/ridges and chaotic areas, Greenberg said.The ridges are thought to be built over thousands of years by water seeping up the edges of cracks and refreezing to form higher and higher edges until the cracks close to form a new ridge.
The chaotic areas are thought to be evidence of the melt-through necessary for exposure to the oceans.
The tidal heat, created by internal friction, could be enough to melt the ice, along with undersea volcanoes - a combination of factors would give organisms a stable but changing environment -- exactly the type that would encourage evolution.
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