Scientists: Europa's Ocean Similar to Earth's, May Contain Life

A new study to be published in Astronomical Journal suggests that the subsurface ocean on Jupiter's moon Europa may be an abode of life. This conclusion is based on recent observations of an Earth-bound telescope in Hawaii.

More evidence that Europa's ocean may contain life

Space Daily reports that a paper to be published by Mike Brown, an astronomer at the California Institute of Technology in Pasadena, Calif., and Kevin Hand from NASA's Jet Propulsion Laboratory, also in Pasadena, provides the strongest evidence yet that Europa's ocean, trapped beneath a crust of solid ice, may contain life because of its chemical composition and its temperature caused by tidal forces. The paper is the result of studies done by the Keck II Telescope on Mauna Kea, Hawaii, and its OSIRIS spectrometer.

Chemical composition of Europa ocean similar to Earth's oceans

The observations detected the presence of magnesium sulfate salt on the icy surface of Europa, according to Space Daily. The material seems to have been generated by sulfur ejected by one of Jupiter's other moons, Io, plus magnesium chloride salt coming up from Europa's subsurface ocean. With chlorides such as sodium and potassium chlorides thought to also exist on Europa's surface, scientists now believe that the subsurface ocean is very similar to that of Earth's oceans.

Options being considered for exploring Europa

With attempts to find microbial life on Mars so far not bearing any fruit, some scientists are increasingly turning to Europa as a possible target of exploration. The European Space Agency Jupiter Icy Moon Explorer, in which NASA is a participant, will conduct a number of flybys of Europa, but is more focused on another of Jupiter's moons, Ganymede. While NASA has studied an Europa orbiter for some years, recent Obama administration budget cuts have forced a descoping of such a mission to consist of a number of flybys of the icy moon in a mission called Europa Clipper, according to Space.com. The probe would include a number of instruments, including an ice-penetrating radar, a topographical imager, a magnetometer, an infrared spectrometer, and a neutral mass spectrometer. If approved, the Europa Clipper would launch in 2021 and would cost $2 billion.

Landing on Europa

Further into the future, NASA dreams of sending a probe to land on Europa. According to a Space.com story published on the NBC News site, the holy grail of a robotic mission to Europa would consist of a small submarine that would somehow penetrate the icy crust of the moon and explore the subsurface ocean, finding out once and for all whether life exists there. That mission will occur, if at all, further into the current century due to NASA's lean budget.

Mark R. Whittington is the author of Children of Apollo and The Last Moonwalker. He has written on space subjects for a variety of periodicals, including The Houston Chronicle, The Washington Post, USA Today, the L.A. Times, and The Weekly Standard.

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Leap Second Science: NASA Explains Earth's Longer Day Today

Today will be one second longer than usual, and we have the moon to thank for the extra time.

A "leap second" will be added to the world's official clocks this evening (June 30), to account for the fact that Earth's rotation is slowing ever so slightly — meaning our days are getting longer, at the rate of about 1.4 milliseconds every 100 years.

"At the time of the dinosaurs, Earth completed one rotation in about 23 hours," Daniel MacMillan, of NASA’s Goddard Space Flight Center in Greenbelt, Md., said in a statement. "In the year 1820, a rotation took exactly 24 hours, or 86,400 standard seconds. Since 1820, the mean solar day has increased by about 2.5 milliseconds."

It's happening because of tidal forces between the Earth and moon. This mutual gravitational jostling results in the transfer of our planet's rotational momentum to the moon, pushing it away from us at about 1.6 inches (4 centimeters) per year.

Earth's rotational slowdown won't stop until it becomes tidally locked to the moon, researchers say — meaning we will always show the same face to our celestial neighbor. The moon is tidally locked to Earth now, keeping its far side forever out of sight. [Hit Snooze: 10 Best Alarm Clocks]

Scientists figured out the planet's lagging rotation rate using a technique called Very Long Baseline Interferometry. VLBI measures how long it takes radio waves emitted by faraway active black holes called quasars — the brightest objects in the universe — to reach a network of telescopes set up around the world.

From the tiny differences in arrival times to these various instruments, researchers can calculate Earth's rotational speed and a number of other interesting characteristics about our planet and its path through space.

Decades ago, scientists realized that some measurements and technologies required more precise timekeeping than Earth's rotation could provide. So in 1967, they officially changed the definition of a second, basing it on measurements of electromagnetic transitions in cesium atoms rather than the length of a day.

Such "atomic clocks" are accurate to approximately one second in 200 million years, researchers say. The widely used time standard based on the cesium atom is called Coordinated Universal Time, or UTC.

Timekeepers add leap seconds to UTC every once in a while to square it up with another time standard that's based on Earth's day length. So June 30 will get an extra second just before 8 p.m. EDT (midnight GMT on July 1).

The master clock at the U.S. Naval Observatory will move to 7:59:60 p.m. EDT, or 23:59:60 UTC, before ticking over. In practice, this means that clocks in many systems will be turned off for one second, NASA researchers said.

Saturday's adjustment will mark the 25th time a leap second has been added since the practice was initiated in 1972. The most recent leap second was inserted on New Year's Eve of 2008.

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