Water on the moon came from the sun

Dear readers and followers,

on Monday october 6th, scientifs published really interesting work about the origin of water on Moon. Water trapped in rocks on the moon's surface probably originated mostly from streams of energetic particles blasted from the sun and not from cosmic impacts from comets, researchers say.

For years, scientists argued over whether the moon harbored water or not. Recent findings confirmed that water does exist on the moon, although its surface remains drier than any desert on Earth. +NASA officials have suggested this water could one day help support colonies on the moon and missions to Mars and beyond.

It remained uncertain where all of this water came from. One possibility is that it was delivered by impacts from carbonaceous chondrites, meteorites that can be rich in water, and from comets. Another is that water formed on the moon after exposure to the solar wind, streams of high-energy particles from the sun. Atoms of hydrogen in the solar wind can react with oxygen trapped in moon rocks to form water.

To help find out where lunar water came from, scientists analyzed 45 microscopic grains of dust that astronauts on NASA's Apollo 16 and 17 missions brought from the moon. They focused on levels of different isotopes of elements within these dust grains. Isotopes differ from each other in how many neutrons there are in their atoms — for instance, normal hydrogen atoms do not have any neutrons, while atoms of deuterium, an isotope of hydrogen, each possess one neutron. Water can be made with deuterium as well as with normal hydrogen.

The sun is naturally low in deuterium because its nuclear reactions quickly consume the isotope. All other bodies in the solar system possess relatively high levels of deuterium, remnants that existed in the nebula of gas and dust that gave birth to the solar system. By analyzing the ratio of deuterium to hydrogen in the water in moon dust, the researchers could deduce whether the water originated from the sun or elsewhere, such as chondrites.

One complicating factor in this analysis is that cosmic rays — high-energy particles from deep space — can generate deuterium when they slam into the moon. To account for how cosmic rays can influence deuterium levels on the moon, the scientists also looked at levels of lithium-6, an isotope of lithium that cosmic rays would also generate when they hit the moon. By examining the ratio of lithium-6 to normal lithium, the researchers deduced how often cosmic rays struck the moon and generated deuterium as well as lithium-6.

The researchers expected to find water from chondrites in the interiors of the lunar dust grains and water from both chondrites and the solar wind in the exteriors or rims of these grains. Surprisingly, the water in both the interiors and exteriors of these dust grains apparently originated mainly from the solar wind.

These findings suggest that any water that cosmic impacts bring to the moon is not retained much. At most, an average of 15 percent of the hydrogen in lunar soil may come from chondritic water, the researchers said.

Source: journal Proceedings of the National Academy of Sciences

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Orion spacecraft flight testing

Dear readers and followers,

NASA’s newest spacecraft, Orion, will be launching into space for the first time in December 2014, on a flight that will take it farther than any spacecraft built to carry humans has gone in more than 40 years and through temperatures twice as hot as molten lava to put its critical systems to the test.

Testing of Orion system and capsule continue. Actually, in June 2014, NASA performed tests of the parachute system of the new spacecraft called Orion. A test version of Orion is loaded onto a C-17 for a previous test of its parachute system.

As the flight test of NASA’s Orion spacecraft nears, a new video -- called "Trial By Fire" -- details the spacecraft’s test and the critical systems engineers will evaluate during the Dec. 4 flight. Orion is in the final stages of preparation for the uncrewed flight test that will take it 5800 km above Earth on a 4.5 hours mission to test many of the systems necessary for future human missions into deep space.

Few weeks ago, +NASA has officially announced they have completed a rigorous review of the Space Launch System (SLS). SLS is a heavy-lift, exploration class rocket which is still under development to take humans beyond Earth orbit and to Mars. Finally, after many months of budget difficulty, NASA has approved the program's progression from formulation to development. 

SLS will be the world's most capable rocket. In addition to opening new frontiers for explorers traveling aboard the Orion capsule, the SLS may also offer benefits for science missions that require its use and can’t be flown on commercial rockets.

Source

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Is Pluto a planet? The votes are IN !!

Dear readers and followers,

What is a planet? For generations of kids the answer was easy. A big ball of rock or gas that orbited our Sun, and there were nine of them in our solar system. But then astronomers started finding more Pluto-sized objects orbiting beyond Neptune. Then they found Jupiter-sized objects circling distant stars, first by the handful and then by the hundreds. Suddenly the answer wasn’t so easy. Were all these newfound things planets?

Since the International Astronomical Union (IAU) is in charge of naming these newly discovered worlds, they tackled the question at their 2006 meeting. They tried to come up with a definition of a planet that everyone could agree on. But the astronomers couldn’t agree. In the end, they voted and picked a definition that they thought would work.

The current, official definition says that a planet is a celestial body that: "is in orbit around the Sun, is round or nearly round, and has “cleared the neighborhood” around its orbit."

But this definition baffled the public and classrooms around the country. For one thing, it only applied to planets in our solar system. What about all those exoplanets orbiting other stars? Are they planets? And Pluto was booted from the planet club and called a dwarf planet. Is a dwarf planet a small planet? Not according to the IAU. Even though a dwarf fruit tree is still a small fruit tree, and a dwarf hamster is still a small hamster.

Eight years later, the Harvard-Smithsonian Center for Astrophysics decided to revisit the question of “what is a planet?” On September 18th, a debate has been organized and its goal: to find a definition that the eager public audience could agree on!

Science historian Dr. Owen Gingerich, who chaired the IAU planet definition committee, presented the historical viewpoint. Dr. Gareth Williams, associate director of the Minor Planet Center, presented the IAU’s viewpoint. And Dr. Dimitar Sasselov, director of the Harvard Origins of Life Initiative, presented the exoplanet scientist’s viewpoint.

Zingerich argued that “a planet is a culturally defined word that changes over time,” and that Pluto is a planet. Williams defended the IAU definition, which declares that Pluto is not a planet. And Sasselov defined a planet as “the smallest spherical lump of matter that formed around stars or stellar remnants,” which means Pluto is a planet.

After these experts made their best case, the audience got to vote on what a planet is or isn’t and whether Pluto is in or out. The results are in, with no hanging chads in sight.

According to the audience, Sasselov’s definition won the day, and Pluto IS a planet.

Source


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