Bad Night's Sleep? The Moon Could Be to Blame

Bad Night's Sleep? The Moon Could Be to Blame

  7:26:00 PM    Science Lover

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Many people complain about poor sleep around the full moon, and now a report appearing in Current Biology, a Cell Press publication, on July 25 offers some of the first convincing scientific evidence to suggest that this really is true. The findings add to evidence that humans -- despite the comforts of our civilized world -- still respond to the geophysical rhythms of the moon, driven by a circalunar clock.

Many people complain about poor sleep around the full moon, and now a report appearing in Current Biology, a Cell Press publication, on July 25 offers some of the first convincing scientific evidence to suggest that this really is true. The findings add to evidence that humans -- despite the comforts of our civilized world -- still respond to the geophysical rhythms of the moon, driven by a circalunar clock. (Credit: Current Biology, Cajochen et al.)

"The lunar cycle seems to influence human sleep, even when one does not 'see' the moon and is not aware of the actual moon phase," says Christian Cajochen of the Psychiatric Hospital of the University of Basel.

In the new study, the researchers studied 33 volunteers in two age groups in the lab while they slept. Their brain patterns were monitored while sleeping, along with eye movements and hormone secretions.

The data show that around the full moon, brain activity related to deep sleep dropped by 30 percent. People also took five minutes longer to fall asleep, and they slept for twenty minutes less time overall. Study participants felt as though their sleep was poorer when the moon was full, and they showed diminished levels of melatonin, a hormone known to regulate sleep and wake cycles.

"This is the first reliable evidence that a lunar rhythm can modulate sleep structure in humans when measured under the highly controlled conditions of a circadian laboratory study protocol without time cues," the researchers say.

Cajochen adds that this circalunar rhythm might be a relic from a past in which the moon could have synchronized human behaviors for reproductive or other purposes, much as it does in other animals. Today, the moon's hold over us is usually masked by the influence of electrical lighting and other aspects of modern life.

The researchers say it would be interesting to look more deeply into the anatomical location of the circalunar clock and its molecular and neuronal underpinnings. And, they say, it could turn out that the moon has power over other aspects of our behavior as well, such as our cognitive performance and our moods.

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Solar wind samples give insight into birth of solar system

Solar wind samples give insight into birth of solar system

  9:33:00 AM    Science Lover

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Two papers in this week's issue of Science report the first oxygen and nitrogen isotopic measurements of the Sun, demonstrating that they are verydifferent from the same elements on Earth. These results were the top two priorities of NASA's Genesis mission, which was the first spacecraft to return from beyond the Moon, crashing in the Utah desert in 2004 after its parachute failed to deploy during re-entry.

The Solar Wind Concentrator is a special instrument built
by a team at Los Alamos National Laboratory to enhance
the flow of solar wind onto a small target to make possible
oxygen and nitrogen measurements. Shown here, the target
section of the concentrator, which produced essential
samples of nitrogen and oxygen.

Most of the Genesis payload consisted of fragile solar-wind collectors, which had been exposed to the solar particles over a period of two years. Nearly all of these collectors were decimated during the crash. But the capsule also contained a special instrument built by a team at Los Alamos National Laboratory to enhance the flow of solar wind onto a small target to make possible oxygen and nitrogen measurements. The targets of this Solar Wind Concentrator survived the crash and eventually yielded today's solar secrets.

"Genesis is the biggest comeback mission since Apollo 13," said Roger Wiens, a Los Alamos National Laboratory physicist and Genesis flight payload lead. "Everyone who saw the crash thought it was a terrible disaster, but instead the project has been fully successful, and the results are absolutely fascinating."

The results provide new clues to how the solar system was formed. Oxygen and nitrogen samples collected from various meteorites, as well as nitrogen sampled in lunar soil and in the Jupiter atmosphere by the Galileo probe, vary significantly from that on Earth by cosmochemical standards: 38 percent for nitrogen and up to 7 percent for oxygen. With the first solar wind samples in hand, showing the early Sun's composition, scientists can begin the game of determining where Earth's different O and N came from.



"For nitrogen, Jupiter and the Sun look the same," said Wiens. "It tells us that the original gaseous component of the inner and outer solar system was homogeneous for nitrogen, at least. So where did Earth gets its heavier nitrogen from? Maybe it came here in the material comets are made of. Perhaps it was bonded with organic materials."

For oxygen, the evidence points toward a different astrophysical mechanism called photochemical self-shielding, which the authors believe modified the composition of space dust before it coalesced to form the planets, including Earth. According to the article, the Sun shows an enrichment of pure 16O relative to Earth instead of differences in 16O, 17O, and 18O that are proportional to their atomic weight or some other mixture that doesn't show exclusive enrichment of a single isotope. This unique arrangement strongly favors the self-shielding theory, in which solar UV radiation was responsible for uniformly enhancing the two rarer isotopes, 17O and 18O, in the terrestrial planets.

The Science papers are titled "A 15N-poor isotopic composition for the solar system as shown by Genesis solar wind samples" and "The oxygen isotopic composition of the Sun inferred from captured solar wind." Wiens is among several collaborating authors on both papers, which together are cover stories for this issue. Other LANL coauthors, Beth Nordholt and Ron Moses, along with former LANL scientist Dan Reisenfeld, were all part of the team to develop and fly the Solar Wind Concentrator that provided the samples for the studies reported in Science.

And now that some of the particles flowing past Earth from the sun are in hand, "It's going to make a mission to a comet all the more interesting," Wiens said.

Provided by Los Alamos National Laboratory

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How The Moon Produces Its Own Water

How The Moon Produces Its Own Water

  6:48:00 PM    Science Lover

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The Moon is a big sponge that absorbs electrically charged particles given out by the Sun. These particles interact with the oxygen present in some dust grains on the lunar surface, producing water. This discovery, made by the ESA-ISRO instrument SARA onboard the Indian Chandrayaan-1 lunar orbiter, confirms how water is likely being created on the lunar surface.

Chandrayaan-1 SARA measurements of hydrogen flux recorded on the Moon on 6 February 2009. (Credit: Elsevier 2009 (Wieser et al.), ESA-ISRO SARA data)

It also gives scientists an ingenious new way to take images of the Moon and any other airless body in the Solar System.

The lunar surface is a loose collection of irregular dust grains, known as regolith. Incoming particles should be trapped in the spaces between the grains and absorbed. When this happens to protons they are expected to interact with the oxygen in the lunar regolith to produce hydroxyl and water. The signature for these molecules was recently found and reported by Chandrayaan-1’s Moon Mineralogy Mapper (M3) instrument team.

The SARA results confirm that solar hydrogen nuclei are indeed being absorbed by the lunar regolith but also highlight a mystery: not every proton is absorbed. One out of every five rebounds into space. In the process, the proton joins with an electron to become an atom of hydrogen. “We didn’t expect to see this at all,” says Stas Barabash, Swedish Institute of Space Physics, who is the European Principal Investigator for the Sub-keV Atom Reflecting Analyzer (SARA) instrument, which made the discovery.

Although Barabash and his colleagues do not know what is causing the reflections, the discovery paves the way for a new type of image to be made. The hydrogen shoots off with speeds of around 200 km/s and escapes without being deflected by the Moon’s weak gravity. Hydrogen is also electrically neutral, and is not diverted by the magnetic fields in space. So the atoms fly in straight lines, just like photons of light. In principle, each atom can be traced back to its origin and an image of the surface can be made. The areas that emit most hydrogen will show up the brightest.

Whilst the Moon does not generate a global magnetic field, some lunar rocks are magnetised. Barabash and his team are currently making images, to look for such ‘magnetic anomalies’ in lunar rocks. These generate magnetic bubbles that deflect incoming protons away into surrounding regions making magnetic rocks appear dark in a hydrogen image.

The incoming protons are part of the solar wind, a constant stream of particles given off by the Sun. They collide with every celestial object in the Solar System but are usually stopped by the body’s atmosphere. On bodies without such a natural shield, for example asteroids or the planet Mercury, the solar wind reaches the ground. The SARA team expects that these objects too will reflect many of the incoming protons back into space as hydrogen atoms.

This knowledge provides timely advice for the scientists and engineers who are readying ESA’s BepiColombo mission to Mercury. The spacecraft will be carrying two similar instruments to SARA and may find that the inner-most planet is reflecting more hydrogen than the Moon because the solar wind is more concentrated closer to the Sun.

SARA was one of three instruments that ESA contributed to Chandrayaan-1, the lunar orbiter that finished its mission in August 2009. The instrument was built jointly by scientific groups from Sweden, India, Japan, and Switzerland: Swedish Institute of Space Physics, Kiruna, Sweden; Vikram Sarabhai Space Centre, Trivandrum, India; University of Bern, Switzerland; and Institute of Space and Astronautical Science, Sagamihara, Japan. The instrument is led by Principal Investigators Stanislav Barabash, IRF, Sweden, and Anil Bhardwaj, VSSC, India.
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