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New Research Shows Mars-Bound Astronauts Need Their Sleep

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It might not be one giant leap for mankind, but a mission completed on November 4, 2011, is definitely one small step toward sending men to Mars. On that date, a team of six international volunteers finished a 520-day simulated trip to our red neighbor that included more than 90 experiments and realistic scenarios astronauts might encounter on the journey. The goal of the simulation was to gather psychological and medical data on the effects of long-term deep space flight, and yesterday, a team of researchers led by faculty at the Perelman School of Medicine at the University of Pennsylvania and the Baylor College of Medicine released the results of their study, which looked at the impact of prolonged confinement on sleep, performance, and mood in astronauts.

"The success of human interplanetary spaceflight, which is anticipated to be in this century, will depend on the ability of astronauts to remain confined and isolated from Earth much longer than previous missions or simulations," said Dr. David F. Dinges, professor and chief, Division of Sleep and Chronobiology in the Department of Psychiatry at the Perelman School of Medicine, and co-lead author of the new study. "This is the first investigation to pinpoint the crucial role that sleep-wake cycles will play in extended space missions."

The mission, developed by the Institute for Biomedical Problems (IBMP) of the Russian Academy of Sciences, was broken into three phases: 250 days for the journey to Mars, 30 days on the surface, and 240 days for the return to Earth. The astronauts were confined in a 723 square foot spacecraft-like facility in Russia for the duration of the simulated mission. During that time, the U.S. research team continuously monitored the crew’s rest-activity patterns, monitored light exposure, and administered weekly, computer-based neurobehavioral assessments to determine the extent that sleep loss, fatigue, stress, mood changes, and conflicts occurred in the 17 months of confinement.

The data gathered by the researchers, published in Proceedings of the National Academy of Sciences, revealed that as the mission progressed, the crew grew more sedentary; there was less waking movement and more sleep and rest time. Most crewmembers had one or more disturbances of sleep and altered sleep-wake intervals, which suggests a disruption of circadian rhythm. Crewmembers also showed decreased alertness.

Preventing these types of disturbances will be a matter of building the right kind of spacecraft, one that artificially mimics Earth’s sleep-wake cycles using light exposure. Appropriate nutrition and exercise will also be factors in keeping crewmembers on circadian rhythm.

This research doesn’t just have takeaways for people hoping to take a trip to Mars; in fact, it underscores how important getting a good night’s sleep is for everyone. “As a global society, we need to reevaluate how we view sleep as it relates to our overall health and ability to lead productive lives,” Dinges said. “Whether it is an astronaut being challenged to reach another planet or a newborn baby just learning to walk, the human body's need for sleep is as essential as our need for food and water and integral to our ability to thrive."

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Belly Flop Physics 101: The Science Behind the Sting
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Belly flops are the least-dignified—yet most painful—way of making a serious splash at the pool. Rarely do they result in serious physical injury, but if you’re wondering why an elegant swan dive feels better for your body than falling stomach-first into the water, you can learn the laws of physics that turn your soft torso a tender pink by watching the SciShow’s video below.

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What's the Saltiest Water in the World?
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Saltwater is common around the world—indeed, salty oceans cover more than two-thirds of the globe. Typical saltwater found in our oceans is about 3.5% salt by weight. But in some areas, we find naturally occurring saltwater that's far saltier. The saltiest water yet discovered is more than 12 times saltier than typical seawater.

Gaet’ale is a pond in Ethiopia which currently holds the record as the most saline water body on Earth. The water in that pond is 43.3% dissolved solids by weight—most of that being salt. This kind of water is called hypersaline for its extreme salt concentration.

In the video below, Professor Martyn Poliakoff explains this natural phenomenon—why it's so salty, how the temperature of the pond affects its salinity, and even why this particular saltwater has a yellow tint. Enjoy:

For the paper Poliakoff describes, check out this abstract.

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