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Reduced Gravity Levels Linked to Astronauts’ Weight

Relationship between Gravity and Astronauts' weight

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Reduced gravity linked to astronauts' weight
Reduced Gravity Levels Linked to Astronauts' Weight. Pixabay
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The study, led by Jay C. Buckey at Dartmouth College in New Hampshire, US, showed that reduced gravity levels (microgravity) in space can lead to spaceflight-associated neuro-ocular syndrome (SANS) in some astronauts.

SANS refers to structural changes in the eye that may impair vision, including swelling of the optic nerve (optic disc edema) and coloured indentations (choroidal folds) in the blood vessel network at the back of the eye.

“Pre-flight weight, waist circumference and chest circumference were all significantly greater in those who developed either disc edema or choroidal folds,” Buckey said.

On Earth, the weight of the body’s tissues presses against other bodily structures (e.g., bones, muscles, organs, veins) creating compressive forces, which can affect pressures in blood vessels and in organs throughout the body.

These compressive forces increase as body weight increases. In microgravity, body tissue is weightless, so compressive forces against the rest of the body are absent, the researchers said.

People with more body tissue — and therefore a higher body weight — are proportionately more likely to experience physiological changes in a low-gravity environment because they experience a greater change in these compressive forces, Buckey hypothesised.

For the study, published in the American Journal of Physiology, the team examined data collected by NASA from astronauts who had made long-duration space flights (averaging 165 days).

Reduced gravity levels linked to astronauts' weight
Representational image. Pixabay

Also Read: Video: Gravity Could be Sustainable Source of Energy

“The results from this study show a strong relationship between body weight and the development of ocular changes in space,” he added.

The team also found that none of the female astronauts analysed — who weighed less than the males — returned to Earth with symptoms of SANS. (IANS)

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Finally The Cause Of Mysterious Martian Rock Formation Discovered

The new finding add to scientists' understanding of Mars's interior and its past potential for habitability

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Finally The Cause Of Mysterious Martian Rock Formation Discovered
Finally The Cause Of Mysterious Martian Rock Formation Discovered, flickr

Explosive volcanic eruptions that shot jets of hot ash, rock and gas skyward are the probable source of a mysterious Martian rock formation near the planet’s equator, says a new study.

The Medusae Fossae Formation is a massive, unusual deposit of soft rock with undulating hills and abrupt mesas.

Scientists first observed the Medusae Fossae with NASA’s Mariner spacecraft in the 1960s but were perplexed as to how it formed.

The current study, published in the Journal of Geophysical Research: Planets, suggests the formation was deposited during explosive volcanic eruptions on the Red Planet more than three billion years ago.

The formation is about one-fifth as large as the continental US and 100 times more massive than the largest explosive volcanic deposit on Earth, making it the largest known explosive volcanic deposit in the solar system, according to the study authors.

“This is a massive deposit, not only on a Martian scale, but also in terms of the solar system, because we do not know of any other deposit that is like this,” said study lead author Lujendra Ojha, a planetary scientist at Johns Hopkins University in Baltimore, Maryland, US.

Volcanic eruption
Volcanic eruption, pixabay

The researchers believe that the new finding could add to scientists’ understanding of Mars’s interior and its past potential for habitability.

The eruptions that created the deposit could have spewed massive amounts of climate-altering gases into Mars’ atmosphere and ejected enough water to cover Mars in a global ocean more than nine centimeters thick, Ojha said.

Previous radar measurements of Mars’s surface suggested the Medusae Fossae had an unusual composition, but scientists were unable to determine whether it was made of highly porous rock or a mixture of rock and ice.

In the new study, the researchers used gravity data from various Mars orbiter spacecraft to measure the Medusae Fossae’s density for the first time.

They found the rock is unusually porous — it is about two-thirds as dense as the rest of the Martian crust.

They also used radar and gravity data in combination to show the Medusae Fossae’s density cannot be explained by the presence of ice, which is much less dense than rock.

Because the rock is so porous, it had to have been deposited by explosive volcanic eruptions, according to the researchers.

volcano
Active volcano, Pixabay

Greenhouse gases exhaled during the eruptions that spawned the Medusae Fossae could have warmed Mars’s surface enough for water to remain liquid at its surface, but toxic volcanic gases like hydrogen sulfide and sulfur dioxide would have altered the chemistry of Mars’ surface and atmosphere.

Also read: Earthquake Then Volcano, There is No Relief For the Hawaii Residents

Both processes would have affected Mars’ potential for habitability, Ojha said. (IANS)