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STUDY: Lakes on Mars dried up 3.5bn years ago

A study reveals that lakes on Mars dried up 3.5bn years ago.

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Red Planet: Mars to Come Closest to Earth in 15 Years Next Month. Pixabay
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The discovery of cracks on the surface of Mars by NASA’s Curiosity rover in early 2017 are evidence of lakes that likely dried up 3.5 billion years ago, confirmed a study, revealing details about the red planet’s ancient climate.

In early 2017 scientists announced the discovery of possible desiccation cracks in Gale Crater, which was filled by lakes 3.5 billion years ago.

“We are now confident that these are mudcracks,” said lead author Nathaniel Stein, a geologist at the California Institute of Technology in Pasadena, US.

Since desiccation mudcracks form only where wet sediment is exposed to air, their position closer to the centre of the lake bed rather than the edge also suggests that lake levels rose and fell dramatically over time.

“The mudcracks show that the lakes in Gale Crater had gone through the same type of cycles that we see on Earth,” Stein added.

Representational image for planet Mars.
Representational image. Pixabay

Although scientists have known almost since the moment Curiosity landed in 2012 that Gale Crater once contained lakes, “the mudcracks are exciting because they add context to our understanding of this ancient lacustrine system”, Stein explained, in the paper published in the journal Geology.

“We are capturing a moment in time. This research is just a chapter in a story that Curiosity has been building since the beginning of its mission,” he said.

Also Read: SpaceX to build Mars rockets in Los Angeles

For the study, the team focused on a coffee table-sized slab of rock nicknamed “Old Soaker”.

Old Soaker is crisscrossed with polygons identical in appearance to desiccation features on Earth.

They found that the polygons — confined to a single layer of rock and with sediment filling the cracks between them — formed from exposure to air, rather than other mechanisms such as thermal or hydraulic fracturing, the researchers said.  IANS

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Old Dusty Kilogram Swapped for Something More Stable: Scientists

It has taken years of work to fine-tune the new definition to ensure the switchover will be smooth.

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Kilogram
The International Prototype of the Kilogram (IPK) is pictured in Paris, France, in this undated photo obtained from social media. VOA

After years of nursing a sometimes dusty cylinder of metal in a vault outside Paris as the global reference for modern mass, scientists are updating the definition of the kilogram.

Just as the redefinition of the second in 1967 helped to ease communication across the world via technologies like GPS and the internet, experts say the change in the kilogram will be better for technology, retail and health — though it probably won’t change the price of fish much.

The kilogram has been defined since 1889 by a shiny piece of platinum-iridium held in Paris. All modern mass measurements are traceable back to it — from micrograms of pharmaceutical medicines to kilos of apples and pears and tons of steel or cement.

kilogram, weight
Border Security Force officials showing 17 kilogram heroine.

The problem is, the “international prototype kilogram” doesn’t always weigh the same. Even inside its three glass bell jars, it gets dusty and dirty, and is affected by the atmosphere. Sometimes, it really needs a wash.

“We live in a modern world. There are pollutants in the atmosphere that can stick to the mass,” said Ian Robinson, a specialist in the engineering, materials and electrical science department at Britain’s National Physical Laboratory.

“So when you just get it out of the vault, it’s slightly dirty. But the whole process of cleaning or handling or using the mass can change its mass. So it’s not the best way, perhaps, of defining mass.”

What’s needed is something more constant.

kilogram, weight
The Kilogram. Flickr

So, at the end of a week-long meeting in the Palace of Versailles, Paris, the world’s leading measurement aficionados at the International Bureau of Weights and Measures will vote Friday to make an “electronic kilogram” the new baseline measure of mass.

Just as the meter — once the length of a bar of platinum-iridium, also kept in Paris — is now defined by the constant speed of light in a vacuum, so a kilogram will be defined by a tiny but immutable fundamental value called the “Planck constant.”

The new definition involves an apparatus called the Kibble balance, which makes use of the constant to measure the mass of an object using a precisely measured electromagnetic force.

Paris,diesel,kilogram, weight
The kilogram has been defined since 1889 by a shiny piece of platinum-iridium held in Paris.VOA

“In the present system, you have to relate small masses to large masses by subdivision. That’s very difficult — and the uncertainties build up very, very quickly,” Robinson said.

“One of the things this [new] technique allows us to do is to actually measure mass directly at whatever scale we like, and that’s a big step forward.”

Also Read: NASA to Send Organ-on-Chips to Test Human Tissue Health in Space

He said it had taken years of work to fine-tune the new definition to ensure the switchover will be smooth.

But while the extra accuracy will be a boon to scientists, Robinson said that, for the average consumer buying flour or bananas, “there will be absolutely no change whatsoever.” (VOA)