Connect with us

Science

Lakes formed from melting glaciers increase 50% in just 30 years, satellite survey finds – Yahoo Canada Sports

Published

 on


Lake Imja near Mount Everest has tripled in length (Planetary Science Institute)
Lake Imja near Mount Everest has tripled in length. (Planetary Science Institute)
<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Melting glaciers have increased the volume of glacial lakes by 50% in just 30 years, researchers have found.&nbsp;” data-reactid=”23″>Melting glaciers have increased the volume of glacial lakes by 50% in just 30 years, researchers have found. 

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="A study using 30 years of NASA satellite data showed how rapidly glacial lakes have expanded since 1990.&nbsp;” data-reactid=”24″>A study using 30 years of NASA satellite data showed how rapidly glacial lakes have expanded since 1990. 

Glacial lake volumes worldwide now total 37.4 cubic miles, the researchers believe, and some could put local populations at risk from floods.

The study shows the impact of global temperatures on the world’s glaciers and provides scientists with a clearer picture of how much of this water has been stored in lakes.

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Read more: Antarctic records hottest temperature ever” data-reactid=”27″>Read more: Antarctic records hottest temperature ever

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="The findings were published in the journal Nature Climate Change.” data-reactid=”28″>The findings were published in the journal Nature Climate Change.

“We have known that not all meltwater is making it into the oceans immediately,” said lead author Dan Shugar, of the University of Calgary in Canada. 

“But until now there were no data to estimate how much was being stored in lakes or groundwater.” 

Shugar and his colleagues initially aimed to use satellite imaging and other remote-sensing data to study two dozen glacial lakes in High Mountain Asia, the geographic region that includes the Tibetan Plateau and surrounding mountain ranges, including the Himalaya.

But the researchers used 250,000 scenes from NASA’s Landsat satellite missions to estimate the volume of glacial lakes worldwide. 

“We wrote scripts in Google Earth Engine, an online platform for very large analyses of geospatial data, to look only at High Mountain Asia, and then decided to look at all glacial lakes in the world,” Shugar said. 

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Read more: Scientists drill into mysterious lake buried 3,500 feet under Antarctica” data-reactid=”35″>Read more: Scientists drill into mysterious lake buried 3,500 feet under Antarctica

“From there, we were able to build a scaling relationship to estimate the volume of the world’s glacial lakes based on the area of this large population of lakes.”

Meltwater stored in this way can have a major impact on mountain communities downstream of these glacial lakes, the researchers warn.

“This is an issue for many parts of the world where people live downstream from these hazardous lakes, mostly in the Andes and in places like Bhutan and Nepal, where these floods can be devastating,” Shugar said. 

“Fortunately, organizations like the United Nations are facilitating a lot of monitoring and some mitigation work where they’re lowering the lakes to try and decrease the risks.”

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Read more: Melting snow in Himalayas drives growth of green sea slime visible from space” data-reactid=”40″>Read more: Melting snow in Himalayas drives growth of green sea slime visible from space

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Earlier this year, satellite analysis found that 28 trillion tonnes of ice has disappeared from Earth’s surface since 1994.” data-reactid=”41″>Earlier this year, satellite analysis found that 28 trillion tonnes of ice has disappeared from Earth’s surface since 1994.

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Researchers from Edinburgh University, the University of Leeds and UCL analysed satellite surveys across the world – and found “staggering” ice loss.&nbsp;” data-reactid=”42″>Researchers from Edinburgh University, the University of Leeds and UCL analysed satellite surveys across the world – and found “staggering” ice loss

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Professor Andy Shepherd, of Leeds University, told The Guardian, “In the past researchers have studied individual areas – such as the Antarctic or Greenland – where ice is melting.&nbsp;” data-reactid=”43″>Professor Andy Shepherd, of Leeds University, told The Guardian, “In the past researchers have studied individual areas – such as the Antarctic or Greenland – where ice is melting. 

“But this is the first time anyone has looked at all the ice that is disappearing from the entire planet. What we have found has stunned us.”

Let’s block ads! (Why?)



Source link

Continue Reading

Science

‘Earthgrazer’ meteor filmed skimming Earth’s atmosphere and bouncing into space – Yahoo Canada Sports

Published

 on


The earthgrazer streaked across the sky above Germany (ESA)
The earthgrazer streaked across the sky above Germany (ESA)
<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Cameras on Earth captured a rare sight, an ‘earthgrazer’, a meteoroid which skims Earth’s atmosphere before ‘bouncing’ back into space.&nbsp;” data-reactid=”23″>Cameras on Earth captured a rare sight, an ‘earthgrazer’, a meteoroid which skims Earth’s atmosphere before ‘bouncing’ back into space. 

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="This particular meteoroid got hair raisingly close, flying as low as 56 miles up, far below any orbiting satellites, before bouncing back out.” data-reactid=”24″>This particular meteoroid got hair raisingly close, flying as low as 56 miles up, far below any orbiting satellites, before bouncing back out.

The space rock whizzed through the night sky above Northern Germany and the Netherlands in the early hours of 22 September. 

A meteoroid is typically a fragment of a comet or asteroid that becomes a meteor (a bright light streaking through the sky) when it enters the atmosphere. 

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Read more: There might once have been life on the moon

Most of them disintegrate, possibly with pieces reaching the ground as meteorites.&nbsp;” data-reactid=”29″>Read more: There might once have been life on the moon

Most of them disintegrate, possibly with pieces reaching the ground as meteorites. 

Earthgrazers are a bit luckier, and don’t burn up, but bounce back out, only grazing the edges of our planet’s protective gassy shield.

Earthgrazers don’t happen very often, just a handful of times per year.

It was spotted by cameras in the Global Meteor Network, a project which aims to cover the globe with meteor cameras and provide the public with real time alerts, building a picture of the meteoroid environment around Earth.

“The network is basically a decentralised scientific instrument, made up of amateur astronomers and citizen scientists around the planet each with their own camera systems” explains Denis Vida, who founded it.

<p class="canvas-atom canvas-text Mb(1.0em) Mb(0)–sm Mt(0.8em)–sm" type="text" content="Read more: Exoplanet twice the size of Earth ‘could be habitable’” data-reactid=”34″>Read more: Exoplanet twice the size of Earth ‘could be habitable’

“We make all data such as meteoroid trajectories and orbits available to the public and scientific community, with the goal of observing rare meteor shower outbursts and increasing the number of observed meteorite falls and helping to understand delivery mechanisms of meteorites to Earth”.

Tens of thousands of meteorites have been found on Earth, yet, of these only about 40 can be traced back to a parent asteroid or asteroidal source.

By better understanding these small bodies we are able to build up a more complete image of the Solar System, including potentially dangerous asteroids, meteor shower outbursts which could endanger satellites, as well as the chemistry and origins of our Solar System itself.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Salty lake, ponds may be gurgling beneath South Pole on Mars – iNFOnews

Published

 on



This Aug. 26, 2003 image made available by NASA shows Mars photographed by the Hubble Space Telescope on the planet’s closest approach to Earth in 60,000 years. A network of salty ponds may be gurgling beneath Mars’ South Pole alongside a large underground lake, raising the prospect of tiny, swimming Martian life. Italian scientists reported their findings Monday, Sept. 28, 2020 two years after identifying what they believed to be a large subglacial lake.
Image Credit: AP, NASA

September 29, 2020 – 5:30 AM

CAPE CANAVERAL, Fla. – A network of salty ponds may be gurgling beneath Mars’ South Pole alongside a large underground lake, raising the prospect of tiny, swimming Martian life.

Italian scientists reported their findings Monday, two years after identifying what they believed to be a large buried lake. They widened their coverage area by a couple hundred miles, using even more data from a radar sounder on the European Space Agency’s Mars Express orbiter.

In the latest study appearing in the journal Nature Astronomy, the scientists provide further evidence of this salty underground lake, estimated to be 12 miles to 18 miles (20 kilometres to 30 kilometres) across and buried 1 mile (1.5 kilometres) beneath the icy surface.

Even more tantalizing, they’ve also identified three smaller bodies of water surrounding the lake. These ponds appear to be of various sizes and are separate from the main lake.

Roughly 4 billion years ago, Mars was warm and wet, like Earth. But the red planet eventually morphed into the barren, dry world it remains today.

The research team led by Roma Tre University’s Sebastian Emanuel Lauro used a method similar to what’s been used on Earth to detect buried lakes in the Antarctic and Canadian Arctic. They based their findings on more than 100 radar observations by Mars Express from 2010 to 2019; the spacecraft was launched in 2003.

All this potential water raises the possibility of microbial life on — or inside — Mars. High concentrations of salt are likely keeping the water from freezing at this frigid location, the scientists noted. The surface temperature at the South Pole is an estimated minus 172 degrees Fahrenheit (minus 113 degrees Celsius), and gets gradually warmer with depth.

These bodies of water are potentially interesting biologically and “future missions to Mars should target this region,” the researchers wrote.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

News from © The Associated Press, 2020

The Associated Press

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Buried lakes of liquid water discovered on Mars – BBC News

Published

 on


Three underground lakes have been detected near the south pole of Mars.

Scientists also confirmed the existence of a fourth lake – the presence of which was hinted at in 2018.

Liquid water is vital for biology, so the finding will be of interest to researchers studying the potential for life elsewhere in the Solar System.

But the lakes are also thought to be extremely salty, which could make it difficult for any microbial life to survive in them.

Mars’ thin atmosphere means that the presence of liquid water on the surface is a near-impossibility. But water could remain liquid below ground.

The latest discovery was made using data from a radar instrument on the European Space Agency’s (Esa) Mars Express spacecraft, which has been orbiting the Red Planet since December 2003.

In 2018, researchers used data from the Marsis radar to report signs of a 20km-wide subsurface lake located 1.5km under Mars’ south polar layered deposits, a thick polar cap formed by layers of ice and dust.

However, that finding was based on 29 observations collected by Marsis between 2012 and 2015. Now, a team including many of the same scientists from the 2018 study have analysed a much bigger dataset of 134 radar profiles gathered between 2010 and 2019.

“Not only did we confirm the position, extent and strength of the reflector from our 2018 study, but we found three new bright areas,” said co-author Elena Pettinelli from Roma Tre University in Italy.

“The main lake is surrounded by smaller bodies of liquid water, but because of the technical characteristics of the radar, and of its distance from the Martian surface, we cannot conclusively determine whether they are interconnected.”

The team borrowed a technique commonly used in radar sounder investigations of sub-glacial lakes in Antarctica, Canada and Greenland, adapting the method to analyse the data from Marsis.

“The interpretation that best reconciles all the available evidence is that the high intensity reflections (from Mars) are coming from extended pools of liquid water,” said co-author Sebastian Lauro, also from Roma Tre University.

There’s not enough heat at these depths to melt the ice, so scientists believe the liquid water must contain high concentrations of dissolved salts. These chemical salts (different to the stuff we sprinkle on our chips) can significantly lower water’s freezing point.

In fact, recent experiments have shown that water with dissolved salts of magnesium and calcium perchlorate (a chemical compound containing chlorine bound to four oxygens) can remain liquid at temperatures of -123C.

“These experiments have demonstrated that brines can persist for geologically significant periods of time even at the temperatures typical of the Martian polar regions (considerably below the freezing temperature of pure water),” said co-author Graziella Caprarelli, from the University of Southern Queensland, Australia.

“Therefore we think that any process of formation and persistence of sub-ice water beneath the ice polar caps requires the liquid to have high salinity.”

Whether life could survive in such conditions depends on just how salty these Martian pools are. On Earth, only very specific types of microbes, known as halophiles, can survive in the saltiest bodies of water.

Roberto Orosei, chief scientist on the Marsis experiment, said: “While the existence of a single sub-glacial lake could be attributed to exceptional conditions such as the presence of a volcano under the ice sheet, the discovery of an entire system of lakes implies that their formation process is relatively simple and common, and that these lakes have probably existed for much of Mars’ history.

“For this reason, they could still retain traces of any life forms that could have evolved when Mars had a dense atmosphere, a milder climate and the presence of liquid water on the surface, similar to the early Earth.”

Let’s block ads! (Why?)



Source link

Continue Reading

Trending