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lcls SLAC National Accelerator Laboratory

Researchers produce the loudest possible sound in water

For human beings, sound is a perception of waves in the brain. However, physically it is the propagation of vibration as an audible pressure wave which requires a medium for its transmission. The medium need not be air always as loud sounds can also propagate through water.

A group of scientists of SLAC National Accelerator Laboratory, Department of Energy took an X-Ray laser to generate a very loud sound in water. The team reported that the loudness was such that it was almost at the edge of being the loudest sound which could be produced through water. The results of the experiment were reported in Physical Review Fluids. 

Physicist Claudiu Stan of Rutgers University Newark said that the produced sound was slightly below the threshold that would be enough for boiling the water. To achieve this result, scientists used an equipment known as Linac Coherent Light Source (LCLS). This is a very powerful X-ray laser which is capable of creating molecular black holes and also raise the temperature of water to 100,000 degrees celsius in a time period which is lesser than millionth of a millionth of second. The X-rays produced by the laser have very high brightness and is considered to be the most powerful X-ray source in the world.

LCLS was used by scientists to understand how the high-intensity sound waves that generate very loud sounds impact materials. For the experiment, researchers blasted very small liquid water microjets with a thickness less than hair strand in a vacuum chamber having X-ray pulses.

As the water stream was intercepted by the laser, very rapid ionisation occurred in the microjet due to heating of the water leading to its vapourisation which in turn produced shock waves.

The researchers found out that these shock waves had peak pressures which match with high sound intensity and sound pressures above 270 decibels. This is louder than a rocket launch or a jet plane taking off. It has been found that it is not possible to reach an intensity louder than this as it would result in the break down of water.

Researchers explained that the magnitudes of the sound intensity were restricted since the wave would destroy the medium of propagation though cavitation. This makes the ultrasonic waves in jets as one of the most intense sounds possible to be generated in water. Scientists also estimate these sound waves to be the highest intensity sound waves produced in water till date.

 

 

gas giant interior

Formation of superionic ice helps to detect internal structure of Neptune and Uranus

The magic of science has just achieved the unachievable – the most bizarre existence of “supersonic hot ice”. It is called as such because of the peculiarity of frozen water that can remain solid even at extremely high temperature.

Extreme temperature and pressure can crush the frozen substance into increasingly odd varieties. Superionic materials are dual beasts that can exist in dual state-partly solid and liquid at the same time. It is highly conductive material that exists at high pressures such as, one and four million times more than that at sea level and temperature half as hot as the surface of the sun. These conditions are fulfilled by exoplanets like Uranus and Neptune.

After a lot of research conducted by scientists, it was found that water ice becomes hundred times more electrically more conductive. But achieving above mentioned extreme conditions was not a cake walk for scientists. The study has been published in the Nature journal. 

Marius Millot, study leader and researcher at the Lawrence Livermore National Laboratory, California remarked that the ice sample which they have observed is at a very high temperature, ranging to thousands of degrees.

Scientists have already known that there are 17 varieties of crystalline ice and they had predicted 30 years back that water can be squeezed to superionic forms through application of extreme pressure.

For that, a set up was made in which a thin layer of water was placed between 2 diamond anvils and then six giant lasers were used to generate shockwaves at pressure up to 1 to 4 million times Earth’s atmospheric pressure and temperature between 1650 and 2760 degree Celsius. But all these could only be maintained for a fraction of a second, so physicists used lasers to blast a tiny piece of iron foil creating a wave of plasma. The X-rays showed unprecedented cubic lattice structure with oxygen at each corner and one at the face.

After these persistent and consistent experiments of scientists, they finally got a hint about the unusual tilting of the magnetic field of Neptune and Uranus. They concluded that Uranus and Neptune should have superionic ice layers that act as our planet mantle and that is responsible for their unusual magnetic field tilting at different angles.

Roberto Car, a physicist at Princeton University remarked that more investigations are needed to prove that ice is superionic, although this experiment is an important step in understanding the variableness of water.

Thus, this bizarre and unprecedented but the most thrilling creation is going to help in unpuzzling the various reasons for the origin, existence and evolution of these exoplanets.

Schematic view of asteroid Itokawa

New clues on origin of life found from water samples on Asteroid Itokawa

Water is a precious and limited resource yet humans have not valued it only until recent times where there is awareness about the shortage of water and global warming. Nowadays, a lot of research is going on to find traces of life outside the Earth and various space missions are held which have successfully found traces of water on the moon and Mars.

In 2010 however, Japan Aerospace Exploration Agency (JAXA) made history when its Hayabusa probe brought back samples from the Asteroid Itokawa, it was the first time mankind had gone to an asteroid, collected samples and brought it back safely to the Earth. After studying those samples a study was published in the Journal of Advanced Sciences that they contain lots of water inside them.

A cosmochemist at the Arizona State University, Maitrayee Bose had commented that no one really expected to find water samples on Itokawa as it was known that Itokawa asteroid faces temperatures up to 1500 degrees Fahrenheit and faces many collisions in space in the voyage. So there wasn’t much hope to find traces of water until we did a lot of calculations which showed that indeed it might be possible. Itokawa is a 1,800 foot long and 1,000-foot wide satellite which orbits the sun every 18 months, Itokawa was an asteroid which was remains of a bigger asteroid close to 12 miles long. The research done by Bose aims to study the internal chemistry of small building blocks for life. He is interested in finding out whether asteroids and other eternal bodies are able to deliver water and organic chemicals to other planets, and also find planets with the existence of water other than our Earth.

The samples from the JAXA which were brought back to Earth contained 5 samples which were half as thick as the sample of hair. Two of these samples contained mineral pyroxene. Pyroxenes contain water as a part of their crystalline structure and which then suspected Itokawa to contain water. To study these samples which were half the thickness of the strand of hair, the team used ASU’s Nanoscale Secondary Ion Mass Spectrometer (NanoSIMS), which can measure such tiny mineral grains with great sensitivity.

The results showed the presence of water and those relatively dry asteroids like Itokawa can also contain traces of water. Itokawa is an S-class satellite based on its spectrum. Bose further added that S – class satellites are most common objects in the asteroid belt and although they are small and have contained water and other volatile minerals which they are made up of. The race for exploration of water and life is heating up between countries and for the good of humanity.

itokawa

Scientists detect presence of water in dust particles from asteroid Itokawa

Researchers have detected presence of water in grains of dust obtained from the asteroid Itokawa. This finding can be a important clue on how water formed in Earth. The studies have been published in the journal Science Advances.

The peanut shaped asteroid, Itokawa was found in 1998 by LINEAR, a collaboration of NASA with United States Air Force. It has been named after Japanese engineer, Hideo Itokawa. It has a very low density and has a rotation time of 12 hours.

A team of researchers from Arizona State University has measured the quantity of water in the small particles of dust which were carried to earth by the Japanese spacecraft, Hayabusa. Hayabusa, a robotic space probe is manufactured by the Japan Aerospace Exploration Agency for studying the elements, characteristics of Itokawa. It started its journey, collected more than 1500 regolith particles and returned back to Earth in 2010. Though this is not the first evidence of presence of water in an asteroid, scientists have detected water for the first time in laboratory. In other cases, it was done with the help of information collected by telescopes or the equipments present in the spacecrafts.

The first proof of water in asteroid was found in 2010 when scientists used Infrared Telescope Facility of NASA to detect water ice on the asteroid Themis. Also in December, 2018 scientists detected hydrated minerals while studying the rocks of the asteroid Bennu. After these discoveries, scientists have come to the conclusion that presence of water is quite common in our solar system. It may be present either in the form of water ice or hydrated minerals.

From the current findings, the scientists at ASU have concluded that the silaceous asteroids like Itokawa , which are stony asteroids composed of silicates and also one of the most frequently found rocks in space might have delivered almost half of Earth’s water during its formation.

Ziliang Jin, researcher at School of Earth and Space Exploration at ASU along with fellow cosmochemist Maitrayee Bose calculated the abundance of water along with the percentage composition of deuterium and hydrogen, a factor which can indicate the similarity of the water to the water found on Earth. It has been found that the composition of isotopes of hydrogen are similar to Earth.

The team at ASU received five samples out of the 1500 ones brought by spacecraft Hayabusa. Each one measured about half of width of human hair. They have been obtained from the Moses Sea, lying in the middle of the asteroid Itokawa.

Sperm whales off Mauritius coast

Discovery of four legged whale ancestors is an evolutionary missing link

A research published in the Current Biology, reveals the discovery of a new species of ancestral whale that walked the land and sea in Peru. We may consider them as smooth, two-limbed marine mammals that even struggled to survive the Thames, but the whales originated more than 50 million years ago from land-dwelling, hooved mammals called artiodactyls. The ancestors of the whales resembled a small deer. A fossilised “missing link” discovered in India claimed that the last whale precursors took to the water when danger dawned upon them but would come onto land for reproduction and feeding.

They would generally spend a considerable amount of time slopping in shallow water, quenching for aquatic vegetation and invertebrates.

The oldest whale fossils date back 53 million years ago and were found at numerous sites located in the northern Indian Himalayas. The fossils talk of the gradual transition from simple slopping to life long living in deeper water, while retaining the ability of locomotion on land.

42 million years ago, the freshly discovered Peregocetus pacificus started an epic journey to the other side of the world. In the Middle Eocene era (roughly 48 to 38 million years ago) when Africa and South America were far apart these animals who were smaller than 3m swam their way across, not used to marine life back then.

The hind limbs were not as small as its forelimbs, and it had really tiny hooves, suggesting that it was still quite capable of hoisting itself out of the water and then trotting about on land, that is capable of getting out of water and walking on land. However, the skeleton suggested that it was well adapted to an aquatic life that was about to become dominant. It was carnivorous, as demonstrated by its scissors- like teeth. It ate large bony fish, just as the whales do now. However, P. Pacificus had teeth which resembled that of the modern carnivores.

By using microfossils, the sediment layers where the skeleton was claimed to be positioned were precisely dated and then the details of the skeleton allowed them to conclude that the animal was capable of carrying its body both on land and in the water. However, over the millennia, their pelvic bones unattached themselves from the spine to enable more efficient swimming while increasing the time in buoyant, the gravity-easing water reduced the evolutionary resources to strong, weight-bearing legs that they possessed. Forelimbs morphed into flippers, while hind limbs shrunk and disappeared.

Moon Water LRO Image

Water molecules found hopping on the moon’s surface by NASA

NASA has recently spotted layers of water molecules on the moon’s surface by the spacecraft Lunar Reconnaissance Orbiter (LRO). The LRO has observed water molecules moving around during dayside on Moon. It was astonishing as scientists thought that the Moon was dry and arid, water only exists in the form of shaded craters near the poles.

According to the paper published in Geophysical Research Letters, The instrument Lyman Alpha Mapping Project (LAMP) was responsible for measuring sparse layer of molecules temporarily stuck to the Moon’s surface, which helped to measure lunar hydration, changes over the course of a day.

Scientists have discovered surface water in sparse populations of molecules bound to the lunar soil, or regolith. But, the amount and locations were found to vary based on the time of day. The lunar water is more common at higher latitudes and tends to bounce around when the temperature of surface soars up.

Earlier the scientists had assumed that hydrogen ions in the solar wind may be the source of most of the Moon’s surface water. But when the Moon passes behind the Earth and is shielded from the solar wind, the “water spigot” should necessarily turn off.

Surprisingly, the water identified by LAMP does not decrease when the Moon is shielded by the Earth and the region influenced by its magnetic field, suggesting water builds up over time, rather than “raining” down directly from the solar wind.

John Keller, LRO deputy project scientist from NASA’s Goddard Space Flight Centre in Maryland said, “The study is an important step in advancing the water story on the Moon and is a result of years of accumulated data from the LRO mission”.

Lunar Reconnaissance Orbiter LRO

Artist concept of NASA’s Lunar Reconnaissance Orbiter. (Credit: NASA)

Dr. Kurt Retherford, the principal investigator of the LAMP instrument from Southwest Research Institute in San Antonio, Texas addressed, “This is an important new result about lunar water, a hot topic as our nation’s space program returns to a focus on lunar exploration. We recently converted the LAMP’s light collection mode to measure reflected signals on the lunar dayside with more precision, allowing us to track more accurately where the water is and how much is present.”

“These results aid in understanding the lunar water cycle and will ultimately help us learn about the accessibility of water that can be used by humans in future missions to the Moon,” said lead author Amanda Hendrix, a senior scientist at the Planetary Science Institute and lead author of the paper.

“Lunar water can potentially be used by humans to make fuel or to use for radiation shielding or thermal management; if these materials do not need to be launched from Earth, that makes these future missions more affordable,” she added.

Published Researchhttps://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081821

NASA Curiosity Rover at Gale Crater Mars Illustration

Traces of groundwater system found on Mars

Scientists in Geneva have declared, lately, that they have perceived the first ever evidence of an ancient groundwater system consisting of interconnected lakes on Mars. These interconnected lakes lay deep beneath the planet’s surface, five of which may have minerals vital for survival.

Although Mars appears to be a sterile land, its surface shows potent signs that once there were large quantities of water existing on the planet.

Researches and researchers have said that the history of water on Mars has been a complicated topic, and is intricately associated with understanding whether or not life ever arose there – and, if so, where, when, and how it did so.

The recent study, which was earlier predicted by models, says that: “Early Mars was a watery world, but as the planet’s climate changed, this water retreated below the surface to form pools and groundwater“.

The lead author Francesco Salese of Utrecht University, further added – “We traced this water in our study, as its scale and role is a matter of debate, and we found the first geological evidence of a planet-wide groundwater system on Mars”.

Salese and his colleagues explored 24 deep, enclosed craters in the northern hemisphere of Mars, with floors lying roughly 4000 meters below Martian ‘sea level’ (a level that, given the planet’s lack of seas, is arbitrarily defined on Mars based on elevation and atmospheric pressure).

Global Groundwater

How Mars Express gathered evidence for groundwater on Mars. (Source: NASA/JPL-CALTECH/MSSS; DIAGRAM ADAPTED FROM F. SALESE ET AL. (2019))

They found features on the floors of these craters that could only have formed in the presence of water. Many craters contain multiple features, all at depths of 4000 to 4500 meters – indicating that these craters once contained pools and flows of water that transformed and diminished over time.

These features include channels etched into crater walls, valleys carved out by sapping groundwater, dark, curved deltas thought to have formed as water levels rose and fell ridged terraces within crater walls formed by standing water, and fan-shaped deposits of sediment associated with flowing water. The water level aligns with the proposed shorelines of a putative Martian ocean thought to have existed on Mars between three and four billion years ago.

“We think that this ocean may have connected to a system of underground lakes that spread across the entire planet,” adds co-author Gian Gabriele Ori, director of the Università D’Annunzio’s International Research School of Planetary Sciences, Italy.

“These lakes would have existed around 3.5 billion years ago, so may have been contemporaries of a Martian ocean.”

Exploring these sites reveal the conditions suitable for finding past life, and are therefore highly relevant to astrobiological missions such as ExoMars – a joint ESA and Roscosmos endeavor. While the ExoMars Trace Gas Orbiter is already studying Mars from above, the next mission will launch next year.

ExoMars Trace Gas Orbiter Model at ESOC

ExoMars Trace Gas Orbiter, seen at ESOC in Darmstadt, Germany (Source: wikimedia.org)

Mars Express was launched on 2 June 2003 and reached 15 years in space in 2018. The studies and researches conducted lately, have been proved to be fruitful as we have got some really good results from them.