Where Did Earth’s Water Come From?


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Where Did Earth’s Water Come From?

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Where Did Earth's Water Come From?
Earth is quite a watery place. Here, a stunning view of our blue planet captured by NOAA’s GOES-East satellite on April 22, 2014.

Credit: NASA/NOAA/GOES Project

Look at Earth compared to other rocky planets in the neighborhood, and the first thing that would likely jump out is that there’s A LOT of water. So how did 70 percent of our planet’s surface become covered in this essential life ingredient?

That question is the subject of lively scientific debate, it turns out.

There are two prevailing theories: One is that the Earth held onto some water when it formed, as there would have been ice in the nebula of gas and dust (called the proto-solar nebula) that eventually formed the sun and the planets about 4.5 billion years ago. Some of that water has remained with the Earth, and might be recycled through the planet’s mantle layer, according to one theory.

[What Will Happen to Earth When the Sun Dies?]

The second theory holds that the Earth, Venus, Mars and Mercury would have been close enough to that proto-solar nebula that most of their water would have been vaporized by heat; these planets would have formed with little water in their rocks. In Earth’s case, even more water would have been vaporized when the collision that formed the moon happened. In this scenario, instead of being home-grown, the oceans would have been delivered by ice-rich asteroids, called carbonaceous chondrites.

More and more research suggests that asteroids delivered at least some of Earth's water.
More and more research suggests that asteroids delivered at least some of Earth’s water.

Credit: ESA/P. Carril

 

Scientists can track the origin of Earth’s water by looking at the ratio of two isotopes of hydrogen, or versions of hydrogen with a different number of neutrons, that occur in nature. One is ordinary hydrogen, which has just a proton in the nucleus, and the other is deuterium, also known as “heavy” hydrogen, which has a proton and a neutron.

The ratio of deuterium to hydrogen in Earth’s oceans seems to closely match that of asteroids, which are often rich in water and other elements such as carbon and nitrogen, rather than comets. (Whereas asteroids are small rocky bodies that orbit the sun, comets are icy bodies sometimes called dirty snowballs that release gas and dust and are thought to be leftovers from the solar system’s formation.)

Meteorite EET 83309 contains tiny fragments of opal, a material that requires water to form. In this backscattered electron image, a narrow opal rim surrounds a bright metallic mineral inclusion.
Meteorite EET 83309 contains tiny fragments of opal, a material that requires water to form. In this backscattered electron image, a narrow opal rim surrounds a bright metallic mineral inclusion.

Credit: H. Downes

Scientists have also discovered opals in meteoritesthat originated among asteroids (they are likely pieces knocked off of asteroids). Since opals need water to form, this finding was another indication of water coming from space rocks. These two pieces of evidence would favor an asteroid origin. In addition, deuterium tends to gather farther out in the solar system than hydrogen does, so water formed in the outer regions of the system would tend to be deuterium-rich.

[See Photos of Meteorites Discovered Around the World]

And on top of that, the rocky inner planets hold relatively little water (relative to their masses) compared with the icy moons of Jupiter, Saturn, Uranus and Neptune, and even the gas giants themselves. That would support the idea that in the inner system, the water evaporated, while in the outer system, it didn’t. If water evaporated on Earth it would have to be replaced from somewhere else, and water-rich asteroids are abundant in the outer reaches of the system.

More supporting evidence comes from NASA’s DAWN spacecraft, launched in 2007, which found evidence of water on Ceres and Vesta, the two largest objects in the main asteroid belt located between Mars and Jupiter.

This false-color image of Ceres from NASA’s Dawn probe highlights the differences in surface materials across the dwarf planet.
This false-color image of Ceres from NASA’s Dawn probe highlights the differences in surface materials across the dwarf planet.

Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

A slam dunk for asteroids? Not so fast. For this scenario to work, the isotope ratio had to have stayed the same in the oceans over the last few billion years.

But what if it didn’t?

Lydia Hallis, a planetary scientist with the University of Glasgow in the United Kingdom, thinks that the hydrogen present on the early Earth had much less deuterium in it than it does now. The ratio changed because in the early history of the Earth the radiation from the sun heated up both hydrogen and deuterium. Hydrogen, being lighter, was more likely to fly off into outer space, leaving more deuterium behind.

[What If Earth Were Twice as Big?]

Also, in the last several years, newer models seem to show that the Earth retained a lot of water as it formed, and that the oceans might have been present for much longer than anyone thought.

Hallis and her colleagues looked at hydrogen isotope ratios in ancient Canadian rocks, some of the oldest rocks on Earth. The isotope ratios looked a lot less like asteroids and a lot more like the water one would expect from the early solar nebula in the region — the rocks had more ordinary hydrogen and less deuterium. But the current ocean ratio looks like asteroids. That would seem to indicate something changed in the last few billion years. The research was published in Science in 2015.

If the Earth’s oceans were formed from water on our own planet, rather than asteroids, that would solve a couple of problems for planetary scientists. One is why Earth seems to have so much water in the first place. Another is why life, which as far as anyone knows requires water, seems to have appeared so quickly once the Earth had a solid surface.

Besides the work of Hallis, other scientists have studied ways water could be recycled from Earth’s interior. In 2014, Wendy Panero, an associate professor of earth sciences at Ohio State, and doctoral student Jeff Pigott proposed the theory that Earth was formed with entire oceans of water in its interior. Via plate tectonics, that water has been supplying the oceans. They studied garnet, and found it could work with another mineral, called ringwoodite, to deliver water to the Earth’s interior – water that would later come up as the mantle material circulated.

Complicating the picture, neither of these hypotheses is mutually exclusive. Asteroids could deliver water while some could come from the Earth’s interior. The question is how much each would deliver — and how to find that out.

So this mystery will remain one, at least for a little while longer.

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Ridiculous Contraption Takes All the Learning Out of Learning the Guitar


Post 7755

Ridiculous Contraption Takes All the Learning Out of Learning the Guitar

Yesterday 12:23pm

 http://sploid.gizmodo.com/ridiculous-contraption-takes-all-the-learning-out-of-le-1783392817

Being able to play music is a gift, but learning to play an instrument is morass of frustration—especially teaching yourself the guitar. Hands have to be bent in uncomfortable positions, uncalloused fingers get sore, and it becomes clear that human extremities innately possess the coordination of a newborn deer that’s been grazing in a field of ketamine. Sucks to suck, and learning is for chumps.

Rather than quit outright (like so many of us), YouTuber WayOutWest built a big goofy contraption that fingers whole chords on a guitar at the push of a button. He calls it the Chordelia. The wooden housing clamps to the neck of his Yamaha, and each of the chord paddles triggers levers that do all the work. It looks absurd, but astonishingly it works.

While it won’t help you shred Judas Priest riffs or strum a G7sus4 in your jazz trio, the Chordelia is able to produce five chords—G, D, C, A minor, and E minor, which is really all that’s needed to play 90% of pop music. Unfortunately, at about $260 they’re not cheap, but think of all the time saved by never having to do any practice.

 https://youtu.be/n5gtluPTPq4

‘Bomb Robot’ Kills Dallas Shooter: How Police Did It


Post 7754

‘Bomb Robot’ Kills Dallas Shooter: How Police Did It

'Bomb Robot' Kills Dallas Shooter: How Police Did It

Robots designed for bomb disposal can safely handle explosives while being remotely controlled.

Credit: Jaromir Chalabala

A suspect in yesterday’s (July 7) Dallas shooting — during which five police officers were killed and seven officers were injured — died after police deployed a remote-controlled bomb-disposal robot carrying an explosive device.

Dallas Police Chief David Brown explained during a press conference that police sent the robot in after negotiations with the suspect broke down and he exchanged gunfire with officers.

“We saw no other option but to use our bomb robot and place a device on its extension for it to detonate where the suspect was,” Brown told reporters, adding that police confirmed shortly after the explosion that the suspect had died. [5 Surprising Ways Drones Could Be Used in the Future]

The police considered other options for subduing the suspect, Brown said, but those would have required placing officers “in grave danger.”

Robots that are capable of handling or disarming explosives have become a more common sight in police departments in recent years, due to a Defense Department initiative known as the 1033 Program, which redistributes surplus military equipment. Approximately 200 law enforcement agencies — federal, state and local — across the U.S. have at least one so-called “bomb robot” provided by the 1033 Program, according to a 2015 report published by the Center for the Study of the Drone at Bard College.

While the U.S. military has used drones internationally as remote bombers, this could be the first instance of a U.S. police force’s robot killing a suspect, said Peter W. Singer, a political scientist and strategist for New America, a non-partisan think tank addressing public policy issues.

Singer said in a tweet that he had heard of U.S. troops in Iraq using robots in a manner similar to the Dallas situation — modified to deliver explosives. While conducting an interview for his book “Wired for War: The Robotics Revolution and Conflict in the 21st Century” (Penguin Books, 2009), he learned of an incident in which soldiers duct-taped an anti-personnel mine to a type of surveillance robot called a MARCBot, sending the machine into an alley after an insurgent.

Singer added that this happened in an unusual circumstance, “just troops working up a solution on the fly” to lessen the risk, he said.

Robots in law enforcement are most commonly associated with bomb disposal, but police have also used the devices to respond to situations deemed too dangerous for people.

In 2012, police in Greensboro, North Carolina, used a robot equipped with an audio and video link to communicate with an armed suspect. The man had barricaded himself inside a house after firing shots at the officers. Police later subdued the man and took him into custody, Police: The Law Enforcement Magazine reported.

Officers in Richland County, Ohio, used a robot to monitor the position of a robbery suspect during a 9-hour standoff in 2014. They later used the robot to spray the suspect with tear gas, allowing officers to safely enter the building.

And during a 2015 standoff in San Jose, California, police used a bomb-disposal robot to deliver a phone — and a pizza — to a man threatening suicide on a freeway overpass, reported IEEE Spectrum.

On Friday morning (July 8), a law enforcement source identified the suspect in the Dallas shooting as Micah Xavier Johnson of Mesquite, Texas, according to a report by CBS local news in Dallas/Fort Worth. Brown said in a statement that during negotiations with police, Johnson affirmed he was not affiliated with any organization and that he acted alone.

Original article on Live Science.

Wedge-tailed eagle


Post 7753

This article special for my lovely daughter Natasha Valentina who lives in Australia… miss  and love you always .image2

Wedge-tailed eagle

From Wikipedia, the free encyclopedia
Wedge-tailed eagle

Aquila audax - Captain's Flat.jpg

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Genus: Aquila
Species: A. audax
Binomial name
Aquila audax
(Latham, 1801)

The wedge-tailed eagle (Aquila audax), sometimes known as the eaglehawk, is the largest bird of prey in Australia, and is also found in southern New Guinea, part of Papua New Guinea and Indonesia. It has long, fairly broad wings, fully feathered legs, and an unmistakable wedge-shaped tail.

The wedge-tailed eagle is one of 12 species of large, predominantly dark-coloured booted eagles in the genus Aquila found worldwide. A large brown bird of prey, it has a wingspan up to 2.84 m (9 ft 4 in) and a length up to 1.06 m (3 ft 6 in).

Description

 

In flight, the wedged tail is clearly visible.

 

Taking off from its perch, the long legs of this adult female are clearly visible.

 

Nest site in the Barmah-Millewa Forest

 

At Symbio Wildlife Park, New South Wales, Australia

 

Wedge-tailed eagle

The female wedge-tailed eagle weighs between 3 and 5.77 kg (6.6 and 12.7 lb), while the smaller males weigh 2 to 4 kg (4.4 to 8.8 lb). Length varies between 81 and 106 cm (32 and 42 in) and the wingspan typically is between 182 and 232 cm (6 ft 0 in and 7 ft 7 in). In 1930, the average weight and wingspans of 43 birds was 3.4 kg (7.5 lb) and 204.3 cm (6 ft 8 in). The same average figures for a survey of 126 eagles in 1932 were 3.63 kg (8.0 lb) and 226 cm (7 ft 5 in), respectively. The largest wingspan ever verified for an eagle was for this species. A female killed in Tasmania in 1931 had a wingspan of 284 cm (9 ft 4 in), another female measured barely smaller at 279 cm (9 ft 2 in). Reported claims of eagles spanning 312 cm (10 ft 3 in) and 340 cm (11 ft 2 in) were deemed to be unreliable.This eagle’s great length and wingspan place it among the largest eagles in the world, but its wings, at more than 65 cm (26 in), and tail, at 45 cm (18 in), are both unusually elongated for its body weight, and eight or nine other eagle species regularly outweigh it.

Young eagles are a mid-brown colour with slightly lighter and reddish-brown wings and head. As they grow older, their colour becomes darker, reaching a dark blackish-brown shade after about 10 years (birds in Tasmania are usually darker than those on the mainland). Adult females tend to be slightly paler than males. Although it rarely needs to be distinguished from other Aquila eagles, its long, wedge-shaped tail is unique to this species.

Its range and habitat sometimes overlap with the white-bellied sea eagle, which is similar in size and shape, and also has a somewhat wedge-shaped tail, although rather smaller and less distinctive. In silhouette and poor light, the two can look somewhat similar. Closer examination reveals the belly colour or tail size to distinguish the two.

Breeding and habitat

 

Aquila audax egg – MHNT

Wedge-tails are found throughout Australia, including Tasmania, and southern New Guinea in almost all habitats, though they tend to be more common in lightly timbered and open country in southern and eastern Australia. In New Guinea, the birds can be found in the Trans Fly savanna and grasslands.

As the breeding season approaches, wedge-tailed eagle pairs perch close to each other and preen one another. They also perform dramatic aerobatic display flights together over their territory. Sometimes, the male dives down at breakneck speed towards his partner. As he pulls out of his dive and rises just above her on outstretched wings, she either ignores him or turns over to fly upside down, stretching out her talons. The pair may then perform a loop-the-loop. The wedge-tailed eagle usually nests in the fork of a tree between one and 30 m above the ground, but if no suitable sites are available, it will nest on a cliff edge.

www.birdphotos.com.au

Before the female lays eggs, both birds either destroy the large stick nest or add new sticks and leaf lining to an old nest. Nests can be 2–5 m deep and 2–5 m wide. The female usually lays two eggs, which are incubated by both sexes. After about 45 days, the chicks hatch. At first, the male does all the hunting. When the chicks are about 30 days old, the female stops brooding them and joins her mate to hunt for food.

The young wedge-tailed eagles depend on their parents for food up to six months after hatching. They leave only when the next breeding season approaches.

 

Behaviour and diet

Wedge-tailed eagles are highly aerial, soaring for hours on end without wingbeat and seemingly without effort, regularly reaching 1,800 m (5,900 ft) and sometimes considerably higher. The purpose of this very high flight is unknown. Their keen eyesight extends into ultravioletbands.

 

Feeding on carrion in the Pilbara region of Western Australia

Most prey is captured on the ground in gliding attacks or (less frequently) in the air. Choice of prey is very much a matter of convenience and opportunity; since the arrival of Europeans, the introduced rabbit and brown hare have become the primary items of the eagle’s diet in many areas. Larger introduced mammals such as foxes and feral cats are also occasionally taken, while native animals such as wallabies, small kangaroos, possums, koalas, and bandicoots are also preyed on. In some areas, birds such as cockatoos, bush turkeys, ducks,crows, ibises, and even emus are more frequent prey items. Reptiles are less frequently taken, but can include frill-necked lizards,goannas, and brown snakes.

www.smh.com.au

They display considerable adaptability, and have been known to team up to hunt large red kangaroos, to cause goats to fall off steep hillsides and injure themselves, or to drive flocks of sheep or kangaroos to isolate a weaker animal.

Carrion is a major diet item, also; wedge-tails can spot the activity of Australian ravens (sometimes known as crows) around a carcass from a great distance, and glide down to appropriate it. Wedge-tailed eagles are often seen by the roadside in rural Australia, feeding on animals that have been killed in collisions with vehicles.

wall.alphacoders.com

This impressive bird of prey spends much of the day perching in trees or on rocks or similar exposed lookout sites such as cliffs from which it has a good view of its surroundings. Now and then, it takes off from its perch to fly low over its territory. During the intense heat of the middle part of the day, it often soars high in the air, circling up on the thermal currents that rise from the ground below. Each pair occupies a home range, which may extend from as little as 9 km2 (3.5 sq mi) to more than 100 km2 (39 sq mi). Within this home range lies a breeding territory around the nest. The eagle patrols the boundary of this home range and advertises its ownership with high-altitude soaring and gliding flights. It may defend its territory by diving on intruders. Adults are avian apex predators and have no natural predators, but must defend their eggs and nestlings against nest predators such as corvids, currawongs, or other wedge-tailed eagles, and in Tasmania, conflict with the white-bellied sea eagle often occurs over nest sites.

www.abc.net.au

The wedge-tailed eagle is the only bird that has a reputation for attacking hang gliders and paragliders (presumably defending its territory). Cases are recorded of the birds damaging the fabric of these gliders with their talons.

The presence of a wedge-tailed eagle often causes panic among smaller birds, and as a result, aggressive species such as magpies, butcherbirds,masked lapwings, and noisy miners aggressively mob eagles (see video).

www.keyword-suggestions.com

Conservation status

The subspecies from Tasmania (Aquila audax fleayi) is listed as endangered by the Environment Protection and Biodiversity Conservation Act 1999 with fewer than 200 pairs left in the wild. Like the thylacine, the eagle was once subject to a bounty in Tasmania, as it was believed to prey on livestock.

Decreasing numbers of Tasmanian devils may be beneficial to the wedge-tailed eagles in Tasmania, as it could reduce competition for roadkill and devil predation on wedge-tailed eagle young.

As an emblem

The bird is an emblem of the Northern Territory. The Parks and Wildlife Service of the Northern Territory uses the wedge-tailed eagle, superimposed over a map of the Northern Territory, as their emblem. The New South Wales Police Force emblem contains a wedge-tailed eagle in flight, as does the Northern Territory Correctional Services. La Trobe University in Melbourne also uses the wedge-tailed eagle in its corporate logo and coat of arms.The wedge tailed eagle is also a symbol of the Australian Defence Force, featuring prominently on the ADF Flag, and the Royal Australian Air Force and Australian Air Force Cadets both use a wedge-tailed eagle on their badges. The Royal Australian Air Force has named its airborne early warning and control aircraft after the bird, the Boeing 737 AEW&C Wedgetail.

www.deviantart.com

Early in 1967, the Australian Army 2nd Cavalry Regiment received its new badge, a wedge-tailed eagle swooping, carrying a lance bearing the motto “Courage” in its talons. The regiment’s mascot is a wedge-tailed eagle named “Courage”. Since its formation, there have been two, Courage I and Courage II. In 1997, while on flight training with his handlers, Corporal Courage II refused to cooperate and flew away, not being found for two days following an extensive search. He was charged with being AWOL and reduced to the rank of trooper. He was promoted back to corporal in 1998.

The West Coast Eagles AFL football club from Western Australia use a stylised wedge-tailed eagle as their club emblem. In recent years, they have had a real-life wedge-tailed eagle named “Auzzie” perform tricks before matches.

Wedge-tailed Eagle

http://www.planetofbirds.com/accipitriformes-accipitridae-wedge-tailed-eagle-aquila-audax

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savethewedgetailedeagle.weebly.com

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