© Copyright, 2015 (PHNO)
 http://newsflash.org

PHNO SCIENCE & INFOTECH NEWS
(Mini Reads followed by Full Reports)

4.1 BILLION YEARS AGO? HINTS OF LIFE ON WHAT WAS THOUGHT TO BE DESOLATE EARLY EARTH


Earliest Life This photo provided by the Proceedings of the National Academy of Sciences (PNAS), taken in 2005, shows fossil-like rock found in Australia containing hints of life from 4.1 billion years ago. Life on a near primordial Earth may have been around 4.1 billion years ago, 300 million years earlier than thought, hints a chemical fossil-like rock found in Australia. It also gives more hope for life elsewhere in the universe. AP Scientists have found fossil-like hints that some kind of life existed on Earth 4.1 billion years ago—when the planet was a mere volcanic toddler. That’s 300 million years earlier for life to pop up than previously thought. Not only does that change the way scientists thought Earth was like soon after it formed 4.5 billion years ago, but gives them reason to theorize that life itself is more plentiful throughout the universe because it seemed to start up so quickly. Researchers examined tiny grains of the mineral zircon from western Australia’s Jack Hills and chemically dated them to when Earth was barely 400 million years old. Inside one of the 160 some grains they found what they call a “chemo-fossil” or a certain mix of carbon isotopes, according to a study published Monday in the journal Proceedings of the National Academy of Sciences. Think of it as “the gooey remains of biotic life or anything more complicated,” said study co-author Mark Harrison, a UCLA geochemistry professor. There are different types of carbon with different weights. This carbon residue had a higher percentage of the lighter type of carbon, which is what scientists usually find in remnants of life, the same as if your finger decayed, Harrison said. READ MORE...

ALSO LAST YEAR REPORT: Earth’s crust at least 4.4 billion years old – study


A timeline of the history of our planet places the formation of the Jack Hills zircon and a "cool early Earth" at 4.4 billion years. Graphic: Andree Valley PARIS – A microscopic grain of Earth’s oldest known mineral has been dated to 4.4 billion years ago, shedding light on our planet’s infancy and how it came to harbor life, researchers said Sunday. The finding proves that Earth remained a fiery ball covered in a magma ocean for a shorter period of time after its creation than previously thought. The Earth is thought to have formed about 4.5 billion years ago, but little is known about its early years, particularly when it became cool enough for the crust to congeal from a sea of molten rock and for liquid water to form. Some had postulated the cooling would have required as much as 600 million years. But the discovery in recent decades of zircon crystals, some estimated to be as old as 4.4 billion years, threw that theory into doubt, even though the minerals’ age was not conclusively proven. Until now. The new study confirms that zircon grains harvested from western Australia’s Jack Hills region crystallised with the formation of the Earth’s crust some 4.374 billion years ago, its authors said. This was about 160 million years after the creation of the Earth and other planets in our solar system – “much earlier than previously believed”, according to a press statement. The findings strengthen the theory of a “cool early Earth”, with temperatures low enough for liquid water, oceans and a hydrosphere – 0the combined mass of water on a planet – to form not long after the crust during a period known as the Hadean. READ MORE...

ALSO: Earth: Introduction earth, in geology and astronomy


EARTH AT NIGHT. PHOTO BY NASA Earth is the 3rd planet of the solar system and the 5th largest, the only planet definitely known to support life. Gravitational forces have molded the earth, like all celestial bodies, into a spherical shape. However, the earth is not an exact sphere, being slightly flattened at the poles and bulging at the equator. The equatorial diameter is c.7,926 mi (12,760 km) and the polar diameter 7,900 mi (12,720 km); the circumference at the equator is c.24,830 mi (40,000 km). The surface of the earth is divided into dry land and oceans, the dry land occupying c.57.5 million sq mi (148.9 million sq km), and the oceans c.139.5 million sq mi (361.3 million sq km). The earth is surrounded by an envelope of gases called the atmosphere, of which the greater part is nitrogen and oxygen.
The Geologic Earth Knowledge of the earth's interior has been gathered by three methods: by the analysis of earthquake waves passing through the earth (see seismology), by analogy with the composition of meteorites, and by consideration of the earth's size, shape, and density. Research by these methods indicates that the earth has a zoned interior, consisting of concentric shells differing from one another by size, chemical makeup, and density. The earth is undoubtedly much denser near the center than it is at the surface, because the average density of rocks near the surface is c.2.8 g/cc, while the average density of the entire earth is c.5.5 g/cc.  The Earth's Crust and the Moho The outer shell, or crust, varies from 5 to 25 mi (8 to 40 km) in thickness, and consists of the continents and ocean basins at the surface. The continents are composed of rock types collectively called sial, a classification based on their densities and composition. Beneath the ocean basins and the sial of continents lie denser rock types called sima. The sial and sima together form the crust, beneath which lies a shell called the mantle. The boundary between the crust and the mantle is marked by a sharp alteration in the velocity of earthquake waves passing through that region. This boundary layer is called the Mohorovičić discontinuity, or Moho. READ MORE...


READ FULL MEDIA REPORTS:

Hints of life on what was thought to be desolate early Earth


Earliest Life This photo provided by the Proceedings of the National Academy of Sciences (PNAS), taken in 2005, shows fossil-like rock found in Australia containing hints of life from 4.1 billion years ago. Life on a near primordial Earth may have been around 4.1 billion years ago, 300 million years earlier than thought, hints a chemical fossil-like rock found in Australia. It also gives more hope for life elsewhere in the universe. AP

WASHINGTON, OCTOBER 26, 2015 (INQUIRER) @inquirerdotnet Associated Press 08:19 AM October 20th, 2015# sthash.wY7TC0cc.dpuf - Scientists have found fossil-like hints that some kind of life existed on Earth 4.1 billion years ago—when the planet was a mere volcanic toddler.

That’s 300 million years earlier for life to pop up than previously thought.


EARTH TODAY

Not only does that change the way scientists thought Earth was like soon after it formed 4.5 billion years ago, but gives them reason to theorize that life itself is more plentiful throughout the universe because it seemed to start up so quickly.

Researchers examined tiny grains of the mineral zircon from western Australia’s Jack Hills and chemically dated them to when Earth was barely 400 million years old. Inside one of the 160 some grains they found what they call a “chemo-fossil” or a certain mix of carbon isotopes, according to a study published Monday in the journal Proceedings of the National Academy of Sciences.

Think of it as “the gooey remains of biotic life or anything more complicated,” said study co-author Mark Harrison, a UCLA geochemistry professor. There are different types of carbon with different weights. This carbon residue had a higher percentage of the lighter type of carbon, which is what scientists usually find in remnants of life, the same as if your finger decayed, Harrison said.

READ MORE...

There are rare cases where this particular carbon signature wouldn’t be from life, but they are exceedingly unusual and only in certain situations. Harrison theorizes that the carbon is from a colony of tiny organisms of some unknown type.

Life existing 300 million years earlier than science thought is the most logical and simplest explanation, but “this is not smoking gun evidence,” Harrison said. The common thinking of early volcanic Earth is that it was too molten and there was not enough liquid water for life to take hold this early. But, Harrison said, there’s no physical evidence for this theory. What the zircon shows is “the Earth by 4.1, 4.2 billion years ago was basically behaving like it is today.”

“This is what transformative science is all about,” said Stephen Mojzsis, a University of Colorado scientist who wasn’t part of the research. “

”If life is responsible for these signatures, it arrives fast and early.”

Blair Hedges of Temple University, who also wasn’t part of the study, said Harrison’s findings makes sense and the accelerated timeline of life fits with his genetic tracking work.

“If life arose relatively quickly on Earth,” Hedges wrote in an email, “then it could be common in the universe.”


INQUIRER

Earth’s crust at least 4.4 billion years old – study @inquirerdotnet Agence France-Presse
06:56 AM February 24th, 2014


A timeline of the history of our planet places the formation of the Jack Hills zircon and a "cool early Earth" at 4.4 billion years. Graphic: Andree Valley

PARIS – A microscopic grain of Earth’s oldest known mineral has been dated to 4.4 billion years ago, shedding light on our planet’s infancy and how it came to harbor life, researchers said Sunday.

The finding proves that Earth remained a fiery ball covered in a magma ocean for a shorter period of time after its creation than previously thought.

The Earth is thought to have formed about 4.5 billion years ago, but little is known about its early years, particularly when it became cool enough for the crust to congeal from a sea of molten rock and for liquid water to form.

Some had postulated the cooling would have required as much as 600 million years.

But the discovery in recent decades of zircon crystals, some estimated to be as old as 4.4 billion years, threw that theory into doubt, even though the minerals’ age was not conclusively proven. Until now.

The new study confirms that zircon grains harvested from western Australia’s Jack Hills region crystallised with the formation of the Earth’s crust some 4.374 billion years ago, its authors said.

This was about 160 million years after the creation of the Earth and other planets in our solar system – “much earlier than previously believed”, according to a press statement.

The findings strengthen the theory of a “cool early Earth”, with temperatures low enough for liquid water, oceans and a hydrosphere – 0the combined mass of water on a planet – to form not long after the crust during a period known as the Hadean.

READ MORE...

“The study reinforces our conclusion that Earth had a hydrosphere before 4.3 billion years ago”, and possibly life not long after, said study co-author John Valley, a geochemist from the University of Wisconsin Madison.

The study was conducted with a new technique called atom-probe tomography that could accurately determine the age of the miniscule mineral fragment by measuring individual lead atoms inside it.

Due to its durability, zircon can withstand billions of years of erosion to remain chemically intact, and contains a wealth of geological information.

It is found locked up in younger rocks and even in sand.

This new knowledge about when the Earth cooled “may also help us understand how other habitable planets would form,” said Valley.


INFOPLEASE.COM ENCYCLOPEDIA

Earth: Introduction earth, in geology and astronomy


EARTH AT NIGHT. PHOTO BY NASA

Earth is the 3rd planet of the solar system and the 5th largest, the only planet definitely known to support life. Gravitational forces have molded the earth, like all celestial bodies, into a spherical shape.

However, the earth is not an exact sphere, being slightly flattened at the poles and bulging at the equator. The equatorial diameter is c.7,926 mi (12,760 km) and the polar diameter 7,900 mi (12,720 km); the circumference at the equator is c.24,830 mi (40,000 km).

The surface of the earth is divided into dry land and oceans, the dry land occupying c.57.5 million sq mi (148.9 million sq km), and the oceans c.139.5 million sq mi (361.3 million sq km).

The earth is surrounded by an envelope of gases called the atmosphere, of which the greater part is nitrogen and oxygen.

The Geologic Earth

Knowledge of the earth's interior has been gathered by three methods: by the analysis of earthquake waves passing through the earth (see seismology), by analogy with the composition of meteorites, and by consideration of the earth's size, shape, and density.

Research by these methods indicates that the earth has a zoned interior, consisting of concentric shells differing from one another by size, chemical makeup, and density.

The earth is undoubtedly much denser near the center than it is at the surface, because the average density of rocks near the surface is c.2.8 g/cc, while the average density of the entire earth is c.5.5 g/cc.

The Earth's Crust and the Moho


The Mohorovičić discontinuity, or simply the Moho, is the transitional boundary between the crust of the Earth and the underlying mantle located 5-10 km (3-6 mi) beneath the ocean floor and 20-90 km (10-60 mi) beneath the surface of continents.

The outer shell, or crust, varies from 5 to 25 mi (8 to 40 km) in thickness, and consists of the continents and ocean basins at the surface.

The continents are composed of rock types collectively called sial, a classification based on their densities and composition. Beneath the ocean basins and the sial of continents lie denser rock types called sima.

The sial and sima together form the crust, beneath which lies a shell called the mantle. The boundary between the crust and the mantle is marked by a sharp alteration in the velocity of earthquake waves passing through that region. This boundary layer is called the Mohorovičić discontinuity, or Moho.

READ MORE...

The Earth's Mantle

Extending to a depth of c.1,800 mi (2,900 km), the mantle probably consists of very dense (average c.3.9 g/cc) rock rich in iron and magnesium minerals. Although temperatures increase with depth, the melting point of the rock is not reached because the melting temperature is raised by the great confining pressure.

At depths between c.60 mi and c.125 mi (100 and 200 km) in the mantle, a plastic zone, called the asthenosphere, is found to occur. Presumably the rocks in this region are very close to melting, and the zone represents a fundamental boundary between the moving crustal plates of the earth's surface and the interior regions.

 The molten magma that intrudes upward into crustal rocks or issues from a volcano in the form of lava may owe its origin to radioactive heating or to the relief of pressure in the lower crust and upper mantle caused by earthquake faulting of the overlying crustal rock. Similarly, it is thought that the heat energy released in the upper part of the mantle has broken the earth's crust into vast plates that slide around on the plastic zone, setting up stresses along the plate margins that result in the formation of folds and faults (see plate tectonics).

The Earth's Core


At the very center of the earth is the inner core . It is believed to be 700-900 miles in diameter. The pressure is so great in this layer that it is solid. It is made up of iron and other metals that can be up to 13,000°F (7,000°C)

Thought to be composed mainly of iron and nickel, the dense (c.11.0 g/cc) core of the earth lies below the mantle. The abrupt disappearance of direct compressional earthquake waves, which cannot travel through liquids, at depths below c.1,800 mi (2,900 km) indicates that the outer 1,380 mi (2,200 km) of the core are molten.

The inner 780 mi (1,260 km) of the core are solid, and the innermost 190 mi (300 km) of that may be almost pure iron.

The outer core is thought to be the source of the earth's magnetic field: In the "dynamo theory" advanced by W. M. Elasser and E. Bullard, tidal energy or heat is converted to mechanical energy in the form of currents in the liquid core; this mechanical energy is then converted to electromagnetic energy, which we see as the magnetic field.

The magnetic field undergoes periodic reversals of its polarity on a timescale that ranges from a few thousand years to 35 million years. The last reversal occurred some 780,000 years ago.

The Astronomical Earth

Of the planets, only Mercury and Venus are nearer to the sun; the mean distance from the earth to the sun is c.93 million mi (150 million km).

Rotation and Revolution

The earth rotates from west to east about a line (its axis) that is perpendicular to the plane of the equator and passes through the center of the earth, terminating at the north and south geographical poles. The period of one complete rotation is a day; the rotation of the earth is responsible for the alternate periods of light and darkness (day and night).

The earth revolves about the sun once in a period of a little more than 3651/4 days (a year). The path of this revolution, the earth's orbit, is an ellipse rather than a circle, and the earth is consequently nearer to the sun in January than it is in July; the difference between its maximum and minimum distances from the sun is c.3 million mi (4.8 million km). This difference is not great enough to affect climate on the earth.

The Change in Seasons


TREE OF FOUR SEASONS

The change in seasons is caused by the tilt of the earth's axis to the plane of its orbit, making an angle of c.66.5°.

When the northern end of the earth's axis is tilted toward the sun, the most direct rays of sunlight fall in the Northern Hemisphere. This causes its summer season.

At the same time the Southern Hemisphere experiences winter since it is then receiving indirect rays. Halfway between, in spring and in autumn, there is a time (see equinox) when all parts of the earth have equal day and night.

When the northern end of the earth's axis is tilted away from the sun, the least direct sunlight falls on the Northern Hemisphere. This causes its winter season.


Nasa Earth At Night From Space

The Origin of the Earth

The earth is estimated to be 4.5 billion to 5 billion years old, based on radioactive dating of lunar rocks and meteorites, which are thought to have formed at the same time.

The origin of the earth continues to be controversial.

Among the theories as to its origin, the most prominent are gravitational condensation hypotheses, which suggest that the entire solar system was formed at one time in a single series of processes resulting in the accumulation of diffuse interstellar gases and dust into a solar system of discrete bodies.

The generally accepted theory of the moon's formation hypothesizes that the early earth was impacted by a Mars-sized object, and that the collision ejected material that later formed the moon.

Older and now generally discredited theories of the earth's formation invoked extraordinary events, such as the gravitational disruption of a star passing close to the sun or the explosion of a companion star to the sun.


Chief News Editor: Sol Jose Vanzi
© Copyright, 2015 by PHILIPPINE HEADLINE NEWS ONLINE
All rights reserved


PHILIPPINE HEADLINE NEWS ONLINE [PHNO] WEBSITE