How Can science prove the age of the earth?

No scientific method can prove the age of the earth and the universe, and that includes the ones we have

listed here. Although age indicators are called ‘clocks’ they aren’t, because all ages result from calculations that necessarily involve making assumptions about the past. Always the starting time of the ‘clock’ has to be assumed as well as the way in which the speed of the clock has varied over time. Further, it has to be assumed that the clock was never disturbed.

There is no independent natural clock against which those assumptions can be tested. For example, the amount of cratering on the moon, based on currently observed cratering rates, would suggest that the moon is quite old. However, to draw this conclusion we have to assume that the rate of cratering has been the same in the past as it is now. And there are now good reasons for thinking that it might have been quite intense in the past, in which case the craters do not indicate an old age at all (see below).

Ages of millions of years are all calculated by assuming the rates of change of processes in the past were the same as we observe today—called the principle of uniformitarianism. If the age calculated from such assumptions disagrees with what they think the age should be, they conclude that their assumptions did not apply in this case, and adjust them accordingly. If the calculated result gives an acceptable age, the investigators publish it.

Examples of young ages listed here are also obtained by applying the same principle of uniformitarianism. Long-age proponents will dismiss this sort of evidence for a young age of the earth by arguing that the assumptions about the past do not apply in these cases. In other words, age is not really a matter of scientific observation but an argument about our assumptions about the unobserved past.

The assumptions behind the evidences presented here cannot be proved, but the fact that such a wide range of different phenomena all suggest much younger ages than are currently generally accepted, provides a strong case for questioning those accepted ages (13.77 billion years for the universe and 4.54 billion years for the solar system).

Also, a number of the evidences, rather than giving any estimate of age, challenge the assumption of slow-and-gradual uniformitarianism, upon which all deep-time dating methods depend. 

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NASA Research Aids Response to California Napa Quake

NASA data and expertise are proving invaluable in California’s ongoing response to the Aug. 24 magnitude 6.0 earthquake in Napa Valley, northeast of San Francisco. The quake was the strongest to occur in the San Francisco Bay Area in a quarter-century and caused significant regional damage.

Analyses by scientists at NASA’s Jet Propulsion Laboratory, Pasadena, California, of airborne data from NASA’s Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), GPS data and radar imagery from the Italian Space Agency’s COSMO-SkyMed satellites, are revealing important details of how the ground deformed in the region and the nature of the fault movements. In addition, a NASA-funded disaster decision support system has provided a series of rapid-response data maps to decision makers at the California Earthquake Clearinghouse. Those maps are being used to better direct response efforts.

NASA has been monitoring active earthquake faults in California using a variety of remote sensing and ground-based techniques. The JPL-developed UAVSAR, in use since 2009, is an L-band Interferometric Synthetic Aperture Radar instrument that flies mounted underneath a NASA C-20A Earth science research aircraft from NASA’s Armstrong Flight Research Center, Edwards, California. UAVSAR is able to detect minute changes in Earth’s surface that occur over time between flights of the instrument. UAVSAR has monitored the Napa area about every six months since November 2009.

 

A comparison of UAVSAR data collected on May 29, 2014, three months before the quake, and on Aug. 29, 2014, five days after the quake, reveals that multiple strands of the fault slipped near the quake’s epicenter. A new UAVSAR image showing these changes is available at:

http://photojournal.jpl.nasa.gov/catalog/pia18801

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NASA Research Gives Guideline for Future Alien Life Search

Astronomers searching the atmospheres of alien worlds for gases that might be produced by life can't rely on

the detection of just one type, such as oxygen, ozone, or methane, because in some cases these gases can be produced non-biologically, according to extensive simulations by researchers in the NASA Astrobiology Institute’s Virtual Planetary Laboratory. 

The researchers carefully simulated the atmospheric chemistry of alien worlds devoid of life thousands of times over a period of more than four years, varying the atmospheric compositions and star types. "When we ran these calculations, we found that in some cases, there was a significant amount of ozone that built up in the atmosphere, despite there not being any oxygen flowing into the atmosphere," said Shawn Domagal-Goldman of NASA's Goddard Space Flight Center in Greenbelt, Maryland. "This has important implications for our future plans to look for life beyond Earth."

Methane is a carbon atom bound to four hydrogen atoms. On Earth, much of it is produced biologically (flatulent cows are a classic example), but it can also be made inorganically; for example, volcanoes at the bottom of the ocean can release the gas after it is produced by reactions of rocks with seawater.

Ozone and oxygen were previously thought to be stronger biosignatures on their own. Ozone is three atoms of oxygen bound together. On Earth, it is produced when molecular oxygen (two oxygen atoms) and atomic oxygen (a single oxygen atom) combine, after the atomic oxygen is created by other reactions powered by sunlight or lightning. Life is the dominant source of the molecular oxygen on our planet, as the gas is produced by photosynthesis in plants and microscopic, single-cell organisms. Because life dominates the production of oxygen, and oxygen is needed for ozone, both gases were thought to be relatively strong biosignatures. But this study demonstrated that both molecular oxygen and ozone can be made without life when ultraviolet light breaks apart carbon dioxide (a carbon atom bound to two oxygen atoms). Their research suggests this non-biological process could create enough ozone for it to be detectable across space, so the detection of ozone by itself would not be a definitive sign of life.

"However, our research strengthens the argument that methane and oxygen together, or methane and ozone together, are still strong signatures of life," said Domagal-Goldman. "We tried really, really hard to make false-positive signals for life, and we did find some, but only for oxygen, ozone, or methane by themselves." Domagal-Goldman and Antígona Segura from the Universidad Nacional Autónoma de México in Mexico City are lead authors of a paper about this research, along with astronomer Victoria Meadows, geologist Mark Claire, and Tyler Robison, an expert on what Earth would look like as an extrasolar planet. The paper appeared in the Astrophysical Journal Sept. 10, and is available online.

Methane and oxygen molecules together are a reliable sign of biological activity because methane doesn't last long in an atmosphere containing oxygen-bearing molecules. "It's like college students and pizza," says Domagal-Goldman. "If you see pizza in a room, and there are also college students in that room, chances are the pizza was freshly delivered, because the students will quickly eat the pizza. The same goes for methane and oxygen. If both are seen together in an atmosphere, the methane was freshly delivered because the oxygen will be part of a network of reactions that will consume the methane. You know the methane is being replenished. The best way to replenish methane in the presence of oxygen is with life. The opposite is true, as well. In order to keep the oxygen around in an atmosphere that has a lot of methane, you have to replenish the oxygen, and the best way to do that is with life."

Scientists have used computer models to simulate the atmospheric chemistry on planets beyond our solar system (exoplanets) before, and the team used a similar model in its research. However, the researchers also developed a program to automatically compute the calculations thousands of times, so they could see the results with a wider range of atmospheric compositions and star types.

In doing these simulations, the team made sure they balanced the reactions that could put oxygen molecules in the atmosphere with the reactions that might remove them from the atmosphere. For example, oxygen can react with iron on the surface of a planet to make iron oxides; this is what gives most red rocks their color. A similar process has colored the dust on Mars, giving the Red Planet its distinctive hue. Calculating the appearance of a balanced atmosphere is important because this balance would allow the atmosphere to persist for geological time scales. Given that planetary lifetimes are measured in billions of years, it's unlikely astronomers will happen by chance to be observing a planet during a temporary surge of oxygen or methane lasting just thousands or even millions of years.

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Celebrate World Ozone Day

What is ozone, and why is some ozone “good" while some is "bad?"

Just as humans need sunblock, the Earth needs protection too. Earth’s sunscreen is called ozone. The ozone that protects us, and all life on Earth, from the Sun’s harmful UV radiation is high in the atmosphere, in the stratosphere.

But there is also ozone closer to Earth in the troposphere and that is harmful to the health of people, plants and animals.

Decades ago scientists discovered that the Earth’s “good” ozone layer was thinning. It was being depleted by chlorofluorocarbons (CFCs). But the international community came together with an agreement to vastly curtail the use CFCs. The UN General Assembly proclaimed September 16 the International Day for the Preservation of the Ozone Layer, commemorating the date of the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer. The theme for this year’s celebration is “Ozone Layer Protection: The Mission Goes On.”

The Montreal Protocol has so far been successful in meeting some of its targets, as a result, the abundance of ozone-depleting substances in the atmosphere is declining and the ozone layer is expected to recover around the middle of this century.

Source: NASA News

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The Age of Comets

Whistling and moaning, a 50-mile-an-hour (80-kilometer-an-hour) wind whipped among the telescope

domes atop Kitt Peak. Just a few feet below, turning gray in the dusk, slid a river of clouds that had been rising and dropping all day. And high above, comet Hale-Bopp hung suspended like a feathery fishing lure, its tail curving off a bit, as if blown to the side by the punishing wind.

One by one, stars winked on in a darkening sky. In each of the telescope domes, teams of astronomers prayed that the wind would drop below 40 miles per hour (64 kilometers an hour), the point at which they'd be able to open the sliding doors and get back to work.

The sky turned indigo. Then black. Viewed from the summit, 6,873 feet (2,095 meters) above Arizona's Sonoran Desert, Hale-Bopp's bright dust tail, along with a dimmer, all but transparent blue one, seemed to grow by degrees. Among the brightest comets ever seen, Hale-Bopp had been visible for months from midtown Manhattan, of all places. But here, on a moonless night in the mountains in the desert, the length of Hale-Bopp's tail became visible—a wispy, delicate veil.

Along with eclipses, comets have been the most feared and admired sky spectacles of all. But while astronomers have been able to predict eclipses for thousands of years, only in the 1700s was a comet's return correctly predicted, by Edmond Halley.

Some comets swing around the sun every few years. Others, like Hale-Bopp, may take thousands of years. Most can be seen only with a telescope. But every once in a while—a few times a century, perhaps—an impressive one is visible to the naked eye. And in the past two years the world has witnessed not one but two of them.

Hyakutake in 1996 had one of the longest tails on record, stretching more than halfway across the sky; Hale-Bopp in 1997 had one of the most brilliant heads, nearly as bright as the star Sirius. Add the Jupiter crash of comet Shoemaker-Levy in 1994, Halley's most recent visit in 1986, vivid comet West in 1976, and the scientifically signifiant—if visually disappointing—Kohoutek in 1973-74, and you could say that we are indeed living in the age of comets.

Hovering in the most fragile of gravitational balances, a fleet of dirty, lumpy snowballs numbering in the trillions is barely held in orbit by the pull of the sun. They are stored in the Oort cloud, a huge, diffuse sphere of cometary nuclei in the far reaches of the solar system. Close to the sun, yet still beyond Neptune, circle what may well be their brethren, in a great disk called the Kuiper belt.

Comets are leftovers, scraps of material that didn't make it to planethood in the events creating our solar system. Once, many astronomers believe, the solar system was full of comet nuclei, chunks of ice and dust left over from the formation of the sun. Most clumped together to form planets, leaving a relative handful—averaging perhaps a few miles wide, with temperatures as low as minus 400 degrees Fahrenheit (minus 240 degrees Celsius)—as time capsules of the early solar system.

They orbit in a perpetual deep freeze until some subtle gravitational nudge upsets the delicate balance. Then the great fall begins. Imperceptibly at first, a snowball drifts toward the sun and steadily accelerates. As solar radiation heats the comet, the ice within sublimates, escaping as gas from vents at the surface. Sometimes jets of sublimating ice whirl off the rotating comet nucleus like a fireworks pinwheel. Dust trapped in the ice breaks free. Pushed back by the pressure of the sun's radiation, the dust streams out behind the comet in what appears as a fiery tail.

Rendezvous with a Comet (From youtube)

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Milky Way is on the outskirts of 'immeasurable heaven' supercluster

Astronomers discover that our galaxy is a suburb of a supercluster of 100,000 large galaxies they have called

Laniakea

In what amounts to a back-to-school gift for pupils with nerdier leanings, researchers have added a fresh line to the cosmic address of humanity. No longer will a standard home address followed by "the Earth, the solar system, the Milky Way, the universe" suffice for aficionados of the extended astronomical location system.

The extra line places the Milky Way in a vast network of neighbouring galaxies or "supercluster" that forms a spectacular web of stars and planets stretching across 520m light years of our local patch of universe. Named Laniakea, meaning "immeasurable heaven" in Hawaiian, the supercluster contains 100,000 large galaxies that together have the mass of 100 million billion suns.

Our home galaxy, the Milky Way, lies on the far outskirts of Laniakea near the border with another supercluster of galaxies named Perseus-Pisces. "When you look at it in three dimensions, is looks like a sphere that's been badly beaten up and we are over near the edge, being pulled towards the centre," said Brent Tully, an astronomer at the University of Hawaii in Honolulu.

Astronomers have long known that just as the solar system is part of the Milky Way, so the Milky Way belongs to a cosmic structure that is much larger still. But their attempts to define the larger structure had been thwarted because it was impossible to work out where one cluster of galaxies ended and another began.

Video from Youtube

Tully's team gathered measurements on the positions and movement of more than 8,000 galaxies and, after discounting the expansion of the universe, worked out which were being pulled towards us and which were being pulled away. This allowed the scientists to define superclusters of galaxies that all moved in the same direction (if you're reading this story on a mobile device, click here to watch a video explaining the research).

The work published in Nature gives astronomers their first look at the vast group of galaxies to which the Milky Way belongs. A narrow arch of galaxies connects Laniakea to the neighbouring Perseus-Pisces supercluster, while two other superclusters called Shapley and Coma lie on the far side of our own.

Tully said the research will help scientists understand why the Milky Way is hurtling through space at 600km a second towards the constellation of Centaurus. Part of the reason is the gravitational pull of other galaxies in our supercluster.

"But our whole supercluster is being pulled in the direction of this other supercluster, Shapley, though it remains to be seen if that's all that's going on," said Tully.

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Earth seen from the International Space Station (Video)

An extraordinary timelapse video created with pictures from the International Space Station shows Earth as

it has never been seen before. The video, called Further Up Yonder, was made by Italian film student Giacomo Sardelli using Nasa stills. Sardelli calls the film a message from the ISS to all humankind 

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Earth, Orbit and rotation

Rotation

 Earth's rotation period relative to the Sun—its mean solar day—is 86,400 seconds of mean solar time (86,400.0025 SI seconds). As the Earth's solar day is now slightly longer than it was during the 19th century due to tidal acceleration, each day varies between 0 and 2 SI ms longer.

Earth's rotation period relative to the fixed stars, called its stellar day by the International Earth Rotation and Reference Systems Service (IERS), is 86,164.098903691 seconds of mean solar time (UT1), or 23^h 56^m 4.098903691^s.^{[2][n 12]} Earth's rotation period relative to the precessing or moving mean vernal equinox, misnamed its sidereal day, is 86,164.09053083288 seconds of mean solar time (UT1) (23^h 56^m 4.09053083288^s) as of 1982.^[2] Thus the sidereal day is shorter than the stellar day by about 8.4 ms.^[129] The length of the mean solar day in SI seconds is available from the IERS for the periods 1623–2005^[130] and 1962–2005.

Apart from meteors within the atmosphere and low-orbiting satellites, the main apparent motion of celestial bodies in the Earth's sky is to the west at a rate of 15°/h = 15'/min. For bodies near the celestial equator, this is equivalent to an apparent diameter of the Sun or Moon every two minutes; from the planet's surface, the apparent sizes of the Sun and the Moon are approximately the same.

Orbit

Main article: Earth's orbit

Earth orbits the Sun at an average distance of about 150 million kilometers every 365.2564 mean solar days, or one sidereal year. From Earth, this gives an apparent movement of the Sun eastward with respect to the stars at a rate of about 1°/day, which is one apparent Sun or Moon diameter every 12 hours. Due to this motion, on average it takes 24 hours—a solar day—for Earth to complete a full rotation about its axis so that the Sun returns to the meridian. The orbital speed of the Earth averages about 29.8 km/s (107,000 km/h), which is fast enough to travel a distance equal to the planet's diameter, about 12,742 km, in seven minutes, and the distance to the Moon, 384,000 km, in about 3.5 hours.

The Moon revolves with the Earth around a common barycenter every 27.32 days relative to the background stars. When combined with the Earth–Moon system's common revolution around the Sun, the period of the synodic month, from new moon to new moon, is 29.53 days. Viewed from the celestial north pole, the motion of Earth, the Moon and their axial rotations are all counterclockwise. Viewed from a vantage point above the north poles of both the Sun and the Earth, the Earth revolves in a counterclockwise direction about the Sun. The orbital and axial planes are not precisely aligned: Earth's axis is tilted some 23.4 degrees from the perpendicular to the Earth–Sun plane (the ecliptic), and the Earth–Moon plane is tilted up to ±5.1 degrees against the Earth–Sun plane. Without this tilt, there would be an eclipse every two weeks, alternating between lunar eclipses and solar eclipses.

The Hill sphere, or gravitational sphere of influence, of the Earth is about 1.5 Gm or 1,500,000 km in radius.^{[135][n 13]} This is the maximum distance at which the Earth's gravitational influence is stronger than the more distant Sun and planets. Objects must orbit the Earth within this radius, or they can become unbound by the gravitational perturbation of the Sun.

Earth, along with the Solar System, is situated in the Milky Way galaxy and orbits about 28,000 light years from the center of the galaxy. It is about 20 light years above the galactic plane in the Orion spiral arm.

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Earth, Composition and structure

Earth is a terrestrial planet, meaning that it is a rocky body, rather than a gas giant like Jupiter. It is the largest surface gravity, the strongest magnetic field, and fastest rotation, and is probably the only one with active plate tectonics.

of the four terrestrial planets in size and mass. Of these four planets, Earth also has the highest density, the highest

The shape of the Earth approximates an oblate spheroid, a sphere flattened along the axis from pole to pole such that there is a bulge around the equator.^[57] This bulge results from the rotation of the Earth, and causes the diameter at the equator to be 43 km (kilometer) larger than the pole-to-pole diameter.^[58] Thus the furthest point on the surface from the Earth's center of mass is the Chimborazo volcano in Ecuador.^[59] The average diameter of the reference spheroid is about 12742 km, which is approximately 40,000 km/π, as the meter was originally defined as 1/10,000,000 of the distance from the equator to the North Pole through Paris, France.^[60]

Local topography deviates from this idealized spheroid, although on a global scale, these deviations are small: Earth has a tolerance of about one part in about 584, or 0.17%, from the reference spheroid, which is less than the 0.22% tolerance allowed in billiard balls.^[61] The largest local deviations in the rocky surface of the Earth are Mount Everest (8,848 m above local sea level) and the Mariana Trench (10911 m below local sea level). Due to the equatorial bulge, the surface locations farthest from the center of the Earth are the summits of Mount Chimborazo in Ecuador and Huascarán in Peru.

 

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Video NASA Discovers Earth2.0

An other earth in our galaxy?? It's possible??

 NASA discovered this..

 The next video provr that.

From youtube

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Video - Have you seen the earth from the space??

Let's go to see our famous earth from the space. It's like a dream.

Video From Youtube

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The Earth ... Our fantastic planet

Let's discaver our planet, When we live.

Earth, also known as the world, Terra, or Gaia, is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only celestial body known to accommodate life. It is home to an untold number of species,^[30] including billions of humans^[31] who depend upon its biosphere and minerals. The Earth's human population is divided among about two hundred independent states that interact through diplomacy, conflict, travel, trade, and media.

According to evidence from sources such as radiometric dating, Earth was formed around four and a half billion years ago. Within its first billion years, life appeared in its oceans and began to affect its atmosphere and surface, promoting the proliferation of aerobic as well as anaerobic organisms and causing the formation of the atmosphere's ozone layer. This layer and Earth's magnetic field block the most life-threatening parts of the Sun's radiation, so life was able to flourish on land as well as in water. Since then, Earth's position in the Solar System, its physical properties and its geological history have allowed life to persist.

Earth's lithosphere is divided into several rigid segments, or tectonic plates, that migrate across the surface over periods of many millions of years. Over 70% percent of Earth's surface is covered with water,^[34] with the remainder consisting of continents and islands which together have many lakes and other sources of water that contribute to the hydrosphere. Earth's poles are mostly covered with ice that is the solid ice of the Antarctic ice sheet and the sea ice that is the polar ice packs. The planet's interior remains active, with a solid iron inner core, a liquid outer core that generates the magnetic field, and a thick layer of relatively solid mantle.

Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, the Earth rotates about its own axis 366.26 times, creating 365.26 solar days, or one sidereal year.^{[n 6]} The Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). The Moon is Earth's only natural satellite. It began orbiting the Earth about 4.53 billion years ago (bya). The Moon's gravitational interaction with Earth stimulates ocean tides, stabilizes the axial tilt, and gradually slows the planet's rotation.

From Wikipedia

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