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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Galaxy Collision (Video)

Two spiral galaxies undergo a protracted crash lasting two billion years, eventually merging into a single
elliptical galaxy. Credit: NCSA/NASA/B. Robertson (Caltech) and L. Hernquist (Harvard Univ.)

Video from youtube

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The stars of the space

A star is a massive, luminous sphere of plasma held together by its own gravity. The nearest star to Earth is Sun, which is the source of most of the planet's energy. Some other stars are visible from Earth during the night, appearing as a multitude of fixed luminous points due to their immense distance. Historically, the most prominent stars were grouped into constellations and asterisms, and the brightest stars gained proper names. Extensive catalogues of stars have been assembled by astronomers, which provide standardized star designations.

the

For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and then radiates into outer space. Once the hydrogen in the core of a star is nearly exhausted, almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the star's lifetime and, for some stars, by supernova nucleosynthesis when it explodes. Near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, luminosity, and spectrum respectively. The total mass of a star is the principal determinant of its evolution and eventual fate. Other characteristics of a star, including diameter and temperature, change over its life, while the star's environment affects its rotation and movement. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung–Russell diagram (H–R diagram), allows the age and evolutionary state of a star to be determined.

A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of^[1] The remainder of the star's interior carries energy away from the core through a combination of radiative and convective processes. The star's internal pressure prevents it from collapsing further under its own gravity. Once the hydrogen fuel at the core is exhausted, a star with at least 0.4 times the mass of the Sun^[2] expands to become a red giant, in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of its matter into the interstellar environment, where it will contribute to the formation of a new generation of stars with a higher proportion of heavy elements.^[3] Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or (if it is sufficiently massive) a black hole.

hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, hydrogen becomes steadily converted into helium through nuclear fusion, releasing energy in the process.

Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution.^[4] Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy.

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the Sun: unlimited power

The sun is the closest star to Earth. Even at a distance of 150 million kilometers (93 million miles), its holds the planet in orbit. It radiates light and heat, or solar energy, which makes it possible for life to exist on Earth. 

Plants need sunlight to grow. Animals, including humans, need plants for food and the oxygen they produce. Without heat from the sun, Earth would freeze. There would be no winds, ocean currents, or clouds to transport water.

Solar energy has existed as long as the sun—about 5 billion years. While people have not been around that long, they have been using solar energy in a variety of ways for thousands of years.

Solar energy is essential to agriculture—cultivating land, producing crops, and raising livestock. Developed about 10,000 years ago, agriculture had a key role in the rise of civilization. Solar techniques, such as crop rotation, increased harvests. Drying food using sun and wind prevented crops from spoiling. This surplus of food allowed for denser populations and structured societies. 

Early civilizations around the world positioned buildings to face south to gather heat and light. They used windows and skylights for the same reason, as well as to allow for air circulation. These are elements of solar architecture. Other aspects include using selective shading and choosing building materials with thermal mass, meaning they store heat, such as stone and concrete. Today, computer programs make applications easier and more precise.

The greenhouse is another early solar development. By converting sunlight to heat, greenhouses make it possible to grow plants out of season and in climates that may not be suited for them. One of the earliest greenhouses dates to 30 CE, before glass was even invented. Constructed from translucent sheets of mica, a thin mineral, it was built for the Roman emperor Tiberius, who wanted to be able to eat cucumbers all year. The general technique is the same today, although there have been many improvements to increase the variety and amount of crops grown.

From: national geographic

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Microscopic Diamonds Suggest Cosmic Impact Responsible For Major Period Of Climate Change

A new study published in The Journal of Geology provides support for the theory that a cosmic impact climate change known as the Younger Dryas stadial, or “Big Freeze.”

event over North America some 13,000 years ago caused a major period of

Around 12,800 years ago, a sudden, catastrophic event plunged much of the Earth into a period of cold climatic conditions and drought. This drastic climate change — the Younger Dryas — coincided with the extinction of Pleistocene megafauna, such as the saber-tooth cats and the mastodon, and resulted in major declines in prehistoric human populations, including the termination of the Clovis culture.

With limited evidence, several rival theories have been proposed about the event that sparked this period, such as a collapse of the North American ice sheets, a major volcanic eruption, or a solar flare.

However, in a study published in The Journal of Geology, an international group of scientists analyzing existing and new evidence have determined a cosmic impact event, such as a comet or meteorite, to be the only plausible hypothesis to explain all the unusual occurrences at the onset of the Younger Dryas period.

Researchers from 21 universities in 6 countries believe the key to the mystery of the Big Freeze lies in nanodiamonds scattered across Europe, North America, and portions of South America, in a 50-million-square-kilometer area known as the Younger Dryas Boundary (YDB) field.

Microscopic nanodiamonds, melt-glass, carbon spherules, and other high-temperature materials are found in abundance throughout the YDB field, in a thin layer located only meters from the Earth’s surface. Because these materials formed at temperatures in excess of 2200 degrees Celsius, the fact they are present together so near to the surface suggests they were likely created by a major extraterrestrial impact event.

In addition to providing support for the cosmic impact event hypothesis, the study also offers evidence to reject alternate hypotheses for the formation of the YDB nanodiamonds, such as by wildfires, volcanism, or meteoric flux.

The team’s findings serve to settle the debate about the presence of nanodiamonds in the YDB field and challenge existing paradigms across multiple disciplines, including impact dynamics, archaeology, paleontology, limnology, and palynology.

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World Ozone Day 2014: Progress, But The Mission Has Not Yet Been Accomplished

The layer of gas that protects us and all life on Earth from the Sun’s harmful ultraviolet radiation may be on
the road to recovery, but as the world commemorates World Ozone Day on Tuesday, officials emphasize there is still much work to be done.
Starting in 1994, the UN Assembly proclaimed that September 16 would be the International Day for the Preservation of the Ozone Layer (or, alternatively, World Ozone Day). The date was chosen because it was on September 16, 1987 that the Montreal Protocol on Substances that Deplete the Ozone Layer was signed into effect.
According to the UN, the theme for this year’s World Ozone Day is “Ozone Layer Protection: The Mission Goes On,” since even though the Montreal Protocol has been somewhat successful to this point, the organization emphasized that there are “some remaining challenges” to overcome.
Earlier this month, scientists from the UN Environment Programme (UNEP) and the World Meteorological Organization (WMO) revealed in a new report that the ozone layer in the stratosphere was starting to thicken, and the whole that appears annually over Antarctica has finally stopped growing larger.
The UNEP and WMO explained it would take decades before the hole begins to shrink. Without the Montreal Protocol and the “concerted international action against ozone depleting substances” it has encouraged, they said, the atmospheric levels of ozone-depleting substances might have increased tenfold by 2050.
“There are positive indications that the ozone layer is on track to recovery towards the middle of the century”, UN Undersecretary General and UNEP Executive Director Achim Steiner said, according to Lydia Smith of International Business Times. “The challenges that we face are still huge. The success of the Montreal Protocol should encourage further action not only on the protection and recovery of the ozone layer but also on climate.”

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NASA’s Chandra X-ray Observatory Finds Planet That Makes Star Act Deceptively Old

A planet may be causing the star it orbits to act much older than it actually is, according to new data from Chandra X-ray Observatory. This discovery shows how a massive planet can affect the behavior of its parent star.
NASA’s
The star, WASP-18, and its planet, WASP-18b, are located about 330 light-years from Earth. WASP-18b has a mass about 10 times that of Jupiter and completes one orbit around its star in less than 23 hours, placing WASP-18b in the “hot Jupiter” category of exoplanets, or planets outside our solar system.
WASP-18b is the first known example of an orbiting planet that has apparently caused its star, which is roughly the mass of our sun, to display traits of an older star.
“WASP-18b is an extreme exoplanet,” said Ignazio Pillitteri of the Istituto Nazionale di Astrofisica (INAF)-Osservatorio Astronomico di Palermo in Italy, who led the study. “It is one of the most massive hot Jupiters known and one of the closest to its host star, and these characteristics lead to unexpected behavior. This planet is causing its host star to act old before its time.”
Pillitteri’s team determined WASP-18 is between 500 million and 2 billion years old, based on theoretical models and other data. While this may sound old, it is considered young by astronomical standards. By comparison, our sun is about 5 billion years old and thought to be about halfway through its lifetime.
Younger stars tend to be more active, exhibiting stronger magnetic fields, larger flares, and more intense X-ray emission than their older counterparts. Magnetic activity, flaring, and X-ray emission are linked to the star’s rotation, which generally declines with age. However, when astronomers took a long look with Chandra at WASP-18 they didn’t detect any X-rays. Using established relations between the magnetic activity and X-ray emission of stars, as well as its actual age, researchers determined WASP-18 is about 100 times less active than it should be.
“We think the planet is aging the star by wreaking havoc on its innards,” said co-author Scott Wolk of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
The researchers argue that tidal forces created by the gravitational pull of the massive planet – similar to those the moon has on Earth’s tides, but on a much larger scale – may have disrupted the magnetic field of the star.
The strength of the magnetic field depends on the amount of convection in the star, or how intensely hot gas stirs the interior of the star.

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Newly Found Ring System Similar To Saturn

The scientists, led by Assistant Professor of Physics and Astronomy Eric Mamajek of Rochester and the
Cerro Tololo Inter-American Observatory, used data from the international SuperWASP (Wide Angle Search for Planets) and All Sky Automated Survey (ASAS) project to study the light curves of young Sun-like stars in the Scorpius-Centaurus association–the nearest region of recent massive star formation to the Sun.
The basic concept of the research is straightforward. Imagine yourself sitting in a park on a sunny afternoon and a softball passes between you and the sun. The intensity of light from the sun would appear to weaken for just a moment. Then a bird then flies by, causing the intensity of the sunlight to again weaken–more or less than it did for the baseball, depending on the size of the bird and how long it took to pass. That’s the principle that allowed the researchers to discover a cosmic ring system.
A light curve is a graph of light intensity over time, and one star in particular showed dramatic changes during a 54 day period in early 2007. University of Rochester graduate student Mark Pecaut and Mamajek discovered the unusual eclipse in December 2010. “When I first saw the light curve, I knew we had found a very weird and unique object. After we ruled out the eclipse being due to a spherical star or a circumstellar disk passing in front of the star, I realized that the only plausible explanation was some sort of dust ring system orbiting a smaller companion–basically a ‘Saturn on steroids,’” said Mamajek.
If a spherical object merely passed in front of the star, the intensity of the light would gradually dim and reach a low point before gradually increasing. That was not the case with the star identified as 1SWASP J140747.93-394542.6. The Rochester team discovered a long, deep, and complex eclipse event with significant on-and-off dimming. At the deepest parts of the eclipse, at least 95% of the light from the star was being blocked by dust.
The shape of the light curve was very similar to that of a well-researched star (EE Cephei), suggesting similar traits in the companion objects. However EE Cephei differs in that it appears to be a thick protoplanetary disk transiting–or passing–in front a massive, hot star. “We suspect this new star is being eclipsed by a low-mass object with an orbiting disk that has multiple thin rings of dust debris,” said Mamajek. The star is similar in mass to the sun, but is much younger – about 16 million years old or 1/300th the age of the solar system – and it lies about 420 light years away.


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NASA Selects Boeing and SpaceX for Commercial Crew Contracts

Under the Commercial Crew Transportation Capability (CCtCap) contracts, the two companies will

continue development of spacecraft capable of transporting NASA astronauts to and from the International Space Station as early as 2017, ending the agency’s dependence on Russian Soyuz spacecraft.

The contracts cover the development and certification of the spacecraft, including at least one test flight with both NASA and commercial crewmembers on board. The awards also fund between two and six operational flights to the ISS, each carrying four astronauts, once NASA certifies each company’s vehicle. Unlike previous phases of NASA’s commercial crew program, which used funded Space Act Agreements that provided greater flexibility, the CCtCap awards are fixed-price contracts.

“This was not an easy choice,” NASA Administrator Charles Bolden said at the Sept. 16 announcement at the Kennedy Space Center, “but this is the best choice for NASA and the nation.”

Boeing will receive $4.2 billion to build the CST-100 spacecraft, which it has been working on since the initial phases of NASA’s commercial crew program in 2010. The spacecraft will be launched on a United Launch Alliance Atlas 5 rocket.

“Boeing has been part of every American human space flight program, and we’re honored that NASA has chosen us to continue that legacy,” John Elbon, Boeing vice president and general manager for space exploration said in a company press release. “The CST-100 offers NASA the most cost-effective, safe and innovative solution to U.S.-based access to low-Earth orbit.”

SpaceX will receive $2.6 billion to build its Dragon V2 spacecraft, an upgraded version of the Dragon spacecraft currently used to transport cargo to and from the ISS. Dragon V2 will launch on the company’s Falcon 9 v1.1 rocket. 

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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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Pluto the 9th planet solar system

Pluto (minor-planet designation 134340 Pluto) is the largest object in the Kuiper belt, and the tenth-Sun. It is the second-most-massive known dwarf planet, after Eris. Like other Kuiper-belt objects, Pluto is composed primarily of rock and ice^[15] and is relatively small, approximately one-sixth the mass of the Moon and one-third its volume. It has an eccentric and highly inclined orbit that takes it from 30 to 49 AU (4.4–7.4 billion km) from the Sun. This causes Pluto to periodically come closer to the Sun than Neptune, but an orbital resonance with Neptune prevents the bodies from colliding. In 2014 it was 32.6 AU from the Sun.

most-massive body observed directly orbiting the

Discovered in 1930, Pluto was originally classified as the ninth planet from the Sun. Its status as a major planet fell into question following further study of it and the outer Solar System over the ensuing 75 years. Starting in 1977 with the discovery of the minor planet 2060 Chiron, numerous icy objects similar to Pluto with eccentric orbits were found.^[16] The most notable of these was the scattered disc object Eris, discovered in 2005, which is 27% more massive than Pluto. The understanding that Pluto is only one of several large icy bodies in the outer Solar System prompted the International Astronomical Union (IAU) to define formally in 2006 what it means to be a "planet". This definition excluded Pluto and reclassified it as a member of the new "dwarf planet" category (and specifically as a plutoid).^[18] Astronomers who oppose this decision hold that Pluto should have remained classified as a planet, and that other dwarf planets and even moons should be added to the roster of planets along with Pluto.

Pluto has five known moons: Charon (the largest, with a diameter just over half that of Pluto), Nix, Hydra, Kerberos, and Styx. Pluto and Charon are sometimes described as a binary system because the barycenter of their orbits does not lie within either body.^[23] The IAU has yet to formalise a definition for binary dwarf planets, and Charon is officially classified as a moon of Pluto.^[24]

On July 14, 2015, the Pluto system is due to be visited by spacecraft for the first time. The New Horizons probe will perform a flyby during which it will attempt to take detailed measurements and images of the plutoid and its moons.

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Why Our Standard Candle Isn’t Really Standard

When a runaway thermonuclear explosion rips through a white dwarf star and blows the star to bits, it’s called a type 1a supernova. These explosions are incredibly violent and incredibly bright, sometimes outshining entire galaxies. Thought to occur about once every two centuries in a galaxy like the Milky Way, these stellar cataclysms are relatively frequent events.

The star doing the exploding is a white dwarf with a fairly standard mass, so the supernova’s brightness is predictable. And because luminosity decreases with distance, scientists can use the difference between an explosion’s observed and predicted brightness to determine how far away the blazing starstuff is. That characteristic has led to type 1a supernovae being called “cosmic mile markers” and “standard candles.”

There’s controversial evidence for the presence of an ex-companion star in Tycho’s supernova remnant. The explosion happened in 1572. (NASA/CXC/Chinese Academy of Sciences/F. Lu)

In the late 1990s, distance measurements based on type 1a supernovae revealed that the expanding universe is accelerating. In other words, it’s flying apart more quickly now than it was billions of years ago. Scientists still don’t know exactly what’s going on, but they attribute the phenomenon to an enigmatic thing called dark energy. The discovery represented a fundamental shift in cosmology and earned the Nobel Prize in physics in 2011.

But here’s the thing: Despite their crucial cosmological importance, type 1a supernovae are still very much a mystery. As astronomers study more and more of them, it’s becoming increasingly clear just how non-standard these explosions actually are – and how little we really know about them.

“They’re standardizable candles, not standard candles,” astrophysicist Brad Tucker told me a bit ago, while I was working on a feature describing type 1a supernovae for the Proceedings of the National Academy of Sciences. Tucker splits his time between UC Berkeley and the Australian National University.

“These are very powerful tools in cosmology,” he said. “But we really don’t know what’s going on with them.”

It’s true. The uncertainties swirling around these fascinating explosions are kind of astonishing. Here are a few.

1. Until now, there was no proof that white dwarfs were doing the exploding.

For starters, we didn’t have solid observational evidence pointing to white dwarfs as the culprits behind type 1a supernovae until earlier this year, as reported yesterday in the journal Nature. Decades of solid theoretical work (and circumstantial evidence) suggested as much, but the observations weren’t there to back it up.

But in January, a star exploded in the Cigar Galaxy. Essentially next door at only 11.5 million light-years away, it was the closest type 1a supernova to Earth in four centuries. Chemical signatures in the billowing debris cloud revealed that supernova 2014J, as it’s called, is a type 1a supernova. Because the explosion was so nearby, astronomers were able to detect gamma-rays coming from the debris, a type of radiation that hasn’t been observable in other type 1a supernovae.

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The Monkey Head Nebula Is a Glittering Stellar Nursery

Peer closely at this photo and in the background, you’ll see galaxies the size of stars, and stars the size of huge version here]. But in the foreground is the Monkey Head Nebula (NGC 2174), captured in the infrared by the Hubble space telescope. It’s a region of wispy, turbulent gas and dust clouds — chaos enveloping a twinkling stellar nursery. This beautiful patch of starry sky is in the constellation Orion, about 6,500 light-years away. The nebula gets its name from the shape it takes when viewed in wide-field. This image doesn’t really give you the full primate-in-the-sky experience, so I’ve used that as an excuse to paste in a set of photos below. Sit back and stare, click to enlarge. 

galaxies

The Monkey Head' Nebula (Youtube)

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Mission to Pluto Is Like a Next-Gen Voyager

Yesterday, a cosmic coincidence brought together two spacecraft. One, a veteran cosmic explorer, is hurtling

ever outward toward the hinterlands of the solar system. The curtain is still waiting to rise on the other, a relative youngster that will soon be stepping into the spotlight.

On August 25, the Pluto-destined New Horizons spacecraft crossed Neptune’s orbit — 25 years to the day after its elder sibling, Voyager 2, swooped in for a close look at the big, blue ice giant and its curious, geyser-spewing moon.

That cosmic collusion of events helps mark the passing of a torch from one generation of space explorers to another, scientists said during a press conference commemorating the occasion.

A quarter-century ago, Voyager 2 beamed the first good images of Neptune back to Earthly eyes. Now, of course, Neptune isn’t anywhere near where it was then. But that didn’t stop New Horizons from snapping a quick photo as it zoomed over Neptune’s invisible footsteps. From 4 billion kilometers away, the giant planet and its weird moon Triton appear as nothing more than a few tiny pixels, a bit brighter than the inky black background.

For many, exploring the Pluto system will be the modern equivalent of the Voyager mission, says New Horizons principal investigator Alan Stern.

“This is the first opportunity in a generation to really explore a new planetary system for the first time,” he said. “When I was growing up, we had the privilege of seeing the first orbiter at Mars, and the first landers. And then, the first missions to Jupiter, to Saturn and Uranus and Neptune. And they were enthralling. And they were mind-blowing in terms of the richness of nature. But there hasn’t been anything like this yet in a long time.”

I think it’s safe to say that the spotlight will be firmly fixed on New Horizons when it pulls up next to Pluto in July 2015 and sends those first detailed images of the dwarf planet back to Earth. It’ll be like sending a long-awaited interplanetary postcard to millions of people at once.

Pluto is the most farflung system we will have explored. That enormous distance means we know relatively little about the tiny planet, which is faint and hard to see, even for the most powerful telescopes. “Even with all of our modern technology, everything we know about the Pluto system today would probably fit on one piece of paper,” Stern said, gesturing to a regular old piece of paper.

The same could probably be said for several of the giant planets in the 1980s. Putting the issues of politics and funding aside, these are stories of discovery on the grandest scale, of visiting new worlds and revealing new vistas.

Erupting Ice

Take Neptune, for example. Until Voyager arrived in 1989, the planet was a small blue smear in the sky. But Voyager saw much more than that. Fragments of rings gracefully hugged the space near the planet’s equator. A storm the size of Earth left a large, dark blue blotch on the cerulean surface (the Great Dark Spot had disappeared by the time Hubble aimed its eye at Neptune five years later). Methane clouds high in Neptune’s atmosphere hovered in relief above the otherwise smooth, gassy world. “The planet also had the highest speed winds of any that we had seen in the solar system — over 1,000 milers per hour,” says Voyager project scientist Ed Stone. “We were surprised to find such an active atmosphere so far from the sun.”

High altitude clouds streak Neptune’s atmosphere. (NASA/JPL)

And then there was Neptune’s strange little moon, Triton. Before Voyager arrived, teams had no idea what they would find. Unlike some of the other outer planet moons, Triton was not formed in the same neighborhood as Neptune. Instead, it grew up far, far away, in a region known as the Kuiper Belt. That distant band of rocky objects is home to the likes of Pluto and its dwarfy brethren.

“Triton was captured by Neptune and probably had geologic activity early in its history. But we had no idea, really, what it was going to look like,” Stone says. “There were many surprises ahead for us.”

The flyby revealed an active world with strange surface features (dubbed “cantaloupe terrain”), fractures, icy lava and geysers strewing dark material across the moon’s bright polar cap. “Even at the most remote edges, we have an active, alive surface on this cold little moon,” Stone says.

Now, a new animation using re-processed images from Voyager recreates that early flyby.

Voyager 2 Encounter with Triton(Youtube)

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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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The magic black Hole (Video)

See the black hole on video... it's magic and danger dream

Let' see the video tougether

From Youtube

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