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Friday, October 24, 2014

Half of Earth's water formed before the sun was born

Ice that formed in the interstellar cloud that gave birth to the sun survived that process to fill our oceans.
BILL SAXTON/NSF/AUI/NRAO
Ice that formed in the interstellar cloud that gave birth to the sun survived that process to fill our oceans.

Half of Earth's water formed before the sun was born

Daniel is a deputy news editor forScience.
Good news for hunters of extraterrestrial life: Water may be more widespread in planetary systems than previously thought. A team of researchers studying the origin of the water in our solar system has concluded that up to half of it formed before the sun itself was born—that is, in the cloud of dust and gas that was the progenitor of our solar system. If water can form in abundance in such clouds, then it may be found everywhere.

Our solar system is awash with water. Apart from Earth, water is found on the moon, Mars, Mercury, comets, and the icy moons of the giant planets. But where did it come from? Water is known to form in the clouds of gas and dust of the interstellar medium (ISM) from which planetary systems coalesce, but is it destroyed when the newly formed sun starts pumping out heat and light, only to be formed again later? Or does that primordial water survive star formation and remain around us today?


To answer that question, a team led by astronomer L. Ilsedore Cleeves of the University of Michigan, Ann Arbor, focused on deuterium, a heavy form of hydrogen that was created in the big bang along with normal hydrogen. There are about 26 deuterium atoms for every million hydrogen atoms across the universe, but it is six times as prevalent in the water on Earth and in other solar system bodies. Scientists conclude that when the water formed, the reaction creating deuterium-rich “heavy water” was slightly faster than the one creating normal water, so the proportion of deuterium in water increased.

But that enrichment of deuterium happens only under certain conditions: It has to be very cold (only a few tens of degrees above absolute zero), plus you need oxygen and some sort of ionizing radiation to get the reaction going. All of those things are available in the ISM. The ionizing radiation there is cosmic rays, particles from distant sources that zip through space at high speed. And astronomers have observed water in the ISM that is highly enriched in deuterium, so that could be source of the solar system’s water.

Still, there’s a question mark over whether this interstellar water could survive the violence of the sun’s birth. To find out, Cleeves and her colleagues sought to determine whether the same water-forming reactions could have occurred after the sun’s formation, in the protoplanetary disk of gas and dust from which planets form. Such a disk would offer low temperatures and an oxygen supply just as the ISM does, but would there be enough ionizing radiation?

The team constructed a detailed model of the chemical processes creating water in a protoplanetary disk. Much of the cosmic rays are fended off by the young star’s magnetic field and particles streaming out from the star, but there are other sources of radiation: x-rays from the star and short-lived radionuclides in the disk. As the researchers report online today in Sciencethose sources of radiation just don’t produce heavy water fast enough. “We found that heavy water didn’t form in any abundance over a million years,” Cleeves says.

In fact, the team estimates that as much as 50% of the water now on Earth may have existed since before the birth of the sun 4.5 billion years ago. And that’s good news for other planetary systems. The conditions in the ISM are far more uniform across space than those in protoplanetary disks, so it’s likely that there is water everywhere waiting for planets to form. “As the number of confirmed planetary systems increases, it’s reassuring that … water is available,” Cleeves says.

“This is a very interesting result. We’ve been debating this for years, whether or not the ices have an interstellar heritage,” says astrophysicist Karen Willacy of NASA’s Jet Propulsion Laboratory in Pasadena, California. She says that other groups have tried to model the collapse of clouds in the ISM into planetary systems to see if ice would survive, but “with various results, that don’t always agree,” Willacy says. “This is much more simple approach, just using the chemistry which is well understood.”


Posted in EarthPhysicsSpace

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How to Digitally Record/Video a UFO sighting:


Como registar digitalmente ou gravar um vídeo de um avistamento de um UFO:




Stabilize the camera on a tripod. If there is no tripod, then set it on top of a stable, flat surface. If that is not possible lean against a wall to stabilize your body and prevent the camera from filming in a shaky, unsteady manner.

Estabilize a camera com um tripé. Se não tiver um tripé, então coloque-a em cima de uma superfície estável. Se não for possível, então encoste-se a uma parede para estabilizar o corpo e evitar que a camera registe de maneira tremida e instável.

Provide visual reference points for comparison. This includes the horizon, treetops, lampposts, houses, and geographical landmarks (i.e., Horsetooth Reservoir, Mt. Adams, etc.) Provide this in the video whenever is appropriate and doesn’t detract from what your focus is, the UFO.

Forneça pontos visuais de referência para comparação. Isso inclui o horizonte, cimo das árvores, postes de iluminação, pontos de referência geográficos (como o Reservatório de Horsetooth, Mone Adams, etc) Forneça esses pontos no vídeo sempre que for apropriado e não se distraia do que é o seu foco, o UFO/a Nave.

Narrate your videotape. Provide details of the date, time, location, and direction (N,S,E,W) you are looking in. Provide your observations on the weather, including approximate temperature, windspeed, any visible cloud cover or noticeable weather anomalies or events. Narrate on the shape, size, color, movements, approximate altitude of the UFO, etc and what it appears to be doing. Also include any unusual physical, psychological or emotional sensations you might have. Narrate any visual reference points on camera so they correlate with what the viewer will see, and thereby will be better able to understand.

Faça a narração do vídeo. Forneça pormenores sobre a data, hora, local e direcção (Norte, Sul, Este, Oeste) que está a observar. Faça observações sobre as condições atmosféricas, incluindo a temperatura aproximada, velocidade do vento, quantidade de nuvens, anomalias ou acontecimentos meteorológicos evidentes. Descreva a forma, o tamanho, a cor, os movimentos, a altitude aproximada onde se encontra o UFO/nave, etc e o que aparenta estar a fazer. Inclua também quaisquer aspectos pouco habituais de sensações físicas, psicológicas ou emocionais que possa ter. Faça a narração de todos os pontos de referência visual que o espectador irá ver e que, deste modo, será capaz de compreender melhor.

Be persistent and consistent. Return to the scene to videotape and record at this same location. If you have been successful once, the UFO sightings may be occurring in this region regularly, perhaps for specific reasons unknown, and you may be successful again. You may also wish to return to the same location at a different time of day (daylight hours) for better orientation and reference. Film just a minute or two under “normal” circumstances for comparison. Write down what you remember immediately after. As soon as you are done recording the experience/event, immediately write down your impressions, memories, thoughts, emotions, etc. so it is on the record in writing. If there were other witnesses, have them independently record their own impressions, thoughts, etc. Include in this exercise any drawings, sketches, or diagrams. Make sure you date and sign your documentation.

Seja persistente e não contraditório. Volte ao local da cena e registe o mesmo local. Se foi bem sucedido uma vez, pode ser que nessa região ocorram avistamentos de UFOs/naves com regularidade, talvez por razões específicas desconhecidas, e talvez possa ser novamente bem sucedido. Pode também desejar voltar ao mesmo lugar a horas diferentes do dia (durante as horas de luz)para ter uma orientação e referência melhor. Filme apenas um ,inuto ou dois em circunstâncias “normais” para ter um termo de comparação. Escreva tudo o que viu imediatamente após o acontecimento. Logo após ter feito o registo da experiência/acontecimento, escreva imediatamente as impressões, memórias, pensamentos, emoções, etc para que fiquem registadas por escrito. Se houver outras testemunhas, peça-lhes para registar independentemente as suas próprias impressões, pensamentos, etc. Inclua quaisquer desenhos, esbolos, diagramas. Certifique-se que data e assina o seu documento/testemunho.

Always be prepared. Have a digital camera or better yet a video camera with you, charged and ready to go, at all times. Make sure you know how to use your camera (and your cell phone video/photo camera) quickly and properly. These events can occur suddenly, unexpectedly, and often quite randomly, so you will need to be prepared.

Esteja sempre preparado, Tenha sempre uma camera digital, melhor ainda, uma camera vídeo consigo, carregada e pronta a usar sempre que necessário. Certifique-se que sabe como lidar com a sua camera (ou com o seu celular/camera fotográfica) rápida e adequadamente. Esses acontecimentos podem acontecer súbita e inesperadamente e, por vezes, acidentalmente, por isso, necessita estar preparado.

Look up. Be prepared. Report. Share.

Olhe para cima, Esteja preparado, Relate, Partilhe.

MUFON.COM

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