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Tuesday, March 23, 2010

March 23 - Big questions surround big-bang theory‏

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Image: Big bang graphic
Looking beyond the Big Bang
Learn more about cosmic inflation and other ideas about the universe's origin.

Big questions surround big-bang theory

What happened before the universe’s expansion? Will it happen again?

By Clara Moskowitz
updated 9:59 p.m. ET March 19, 2010

The big bang was the beginning of the universe as we know it, most scientists say. But was it the first beginning, and will it be the last?

A popular picture of the early universe imagines a single big bang, after which space blew up quickly like a giant bubble. But another theory posits that we live in a universe of 11 dimensions, where all particles are actually made of tiny vibrating strings. This could create a universe stuck in a cycle of big bangs and big crunches, due to repeat on loop.

Which scenario is closer to the truth remains to be seen, but scientists say new experiments underway could provide more answers soon.

According to big-bang theory, the universe began extremely hot and extremely dense. Around 14 billion years ago, space itself expanded and cooled down, eventually allowing atoms to form and clump together to build the stars and galaxies we see today.

On this, most scientists are agreed.

"I would say that there is 100 percent consensus, really," University of Pennsylvania particle physicist Burt Ovrut said of big-bang theory. "There is overwhelming evidence — all of the predictions are true."

For example, this theory predicted that the universe today would be filled with pervasive light left over from the big bang. This glow, called the cosmic microwave background radiation, was discovered in 1964, almost 20 years after it was forecast.

However, what caused the big bang, what happened at that exact moment, and what came immediately after it are much more open to debate.

A giant bubble
A dominant idea that connects the dots between the big bang and the universe we find today is called inflation. This is the notion that during the first roughly 10-34
seconds (0.0000000000000000000000000000000001 seconds), the universe underwent exponential expansion, doubling in size at least 90 times. During this early stage, matter was in a much different state than it is now.

This theory could explain some of the main conundrums posed by the big bang: Why does the universe appear mostly flat, with roughly the same amount of stuff spread smoothly throughout it in all directions?

"If you imagine the matter was in that different state in the early universe, the whole story changes," said Andreas Albrecht, a theoretical physicist at the University of California at Davis and one of the pioneers of inflation theory. "The physics can create the smoothness for you. Inflation also makes it flat. It all fits beautifully into this story told by inflation."

But Albrecht and others admit the theory doesn't yet explain the whole picture.

"Inflation is easily the most popular theory in cosmology," said theoretical physicist Neil Turok, director of the Perimeter Institute for Theoretical Physics in Ontario, Canada. "It's a good theory, but it has some weak points. It can't describe the moment of the big bang."

Big-bang theory envisions the universe beginning from a singularity — a mathematical concept of infinite temperature and infinite density packed into a single point of space. But scientists don't think this is what actually happened.

"It wouldn't really be infinite," explained physicist Paul Steinhardt, director of the Princeton Center for Theoretical Science at Princeton University in Princeton, N.J., and another architect of inflation theory. "Infinity just means a mathematical breakdown. It's a statement that you shouldn't have extrapolated your equations back that far because they just blew up in your face."

Neither big-bang theory nor inflationary theory can describe what happened at that moment.

And inflation has other problems, in some people's view. Because of quantum fluctuations, different parts of the universe could inflate at different rates, creating "bubble universes" that are much larger than other regions. Our universe may be just one in a multiverse, where different scales and physical laws reign.

"It means everything and anything that can happen, will," Steinhardt told "So basically everything could be a prediction of inflation. This to me is a fundamental problem and we don't know how to get away from it."

Others say that while inflation may not be complete yet, it's still the most useful thing we've got to describe the origin of the universe.

"Even if all things are possible it could turn out that some things are much more possible than others, and you could still have a prediction," Albrecht said. "The real excitement to me is that there's so much data supporting inflation that it really makes it seem worth thinking about these questions."

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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.



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