Time travel

Popular television shows such as "Doctor Who" have brought the idea of time travel into the vernacular of popular culture. But problem of time travel is even more complicated than one might think. LSU's Mark Wilde has shown that it would theoretically be possible for time travelers to copy quantum data from the past.

It all started when David Deutsch, a pioneer of quantum computing and a physicist at Oxford, came up with a simplified model of time travel to deal with the paradoxes that would occur if one could travel back in time. For example, would it be possible to travel back in time to kill one's grandfather? In the Grandfather paradox, a time traveler faces the problem that if he kills his grandfather back in time, then he himself is never born, and consequently is unable to travel through time to kill his grandfather, and so on. Some theorists have used this paradox to argue that it is actually impossible to change the past.

"The question is, how would you have existed in the first place to go back in time and kill your grandfather?" said Mark Wilde. Deutsch solved the Grandfather paradox originally using a slight change to quantum theory, proposing that you could change the past as long as you did so in a self-consistent manner.

"Meaning that, if you kill your grandfather, you do it with only probability one-half," Wilde said. "Then, he's dead with probability one-half, and you are not born with probability one-half, but the opposite is a fair chance. You could have existed with probability one-half to go back and kill your grandfather."

But the Grandfather paradox is not the only complication with time travel. Another problem is the no-cloning theorem, or the no "subatomic Xerox-machine" theorem, known since 1982. This theorem, which is related to the fact that one cannot copy quantum data at will, is a consequence of Heisenberg's famous Uncertainty Principle, by which one can measure either the position of a particle or its momentum, but not both with unlimited accuracy. 

The acidity in the oceans increases nervousness of fishes. - Eric Bravo

Looking for interesting news about science I found a very interesting and worrying new about the sea and the impact that our activites make on the animals that live in it.
Some researchers found that the acidity of the sea, incresed by our chemical productes, our factories, ships and the fishing industry, affect fishes in the way that it increases they nervousness.
For their study, the researchers created a laboratory with an area with light acidic water and one with acid water. A fish that was not exposed to large amounts of acidity in the water, was just swimming normaly. However, with a higher acidification of the water, the fish went crazy and starts going back and forth very quickly, something common that fish do when they feel nervous.

Then they, put the two fishtanks together and they saw that the fishes rarely pass to the acid side.

This, they said, can have serious consequences because it would mean that if some parts of the ocean get acid, fishes will not be able to go there to find food anymore. According to the study , a week passed after they changed type less water acidification. The good news is that this harmful effect seems to be reversible : after 12 days the fishes get better, and none of them was nervous anymore.

This study adds to previous research that had shown that ocean acidification included behavioral and sensory changes , including loss of smell.

Chinese scientists are trying to develop the first invisibility cloak

One of the most recent and relevant news is that some chinese scientists in Pekín are trying to develop "the first invisibility cloak" in the world, trough the technology to prevent the visibility of objects.
The newspaper said that the Chinese government has contributed money to work of about 40 teams of research during the past three years, to develop this idea, for the moment limited only in science-fiction.
Among the ways that scientists explore to achieve invisibility it's developing materials that divert the light from the object you want to hide, by creating electromagnetic fields, and the development of materials of caouflage of high technology.

FROM SPACE TO YOUTUBE

"It started with the questions that made us our families" post-Apolo astronaut Chris Hadfield.

The most famous post-apolo astronaut, Chris Hadfield, that became famous thanks to upload  some videos on famous web "Youtube".
In some videos, Chris, ask to their viewers to send him questions and all sorts of things they would like to do in the ISS to upload to next video. The videos were made famous around the world, they collected thousands and even millions of views in a few days.
Now a days on earth, Chris, after leave the Canadian Space Agency has published his new book, An Astronaut’s Guide to Life on Earth, that includes all he learnt in the agency and some experiments that he did in the ISS.

To read the new and a little interview.

Fractals

Hello everybody! Now, I'll explain a bit of the fractals.

Fractals are typically self-similar patterns, which means that it's seen the same from near as from far. Fractals may be exactly the same at every scale, or they may be nearly the same at different scales.

Using this, there's an interesting aplication of fractals that may surprise you. Upon measuring Great Britain's coast, one may assume it measures 18000 km long, but if one measures it more precisely, it measures nearly as twice as long.


Also, the image of the snowflake shows that with every division the lenght of the perimeter increases by 4/3 each time, so the last frame of the GIF is (4/3)^6 times longer, or a bit more than five times and a half (5,61865569...).

Wednesday 4th of December

On Wednesday December 4, in science of contemporary world, we saw a video of powers of ten, from 24 to -15 power of ten, and a sheet of paper, you should write see the different powers of ten.The video was in English, so that was hard to understand what it said, in the video you could see the DNA, neutrons, electrons and protons, atoms, the more galaxies properly than our, the orbits of planets in the solar system and more. But now we have a task and we have to fill a table we see the video to homeworks.

Are found Two black hole Intertwined in a cosmic dance

-A group of astronomers has discovered what appear to be two supermassive black holes at the center of a remote galaxy , at 3,800 million light- Earth rotating together like dance partners years.

At first moment, scientists thought that the strange structure was forming new stars at a frantic pace , but after inspecting it further, they realized that the phenomenon " is more like a fusion of giant black holes '.

The " dance " of these two black holes begins slowly spinning objects with each other at a distance of a few thousand light years. Few black holes have been identified at this early stage of fusion. As they continue circling around each other , are close , separated only by a few light years .

In the final step in the merger of black holes , gravitational waves they send through space and time. Researchers are actively seeking these waves using dead stars called pulsars hoping to better understand how the dancers black holes.

URL: http://www.abc.es/ciencia/20131206/abci-hallan-agujeros-negros-entrelazados-201312051827.html