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     Volume 2 Issue 103 | January 25, 2009|


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Science Feature

Gravity. Is it really a pulling force?
János Rohán

WHAT is the evidence that gravity is a pulling force? Nothing. Nothing at all. (I'm asking experimental or any other STRONG evidence which prove the pulling nature of Gravity.) Did you know a better evidence?

An apple falls to the ground. Therefore, it is stated, the Earth pulls - Sir Isac Newton: The Universal law of Gravitation. And with that the evidence is exhausted.

However, the apple will likewise fall if the force does not pull it down, but pushes it down. To satisfy this latter condition, we need the assumption that space is not empty, but is filled with gravity. This does not seem such a fantastic idea today if we remember that cosmologists recently presumed that the Universe is filled with dark energy.

It is obvious that the Universe is filled with electromagnetic radiation, and the (vacuum) space is assumed to be filled with Higgs bosons. Bosons are particles which form totally-symmetric composite quantum states. The spin-statistics theorem states that bosons have integer spin. Bosons are the only particles which can occupy the same state as one another. All elementary particles are either bosons or fermions.

Gauge bosons are elementary particles which act as the carriers of the fundamental forces: photons (probably NOT an elementary particle, mediates the electromagnetic force), gluons (mediates the strong nuclear force), W-and Z bosons (mediates the weak nuclear force). Numerous problems of cosmologists would be solved if gravity were not regarded as a pulling force. The idea of pushing gravity is not a recent one: it reaches back as far as Georges-Louis Le Sage (1724-1803). If gravity is a pushing force, mass will not emit, but absorb gravitational waves.

1. Let us consider the recently discovered accelerating movement of distant galaxies. With pulling gravity, this seems impossible to explain, but if we consider gravity as a property of space, which would like to compress everything, the accelerating movement become logical as this compressing force would remain unresisted at the edge of the Universe: no pushing force acts from outside, so the pushing force of the Universe will accelerate the most outlying galaxies. No assumption of any antigravitational effect is necessary.

2. The problem of singularity, which arises only with the pulling gravity model, will also be avoidable. Let us consider the Earth, for example. As an object moves closer to the Earth, the gravitational force becomes higher. This is true as long as the Earth is regarded as a point. However, the Earth is not a point. In theory, the object can pass below the surface, towards the centre of the Earth. The cause of the gravitational force is not a single point, but the whole mass of the Earth, which at the centre is in equilibrium, so no gravitational force is acting at the centre of the Earth.

According to the pulling gravity model, the density at the centre of a black hole would become infinite and the mathematical consequence would be singularity. It appears more logical, therefore, that the pulling force does not become infinite by large as we go toward the centre of a black hole, but, on the contrary, decreases. Moreover, with the pushing gravity model, there is no need for the singularity concept, because the pressure at the centre of a black hole depends on the nearly constant gravitational field of the Universe, so gravity does not increase infinitely.

3. With the pushing gravity model, the mystery would be solved of why no matter or radiation can leave the event horizon of a black hole, but all kinds of matter can still be pulled in. How can any force come out if nothing can come out? This problem would not arise with the pushing gravity model, because gravity then streams inwards, and the force is also directed inwards.

4. It could similarly solve the mystery of why the larger planets emit considerably more heat than they receive from the Sun. The surplus energy emitted should be generated by the planets themselves, but radioactivity or heating by tidal forces do not seem to offer sufficient explanation of the excess heat radiation. It appears simpler to conceive that the planets probably gain their surplus energy by the absorption of gravitational radiation.

Source: Internet (Slightly abridged)

The B Membrane PC

Conceived by Korean designer Won-Seok-Lee, the 'B-membrane' is one of the most interesting PC prototypes to have come out.

The B-membrane looks nothing like a conventional computer, more like a spaceship or space station, but it is indeed a PC, able to project an image of your desktop on any surface you can point its omni-directional projector at, thus rendering even the slimmest LCD monitor useless. It also has a membrane keyboard and mouse that appear only when you need them too, and an optical drive.

The B-membrane isn't useless even when it is shut-down; its smart projector turns it into an ambient light-effects system to spice up the look of your place.

Source: Internet

Sign-Language Translator

The first sign-language dictionary that's searchable by gesture.

Bilingual dictionaries are usually a two-way street: you can look up a word in English and find, say, its Spanish equivalent, but you can also do the reverse. Sign-language dictionaries, however, translate only from written words to gestures. This can be hugely frustrating, particularly for parents of deaf children who want to understand unfamiliar gestures, or deaf people who want to interact online using their primary language. So Boston University (BU) researchers are developing a searchable dictionary for sign language, in which any user can enter a gesture into a dictionary's search engine from her own laptop by signing in front of a built-in camera.

"You might have a collection of sign language in YouTube, and now to search, you have to search in English," says Stan Sclaroff, a professor of computer science at BU. It's the equivalent, Sclaroff says, of searching for Spanish text using English translations. "It's unnatural," he says, "and it's not fair."

Sclaroff is developing the dictionary in collaboration with Carol Neidle, a professor of linguistics at BU, and Vassilis Athitsos, assistant professor of computer science and engineering at the University of Texas at Arlington. Once the user performs a gesture, the dictionary will analyze it and pull up the top five possible matches and meanings.

"Today's sign-language recognition is about the stage where speech recognition was 20 years ago," says Thad Starner, head of the Contextual Computing Group at the Georgia Institute of Technology. Starner's group has been developing sign-language recognition software for children, using sensor-laden gloves to track hand movements.

Source: MIT Website

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