Posts Tagged ‘theory’

Mystery Mystery Mystery

Pooja asked

Any theory on what is the cause of the ‘taos hum’?It is a low-pitched sound heard in many parts of the world.until now the scientists haven’t been able to unravel the mystery.
  Also another mystery that has been nagging me is the unexplained lighting of the ‘magarajyothi’ at Sabarimala.How does that happen at the same time,same day for the past decades?

(Expect a response soon – Not the ANSWER)

Cosmological Constant and its Significance

Abdul Najeeb asked via Facebook:

Would you plz explain me what is a cosmological constant? When Einstein snubbed it as the "biggest blunder" in his life, what else is the real importance of the constant? Also what is cosmological acceleration and its’ effect on the constant…plz…but in simple words…plzzzz:)))))

Ans:

The cosmological constant was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe.

Einstein abandoned the concept after the observation of the Hubble redshift indicated that the universe might not be stationary, as he had based his theory on the idea that the universe is unchanging.However, the discovery of cosmic acceleration in the 1990s has renewed interest in a cosmological constant.

{courtesy : Wikipedia}

More details will be added soon

M – Theory, String Theory and more

Nijisha’s Question: There are various forces we see in nature, and among them, gravitational force is the weakest. If we think about it ,the entire earth is pulling on us and yet we can manage to pick thinks up. I’ve heard somewhere that we can explain this weakness of gravitational force with the help of extra dimensions ( Something related to M theory? ). Can you explain this theory ?

Ans:

It’s a little bit difficult to discuss in detail the M theory in detail as such at School level. However, I’ll try to give a brief idea about it.

M-theory is an extension of string theory in which 11 dimensions are identified. This is a theory currently in development

To quote from Wikipedia:

“In the 1980s, a new mathematical model of theoretical physics called string theory emerged. It showed how all the particles, and all of the forms of energy in the universe, could be constructed by hypothetical one-dimensional “strings,” infinitely small building-blocks that have only the dimension of length, but not height or width. Further, string theory suggested that the universe is made up of multiple dimensions. We are familiar with height, width, and length as three dimensional space, and time gives a total of four observable dimensions. However, string theories initially supported the possibility of ten dimensions—the remaining 6 of which we can’t detect directly. This was later increased to 11 dimensions based on various interpretations of the ten dimensional theory”

In M-theory may stand for membrane. (Some claim M for mother, matrix,mystery etc)

M-Theory brought all of the string theories together. It did this by asserting that strings are really 1-dimensional slices of a 2-dimensional membrane vibrating in 11-dimensional space.

Though M – Theory is developed mathematically, it is not proved physically. Scientists and Mathematicians take M-Theory as the only theory developed so far which can explain all the aspects of Universe (or multiverse) as a whole. But, I am sure, new theories will come and take over as we develop our understanding further.

Stephen Hawking’s New work The Grand Design talks about the Multiverse and the God’s intervention in the creation of Universe (which he says not necessary)

Ref:

•   http://www.damtp.cam.ac.uk/research/gr/public/qg_home.html
• wikipedia

(I fear that I’ve brought more unknowns in explaining the one unknown. However, it will be good if the discussion goes on.)

Particle theory of light and refraction

According to particle theory of light if a light ray bends toward the normal while entering from medium 1 to medium 2 then how the velocity of light in medium 2 is greater than the velocity of light in medium 1 ?

Answer:

When a medium enters a denser medium from a rarer medium, it bends towards the normal. This is the observation we have in hand and this phenomenon is called refraction.

Sir Isaac Newton tried to explain the phenomenon of refraction using his particle theory. He said that the particles of the denser medium attracts the particles with stronger force towards it which makes it bend towards the normal.

If there is such a force of attraction, then the speed of light would increase inside a denser medium. When the velocity of light in different media was determined by Foucault and other scientists, it was found that the velocity of light in denser medium is less than that in a rarer medium. So, Newton’s explanation of refraction was proved wrong.