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- What, exactly, is a Calabi-Yau manifold?
- Why women live longer?
- Higgs Boson- the God particle.
- Asteroid Threat in 2040???
- All about Curveball
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String theory describes one of the smallest things you can possibly imagine — six-dimensional geometric spaces that may be more than a trillion times smaller than an electron — that could be one of the defining features of our universe. The story of these spaces, can be explained by what physicists call “Calabi-Yau manifolds,”
Superstring theory is a unified theory for all the forces of nature including quantum gravity. In superstring theory, the fundamental building block is an extended object, namely a string, whose vibrations would give rise to the particles encountered in nature. The constraints for the consistency of such a theory are extremely stringent. They require in particular that the theory takes place in a 10-dimensional space-time. To make contact with our 4-dimensional world, it is expected that the 10-dimensional space-time of string theory is locally the product M 4 ×X of a 4-dimensional Minkowski space M 3,1 with a 6-dimensional space X . The 6-dimensional space X would be tiny, which would explain why it has not been detected so far at the existing experimental energy levels. Each choice of the internal space X leads to a different effective theory on the 4-dimensional Minkowski space M 3,1 , which should be the theory describing our world.
It has long been argued that, in order to solve certain classic problems of unified gauge theories such as the gauge hierarchy problem, the 4-dimensional effective theory should admit an N=1 supersymmetry. In a fundamental paper, Candelas, Horowitz, Strominger and Witten (1985) analyzed what the constraint of that N=1 supersymmetry would mean for the geometry of the internal space X . They found that, for the most basic product models with N=1 supersymmetry, the space X must be a Calabi-Yau manifold of complex dimension 3. Shortly afterwards, Strominger (1986) considered slightly more general models, allowing warped products. For these models, the N=1 supersymmetry constraint results in a modification of the Ricci-flat equation of the earlier model.
The answer to the mystery of why women tend to live longer than men was found in the mitochondrial DNA studies of fruit flies.
Mitochondria are inherited only from mothers, never from fathers, so there is no way to weed out mutations that damage a male's prospects.
But one ageing expert said there were many factors that explained the gender difference in life expectancy.
It is not only in human, females outlive males in many other species.
Mitochondria, which exist in almost all animal cells, convert food into the energy that powers the body.
Group of scientists from Monash University found numerous mutations within mitochondrial DNA that affect how long males live, and the speed at which they age. Mitochondrial mutations they uncovered will generally cause faster male ageing across the animal kingdom.
They suggested this is because there is no evolutionary reason for the faults that affect males to be picked up - because mitochondria are passed down by females.
Lot of news is pouring about Higgs Boson- the God particle after European Center for Nuclear Research says its teams have discovered a new particle that is consistent with the Higgs boson -- a subatomic particle considered so significant to the understanding of the universe that it has been called the God particle.
So what's the Higgs boson?
The Higgs particle, and its associated field, were hypothesized back in the 1960s by British physicist Peter Higgs and others to fill a weird gap in the Standard Model, one of physics' most successful theories. The model as it stood had no mechanism to explain why some particles are massless (such as the photon, which is the quantum bit for light and other types of electromagnetic radiation), while other particles have varying degrees of mass (such as the W and Z bosons, which play a part in the weak nuclear force). By rights, all particles should be without mass and zipping around freely.
They suggested that all particles had no mass just after the Big Bang. As the Universe cooled and the temperature fell below a critical value, an invisible force field called the ‘Higgs field’ was formed together with the associated ‘Higgs boson’. The field prevails throughout the cosmos: any particles that interact with it are given a mass via the Higgs boson. The more they interact, the heavier they become, whereas particles that never interact are left with no mass at all.
This idea provided a satisfactory solution and fitted well with established theories and phenomena. The problem is that no one has ever observed the Higgs boson in an experiment to confirm the theory. Finding this particle would give an insight into why particles have certain mass, and help to develop subsequent physics. The technical problem is that we do not know the mass of the Higgs boson itself, which makes it more difficult to identify. Physicists have to look for it by systematically searching a range of mass within which it is predicted to exist. The yet unexplored range is accessible using the Large Hadron Collider, which will determine the existence of the Higgs boson. If it turns out that we cannot find it, this will leave the field wide open for physicists to develop a completely new theory to explain the origin of particle mass.
The international effort to find it has used tremendous amounts of energy to crash subatomic particles into one another in giant underground tracks, where they are steered by magnetic fields. Several different experiments have been done by independent teams to ensure accuracy.
It is believed that Fermilab's atom smasher, called the Tevatron, must have produced thousands of Higgs particles over its life before it was shut down last year after it was overshadowed by CERN's more powerful Large Hadron Collider.
Two independent teams at CERN, the physics lab in the Alps on the French-Swiss border, have now said that they have "observed" the new boson, or subatomic particle. The CERN teams did not outright say that they have discovered the Higgs boson itself, which has been the focus of a 40-plus year pursuit.
There is an asteroid called 2011 AG5, and if it follows the orbit scientists have plotted for it so far, there is a small, small chance that it could hit Earth in February 2040. Astronomers, who have been tracking the asteroid since January 2011, say it is in an elliptical orbit that could bring it somewhere near Earth in 2040. Earth is about 8,000 miles in diameter; the asteroid appears to be about 450 feet across.
The problem is that having watched it for only about half an orbit around the Sun, the scientists cannot say for certain where it will be 28 years from now. So, for the moment, NASA's Near Earth Object Program says the odds are about one in 625 that it could hit us in that still-distant future.
Scientists have discussed all sorts of far-out plans in case a future asteroid truly does turn out to be coming our way. If they have enough lead time, they might send a probe with thruster rockets, or even explosives, to nudge an asteroid into a slightly different orbit. A very small course change, years in advance, could make a big difference by 2040, they say. Even if the asteroid misses Earth by less than a hundred miles, its passing will be a non-event.
There are asteroids wandering around the inner solar system all the time -- one of them, called 2005 YU55, passed within 201,000 miles of Earth in November, closer than the moon is to us.
But about half a dozen times since the planet formed, there have been major for-real impacts with catastrophic results. The last, 65 million years ago, is believed to have killed off the last of the dinosaurs with the dust and ash that darkened the skies after it hit, though there have been scientists who disagree.
Scientists estimate that the asteroid from back then was about nine miles across at its widest, far larger than 2011 AG5. And they point out that they know very little about 2011 AG5; they cannot say whether it is a solid hunk of rock or a loose jumble of debris flying together in space. All they know is that it's in a long, elliptical orbit that takes it almost twice as far from the sun as we are.
is a type of pitch in baseball thrown with a characteristic grip and hand movement that imparts forward spin to the ball causing it to dive in a downward path as it approaches the plate.
Generally the Magnus effect describes the laws of physics that make a curveball
curve. A fastball travels through the air with backspin, which creates a higher pressure zone in the air ahead of and under the baseball. The baseball's raised seams augment the ball's ability to churn the air and create higher pressure zones. The effect of gravity is partially counteracted as the ball rides on and into energized air. Thus the fastball falls less than a ball thrown without spin (neglecting knuckleball effects) during the 60 feet 6 inches it travels to home plate.
The Magnus effect
is the phenomenon whereby a spinning object flying in a fluid creates a whirlpool of fluid around itself, and experiences a force perpendicular to the line of motion. The overall behaviour is similar to that around an airfoil (see lift force) with a circulation which is generated by the mechanical rotation, rather than by aerofoil action.
In many ball sports, the Magnus effect
is responsible for the curved motion of a spinning ball. The effect also affects spinning missiles, and is used in rotor ships and Flettner aeroplanes.
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