Tuesday, March 24, 2009

Science is conjointly fun when it goes ‘bang’

How many people know, Marasinghe said, that understanding Einstein's theory of relativity is what acknowledges the global positioning system to work?

The theory explains that for an object that's traveling very fast — say, a satellite traveling at 18,000 mph relative to the Earth's surface — span flows slower. Because GPS receivers triangulate their location along Earth by timing the signals from the satellites, it's critical that they adjust for tiny changes in the flow of period.

So, e=mc2 eventually led to a helpful not much gadget that says “turn left this day."

“By the time students get to high school level, in a ritual, they are programmed to think science should be hard including not something they want to follow," Marasinghe said.

They're easier to reach when they're younger, he said.

Friday, March 20, 2009

Question on a forum

Einstein's relativity theory? can somebody answer my question, I dont understand.

Why is it that if something goes really fast, it looks smaller?

Why is it that the faster you go, the more time slows down? So if I went for a jog, my clock will tick slower than if I left it?

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Tuesday, March 17, 2009

General Theory of Relativity

Posterior 1905, Einstein advanced working in full three of his works in the 1905 papers. He assembled prominent contributions to the quantum theory, while increasingly he sought to extend the special theory of relativity to phenomena involving increasing speed. The key to an elaboration emerged in 1907 with the principle of equivalence, in which gravitational speeding up was owned a priori indistinguishable from acceleration caused by mechanical forces; gravitational mass was therefore identical regardless of inertial mass. Einstein elevated this identity, which is implicit in the work of Isaac Newton, to a guiding principle in his attempts to explain both electromagnetic and gravitational quickening according to one set of physical laws. In 1907 he proposed that if mass were equivalent to energy, then the principle of equivalence required that gravitational mass would interact regardless of the apparent mass of electromagnetic radiation, which includes light. By 1911, Einstein was able to expand preliminary predictions approximately how a ray of light from a distant star, passing near the Sun, would exist to be attracted, or bent slightly, in the direction of the Sun's mass. At the same time, light radiated from the Sun would interact regardless of the Sun's mass, resulting in a slight change toward the infrared end of the Sun's optical spectrum. At this juncture Einstein moreover knew that any new theory of gravitation would benefit from to account for a small but persistent anomaly in the perihelion motion of the planet Mercury.

Friday, March 13, 2009

Theory of Relativity Passes Another Test

Einstein's theory of General Relativity has been around for 93 years, also it barely keeps hanging in there. Despite advances in technology has come the ability to put the theory under some scrutiny. Earlier, taking advantage of a unique cosmic coincidence, inclusive of a pretty darn good telescope, astronomers looked at the strong gravity from a pair of superdense neutron celebrities furthermore measured an actualize predicted by General Relativity. The theory came through regardless of flying colors.
Einstein's 1915 theory predicted that in a close system of two very massive objects, such as neutron stars, one object's gravitational tug, also an bring off of its spinning around its axis, should cause the spin axis of the other to wobble, or precess. Studies of other pulsars in binary systems had indicated that such wobbling occurred, however could not make precise measurements of the amount of wobbling.
"Measuring the amount of wobbling is what tests the details of Einstein's theory together with stocks a benchmark that any alternative gravitational theories must meet," said Scott Ransom of the National Radio Astronomy Observatory.
The astronomers applied the Country-wide Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to make a four-year study of a double-star system unlike any other known in the Universe. The system is a pair of neutron stars, both of which are seen as pulsars that emit lighthouse-like beams of radio waves.
"Of about 1700 known pulsars, this is the only case where two pulsars are in orbit around each other," said Rene Breton, a graduate student at McGill University in Montreal, Canada. As well as, the celebrities' orbital plane is aligned just about perfectly despite their line of sight to the Earth, so that one passes below a doughnut-shaped region of ionized gas surrounding the other, eclipsing the signal from the pulsar in postliminary.
Animation of double pulsar system
The eclipses allowed the astronomers to pin down the geometry of the double-pulsar system including track changes in the orientation of the spin axis of one of them. As one pulsar's spin axis slowly moved, the pattern of signal blockages as the other passed behind it along changed. The signal from the pulsar in ensuign is absorbed by the ionized gas in the other's magnetosphere.
The pair of pulsars studied despite the GBT is almost 1700 light-years from Earth. The average distance between the two is only approximately twice the distance from the Earth to the Moon. The two orbit each other in merely under two along with a half hours.
"A system like this, despite two very massive objects very close to each other, is precisely the kind of extreme 'cosmic laboratory' needed to test Einstein's prediction," said Victoria Kaspi, leader of McGill University's Pulsar Group.
Theories of gravity don't differ significantly in "ordinary" regions of space such as our own Solar System. In regions of extremely strong gravity fields, such as near a pair of close, massive objects, while, differences are expected to motion picture up. In the binary-pulsar study, General Relativity "passed the test" provided by such an extreme environment, the scientists said.
"It's not quite right to say that we take advantage of today 'proven' General Relativity," Breton said. "Yet, so far, Einstein's theory has passed total the tests that have been conducted, over and above ours."

Tuesday, March 10, 2009

Einstein's relativity theory probed

Einstein's theory of general relativity, significant to our acceptation of the cosmos, is approximately to be put to a rigorous test, using a satellite due to be launched early this week.

The NASA mission is due to be launched from Vandenberg Whiff Force Base in California in the early hours of Tuesday morning (03:01 Australian Eastern Standard Time, or 17:01 Universal Time on Monday).

The US$700 million Gravity Probe B satellite will attempt to verify two very subtle physical effects of the Earth along its surrounds that Einstein predicted more than 40 years ago.

Einstein regarded space along with time as interwoven as well as inseparable, hence the term 'space-time'.

One of his predictions is that spinning a massive object like the Sun or the Earth would distort space-time by dragging it around like a piece of fabric.

Friday, March 6, 2009

Einstein's Relativity Theory Proven With The 'Lead' Of A Pencil

Until now it was only possible to test the theory by building expensive machinery or by studying stars in distant galaxies, but a team of British, Russian and Dutch scientists has now proven it can be done in the lab using an ultra-thin material called Graphene.

The group, led by Professor Andre Geim of the School of Physics and Astronomy, discovered the one atom thick material last year. Graphene is created by extracting one atom thick slivers of graphite via a process similar to that of tracing with a pencil.

Professor Geim, said: "To understand implications of the relativity theory, researchers often have to go considerable lengths, but our work shows that it is possible to set up direct experiments to test relativistic ideas. In theory, this will speed up possible discoveries and probably save billions of pounds now that tests can be set up using Graphene and relatively inexpensive laboratory equipment."
In a paper published in Nature (November 10, 2005), the team describes how electric charges in Graphene appear to behave like relativistic particles with no mass (zero rest mass). The new particles are called massless Dirac fermions and are described by Einstein's relativity theory (so-called the Dirac equation).

The team also reports several new relativistic effects. They have shown that massless Dirac fermions are pulled by magnetic fields in such a manner that they gain a dynamic (motion) mass described by the famous Einstein's equation E=mc2. This is similar to the case of photons (particles of light) that also have no mass but can still feel the gravitational pull of the Sun due their dynamic mass described by the same equation.

Dr Kostya Novoselov, a key investigator in this research, added: "The integer and fractional quantum Hall effects are two of the most remarkable discoveries of the late 20th century. It is not easy to explain their significance but both discoveries led to Nobel prizes. One can probably appreciate the importance of our present work in terms of fundamental physics, if I mention that one of the phenomena we report is a new, relativistic type of the quantum Hall effect."

Monday, March 2, 2009

Readers Question

Hi, I really like your blog, but could you explain what the Relativity Theory means? -- John

Hi John, of couse we can.

Einstein's earlier theory of time and space, special relativity, proposed that distance and time are not absolute. The ticking rate of a clock depends on the motion of the observer of that clock; likewise for the length of a "yardstick." Published in 1915, general relativity proposed that gravity, as well as motion, can affect the intervals of time and of space. The key idea of general relativity, called the equivalence principle, is that gravity pulling in one direction is completely equivalent to an acceleration in the opposite direction. A car accelerating forwards feels just like sideways gravity pushing you back against your seat. An elevator accelerating upwards feels just like gravity pushing you into the floor.

If gravity is equivalent to acceleration, and if motion affects measurements of time and space (as shown in special relativity), then it follows that gravity does so as well. In particular, the gravity of any mass, such as our sun, has the effect of warping the space and time around it. For example, the angles of a triangle no longer add up to 180 degrees, and clocks tick more slowly the closer they are to a gravitational mass like the sun.

Many of the predictions of general relativity, such as the bending of starlight by gravity and a tiny shift in the orbit of the planet Mercury, have been quantitatively confirmed by experiment. Two of the strangest predictions, impossible ever to completely confirm, are the existence of black holes and the effect of gravity on the universe as a whole (cosmology).