Friday 21 June 2013

Heliophysics

We live in the extended atmosphere of an active star. While sunlight enables and sustains life, the Sun's variability produces streams of high energy particles and radiation that can harm life or alter its evolution.
NASA’s New Eye on the Sun Delivers Stunning First ImagesUnder the protective shield of a magnetic field and atmosphere, the Earth is an island in the Universe where life has developed and flourished. The origins and fate of life on Earth are intimately connected to the way the Earth responds to the Sun's variations.
Understanding the Sun, Heliosphere, and Planetary Environments as a single connected system is the goal of the Science Mission Directorate's Heliophysics Research Program. In addition to solar processes, our domain of study includes the interaction of solar plasma and radiation with Earth, the other planets, and the Galaxy. By analyzing the connections between the Sun, solar wind, planetary space environments, and our place in the Galaxy, we are uncovering the fundamental physical processes that occur throughout the Universe. Understanding the connections between the Sun and its planets will allow us to predict the impacts of solar variability on humans, technological systems, and even the presence of life itself.
We have already discovered ways to peer into the internal workings of the Sun and understand how the Earth's magnetosphere responds to solar activity. Our challenge now is to explore the full system of complex interactions that characterize the relationship of the Sun with the solar system. Understanding these connections is especially critical as we contemplate our destiny in the third millennium. Heliophysics is needed to facilitate the accelerated expansion of human experience beyond the confines of our Earthly home. Recent advances in technology allow us, for the first time, to realistically contemplate voyages beyond the solar system.

There are three primary objectives that define the multi-decadal studies needed:
  • To understand the changing flow of energy and matter throughout the Sun, Heliosphere, and Planetary Environments.
  • To explore the fundamental physical processes of space plasma systems.
  • To define the origins and societal impacts of variability in the Earth-Sun System.
A combination of interrelated elements is used to achieve these objectives. They include complementary missions of various sizes; timely development of enabling and enhancing technologies; and acquisition of knowledge through research, analysis, theory, and modeling.

Wednesday 19 June 2013

PLANETS AROUND OTHER STARS

What are exoplanets?

Throughout recorded history and perhaps before, we have wondered about the possible existence of other worlds, like or unlike our own. The earliest understanding of the solar system showed us that there were indeed other worlds in orbit about our Sun, and steadily growing understanding of their natures shows that all are dramatically different from Earth, and mostly very different from one another. As we came to understand that the stars in the sky are other suns, and that the galaxies consist of billions of stars, it appeared a near certainty that other planets must orbit other stars. And yet, it could not be proven, until the early 1990’s. Then, radio and optical astronomers detected small changes in stellar emission which revealed the presence of first a few, and now many, planetary systems around other stars. We call these planets “exoplanets” to distinguish them from our own solar system neighbors.

How we know that there are planets around other stars?

Most of the detected exoplanets have revealed their presence by small effects that they have on their star. As planet follows its orbital path, the star follows a complementary motion of its own. This is a tiny effect proportional to the planet/star mass ratio – in the case of the solar system, the Sun moves in synch with the Earth at the speed of a slow dance – currently too slow to readily detect in a distant system. The motion of the Sun in synch with Jupiter, however, is closer to a fast run – and in favorable cases it can be detected by several methods. The motion of the host star can be measured as a shift in its spectrum (the Doppler shift) or as a change in its position on the sky (astrometry). In both cases these are very challenging measurements and require exquisitely sensitive instruments. Exoplanet orbits presumably have random orientations, and in some cases the orbit carries the planet between us and its star. Then the exoplanet might be detected by the decrease in the light from the star. Such transitshave been observed, and a number of planets discovered by this method.

Another effect that can reveal the presence of a planet around another star is the bending of light from background stars by the gravitational field of an intervening star. If the intervening star has an orbiting planet it may alter the gravitational lensing effect in a noticeable way (microlensing). The large majority of the several hundred known extrasolar planets have been discovered by the Doppler technique, and other methods are contributing more significantly as they are refined and the number of detected exoplanets continues to increase steadily.

What do we know about our exoplanet neighbors?

Although the details are not entirely understood, it is known that stars like the Sun form from spinning protostellar disks of gas and dust. The Earth and other planets of the solar system are believed to have developed from the remains of that disk, and there is no reason to believe that the same process would not be effective throughout the galaxy. Thus a first guess might be that other planetary systems would be like the solar system.
Planet sizing
However, the first detections of exoplanets revealed bodies which are utterly unlike any solar system planet – and subsequent discoveries have shown that many exoplanet systems are very dissimilar from ours. In some exosystems, planets as massive as Jupiter orbit so close to their star that they are heated to high temperature and their upper atmospheres are swept into space. In other systems, planets follow elongated orbits (in contrast to the nearly circular orbits of the solar system). However, our studies of exoplanets are just beginning, and it is not possible to be sure what will prove to be “typical” planets among our neighboring stars. Will most planet systems prove to be much like our own, or are we exceptional in more ways than we can imagine? Only years of further study will tell.

Evidence is accumulating that exoplanet systems which resemble the solar system are being found. The star 55 Cancri, 41 light years away, has a system of 5 planets, with distributions somewhat similar to the solar systems inner planets (though with much higher masses). As our measurements become sensitive to lower masses, some astronomers believe that we will find many such systems with a substantial complement of planets (perhaps even dynamically full – that is, containing as many planets as can coexist in orbital harmony).

In other reports, a number of planets with masses near that of Earth have been detected. The results are few, but because the measurements are very difficult, the detections are considered significant and possibly indicative of many more to be found in the future. Again, only years of study will tell.

What do we want to learn about exoplanets?

A thorough understanding of exoplanets will tell us much about how our solar system formed, why it has small, rocky planets near the Sun, why it has gas giant planets far from the Sun, why the Earth has the conditions and chemicals that can support life, and why conditions on other planets are hostile to life. Theories of planet formation and evolution are incomplete, but offer specific predictions. Detections of exoplanets are already testing, validating, and in some cases invalidating, details of these theories.
Perhaps the most interesting question, and one of the most difficult to answer, concerns the uniqueness of the Earth. Are there planets similar to the Earth around other stars and does life exist on any other planet beyond our own Earth?

Recent Discoveries

April 18, 2013Kepler's Smallest Habitable Zone Planets (Kepler-62 and Kepler-69 systems)
April 5, 2013Dead Star Warps Light of Companion Red Star, Astronomer Say
March 29, 2013Planet Hunters Discover: PH1b (Kepler-64b)
February 20, 2013Tiny Planet System (Kepler-37)
February 6, 2013Earth-size Planet May Be Next Door
January 10, 2013At Least One in Six Stars has an Earth-sized Planet
January 8, 2013Two Belts and Possibility of Planets (Vega)
January 8, 2013Rogue Planetary Orbit for Fomalhaut b
January 3, 2013Billions and Billions of Planets
November 27, 2012Solar System with Extra Comets (GJ 581 and 61 Vir)
November 1, 2012Asteroid Belts of Just the Right Size are Friendly to Life
October 18, 2012Revisiting Exoplanet TrES-2 (Kepler-1b)
October 15, 2012Citizen Scientists Discover Four-Planets
September 11, 2012Extreme Life Forms Might be Able to Survive on Eccentric Exoplanets
August 28, 2012Sharing the Light of Two Suns (Kepler-47c)
August 22, 201241 New Transiting Planets in Kepler Field of View
July 18, 2012Exoplanet is Extremely Hot and Incredibly Close
July 5, 2012Mysterious Case of the Disappearing Dust
June 28, 2012Hubble and Swift Detect First-Ever Changes in an Exoplanet Atmosphere
June 21, 2012Astronomers Discover Planetary Odd Couple (Kepler-36b, Kepler-36c)

How did the universe originate and evolve to produce the galaxies, stars, and planets we see today?

How did we get here? In order to understand how the Universe has changed from its initial simple state following the Big Bang (only cooling elementary particles like protons and electrons) into the magnificent Universe we see as we look at the night sky, we must understand how stars, galaxies and planets are formed.
There are many questions associated with the creation and evolution of the major constituents of the cosmos. A basic question astronomers must address is, how did the Universe create its first stars and galaxies? Once these entities were created, how did they influence subsequent galaxy, star and planet formation? This is an important question, because these later objects are made of elements that can only have been created by the first generation of stars.
It is still unknown whether the Universe created black holes with the first generation of stars or whether these exotic objects were created by the first generation of stars. Because black holes represent the most extreme physical conditions of spacetime and generate some of the most energetic phenomena following the Big Bang, they are the ultimate physical laboratories for testing theories of the Universe.
We now know that our Universe has a "foamy" structure. The galaxies and clusters of galaxies that make up the visible Universe are concentrated in a complex scaffold that surrounds a network of enormous cosmic voids. However, in addition to the "normal" matter that makes up the visible parts of the Universe, scientists have discovered that there are vast amounts of unseen matter. This so-called, "dark matter" makes up roughly 23% of the matter-energy content of the Universe, while the visible pieces account for only about 5% of the total. Clearly, if we hope to understand the structure of the Universe and the processes by which it formed and evolves, we must first understand the distribution of this important but unseen dark matter and the ways in which it interacts with and influences normal matter.
Though astronomers have been studying stars for thousands of years, it is only in the past 35 or so years that they have been able to employ instruments that detect light across the entire electromagnetic spectrum–from radio waves to gamma rays–to peer into the dusty clouds where stars are born in our own Galaxy. If we are to comprehend how the Universe makes stars–and planets that orbit them today–we must continue these studies with ever more powerful telescopes.

Black holes

Don't let the name fool you: a black hole is anything but empty space. Rather, it is a great amount of matter packed into a very small area - think of a star ten times more massive than the Sun squeezed into a sphere approximately the diameter of New York City. The result is a gravitational field so strong that nothing, not even light, can escape. In recent years, NASA instruments have painted a new picture of these strange objects that are, to many, the most fascinating objects in space.
Swift
Intense X-ray flares thought to be caused by a black hole devouring a star. (Video)

Although the term was not coined until 1967 by Princeton physicist John Wheeler, the idea of an object in space so massive and dense that light could not escape it has been around for centuries. Most famously, black holes were predicted by Einstein's theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core. If the core's mass is more than about three times the mass of the Sun, the equations showed, the force of gravity overwhelms all other forces and produces a black hole.
Black Hole Jets
Using radio telescopes located throughout the Southern Hemisphere scientists have produced the most detailed image of particle jets erupting from a supermassive black hole in a nearby galaxy. (Video)

Scientists can't directly observe black holes with telescopes that detect x-rays, light, or other forms of electromagnetic radiation. We can, however, infer the presence of black holes and study them by detecting their effect on other matter nearby. If a black hole passes through a cloud of interstellar matter, for example, it will draw matter inward in a process known as accretion. A similar process can occur if a normal star passes close to a black hole. In this case, the black hole can tear the star apart as it pulls it toward itself. As the attracted matter accelerates and heats up, it emits x-rays that radiate into space. Recent discoveries offer some tantalizing evidence that black holes have a dramatic influence on the neighborhoods around them - emitting powerful gamma ray bursts, devouring nearby stars, and spurring the growth of new stars in some areas while stalling it in others.
Black Hole Jets
Astronomers have identified a candidate for the smallest-known black hole. (Video)

One Star's End is a Black Hole's Beginning
Most black holes form from the remnants of a large star that dies in a supernova explosion. (Smaller stars become dense neutron stars, which are not massive enough to trap light.) If the total mass of the star is large enough (about three times the mass of the Sun), it can be proven theoretically that no force can keep the star from collapsing under the influence of gravity. However, as the star collapses, a strange thing occurs. As the surface of the star nears an imaginary surface called the "event horizon," time on the star slows relative to the time kept by observers far away. When the surface reaches the event horizon, time stands still, and the star can collapse no more - it is a frozen collapsing object.
Even bigger black holes can result from stellar collisions. Soon after its launch in December 2004, NASA's Swift telescope observed the powerful, fleeting flashes of light known as gamma ray bursts. Chandra and NASA's Hubble Space Telescope later collected data from the event's "afterglow," and together the observations led astronomers to conclude that the powerful explosions can result when a black hole and a neutron star collide, producing another black hole.
Babies and Giants
Although the basic formation process is understood, one perennial mystery in the science of black holes is that they appear to exist on two radically different size scales. On the one end, there are the countless black holes that are the remnants of massive stars. Peppered throughout the Universe, these "stellar mass" black holes are generally 10 to 24 times as massive as the Sun. Astronomers spot them when another star draws near enough for some of the matter surrounding it to be snared by the black hole's gravity, churning out x-rays in the process. Most stellar black holes, however, lead isolated lives and are impossible to detect. Judging from the number of stars large enough to produce such black holes, however, scientists estimate that there are as many as ten million to a billion such black holes in the Milky Way alone.
On the other end of the size spectrum are the giants known as "supermassive" black holes, which are millions, if not billions, of times as massive as the Sun. Astronomers believe that supermassive black holes lie at the center of virtually all large galaxies, even our own Milky Way. Astronomers can detect them by watching for their effects on nearby stars and gas.
Black Hole Jets
Astronomers may have found evidence for a cluster of young, blue stars encircling one of the first intermediate-mass black holes ever discovered.Read the full article
Historically, astronomers have long believed that no mid-sized black holes exist.  However, recent evidence evidence from Chandra, XMM-Newton and Hubble strengthens the case that mid-size black holes do exist. One possible mechanism for the formation of supermassive black holes involves a chain reaction of collisions of stars in compact star clusters that results in the buildup of extremely massive stars, which then collapse to form intermediate-mass black holes. The star clusters then sink to the center of the galaxy, where the intermediate-mass black holes merge to form a supermassive black hole.

Monday 17 June 2013

Difference between Normal matter, Dark matter, Anti matter and Negative matter (if existed outside the theories)

Normal matter like that which we are all made of interacts via all four forces in the ways which we are familiar with.  All of the science and technology we have done to this point is based on normal matter and how it behaves.  But for a few experiments and in certain particle accelerators all we have done has been with normal matter.   Hence it's name. 

Anti matter is just like normal matter only the sign of certain properties is different.  The classic case would be the electron, which has as it's anti particle the anti-electron also known as the positron.  Electrons are negatively charged, and Positrons are positively charged.  Yet they are identical in every other way.    Then their are particles like neutrons and protons which are made of even smaller particles called quarks.  Quarks interact via the strong atomic force, and electromagnetism.  Anti Quarks have opposite charges to Quarks in those two forces.

Dark matter on the other hand only interacts by way of gravity and the weak atomic force.  Dark matter does not interact via either the strong atomic force or electromagnetism hence dark matter cannot be seen and is hard to detect.  It only interacts via the weak force which is what keeps neutrons and protons inside the nucleus of atoms together.    Such is why experiments to detect dark matter directly rely on a particle of dark matter bumping into a particle of matter dead bang on the nucleus of an atom of normal matter.  

Most of the reason we think dark matter exists has to do with the fact that it solves problems in cosmology in a very expedient way without us having to alter General Relativity.  It is widely agreed that dark matter whatever it turns out to be quantifies how much we really don't know about the matter in the universe. 

Negative matter is a hypothetical type of matter which if it exist will have negative mass and negative energy.  It will in essence have a negative gravitational charge and repel normal matter.  Yet it will interact just like any other matter in every other way. 

This table summarizes the differences in how each type of matter would interact with the different forces.

 Normal Matter Anti- Dark- Negative- 
Gravity  As usual As usual* As usualOpposite sign 
Electromagnetism As usual Opposite sign No charge ?
Strong Force As usual Opposite sign No charge ?
Weak Force As usual Opposite sign As usual ?


*We assume that antimatter behaves as normal matter under gravity.  The truth is we have never seen a large enough mass of it to know for certain it behaves the same.  When it comes to Negative matter we know nothing and it may not even exist outside of certain theories.  Dark matter is on the edge of being a confirmed real entity. 

Diet coke and mentos eruption

When the Mentos come into contact with the Coke, a reaction causes the rapid formation of foam.
A 2006 episode of the television series MythBusters concluded that the potassium benzoate, aspartame, and CO2 gas contained in the Diet Coke, in combination with the gelatin and gum arabic ingredients of the Mentos, all contribute to formation of the foam. The structure of the Mentos is the most significant cause of the eruption due to nucleation. MythBusters reported that when fruit-flavored Mentos with a smooth waxy coating were tested in carbonated drink there was hardly a reaction, whereas mint-flavored Mentos (with no such coating) added to carbonated drink formed an energetic eruption, affirming the nucleation-site theory. According to MythBusters, the surface of the mint Mentos is covered with many small holes that increase the surface area available for reaction (and thus the quantity of reagents exposed to each other at any given time), thereby allowing CO2 bubbles to form with the rapidity and quantity necessary for the "jet"- or "geyser"-like nature of the effusion. This hypothesis gained further support when rock salt was used as a "jump start" to the reaction.
A paper by Tonya Coffey, a physicist at Appalachian State University in Boone, North Carolina, goes into detail on the reasons and physics behind the reaction. Coffey found that the rough surface of the Mentos candy helps speed the reaction. Coffey also found that the aspartame in diet soda lowers the surface tension and causes a bigger reaction, but that caffeine does not accelerate the reaction.

BUTTERFLY NEBULA- Beauty at its peak

The bright clusters and nebulae of planet Earth's night sky are often named for flowers or insects. Though its wingspan covers over 3 light-years, NGC 6302 is no exception. With an estimated surface temperature of about 250,000 degrees C, the dying central star of this particular planetary nebula has become exceptionally hot, shining brightly in ultraviolet light but hidden from direct view by a dense torus of dust.

This sharp and colorful close-up of the dying star's nebula was recorded in 2009 by the Hubble Space Telescope's Wide Field Camera 3, installed during the final shuttle servicing mission. Cutting across a bright cavity of ionized gas, the dust torus surrounding the central star is near the center of this view, almost edge-on to the line-of-sight. Molecular hydrogen has been detected in the hot star's dusty cosmic shroud. NGC 6302 lies about 4,000 light-years away in the arachnologically correct constellation of the Scorpion (Scorpius).

Image Credit: NASA/ESA/Hubble

Why do onions make us cry?

Unless you've avoided cooking, you've probably cut up an onion and experienced the burning and tearing you get from the vapors. When you cut an onion, you break cells, releasing their contents. Amino acid sulfoxides form sulfenic acids. Enzymes that were kept separate now are free to mix with the sulfenic acids to produce propanethiol S-oxide, a volatile sulfur compound that wafts upward toward your eyes. This gas reacts with the water in your tears to form sulfuric acid. The sulfuric acid burns, stimulating your eyes to release more tears to wash the irritant away.
Cooking the onion inactivates the enzyme, so while the smell of cooked onions may be strong, it doesn't burn your eyes. Aside from wearing safety goggles or running a fan, you can keep from crying by refrigerating your onion before cutting it (slows reactions and changes the chemistry inside the onion) or by cutting the onion under water.

The sulfur-containing compounds also leave a characteristic odor on your fingers. You may be able to remove or reduce some of the smell by wiping your fingers on a stainless steel odor eater.

Why should we stay awake in math class?


Albert Einstein loved to think about physics, especially about light and about gravity. But he really hated school, and particularly math classes. So a classmate would take notes in math classes for Albert, and then Albert would use them to cram for exams, and that way he could devote the time otherwise "wasted" in math class to thinking about what the world would look like while riding on a beam of light or what it would feel like falling down an elevator shaft (I'm not kidding....). Many years later, Einstein was already famous for his Theory of Special Relativity which explains why light behaves the way it does, when he decided to take on gravity.

Although Newton's theory of gravity explained many questions, such as why the planets move the way they do and why things fall, and made very accurate predictions for experimental observations, there were a few things that were amiss. For some strange reason, the planet Mercury's orbit was a little off from what Newton's gravity predicted for its motion, and a few other little things here and there didn't add up perfectly. But for all practical purposes, Newton's theory of gravity worked very well and was a huge leap forward in our understanding of Nature. Einstein, however, wondered about the little odds and ends that weren't explained by Newton's theory.

For eight years, Einstein did nothing but tinker with Newton's theory of gravity. He had many brilliant insights, but the structure of what he put together was very messy mathematically. There was no tidy way to put down in equations the essential meaning of his new ideas. Then he talked to an old classmate who had taken notes for him in math classes. Einstein explained his new hypothesis about gravity and asked the fellow if he had any ideas about how to structure gravity more clearly mathematically. His friend told him about a discipline of mathematics that had been discovered while they had both been in school — tensor calculus and matrix mechanics in linear algebra. When he heard this, Einstein spent a lot of time slapping himself in the head. This mathematics was not only elegant and beautiful, but it took the untidy equations Einstein had formulated and put them in a structure that was compact, showed relationships easily, and brought elegance and ease of understanding to what later became known as Einstein's General Theory of Relativity. Einstein's General Theory of Relativity boils down to this one equation in the language of tensor calculus:
                                                 


Einstein later said that had he attended his math classes in school, he would have heard of these new mathematical disciplines, and instead of his theory taking eight years to develop, it would have taken him only three years at most.

Sunday 16 June 2013

What do the universe comprise of?

One of the greatest mysteries in physics today is trying to figure out all of the stuff in the universe which we can't see. In fact, the results of the WMAP survey has indicated that the majority of the universe is stuff that we can't see: dark matter and dark energy.
This graphic from 2008 shows the results from the WMAP survey in a pie chart, both "Today" and "13.7 Billion Years Ago" (when the universe was only 380,000 years old). This starkly shows the amazing evolution of matter in our universe over time. Here is the description of this data from the WMAP website:

WMAP data reveals that its contents include 4.6% atoms, the building blocks of stars and planets. Dark matter comprises 23% of the universe. This matter, different from atoms, does not emit or absorb light. It has only been detected indirectly by its gravity. 72% of the universe, is composed of "dark energy", that acts as a sort of an anti-gravity. This energy, distinct from dark matter, is responsible for the present-day acceleration of the universal expansion. WMAP data is accurate to two digits, so the total of these numbers is not 100%. This reflects the current limits of WMAP's ability to define Dark Matter and Dark Energy.
Of course, the "13.7 Billion Years Ago" data is based on some serious theoretical extrapolations back in time, so this is our best estimate based on current theories. It's possible that some of these theories will be modified in the years to come and the distribution of matter in the early universe was very different from what we now believe.
Of course, for that matter, we may someday realize that we're wrong about dark matter and dark energy, and even our understanding of the current universe could be wrong. That's always a possibility in science, and part of the reason why it's so interesting. For now, at least, this is the theory that most cosmologists believe has merit.

Saturday 15 June 2013

Why is it impossible to travel at a speed faster then light?

Einstein's Special Theory of Relativity states that it is impossible for any object to travel faster than the speed of light, which is 300 million metres per second.
The reasoning goes like this. We are all probably comfortable with the fact that the heavier an object is, the more work we have to do to achieve a given change in speed – which is why truck engines are bigger than car engines! In fact, as Einstein recognised, it is not the just the mass of an object which determines its resistance to change in speed, but its energy.
This energy consists of the energy the object has when it is at rest (its 'rest energy', proportional to its mass via the famous formula E = mc2), plus the kinetic energy it possesses due to its motion. The faster an object moves, the greater its energy, and hence the greater its resistance to further increases in its speed – meaning we have to do more work to achieve a given additional increase in speed.
This cycle gets out of control as the speed of an object approaches the speed of light, in that it would take infinite amounts of energy to accelerate an object to a speed greater than that of light.

Friday 14 June 2013

NASA may engage a warp drive...

In the recent film Star Trek Into Darkness, the crew of the Enterprise uses a warp engine to move faster than the speed of light. This would normally not be allowed by the laws of physics, specifically Einstein's theory of relativity. However, the limitations from the theory of relativity make it impossible to accelerate past the speed of light limit, but there do exist some intriguing workarounds (in theory, at least).
One possibility is the Alcuberrie drive, which was conceptualized in 1994 as an attempt to create a realistic model for creation of a warp drive. There are now suggestions that NASA may be moving forward to create just such an engine. Dr. Harold White, the NASA physicist who explored Alcubierre's over the last couple of years has come to believe that it was feasible, says that any results that show proof of concept will help push more research in this area. He uses an example he calls the "Chicago Pile" from the middle of the last century:
"In late 1942, humanity activated the first nuclear reactor in Chicago generating a whopping half Watt -- not enough to power a light bulb," he said. "However, just under one year later, we activated a ~4MW reactor which is enough to power a small town. Existence proof is important."
Overall, this does fall in the "I'll believe it when I see it" category ... but I'll confess, this is one radical (and likely over-hyped) scientific announcement that I'dlove to be proven wrong on!

Different types of Dry Ice

Dry ice bubbles as it sublimates in colored water. (Anne Helmenstine)
You probably know you can drop dry ice in warm water to make fog, but you might not know there are different types of dry ice. Ideally, 'dry ice' is just another name for solid carbon dioxide, but it's like any other chemical in that it may or may not be 100% pure. Some impurities may be harmless while others may be potentially nasty contaminants. You can use pretty much any dry ice to make smoke or fog for a party effect. You want to use food-grade dry ice if you intend to put the dry ice in drinks or are going to use it to freeze foods. Your supplier should be able to tell you whether your dry ice is food-grade or not.
If you add dry ice directly to drinks some of the carbon dioxide will be dissolved in the liquid in much the same way as some carbon dioxide stays in carbonated beverages even after the fizzing has stopped. This will make the drink more acidic than it would be otherwise, which will affect the flavor slightly. If dry ice is added to a pool or hot tub, you'll want to pay attention to the change in pH because it could impact your water treatment regimen.
Dry ice sinks in water, so it's fairly easy to avoid direct contact if it's in a drink or if you are in a pool with it. When nearly all of the dry ice has sublimated, then water ice forms around it. This ice containing a dry ice core will float to the top of the liquid. It's very cold, so you don't want to drink it or handle it.

Wednesday 12 June 2013

What is a photon?

http://www.ias.ac.in/resonance/January2013/p39-50.pdf
Really worth reading article.
Don't forget to read it.

What happens if you eat Silica Gel?

Silica gel beads (Balanarayanan)
Silica gel beads are found in those little packets accompanying shoes, clothing and some snacks. The packets contain round or granular bits of silica, which is called a gel but is really a solid. The containers typically carry dire "Do Not Eat" and "Keep Away from Children" warnings. So, what happens if you eat silica?
Usually, nothing. In fact, you eat it all the time. Silica is added to improve flow in powdered foods. It occurs naturally in water, where it may help confer resistance against developing senility. Silica is just another name for silicon dioxide, the main component of sand.
Yet, if silica is harmless to eat, why do the packets carry the warning? The answer is that some silica contains toxic additives. For example, silica gel beads may contain toxic and potentially carcinogenic cobalt(II) chloride, which is added as a moisture indicator. You can recognize silica containing cobalt chloride because it will be colored blue (dry) or pink (hydrated). Another common moisture indicator is methyl violet, which is orange (dry) or green (hydrated). Methyl violet is a mutagen and mitotic poison. While you can expect most silica you encounter will be non-toxic, ingestion of a colored product warrants a call to Poison Control.

Tuesday 11 June 2013

Before the Big Bang.....

 To get really speculative, there have been some papers written recently that try to figure out what happened before the Big Bang. One of the strange ideas is that the universe is merely one plane in a multidimensional space, and that what happened was that two membranes in a multidimensional space collided causing a massive expansion in three of the dimensions. This is all really speculative, but the weird thing is that it isn't totally disconnected from observation. The idea is that you can use this model to predict the initial expansion of the universe, and this might have some effects on the ripples that you see in the cosmic microwave background. The big problem is that the matter that began expanding had to have always existed, yet, because of the predictable nature of the elements, it had to have had a definite, external force to set it in motion that could decide when to start the "chain reaction". Something cannot just be in a stable form, or even an unstable form, forever and finally explode, it has to go in a cycle. In other words, consider the following. Out of nothing, a theretofore nonexistent dense mass spontaneously emerged, which erupted in an enormously powerful fireball by its own theretofore nonexistent energy to spontaneously and immediately create from this chaos the defined fundamental forces of physics and the subatomic fundamental particles, which eventually organized themselves into a variety of atomic species, then into molecules, and then into a diverse assortment of inorganic matter that gravitationally assembled itself into this highly structured and precisely ordered universe. We all know that this is ridiculous, but it is equally ridiculous to say "a theretofore stable mass spontaneously became unstable".
With all of these puzzles, its not clear what is going to happen next. There is a lot of data coming in, and it may be that with new data, it will be possible to make our models of the universe work with minor tweaks here and there, and we can go on in the mode of what Kuhn calls "normal science." It's also possible that one day there will be some observation which is like Galileo seeing the phases of Venus. Some observation that makes absolutely no sense in the current paradigm of things, and this will force people to fundamentally change how we view the universe.

Unfrozen Mystery: H2O Reveals a New Secret

Their work is published in theProceedings of the National Academy of Sciences.
When water freezes into ice, its molecules are bound together in a crystalline lattice held together by hydrogen bonds. Hydrogen bonds are highly versatile and, as a result, crystalline ice reveals a striking diversity of at least 16 different structures.
In all of these forms of ice, the simple H2O molecule is the universal building block. However, in 1964 it was predicted that, under sufficient pressure, the hydrogen bonds could strengthen to the point where they might actually break the water molecule apart. The possibility of directly observing a disassociated water molecule in ice has proven a fascinating lure for scientists and has driven extensive research for the last 50 years. In the mid-1990s several teams, including a Carnegie group, observed the transition using spectroscopic techniques. However, these techniques are indirect and could only reveal part of the picture.
A preferred method is to "see" the hydrogen atoms-or protons-directly. This can be done by bouncing neutrons off the ice and then carefully measuring how they are scattered. However, applying this technique at high enough pressures to see the water molecule dissociate had simply not been possible in the past. Guthrie explained that: "you can only reach these extreme pressures if your samples of ice are really small. But, unfortunately, this makes the hydrogen atoms very hard to see."
The Spallation Neutron Source was opened at Oak Ridge National Laboratory in Tennessee in 2006, providing a new and intensely bright supply of neutrons. By designing a new class of tools that were optimized to exploit this unrivalled flux of neutrons, Guthrie and his team-Carnegie's Russell Hemley, Reinhard Boehler, and Kuo Li, as well as Chris Tulk, Jamie Molaison, and António dos Santos of Oak Ridge National Laboratory-have obtained the first glimpse of the hydrogen atoms themselves in ice at unprecedented pressures of over 500,000 times atmospheric pressure.
"The neutrons tell us a story that the other techniques could not," said Hemley, director of Carnegie's Geophysical Laboratory. "The results indicate that dissociation of water molecules follows two different mechanisms. Some of the molecules begin to dissociate at much lower pressures and via a different path than was predicted in the classic 1964 paper."
"Our data paint an altogether new picture of ice," Guthrie commented. "Not only do the results have broad consequences for understanding bonding in H2O, the observations may also support a previously proposed theory that the protons in ice in planetary interiors can be mobile even while the ice remains solid."
And this startling discovery may prove to be just the beginning of scientific discovery. Tulk emphasized "being able to 'see' hydrogen with neutrons isn't just important for studies of ice. This is a game-changing technical breakthrough. The applications could extend to systems that are critical to societal challenges, such as energy. For example, the technique can yield greater understanding of methane-containing clathrate hydrates and even hydrogen storage materials that could one day power automobiles."
The group is part of Energy Frontier Research in Extreme Environments (EFree), an Energy Frontier Research Center headquartered at Carnegie's Geophysical Laboratory.

Monday 10 June 2013

Scientists Size Up Universe's Most Lightweight Dwarf Galaxy

The findings, made with the world's most powerful telescopes at the W. M. Keck Observatory and published today in The Astrophysical Journal, offer tantalizing clues about how iron, carbon and other elements key to human life originally formed. But the size and weight of Segue 2, as the star body is called, are its most extraordinary aspects.
"Finding a galaxy as tiny as Segue 2 is like discovering an elephant smaller than a mouse," said UC Irvine cosmologist James Bullock, co-author of the paper. Astronomers have been searching for years for this type of dwarf galaxy, long predicted to be swarming around the Milky Way. Their inability to find any, he said, "has been a major puzzle, suggesting that perhaps our theoretical understanding of structure formation in the universe was flawed in a serious way."
Segue 2's presence as a satellite of our home galaxy could be "a tip-of-the-iceberg observation, with perhaps thousands more very low-mass systems orbiting just beyond our ability to detect them," he added.
"It's definitely a galaxy, not a star cluster," said postdoctoral scholar and lead author Evan Kirby. He explained that the stars are held together by a globule called a dark matter halo. Without this acting as galactic glue, the star body wouldn't qualify as a galaxy.
Segue 2, discovered in 2009 as part of the massive Sloan Digital Sky Survey, is one of the faintest known galaxies, with light output just 900 times that of the sun. That's miniscule compared to the Milky Way, which shines 20 billion times brighter. But despite its tiny size, researchers using different tools originally thought Segue 2 was far denser.
""The Keck telescopes are the only ones in the world powerful enough to have made this observation," Kirby said of the huge apparatus housed on the summit of Mauna Kea in Hawaii. He determined the upper weight range of 25 of the major stars in the galaxy and found that it weighs at least 10 times less than previously estimated.
Fellow authors are Michael Boylan-Kolchin and Manoj Kaplinghat of UC Irvine, Judith Cohen of the California Institute of Technology and Marla Geha of Yale University. Funding was provided by the Southern California Center for Galaxy Evolution (a multicampus research program of the University of California) and by the National Science Foundation.

Its time to go solar!

One reason that solar energy has not been widely adopted is because light absorbing materials are not durable. Materials that harvest solar radiation for energy often overheat or degrade over time; this reduces their viability to compete with other renewable energy sources like wind or hydroelectric generators. A new video protocol addresses these issues by presenting a synthesis of two inorganic nanocrystals, each of which is more durable than their organic counterparts.
The article, published in Journal of Visualized Experiments (JoVE), focuses on the liquid phase synthesis of two nanocrystals that produce hydrogen gas or an electric charge when exposed to light. "The main advantage of this technique is that it allows for direct, all inorganic coupling of the light absorber and the catalyst," says the leading author Dr. Mikhail Zamkov of Bowling Green State University.
Zamkov's nanocrystals are unique for two reasons: they separate charge in different ways due to their architectures, and they are inorganic and durable. The first nanocrystal is rod-shaped, which allows the charge separation needed to produce hydrogen gas, a reaction known as photocatalysis. The second nanocrystal is composed of stacked layers and generates electricity, thus being photovoltaic. Because the nanocrystals are inorganic, they are easier to recharge and less sensitive to heat than their organic counterparts. Zamkov's inorganic photocatalytic material allows a rechargeable reaction when exposed to cheap organic solvents, whereas in traditional photocatalytic reactions the catalyst is often irreversibly degraded. The photovoltaic nanocrystals can also withstand higher heat than the traditional photovoltaic cells that do not dissipate heat well.
"We have established a new method for making photocatalytic and photovoltaic materials. This is important primarily as a new strategy for making photovoltaic films that are 100% inorganic, thus producing a more stable solar panel. It is a design that you could reach marketability," Dr. Zamkov says. "It is important to have these steps documented in a video format, as the synthesis of the photocatalytic nanocrystals and the photovoltaic cells are long procedures with detailed steps. It makes our technique more visible and accessible."

Latest Physics inventions-2012



1) Raytheon's XOS 2 Exoskeleton


The new generation exoskeleton was developed by Raytheon. It allows the user to lift 200 pounds hundreds of times without getting tire. The robotic suit was developed for the U.S. Army.

2) Hair-Washing Machine
Developed by Panasonic, the robot is meant to help caregivers that work in hospitals and health care institutions. It makes use of the company's robot hand technology, featuring 16 fingers used to wash your hair.

3) Visually Impaired Assistant (VIA)
Noam Klopper is the author of the invention for the blind. The device is worn on the hand,
 representing a combination of GPS and walking tick. It includes 4 mini cameras and a GPS
 receiver that allows the wearer to dodge obstacles.

4) Technology that Powers Phones with Sound Waves
Sound energy is the vibrations generated by the sound. Speakers makes use of
 electricity to generate sound, but Korean scientists managed to create a device that
 does the opposite. They came up with a technology that turns sound waves into electricity.

5) Virtual Garage
Developed by Jaguar Land Rover, the Virtual garage is a GBP2.5 million project that
 claims to be the most highly developed virtual reality facility among all car manufacturers.
 The virtual garage technology includes 8 Sony 4K digital camera projectors and
 22 Sun Microsystems advanced PCs.

6) Perpetual Motion Device that Produces Power from Gravity
A Somerset engineers managed to develop a device that literally breaks the
 laws of physics, being
 able to generate more energy that it consumes. Called the Alpha Omega Galaxy Freefall
 Generator, it produces power from perpetual motion. To create the device, the inventor
 used mostly bicycle parts.

7) Flexible See-Through Solar Cells for Windows
At present Eight19 is working on the creation of an organic solar photovoltaic technology.
 The latter could later considerably ease the process of installing solar cells, making it cheaper
 as well. Based on the upper mentioned technology, the new solar panels will be made of a
 flexible see-through material.

8) Tread-Walk to Help the Elderly and Disabled
Being developed for the elderly and disabled, the invention boasts an ease control system
that allows a person to dodge obstacles and avoid collisions. The Tread-Walk is able to
 fulfill the personal mobility needs of these people.

9) Battlefield Extraction-Assist Robot
Created by Vecna Robotics, the machine is meant to carry injured soldiers out of battlefield.
It can also break locked doors and lift heavy cargo.

10) Paper-Based Lithium-Ion Batteries
This invention was developed by Stanford researchers. These ultrathin batteries could
 be used to power electronic newspapers. In addition, researchers will be able to make
 smart packaging that would assist marketers.

Wikipedia in space! Asteroid named after Wikipedia.

Main belt asteroid Number 274301 was officially named after the online encyclopedia, Wikipedia on January 31, 2013. Of course, the name was changed because Main Belt asteroid No. 274301 didn't roll quite off the tongue like Wikipedia does.
However, the official press release from the Andrushivka Astronomical Observatory in Ukraine, the same observatory that found the asteroid belt in 2008, stated that they chose the name Wikipedia to honor a website that can educate people around the world for free.
Not only is Wikipedia a free database of information, it is also one of the most visited websites in the world and can be translated into 270 different languages. All of this was achieved within 11 years after Wikipedia launched!

Read more at http://www.omg-facts.com/category/7/Science#QkTd8rwOyrdM3oFc.99