How Big Is The Sun Compared To Earth

The radius of Earth at the equator is 6,378 kilometers, however Earth is not quite a sphere.The planet's rotation causes it to bulge at the equator. Earth's polar radius is 6,356 km  a difference of 22 km.

The sun is nearly a perfect sphere. Its equatorial diameter and its polar diameter differ by only 10 km. The mean radius of the sun is 696,000 kilometers.

Volume of a sphere is V = 4/3 πr³

The ratio of volume of sun to Earth =  (4/3 πR³ ) / (4/3 πr³)

                                                             = (R/r)³

Where R is the radius of Sun and r radius of Earth

The ratio of Sun to Earth radius = R/r = 696,000/6,378  = 109.125

The ratio of volume of sun to Earth = (R/r)³ = (109.125)³ = 1299489 or approximately 1.3 million earths can fit inside Sun. 

The mass of the sun is  1.9891 x 10³⁰ kg about 333,000 times the mass of the Earth. The Sun contains 99.8 percent of the mass of the entire solar system.

   

Einstein Deserves Nobel Prize For Relativity

Einstein was disappointed that he did not receive Nobel prize for the theory of relativity instead he was awarded Nobel prize for photoelectric effect in 1921 ,actually he received it in 1922 . He proposed both photoelectric and relativity theory in 1905 .

Einstein general theory of relativity describes how gravity can distort the path of light,altering its trajectory called gravitational lensing. He was denied Nobel prize because committee decided against his work on the grounds that relativity was unproven. 

Cambridge astrophysicist Arthur Eddington measured the deflection of stars' positions near the Sun, the size of the deflection was exactly as Einstein had predicted from relativity in 1915 using total eclipse. But still he was denied because of the war and politics or may be antisemitism.

Albert Einstein also predicted the existence of gravitational waves in 1916 in his general theory of relativity. According to his theory  massive accelerating objects such as neutron stars or black holes orbiting each other would disrupt space-time in such a way that waves of distorted space would radiate from the source and the ripples would travel at the speed of light through the Universe.

After 100 years of Einstein General theory of Relativity prediction of gravitational waves gets a Nobel prize for the discovery of gravitational waves using the LIGO detector. Nobel Prize was awarded to Rainer Weiss of the Massachusetts Institute of Technology and Barry Barish and Kip Thorne of the California Institute of Technology, all members of the Ligo team. 

One of the most famous equations E=mc²  which revolutionized science comes from special theory of relativity, could have got a Nobel prize on its own. The significance of this equation is that mass and energy are different forms of same thing and transmutable.

Today's solar energy revolution is because of Einstein theory of photoelectric effect. Einstein should have won more than one Nobel Prize.

The Cosmological Constant

The cosmological constant was originally introduced by Einstein in 1917 as a repulsive force required to keep the Universe in static equilibrium which follows steady-state-theory. In trying to solve the differential equations that describe space-time, his field equations predicted that the universe should be either contracting or expanding. In the year 1922, Russian physicist Friedmann derived solutions to Einstein's equations that corresponded to an expanding universe. Einstein needed to add a constant term to avoid having the universe collapse upon itself. This term balances the attractive force of gravity contributed by all of the matter in the universe.  

Hubble's study of nearby galaxies showed that the universe was in fact expanding and that lead to the Big Bang theory, the concept introduced in 1927 by Georges LeMaitre.Einstein regretted the introduction cosmological constant to keep the universe static and termed it as greatest mistake.

After almost 100 years we realized that the Universe does in fact have a non-zero cosmological constant: that’s what we call dark energy, and use to explain the accelerated expansion of the Universe. Physically, this term represents the vacuum energy, the possibility that empty space possesses density and pressure thus preventing the universe from collapsing.

If indeed the cosmological constant represents the dark energy or vacuum energy then Einstein by mistake proposed the dark energy concept.

Why Diamond The Strongest Element

Graphite and Diamond are allotropes of carbon ,meaning any of two or more physical forms in which an element can exit. Diamond is very strong in fact strongest known where as graphite is very soft. Why ?

Let us look at the electronic configuration of carbon, it has 4 valence electrons and each carbon atom is covalently bonded to four other carbon atoms in case of diamond.The crystal structure of a diamond is a face-centered cubic or FCC lattice. Each carbon atom joins four other carbon atoms in regular tetrahedrons (triangular prisms).

Diamond's strength comes from pyramid-like structure which is the strongest structures known to man, This is a giant covalent structure and it continues on and on in three dimensions. It is not a molecule, because the number of atoms joined up in a real diamond is completely variable depending on the size of the crystal. As all the four electrons form covalent bonds, there are no free electrons or ions in diamond, so it does not conduct electricity. It has very high melting point (almost 4000°C) because very high temperatures are required to break the covalent bonds. Each carbon atom is at the same distance to each of its neighbouring carbon atoms. In this rigid network atoms cannot move. This explains why diamonds are so hard and have such a high melting point.

Graphite has a layer structure, each carbon atom uses three of its electrons to form simple bonds to its three close neighbours. The fourth electron is free and no longer associated directly with any particular atom or pair of atoms meaning delocalized, but are free to wander throughout the whole sheet.The distance between the layers is about 2.5 times the distance between the atoms within each layer. A weak Van der Waals force of attraction acts between the layers and these layers of  carbon slide over each other in graphite, that's why it is very soft and conducts electricity.

Climate Change And Rejuvenating The Rivers

Its very heartening to know that Sadhguruji has raised the issue of reviving and rejuvenating the rivers with 'Rally for Rivers' campaign,but people may want to know what is the plan of action .Basically rivers are nothing but carriers of rain water and hence we can't actually control them, depends more on the climatic conditions. Increasing the forest coverage and planting trees along the riversides as suggested by him may help somewhat. 

We are presently facing serious green house effect through burning of fossil fuels and made the earth more warmer  which could have disastrous consequences like  loss of snow cover, sea level rise, change in weather patterns. Many scientists believe that the damage to the Earth's atmosphere and climate is past the point of no return, meaning almost irreversible.

Atmospheric CO2 levels have increased by more than 40 percent since the beginning of the Industrial Revolution, from about 280 parts per million (ppm) in the year 1800 to 400 ppm today.There was a  landmark Paris agreement on climate change effective from  Nov. 4  2016 to strengthen the global response to the threat of climate change by keeping a global temperature rise this century well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius. Controlling and reducing the use of fossil fuels and the urgency to go for renewable energy is the need of the hour.

India has another big problem on hand, severe river pollution , Majority of Indian rivers are polluted because of industrial and human waste,particularly the Ganges . Our immediate concern must be to stop polluting the rivers and start cleaning them which requires massive effort from the government ,industries as well the people. Reducing consumption or usage of a polluting products,treatment of wastes, discharges and disposals of a pollutants. Govt. need to shutdown all the industries causing the river pollution or have strict guidelines for the industries to treat the pollutants and have proper waste management.

It is time for concerted action by world leaders on climate change . The climate change certainly made Harvey and Irma worse though they are not caused by climate change. Hurricanes thrive over warm water and strengthen in intensity, oceans have warmed on an average 1 to 3 degrees Fahrenheit. Climate change is a harbinger of doom.Time to act or face the consequences.

science and Technology blog: Doppler Effect

science and Technology blog: Doppler Effect: The change in the observed frequency of an acoustic or electromagnetic wave due to relative motion of source,observer or both is called Do...

Doppler Effect

The change in the observed frequency of an acoustic or electromagnetic wave due to relative motion of source,observer or both is called Doppler effect. As the source moves towards the observer the frequency increases or wavelength decrease and if the source is moving away then the frequency decrease or wavelength increase.

The movement of the source alters the wavelength and the received frequency of the waves ,even though the source frequency and wave velocity are unchanged. The Doppler effect can be observed for any type of waves like water waves, sound waves, light waves, etc.

There are many practical applications of Doppler effect ,let us look at few specific examples.

Astronomy

Astronomers have found that Universe is expanding by Doppler effect . When a star or a galaxy moves away from us the frequency decreases or wavelength increases.This change to longer wavelengths towards the red end of the visible spectrum for visible wavelengths is called a redshift. Conversely, if the source is moving towards the observer, there is a change to shorter wavelengths, i.e. a blueshift. Most of the galaxies appeared red shifted and hence moving away from us .This is the basis for the conclusion that the Universe is expanding and was one of the greatest intellectual revolutions of the twentieth century.

Radar Gun

Police use Radar gun to measure the speed of moving vehicles ,the radar gun function on the principle of Doppler effect .The radar gun includes a radio wave transmitter integrated with a radio wave receiver. The gun emits radio waves at a particular frequency so that the radio waves travel via the air and bounce off the moving vehicles. Some of these reflected waves will return back to the radar gun, and the waves that are reflected from the vehicles undergo a Doppler Shift.This Doppler shift in turn causes a change in the frequency of the radio waves. The radar gun makes use of this frequency change to measure the speed of the vehicle.

Ocean Depth 

The depth of a ocean can be determined by using Doppler effect ,the sound waves are transmitted from the ship towards the ocean floor using a sonar(sound navigation ranging) and they are reflected from the ocean floor back to the ship.The depth can be 

calulated using the formula

        v X t

   d= --------

            2

where v is the velocity of sound and t is time taken from the ship towards the ocean floor and back to the ship.

Future Trains

Future trains may travel in the air with no tracks hence no surface as well as air friction.Japan is using maglev(magnetic levitation) technology for fast speed trains, levitation means to rise or cause to rise into the air and float in apparent defiance of gravity. Maglev uses magnets to travel above the ground and hence can travel at high speeds.The magnetic field created by the electrified coils in the guideway walls and the track combine to propel the train. Maglev transport systems are in operation in just three countries Japan, South Korea and China.

 

A Japan Railway maglev train hit 603 kilometers per hour on an experimental track in Yamanashi setting a decisive new world record. The train is planned to begin service in 2027. Right now China operates the world's fastest commercial maglev, which has hit 431 kilometers per hour on a route through Shanghai.

Elon Musk new concept of Hyperloop transporation technolgy where a train can travel upto 700 mph .Hyperloop would work by propelling pods at high speeds through a vacuum tube with almost all air removed, capsules carrying passengers or cargo would be pushed along by a series of electromagnets. The almost complete lack of friction due to low air pressure means the train could travel at speeds of over 800mph, and 760mph with passengers on board.

China to take on Elon Musk hyperloop with supersonic flying train .China working on flying train which can travel at around 2500Mils/hour according to China Aerospace Science and Technology Corporation in short called CASC. Although the technology is still in its teething stages,the flying train is in essence a passenger pod that uses magnetic levitation and travels through a near-vacuum tube according to CASC  manager Liu Shiquan. The concept is similar to that of the Hyperloop.

 

 

 

science and Technology blog: Comets,Asteroids and Meteoroids

science and Technology blog: Comets,Asteroids and Meteoroids: Comets are snowballs composed of ice,rock and dust.Comets are formed farther from the Sun where ices would not melt. When a comet approach...

Comets,Asteroids and Meteoroids

Comets are snowballs composed of ice,rock and dust.Comets are formed farther from the Sun where ices would not melt. When a comet approaches the sun ,some of the ice in its nucleus (center) turns into gas .The gas shoots out of the sunlit side of the comet. The solar winds then carries the gas outward forming it into a long tail.

Astronomers divide comets into two main types ,long-period comets ,which take 200 years to orbit the sun ,short-period comets which complete their orbits fewer than 200 years. The two types come from two regions at the edges of the solar system. Long-period comets originate in the Oort cloud ,a cluster of comets far beyond the orbit of Pluto ,the short-period come from the Kuiper belt beyond the orbit of Neptune.

Our solar system most famous comet is probably the Halley's comet.Halley's comet has been spotted from earth every 75 years or so.

Asteroids are minor planets are basically broken pieces of unfinished planets and  leftover debris from the formation of our solar system about 4.6 billion years ago . Most of the asteroids circle around the sun in a region called asteroid belt between Mars and Jupiter .The belt contains more than 200 asteroids larger than 100 kilometers in diameter.

Scientists estimate the asteroid belt also contains between 1.1 million and 1.9 million asteroids larger than 1 km in diameter and millions of smaller ones. Astronomers have found several large asteroids with smaller asteroids orbiting them.The largest asteroid is Ceres, which is 933 kilometers (580 miles) across.

Meteoroids are broken chunks of asteroids that resulted from collisions in the asteroids belt. when meteoroids plunge into earth's atmosphere they form bright streaks of light called meteors as they disintegrate .Some meteoroids reach earth and they become known as meteorites. Some meteoroids are fragments from bodies such as Mars or our moon that have been thrown into space by an impact.

A meteor shower is the result of an interaction between a planet such as Earth and stream of debris from a comet or other source. 

 

Microchip Implants For Employees

We are in the beginning or midst of a new technology a microchip implantation for the employees or cyborg implants, which provide many benefits which outweigh the drawbacks.The microchip uses RFID technology (Radio-frequency identification) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders.

These microchips helps the employee to open the doors, log on to computers , buy snacks, interact with their smartphones, computers, sharing business cards, and storing medical/health information.

Sweden company called Epicenter ,Wisconsin tech company called Three Square Market are already using this new technology for its employees. Don’t be a scaredy-cat ,data in the microchip is encrypted and does not use GPS, so it cannot be used to track employees or obtain private information.

Television and broadcasting company NBC have claimed that by 2017 all Americans will have been implanted with a microchip that will allow for immediate identification of a person’s identity. Of course some are concerned that this gives total control to the government and can track the whereabouts of a person and hence violation of privacy. We become a government controlled cyborg. According to Elon Musk humans must become cyborgs and develop a direct high-bandwidth connection with machines or risk irrelevance and obsolescence.

Cyborgs have been as big a part of sci-fi and many cyborg movies were made on these concepts such as Terminator, Robocop even Star Trek, etc. Of course moral questions are raised around the ethics of this particular technological advancement.

Finally It  may  not  be an overstatement that one day scientists will invent  a super pill which provides everything from Vitamins to minerals ,good fats to bad fats what all your body requires instead of having a cheese burger , a macaroni that regular stuff we eat .These must be considered as human enhancement/augmentation or become less human as some may argue.

 

A New Laser Weapon Just Unveiled

US navy deploys the first laser weapon to protect ships in the Persian gulf.The LAWS, an acronym for Laser Weapons System,  It is deployed on board the USS Ponce amphibious transport ship.  

Since Laser travels with velocity of light its the fastest weapon and its 50000 times faster than an incoming ICBM .The $40 million system requires a team of three to operate it and a small generator to power its electricity supply, according to the Navy. The best part is it only costs American taxpayers about $1 per shot.

It operates in an invisible part of the electromagnetic spectrum so you don't see the beam, it doesn't make any sound, it's completely silent and it's incredibly effective at what it does according to Lt. Cale Hughes, laser weapons system officer.

Air-based laser weapon systems offer flexibility and precision for self defense against aircraft and missiles and weapons on the ground. 

Spontaneous Symmetry Breaking

We know that the Bosons are force carriers namely photon ,W and Z bosons (W+ W- an Z0) ,graviton and Gluon. Gluons mediate the interactions of the strong nuclear force, which binds together quarks to form protons and neutrons also holds the protons and neutrons together within an atom's nucleus.Photons are responsible for electromagnetic interactions,where as W and Z bosons are weak forces.

At enegies greater than 100 Gev these particles photons, W and Z bosons are essentially identical, the weak and electromagnetic interactions were manifestations of a single force but The Weinberg–Salam (spontaneous symmetry breaking) theory predicts that, at lower energies, this symmetry is broken so that the massless photon and the massive W and Z bosons emerge.

The question of how the W and Z got so much mass in the spontaneous symmetry breaking is still a perplexing one.The symmetry-breaking mechanism is called a Higgs field, and requires a new boson, the Higgs boson to mediate it.The graviton is a theoretical particle which has not yet been experimentally detected.

The name boson comes from the surname of Indian physicist Satyendra Nath Bose, a brilliant physicist from the early twentieth century who worked with Albert Einstein to develop a method of analysis called Bose-Einstein statistics.

One of the most dramatic effect of Bose-Einstein statistics is the prediction that bosons can overlap and coexist with other bosons. Fermions, on the other hand, can not do this, because they follow the Pauli Exclusion Principle which states that no two particles can have all 4 quantum numbers or quantum state same they have to differ in at least in one of them.

Einstein tried to show that under the appropriate conditions that is at very high energies prevailed at the big bang, all the fundamental forces of nature could be described as a unified single force. 

New Particle XI-CC++ Discovered

Scientists at CERN discovered a new particle called or named Xi-cc++ pronounced as (Ka-sigh-see-see-plus-plus) which is a doubly charmed Baryon.It consisting of two charm quarks and an up quark weighs approximately 3621 MeV where as a proton with two up quarks and one down quark weighs 938Mev. Both neutron and proton are baryons.As we know baryons are 3 quark particle and mesons are two quark particles basically a quark and anti-quark.

There are totally 6 quarks, the up (u),d own(d),strange(S) are light where as charm(c) ,Bottom(b) and Top (t) are heavy. Scientists predict there are many different combinations that can make up baryons. Until now the only baryons observed contain two light quarks and one heavy quark. Standard model also predicted the existence of heavy baryons made up of heavy charm quarks.This new particle may lead more insight into the strong interactions.

In contrast to other baryons, in which the three quarks perform an elaborate dance around each other, a doubly heavy baryon is expected to act like a planetary system, where the two heavy quarks play the role of heavy stars orbiting one around the other, with the lighter quark orbiting around this binary system, added Guy Wilkinson, former Spokesperson of the collaboration. 

  

Quantum Computers

Quantum computing is based on the concept of quantum nature of particles. Instead of just binary digits 0 and 1,  quantum computation works on several possibilities a quantum state can have. The basic unit of information in quantum computers is quantum bits or qubits. Any two or more quantum states can be added together superposed and the result will be another valid quantum state, conversely every quantum state can be represented as a sum of two or more other distinct states.

Quantum computing primarily employs two important concepts of quantum physics, superposition and quantum entanglement. In superposition particles are thought of as existing across all the possible states at the same time.However, once a measurement of a particle is made, and for example its energy or position is known, the superposition is lost and now we have a particle in one known state.

Quantum entanglement means that multiple particles are linked together in a way such that the measurement of one particle's quantum state determines the possible quantum states of the other particles even if they separated by several light years. Changing one particle will induce a change in the other.

A 2-bit register in an ordinary computer can store only one of four binary configurations (00, 01, 10, or 11) at any given time, a 2-qubit register in a quantum computer can store all four numbers simultaneously or combination of any two or more configurations because each qubit represents two values,That is a qubit can store a zero, a one, both zero and one, or an infinite number of values in between and be in multiple states (store multiple values) at the same time! If more qubits are added, the increased capacity is expanded exponentially.

It is extremely difficult to get particles to behave in the proper way for a significant length of time. A major difficulty in quantum computing has been any disturbance in a quantum system say a stray photon or wave of EM radiation causes the quantum state to collapse, a process known as decoherence. A quantum computer must be totally isolated from all external interference during the computation phase. Some success has been achieved with the use of qubits in intense magnetic fields, with the use of ions.

Although a fully functioning quantum computer is a longer-term goal, many fundamental and practical discoveries have been made in the name of quantum computing.

A team of NASA and Google engineers announced the D-Wave computer, running an optimization problem, came up with an answer 100 million times faster than a conventional computer with a single core processor. What a D-Wave machine does in a second would take a conventional computer with a single core 10,000 years to perform a similar task.

IBM made a new superconducting chip demonstrates a technique crucial to the development of quantum computers. Google, NASA, Microsoft, IBM, and the U.S. government are all working on this new technology.

  

Russian Telescope detects an Alien Signal?

Russian Astronomers claimed to have detected a strong signal from space actually 95 light years away from a star named HD164595 in the Hercules constellation. The star Contains a planet within it which is the size of Neptune and appears to have the right conditions for supporting life.

Seti(Search for Extraterrestrial Intelligence Institute) a private organization, searches the skies for alien life. Seth Shostak, the director for the Center for SETI Research, cautions people to curb their enthusiasm. There are many different possible explanations for what caused the detection.

SETI's Allen Telescope Array, based in northern California is looking for another signal by pointing their radio telescopes in that direction to see if it can pick up a repeat transmission. 

Gravitational Lensing

Gravitational lensing is the warping of light around objects in space that have a strong gravitational pull like our sun.Einstein general theory of relativity describes how gravity can distort the path of light, altering its trajectory.

 

Lensing can produce multiple images of a distant source a phenomenon termed strong lensing. The foreground lens is a galaxy and when the background source is a quasar or resolved jet, the strong lensed images are usually point-like multiple images; When the background source is a galaxy or extended jet emission, the strong lensed images can be arcs or rings.

 

Microlensing ,the temporary brightening of a star due to the magnification induced by a foreground object that crosses the line of sight to the observer. Microlensing has also been effective in the detection of exoplanets as well.

 

Weak gravitational lensing holds enormous promise in observational cosmology, as the technique, properly employed, can reveal the distribution of dark matter independently of any assumptions about its nature. Dark matter does have mass so we can use gravitational lensing to map the dark matter in the universe.

 

We can use the effect to peer deeper into the Universe than would otherwise be possible with our conventional telescopes. In fact, the most distant galaxies ever observed, ones seen just a few hundred million years after the Big Bang, were all discovered using gravitational lensing. Astronomers use gravitational microlensing to detect planets around other stars. The foreground star acts as a lens for a background star.

 

 

https://www.scientificamerican.com/article/for-first-time-einsteins-relativity-used-to-weigh-a-star/?WT.mc_id=SA_TW_SPC_NEWS&sf86652721=1




 

Super Critical CO2 For Power generation

Using CO2 to generate power will revolutionize how power is generated, built, and distributed. Using super critical CO2 to run the turbines for electricity generation instead of conventional steam(water). We all know that water boils at 100 degree C ,but the boiling point can be raised by increasing the pressure, a further increase in pressure and temperature leads us to a point at which the latent heat of vapourisation is zero, or there is no boiling. Water directly becomes steam. This is the Critical Pressure and the Critical Temperature. For steam this occurs at 374 deg C and 220.6 bar.

In super critical condition the density of gas and liquid becomes equal .The critical point for carbon dioxide occurs at a pressure of 73.8 bar and a temperature of 31.1°C. These parameters make equipment design and reaction set-up relatively simple. For water this occurs at 374 deg C and 220.6 bar. The great advantage of CO2 over water it reaches SCF state at almost room temperature.

CO2 is not produced in the the SCF process, rather already existing CO2 is used. There is no addition to any greenhouse effect. 

The use of CO2 in power turbines has been an active area of research for a number of years, and now multiple companies are bringing early stage commercial products to market.

https://www.youtube.com/watch?v=-gCTKteN5Y4&t=175s

Holography

Holography is a three dimensional recording of an image using interference pattern and not regular image focused on film also called lensless photography.The term ‘hologram’ can refer to both the encoded material and the resulting image. Holography was invented by Dennis Gabor in 1948 later awarded Nobel prize.

The light used to make a hologram must be coherent, i.e. of a single wavelength or frequency and with all the waves in phase.  Before reaching the object, the beam is split into two parts, one the reference beam is recorded directly on the photographic plate and the other is reflected from the object to be photographed and is then recorded. Since the two parts of the beam arriving at the photographic plate have traveled by different paths they combine to create an interference pattern of the object. 

A hologram exhibits a property called parallax, the image will change its appearance if you look at it from a different angle, just as if you were looking at a real 3D object.

The image can be reconstructed even from a damaged or partially available film because every point of the hologram contains the image of the object.

The images are scalable. They can be made with one wavelength and viewed with another, with the possibility of magnification.

Applications

Bubble chamber holography has been performed at the Enrico Fermi National Laboratory.Three-dimensional tracks in a 15-foot deep bubble chamber were recorded. The creation and annihilation of matter and antimatter can be seen through these holograms.

Biomedical applications of holography is actively pursued in the U.S. and Europe. Holograms are made inside live organs through optical fibers, providing more details than any previous alternate techniques.

Instantaneous growth rate of a live plant can be directly observed through a hologram. Using optical fibers, the rigid body movements can be isolated from the net growth information.

Bi-focal contact lenses are being manufactured. Compact discs players use holograms to handle light. Grocery store scanners use spinning holograms. High resolution spectrometers use holographic gratings. Anti-counterfeiting in credit card is now a common practice.

 

 

 

 

LASERS

The acronym LASER refers to "Light Amplification by Stimulated Emission of Radiation".The two terms that are important here are one Spontaneous emission and the others stimulated absorption, stimulated emission.

When atom in the ground state absorbs a photon then the atom is excited to higher energy level this is called stimulated absorption, the atom has a short duration to remain in the exited state,the lifetimes are typically a few nanoseconds ( 10^-9  s) and it jumps back to the lower energy state releasing a photon in the process is called spontaneous emission.

While in the excited state if the atom absorbs a photon having an energy equivalent to the energy difference between the two states and jumps back to the lower energy state is called stimulated emission.

There are two conditions for producing LASERS 1) Stimulated emission 2) Population Inversion meaning there are more atoms in the excited state than the ground state.

There are several other important conditions that our laser must satisfy.  First of all, the light that it produces must be coherent. That is to say, it must emit photons that are in-phase with one another. Secondly, it should emit monochromatic light, i.e. photons of the same frequency (or wavelength).  Thirdly, it would be desirable if our laser's output were collimated , producing a sharply defined "pencil-like" beam of light  Lastly, it would also be desirable for our laser to be efficient, i.e. the higher the ratio of output energy - to - input energy, the better.

Types of lasers

Solid-state lasers have lasing material distributed in a solid matrix (such as the ruby or neodymium:yttrium-aluminum garnet "Yag" lasers). 

Gas lasers (helium and helium-neon, He Ne, are the most common gas lasers) have a primary output of visible red light. CO2 lasers emit energy in the far-infrared, and are used for cutting hard materials.

Excimer lasers (the name is derived from the terms excited and dimers) use reactive gases, such as chlorine and fluorine, mixed with inert gases such as argon, krypton or xenon. When electrically stimulated, a pseudo molecule (dimer) is produced. When lased, the dimer produces light in the ultraviolet range.

Dye lasers use complex organic dyes, such as rhodamine 6G, in liquid solution or suspension as lasing media. They are tunable over a broad range of wavelenigths.

Semiconductor lasers, sometimes called diode lasers, are not solid-state lasers. These electronic devices are generally very small and use low power. They may be built into larger arrays, such as the writing source in some laser printers or CD players.

LASER APPLICATIONS

Many scientific, military, medical and commercial laser applications have been developed since the invention of the laser in 1958. They extend from Medical, Welding and cutting ,Surveying, Laser nuclear fusion, Communications, laser printing, spectroscopy, laser cooling ..etc.

Database management systems (DBMS)

A database is a collection of interrelated data in an organized and structured way. DBMS means database management systems which is a Software or collection of programs that enables you to store, modify, and extract information from a database.

 

Basically there are three types of DBMS

 

1) Hierarchical DBMS

2) Network DBMS

3) Relational DBMS

 

In a hierarchical DBMS the data is  organized in a tree-like structure also called a parent-child relationship. In hierarchical database a parent can have multiple children, but a child can only have one parent.

 

Network DBMS is similar to Hierarchical except a child can have more than one-parent. While conceptually simple this database structure can quickly become very complicated.

 

In a relational DBMS data is organized in the form of two dimensional tables where rows are called records and the columns are called fields. 

 

In case of Hierarchical and Network DBMS the data is manipulated using macros and these are mostly implemented on main-frame computers.

 

Where as the RDBMS uses SQL (structured query language) for data manipulations. Oracle, Sybase and SQL server examples of RDBMS. Tables are linked together using a field that uniquely identifies each record this makes the database very effective and called Indexing.

 

The data redundancy is very high in case of Relational database which increases the size of the database and decreases the efficiency of the database while its almost absent in the other two database types. Also need to create Index tables to speed up the query process in case of RDBMS which increases the size of the database further and also requires data purging and Index management.

 

 

 

 

Negative Mass

Washington State University physicists have created a fluid with negative mass. Genrally when you apply force F=ma the mass move in the direction of the force ,but in case of negative mass the direction is opposite to the force applied, that is it accelarates backwards.

 

The necessary conditions for negative mass were created by cooling rubidium atoms to just a hair above absolute zero, creating what is known as a Bose-Einstein condensate called superfluid state in which the particles synchronize and move in unison without losing energy. This was achieved using lasers .

 

A second set of lasers were applied that kicked the atoms back and forth and changed the way they spin. Now when the rubidium rushes out fast enough, it behaves as if it has negative mass. Once you push, it accelerates backwards.

 

The problem with negative mass is that it appears to violate the energy condition. Indeed, that’s how theoretical physicists have been able to show how negative mass could be used to create exotic objects like wormholes.

 

Saoussen Mbarek and Manu Paranjape at the Université de Montréal in Canada say they’ve found a solution to Einstein’s theory of general relativity that allows negative mass without breaking any essential assumptions.

 

The crucial breakthrough by Mbarek and Paranjape is to show that negative mass can produce a reasonable Schwarzschild solution without violating the energy condition. Their approach is to think of negative mass not as a solid object, but as a perfect fluid, an otherwise common approach in relativity.

 

 

 

Flying Cars On The Horizon

Preorder your flying car and it will be available this year, Slovakia based Engineering company AeroMobil recently announced that its latest model will be available this year. This vehicle  is both a four wheeled car as well an aircraft. AeroMobil will be launching the new model at Top Marques Monaco,the most exclusive supercar show on April 20 ,2017.

The flying car was built in compliance with the existing regulatory frameworks for both cars and airplanes which means it is possible that future owners would need both a driver's license and a pilot license to operate the vehicle.

 

Another company Massachusetts-based (US) firm Terrafugia said that its prototype TF-X is expected to be ready by 2018 .Terrafugia’s vision for the future is the TF-X a mass-market flying car with the potential to revolutionize the way we all get around. An all-electric vehicle with vertical takeoff and landing (VTOL) capabilities and computer-controlled flight, the TF-X is the flying car of the future.    

 

The designs include fold-out wings and helicopter-like rotor blades. The vehicle will have a cruising speed of around 200mph (322 km/h).The planned four-person TF-X will be semi-autonomous and use computer-controlled so that passengers can simply type in a destination before taking off.

The vehicle will be able to recharge its batteries either from its engine or by plugging in to electric car charging stations.It is expected to cost around £183,000 ($261,000) when it goes on sale.
 
It will be a thrilling experience to drive as well as fly and they are on the horizon.

 

Watch some of the flying cars

https://www.youtube.com/watch?v=VRZNLBL7Px4



 

Saturn Mission Spacecraft Cassini Final Journey

Cassini-Huygens Launched in 1997 completed 20 years of remarkable journey for studying the Saturn and its moons ,it reached Saturn in 2004 and since then On the final orbit, Cassini will plunge into Saturn’s atmosphere, sending back new and unique science to the very end. After losing contact with Earth, the spacecraft will burn up like a meteor, becoming part of the planet itself.  Cassini the orbiter and Huygens the Titan lander.

It Collected data of the two moons of Saturn, Enceladus and Titan, Cassini data revealed their potential to contain habitable or at least prebiotic environments. On December 25, 2004, Huygens separated from the orbiter, and it landed on Saturn's moon Titan.  It successfully returned data to Earth, using the orbiter as a relay. This was the first landing ever accomplished in the outer Solar System.

Cassini's finale plunge is a truly spectacular end for one of the most scientifically rich voyages yet undertaken in our solar system. From its launch in 1997 to the unique Grand Finale science of 2017, the Cassini-Huygens mission has racked up a remarkable list of achievements. 

NASA has chosen the name as "Cassini Grand Finale" for the dramatic final phase of its Saturn-studying Cassini mission, with a little help from the public.  

Significance of Avogadro's Number

Avogadro's number is the number of atoms,molecules or ions in one mole of a substance. It is the number of atoms in exactly 12 grams of carbon-12 or 16 grams of Oxygen-16. This experimentally determined value is approximately 6.02214179×1023 particles per mole.

We need to look at another parameter called AMU (atomic mass unit).One AMU is the average of the proton rest mass and the neutron rest mass. This is approximately  1.67377 x  10^-24 grams . 

The mass of a mole of substance is called the molar mass of that substance. The molar mass is used to convert grams of a substance to moles and is used often in chemistry.

There are 6 protons and six neutrons in carbon-12.

          so the molar mass of carbon-12 atom = 
           12 x 1.67377 x 10^-24 x 6.02214179×1023

2323

                        = 12.09 grams 

That is 1 mole of carbon is equivalent 12 grams of carbon-12 and contains Avogadro's number of atoms of Carbon-12. An element's atomic mass is listed as the average of all its isotopes on earth and can found in the periodic table. 

Let us calculate the molar mass of water   H2O

Symbol Element  Atomic weight   Atoms  

H Hydrogen 1.00794             2  

O Oxygen        15.9994             1  

Molar mass of H2O = 2 x 1.00794 + 1 X 15.9994 =18.01528 grams/mole

So one mole of any substance contains Avogadro number of  atoms or molecules or ions but molar mass is different.