Ram Pressure

Ram pressure is a pressure exerted on a body which is moving through a fluid medium. It can be said that the molecules in the fluid(only two known fluids i.e, liquids and gases) 'ram' onto the moving particles creating pressure. It causes a strong drag force to be exerted on the body. It is given by:

P = ρv² 

where P is the pressure, ρ(rho) is the density of the fluid and v the velocity of the body. Alternatively the body can be stationary and v describe the velocity of the fluid, e.g. the solar wind.

The best example for this is a meteor traveling through the Earth's atmosphere which produces a shock wave generated by the extremely rapid compression of air(the state doesn't change to plasma state) in front of the meteoroid. It is primarily this ram pressure (and not friction, mainly) which heats the air which in turn heats the meteoroid as it flows around it.

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Meteors, Meteoroid and Meteorites.

Meteoroid is a particle of debris in the Solar System. The meteoroid can be of the size of a speck of sand or even a boulder. The visible path of a meteoroid that enters Earth's (or another body's) atmosphere is called a meteor, or colloquially a shooting star or falling star. If a meteoroid reaches the ground and survives impact, then it is called a meteorite. A meteorite is supposed to have destroyed the whole of the dinosaurs a few million years ago. Many meteors appearing seconds or minutes apart are called a meteor shower. The root word meteor comes from the Greek meteōros, meaning "high in the air".

A meteor in Canada 

Meteoroid: The International Space Union describes a meteoroid as a "solid object that is much smaller than an asteroid but much larger than an atom". Very small meteoroids are known as micrometeoroids or interplanetary dust. 

Meteors: A meteor is the visible path of a meteoroid that has entered the Earth's atmosphere. Millions of meteors occur in the Earth's atmosphere every day. Meteors burn in the atmosphere, not due to friction, but due to ram pressure. The pressure heats it so much that the meteor glows and leaves a tail of glowing gases.

Perseid meteor

Meteorite(s): A meteorite is a portion of a meteoroid or asteroid that touches the surface of the Earth and survives even the impact. Meteorites are sometimes, but not always, found in association with hypervelocity impact craters; during energetic collisions, the entire impactor may be vaporized, leaving no meteorites. 

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Science behind optical illusion

1)

Found anything amazing?

I’ll tell you what is amazing in this. Observe the center of the square as the big circles move in. The square seems full right? Now observe any one big circle as it moves on a side of the square. Its incomplete right? Know why this happens?

Ans: When you look at the center of the square, the brain tries to fill the square and tries to make it look complete though its incomplete without ‘you’ realizing it.

2)

These “fish” may appear to be wiggling, but the only thing changing in this animation is the color.

3)

The illusion in this is that the flat surface seems to move. This is because of a certain pattern of white and pink coloured flowers.  This makes a wave kind of motions which fools our mind and makes our brain think that the surface is moving. The surface can also be imagined as a floor of the swimming pool. The same happen when you look down.

4)

The line doesn’t look straight? Its abrupt? No, not at all. The line is completely straight. It seems to be slanting because of the difference of arrangement of white and black boxes or squares. You can make your own this way.

5)

This will amaze you. The lines that can be seen are straight. Its hard to believe it.

6)

The stairs that you are seeing isn’t really stairs. Its a 2D figure.

This happens because our brain tries to analyze the whole figure as a 3D figure because the blocks are 3D. So it seems that the whole image is 3D but its 2D.

7)

This man is actually bigger than the bottle. He isn’t standing on the cap, but on the floor itself.

Proof: you can see his his shadow right beside him. This illusion happens because the coke bottle is very near to the camera than the man. So you feel that the bottle is bigger than him. This same phenomenon occurs during a solar eclipse. The Moon is so close to the Earth that it actually seems to block the Sun’s rays completely though it is only on a part of the Earth.

8 )  The simplest:

Both the figures the are 2D. But the cube looks 3D because i have joined the three planes or 3 axes viz. x , y, z.

The world we see is in 3D. therefore, our brain tries to imagine everything in 3D. Therefore anything that looks, feels like 3D is imagined as a 3D object by our brain. What if i asked you to imagine even the time axis, i.e 4th dimension? You cant even think of it right? Its the same explanation from above. We haven’t seen the 4th dimension. Therefore, we cant imagine it.

Many other optical illusions.

1:

2:

3:

 4:

 5:

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The Asteroid Belt

The Asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter where a huge number of asteroids revolve around the Sun. These asteroids are also called minor planets. The asteroid belt region is also termed the main asteroid belt or main belt because there are other asteroids in the solar system such as near-Earth asteroids and trojan asteroids. More than half the mass of the main belt is contained in the four largest objects: Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea. Ceres was thought of a an asteroid first, but later was subjected under dwarf planet, just like our Pluto. These have mean diameters of more than 400 km, while Ceres, the main belt's only dwarf planet, is about 950 km in diameter. The remaining bodies range down to the size of a dust particle. 

The asteroid material is so thinly distributed that multiple unmanned spacecraft have traversed it without incident. Nonetheless, collisions between large asteroids do occur, and these can form an asteroid family whose members have similar orbital characteristics and compositions. Collisions also produce a fine dust that forms a major component of the zodiacal light. Individual asteroids within the main belt are categorized by their spectra, with most falling into three basic groups: carbonaceous (C-type), silicate (S-type), and metal-rich (M-type). Have you ever thought why Jupiter has so many moons? The answer lies in the Asteroid Belt. The asteroids revolving, are pulled by the super gravitational force of Jupiter. The pulled asteroid then revolves around Jupiter and slowly turns into a sphere. 

Asteroids are left over materials from the formation of the Solar System.  These materials were never incorporated into a planet because of their proximity to Jupiter's strong gravity.

Asteroids: Asteroids (from Greek ἀστήρ 'star' and εἶδος 'like, in form') are a class of small Solar System bodies in orbit around the Sun. Asteroids are the left over particles in space that didn't combine to form a planet. They have also been called planetoids, especially the larger ones. 

Comets: A comet is an icy, small Solar System body. It displays a visible coma (a thin, fuzzy, temporary atmosphere) and sometimes also a tail when close enough to the Sun. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet. Comet nuclei are themselves loose collections of ice, dust, and small rocky particles, ranging from a few hundred meters to tens of kilometers across. It is like they burn in vacuum. But the so called "shooting stars" must not be mistaken to these comets. A shooting star is considered by people to bring luck and also fulfill their wishes, but a comet is considered to be a bad omen. 

A Shooting Star

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Special article: Android OS

Android

 Android is a software stack for mobile devices. Android includes an operating system,middle ware and key applications. Android OS smartphones are one of the best and most selling phones in the world. It's the best-selling Smartphone platform. All prefer smartphones with Android OS because of the large extent of apps or applications. Google Inc. purchased the initial developer of the software, Android Inc., in 2005. Android's mobile operating system is based on the Linux kernel. Google and other members of the Open Handset Alliance collaborated on Android's development and release. The Android Open Source Project (AOSP) is tasked with the maintenance and further development of Android. 

 Android has a large community of developers writing applications ("apps") that extend the functionality of the devices. There are currently over 200,000 apps available for Android, the main reasons why people prefer Android smartphones. Android Market is the online app store run by Google, though apps can also be downloaded from third-party sites. Developers write primarily in the Java language, controlling the device via Google-developed Java libraries. 

 Voice recognition, hand-writing recognition, smart virtual keypad, many free and fun widgets on your home screen, Quick look features, faster and compliant browsers and many other superb features! are on Android. 

 Games and other apps like angry bird, entangled, Blosics etc. improve the touch experience and make it a place of fun. Special Ringtones, sound effects, 3D effects also enhance it. 

 Over 5MP cameras with auto-focus,  HD cameras, secondary cameras over 1MP, at least 760 MHz processors, LED Flash etc. are also some of the amazing features of Android smartphones.

 The Android open-source software stack consists of Java applications running on a Java-based, object-oriented application framework on top of Java core libraries running on a Dalvik virtual machine featuring JIT compilation. Libraries written in C include the surface manager, OpenCore media framework, SQLite relational database management system, OpenGL ES 2.0 3D graphics API, WebKit layout engine, SGL graphics engine, SSL, and Bionic libc. The Android operating system, including the Linux kernel, consists of roughly 12 million lines of code including 3 million lines of XML, 2.8 million lines of C, 2.1 million lines of Java, and 1.75 million lines of C++.

 All smartphones being capacitive touch, multi-tasking or multi-touch is also available. This brings a whole lot of fun in the ouch experience. 

Recent Versions of Android OS are: 

1. 2.0/2.1 (Eclair)
2. 2.2 (Froyo)
3. 2.3 (Gingerbread)
4. 3.0/3.1 (Honeycomb)
5. Ice Cream Sandwich

 2011, Motorola will be releasing the worlds most powerful smartphone Motorola Atrix 4G. 2011 is awaiting the release of 4G phones. Samsung, HTC, Motorola, Sony Ericsson are some of the leading world phone producers who are releasing 4G phones.

Competitors:  There are many competitors for Android like Mac, Nokia(Symbian) etc. which threaten the company. But the recent growth of android has pushed back its competitors. To compete back with the Android, Nokia is making a new OS which could compete with Android and Mac is upgrading its apps, environment and experience. 

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Capacitive sensing

You have now understood how capacitive touch screens work. Now let me help you in understanding how the designs are mad and how multi-tasking is performed.

Design: Capacitive sensors can be constructed from many different media, such as copper, Indium tin oxide (ITO) and printed ink. Copper capacitive sensors can be implemented on standard FR4 PCBs as well as on flexible material. ITO allows the capacitive sensor to be up to 90% transparent (for one layer solutions). The size and spacing of the capacitive sensor are both very important to the sensor's performance. In addition to the size of the sensor, and its spacing relative to the ground plane, the type of ground plane used is very important. Since the parasitic capacitance of the sensor is related to the electric field's (e-field) path to ground, it is important to choose a ground plane that limits the concentration of e-field lines with no conductive object present.

Designing a capacitance sensing system requires first picking the type of sensing material (FR4, Flex, ITO, etc.). One also needs to understand the environment the device will operate in, such as the full operating temperature range, what radio frequencies are present and how the user will interact with the interface.

There are two types of capacitive sensing system: mutual capacitance, where the object (finger, conductive stylus) alters the mutual coupling between row and column electrodes, which are scanned sequentially; and self- or absolute capacitance where the object (such as a finger) loads the sensor or increases the parasitic capacitance to ground. In both cases, the difference of a preceding absolute position from the present absolute position yields the relative motion of the object or finger during that time. The technologies are elaborated in the following section. 

Surface capacitance:

In this basic technology, only one side of the insulator is coated with a conductive layer. A small voltage is applied to the conductive layer, resulting in a uniform electrostatic field. When a conductor, such as a human finger, touches the uncoated surface, a capacitor is dynamically formed. Due to the sheet resistance of the surface, each corner is measured to have a different effective capacitance. The sensor's controller can determine the location of the touch indirectly from the change in the capacitance as measured from the four corners of the panel; the larger the change in capacitance, the closer the touch is to that corner. As it has no moving parts, it is moderately durable. But it has limited resolution, is prone to false signals from parasitic capacitive coupling, and needs calibration during manufacture. It is therefore most often used in simple applications such as industrial controls and kiosks.

Projected capacitance:

Projected capacitive touch (PCT) technology is a capacitive technology which allows more accurate and flexible operation, by etching the conductive layer. An X-Y grid is formed either by etching one layer to form a grid pattern of electrodes, or by etching two separate, perpendicular layers of conductive material with parallel lines or tracks to form the grid; comparable to the pixel grid found in many liquid crystal displays (LCD).

The greater resolution of PCT allows operation with no direct contact, such that the conducting layers can be coated with further protective insulating layers, and operate even under screen protectors, or behind weather and vandal-proof glass. Due to the top layer of a PCT being glass, PCT is a more robust solution versus resistive touch technology. Depending on the implementation, an active or passive stylus can be used instead of or in addition to a finger. This is common with point of sale devices that require signature capture. Gloved fingers may or may not be sensed, depending on the implementation and gain settings. Conductive smudges and similar interference on the panel surface can interfere with the performance. Such conductive smudges come mostly from sticky or sweaty finger tips, especially in high humidity environments. Collected dust, which adheres to the screen due to the moisture from fingertips can also be a problem. There are two types of PCT: self capacitance, and mutual capacitance.

Mutual capacitance:

Mutual capacitive sensors have a capacitor at each intersection of each row and each column. A 12-by-16 array, for example, would have 192 independent capacitors. A voltage is applied to the rows or columns. Bringing a finger or conductive stylus near the surface of the sensor changes the local electrostatic field which reduces the mutual capacitance. The capacitance change at every individual point on the grid can be measured to accurately determine the touch location by measuring the voltage in the other axis. Mutual capacitance allows multi-touch operation where multiple fingers, palms or stylus can be accurately tracked at the same time.

Self-capacitance:

Self-capacitance sensors can have the same X-Y grid as mutual capacitance sensors, but the columns and rows operate independently. With self-capacitance, the capacitive load of a finger is measured on each column or row electrode by a current meter. This method produces a stronger signal than mutual capacitance, but it is unable to resolve accurately more than one finger, which results in "ghosting", or misplaced location sensing.

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Why do we expect life mostly on Mars?

There had been strange beliefs that life existed on Mars and Moon. But the concept of life on Moon was discarded when the face on the moon(many craters on its surface looked like a face) was proved to be only the craters. But the search for Extra Terrestrial Life continued, and people thought that there was life form on Mars.
 And the main reasons for that are:

Photo of microscopic rock formations
indicating past signs of water

1. Misunderstanding: In 1877, an Italian Astronomer Giovanni Schiparelli saw a series on Mars. He called them canali, the Italian word for channels. This word was translated into English as 'canals', by mistake. Thus many people thought that intelligent life on Mars, dug these canals.
   
2. Discovery of water(indirectly):  The rocks that were found on Mars' surface, showed signs of water. The photo alongside shows the formation of a microscopic rock which is possible only with the presence of water.
   
3. Channels: Viewed from the telescope, Mars shows lines on its surface. These lines must probably be channels in which water would flow, and also to become permanent, it has to be water.
   
4. Discovery of Hydrocarbons: Hydrocarbons like Methane and Formaldehyde were detected on Mars recently by the satellites on Mars and hint that life could have existed in it. Methane gas is produced when organic matter(like life) decomposes.
   
   

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Mars

Mars (Greek: Ares) is the god of War. The planet probably got this name due to its red color; Mars is sometimes referred to as the Red Planet. (An interesting side note: the Roman god Mars was a god of agriculture before becoming associated with the Greek Ares; those in favor of colonizing and terraforming Mars may prefer this symbolism.) The name of the month March derives from Mars.


ARE THERE REALLY CANALS ON MARS?

Mars has been known since prehistoric times. Of course, it has been extensively studied with ground-based observatories. But even very large telescopes find Mars a difficult target, it's just too small. It is still a favorite of science fiction writers as the most favorable place in the Solar System (other than Earth!) for human habitation. But the famous "canals" "seen" by Lowell and others were, unfortunately, just as imaginary as Barsoomian princesses.

The canals weren't actually 'canals'. It was 'canales' which, with passage of time became 'canals' and rumors began that there were ET life on Mars that built the canals.


During the Solar system formation, Mars was created out of the protoplanetary disk that orbited the Sun as the result of a stochastic process of run-away accretion. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points such as chlorine, phosphorus and sulphur are much more common on Mars than Earth; these elements were probably removed from areas closer to the Sun by the young Sun's powerful solar wind.

The Phoenix lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium, sodium,potassium and chloride. These nutrients are found in gardens on Earth, and are necessary for growth of plants. Experiments performed by the Lander showed that the Martian soil has a basic pH of 8.3, and may contain traces of the salt perchlorate.

Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. Sometimes the streaks start in a tiny area which then spreads out for hundreds of meters. They have also been seen to follow the edges of boulders and other obstacles in their path. The commonly accepted theories include that they are dark underlying layers of soil revealed after avalanches of bright dust or dust devils. However, several explanations have been put forward, some of which involve water or even the growth of organisms.

Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing 25–30% of the atmosphere to condense out into thick slabs of CO₂ ice (dry ice).When the poles are again exposed to sunlight, the frozen CO₂ sublimes, creating enormous winds that sweep off the poles as fast as 400 km/h. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds. Clouds of water-ice were photographed by the Opportunity rover in 2004.

The polar caps at both poles consist primarily of water ice. Frozen carbon dioxide accumulates as a thin layer about one metre thick on the north cap in the northern winter only, while the south cap has a permanent dry ice cover about eight metres thick. The northern polar cap has a diameter of about 1,000 kilometres during the northern Mars summer, and contains about 1.6 million cubic kilometres of ice, which if spread evenly on the cap would be 2 kilometres thick. (This compares to a volume of 2.85 million cubic kilometres for the Greenland ice sheet.) The southern polar cap has a diameter of 350 km and a thickness of 3 km. The total volume of ice in the south polar cap plus the adjacent layered deposits has also been estimated at 1.6 million cubic kilometers. Both polar caps show spiral troughs, which are believed to form as a result of differential solar heating, coupled with the sublimation of ice and condensation of water vapor.

The seasonal frosting and defrosting of the southern ice cap results in the formation of spider-like radial channels carved on 1 meter thick ice by sunlight. Then, sublimed CO₂ and probably water increase pressure in their interior producing geyser-like eruptions of cold fluids often mixed with dark basaltic sand or mud. This process is rapid, observed happening in the space of a few days, weeks or months, a growth rate rather unusual in geology, especially for Mars.

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Consequences of rotation of the Earth

The Earth has always been in constant rotation since its formation. Like other planets in the Solar System, Earth was formed by the Molecular Cloud. But the speed of rotation has been decreasing since its formation.

Lets see the results of its rotation. 

1. Day-Night phenomenon: The primary effect is the phenomenon of day-night. As Earth rotates on its axis, the day and nights are caused. The part of the Earth that receives sunlight experiences 'day' and the part that does not experiences 'night'.
   
   
   
2.  Coriolis effect: The rotation of the Earth causes Coriolis Effect and results in changes in weather and atmospheric pressure. This leads to a certain patten of rotation of the winds in both the hemispheres. In the Northern hemisphere, in high pressure winds rotate clockwise and low pressure winds rotate
   anti-clockwise(counter clockwise). Its the vice-versa in the Southern hemisphere. This causes differences in wind pressure all over the world.
   
3. Change in the shape of the Earth: The Earth's shape isn't exactly spherical. Its flattened near the poles and bulged near the Equator. This is due to the rotation of the Earth. Thus the Earth is known as a spheroid or oblate sphere.
   
   
   

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