Constellations

CONSTELLATIONS :

          If you look in the sky year after year, you will see that stars do indeed appear fixed relative to each other. Furthermore, throughout the year each night the entire pattern of stars appears to rigidly orbit the Earth. If you gaze at the sky on a clear, dark night you will  able to notice this patterns, technically called "Asterisms", formed by bright stars. These recognizable patterns of stars are informally called "constellations". The celestial sphere  (click the link) is divided into 88 constellations of different sizes and shapes. The boundaries of the constellations are straight lines that meet at right angles.

ZODIAC CONSTELLATIONS:

        The constellations through which the Sun moves throughout the year as it travels along the ecliptic are called "Zodiac constellations". We cannot see the stars of these constellations when the Sun is among
them, but we can plot the Sun's path on the celestial sphere to determine through which constellations it moves. Basically, there are 12 zodiac constellations whose borders were set in antiquity. Later astronomers confirmed that there were 13 constellations through which the Sun moves throughout the year. In this list, you will find all the 13 zodiac constellations and the time when the sun passes through them.

             In this section, we gonna talk about the basic constellations that we always see by our naked eyes. some of the well-known constellations are "Orion", 'Ursa Major", "Scorpius", "Ursa Minor" etc

CONSTELLATIONS USED IN NAVIGATING OTHER STARS:

         From the ancient time before the invention of compass, people use the constellations in navigation. Constellations can be used to find other stars too.

       🎵 BIG DIPPER:  If you live in northern hemisphere, you can use the Big Dipper to find the north direction by find out the North Star. To do this, at first locate the Big Dipper. if you see the dipper upside down in the sky, imagine the dipper resting on an upside-down table above it. Locate the two stars of the

bowl farthest from dipper's handle. They're called "pointer Stars". Connect the pointer stars by a line and take it away from the table, the first bright star you see is "Polaris". It's also known as "North Star" because it's located almost over the North Pole. So you can easily find North Star like this. North Star is widely used in navigation. Whenever you face Polaris or North Star, you are actually facing north. East is then on your right, south is behind you and west is on your left side.
                                         Now being familiar with Big Dipper, you also easily can locate other stars. Imagine, you gripped the handle of the Dipper and slammed its bowl straight down, the first group of bright stars you encounter will be "Leo". The brightest star in this group is Regulus.

     🎵 WINTER TRIANGLE:  Winter Triangle connects 3 bright stars of the constellations of "Orion",Sirius". While you're facing the Orion locate it's belt, follow the mental line from it to the left, the first bright star that you will encounter is the brightest star in the sky "Sirius".

"Canis Major", "Canis Minor". You can observe this triangle during the winter months in the northern hemisphere. It passes the sky at night during the middle of the winter.If you able to find the winter triangle, you can also encounter the Orion. It will be easy for you then to find the brightest star in the sky "

     🎵 SUMMER TRIANGLE:  The "summer triangle" graces the night sky in summer. It connects 3 bright stars of the constellations of "Lyra", "Cygnus", "Aquila", names of the stars are "Vega", "Deneb", "Altair" from the 3 constellations respectively. A conspicuous portion of the Milky Way forms a beautiful
background for these constellations, Which are nearly overhead during the middle of the summer at midnight.

                     These are some examples which are used to detect other stars or in navigation. apart from these there are some constellations which are very large like "Ursa Major", which can describe an entire area of the sky and all the object in it.       

History of space exploration and achievements

HISTORY OF SPACE EXPLORATION AND ACHIEVEMENTS:


Exploration is always in the genes of human but space exploration became much popular in the early 21st century due to the commercialization of space industry.

       The beginning of space exploration Was in 1957 when Soviet Union sent the first unmanned mission into space. They launched a satellite called "Sputnik 1".Later in

•  Sputnik 1

that year, they again launched another satellite known as "Sputnik 2" which carried a dog into orbit. After experimenting with animals, the first manned mission took place when Russia on April 12, 1961 carried a young man named Yuri Gagarin into the orbit. Followed by that couple of more mission took place.

     With development   of technology it was the time to take human to the moon which turned into reality in 1969 when Neil Armstrong and his crew made a safe landing on moon in Apollo 11. Neil Armstrong became the first human to step foot on the moon.

• Neil Armstrong on the moon

 After triumphing the moon it was the time to give their attention to Mars. In 1971 "Mariner 9" became the first space probe to orbit the red planet. In so many Mars missions organizations around the world faced lot of failures but nothing stop them to exploring the unknown. As a result of constant hard work NASA became the first space organization to land their "Viking Landers" on

• Viking lander on Mars

Martian soil. It just create a whole new enthusiasm among the industry. Later so many Mars missions took place, many succeeded and many didn't. The latest successful mission was taken by India on 24th September 2014. With this India became the first Asian country to successfully send an orbiter to Mars. It was completed in a record budget of $71 million, making it the least expensive Mars mission to date.

        Due to remarkable achievements of mankind, space exploration has now become more popular in 21th century mainly because of the commercialization of space industry. Companies like Space x, Blue origin made space exploration more cheaper than ever.

• Space x

 Space exploration is also done by astronomers with telescopes. Telescopes like Hubble Space Telescope, James Webb Telescope also plays an important part in astronomy. In 2019 Swiss scientists Michel Mayor and Didier Queloz received half of the Nobel Prize award for their ground breaking discovery of an exoplanet orbiting a solar type star. This will disclose a whole new chapter for the space lovers and explorers.

• Hubble Space Telescope

       It's just little more than 60 years of human space explorations and there's a whole bunch of things to be discovered. Hopefully it all will be possible in the near future.

Celestial Sphere

CELESTIAL SPHERE:

                     If you look at the night sky, you will see that all stars always appear fixed relative to each other and the entire pattern of stars rigidly orbit the sun throughout the year in the same manner. We employ this artificial, earth-based view of the heavens to make celestial maps by pretending that the stars are attached to the inside of an enormous hollow shell which is basically the "Celestial Sphere" and the Earth is at the center of the sphere.

THE NIGHT SHY:

                  In day time we can't see the stars due to the sunlight. But at night we can watch the stars quite clearly. The pattern of stars is visible in the dark which is called "Constellation". But the same view is invisible in the big cities due to the light pollution. You can clearly see the difference of the night sky with and without the light pollution in the following picture. In this photograph you can clearly see the difference of the night sky with and without light in Goodwood, Ontario, Canada.[copyright Todd Carlson /skynews Magazine]

CELESTIAL SPHERE IN NAVIGATING THE SKY:

                In celestial sphere stars are seemed fixed because they are too far away. In reality they do move relative to each other. But we neither see their motion nor perceive their relative distances because they are so far from us. Astronomers use celestial sphere in finding stars, but the condition is the stars must be fixed on it, just as cities are fixed on maps of the Earth. They applied a coordinate system to it to locate this quickly.

• CELESTIAL EQUATOR: If we expand the Earth's equator onto the celestial sphere we obtain the "celestial equator",which divides the sky into northern and southern hemispheres same as the Earth's equator divides the Earth into two hemispheres. Now if we stretch the Earth's north and south poles out into space along the Earth's axis of rotation to the celestial sphere, it will give us "north celestial pole' and "south celestial pole"

• DECLINATION AND RIGHT ASCENSION: Using the same conditions as the celestial equator, astronomers divide up the surface of the celestial sphere in precisely the same way that latitude and longitude grid divides the Earth. The equivalent to latitude on Earth is called "declination" on the celestial sphere. It is measured from 0 degree to 90 degree north or south of the celestial equator. The  equivalent of longitude on Earth is called "right ascension" on the celestial sphere, measured from 0 h to 245 h around the celestial equator.

• VERNAL EQUINOX: The Sun also orbit around the our galaxy (Milky Way Galaxy) through out the year.So we can say the Sun also has an orbit in the celestial sphere.Just as the    location of Greenwich, England, defines the prime meridian, or zero of longitude on Earth, we need to establish a zero of right ascension. It is defined as one of the places where the Sun's annual path across the celestial sphere intersects the celestial equator. The celestial equator and the Sun's path intersect at two points. The equivalent on the celestial sphere of the Earth's prime meridian is where the Sun crosses the celestial equator moving northward. Angles of right ascension are measured from this point, called the "vernal equinox".              

What's Del Operator

THE DEL OPERATOR:

Del is not a vector in general.It's actually does not mean much individually untill we provide it some function to act upon.So at first we will understand what's gradient ,then it will be easy for us to understand the Del operator.

WHAT'S GRADIENT:

Let's understand gradient from a example.Suppose,we have a function of three variables say Temperature T(x,y,z) of a room.So if we want to find how the temperature varies from point to point we  have to differentiate the function to get the value.Now in this case this function has three variables(x,y,z).So the function not only varies by distance but also it has a direction.It's really difficult to deal with  functions with more than one variables .So to generalize the notion of derivative to functions like Temperature we'll use the theorem on partial derivative which states that :
dT=(∂T/∂x)dx+(∂T/∂y)dy+(∂T/∂z)dz ............(1)
this tells us how T changes when we alter all three variables by infinitesimal amounts dx,dy,dz.
  we can rearrange equation (1) and we'll get,
dT=[(∂T/∂x) i^+(∂T/∂y) j^+(∂T/∂z) k^].(dx i^+dy j^+dz k^)   [ i^, j^, k^ are unit vectors in respective directions]

 =(∇T).(dl)  [where dl is a vector]
where,
∇T=(∂T/∂x) i^+(∂T/∂y) j^+(∂T/∂z) k^........(2)
is called the Gradient of T.Here,∇T is a vector quantity.
Properties of ∇:
From equation (2), the term in parentheses is called Del:
∇=(∂/∂x) i^ +(∂/∂y) j^+(∂/∂y) k^
 We have learnt earlier that ∇ itself is not a vector.But it mimics the behaviour of an ordinary vector in every way.That means we can do almost any sort of application of it so as the vector.

HOW THE OPERATOR ∇ WORKS:

Like an ordinary vector we can use ∇ in three different ways:

1. On a scalar function T: ∇T (the gradient);
2. on a vector function v,by dot product: ∇.v (the divergence);
3. on a vector function v,by cross product: ∇×v (the curl); 

You can learn more about operator and it's application in the below e-books: click on the book icon;

                                    https://amzn.to/2YUC0o2

The First Human On Mars May Be A Woman

"Always follow your dream and don't let anyone take it from you"
Alyssa carson (code name: Bluebarry)


    From several decades scientists are trying to terraform the most suitable earth like planet "Mars".Space organisations around the world have send many missions to mars. Some of them are Mars Exploring Rover(MER), curiosity Rover etc.But we never send humans on mars.A girl named Alyssa Carson from Baton Rouge, Louisiana could be the first person to step foot on mars.She was 3 years old when she told her father "Daddy, I want to be an astronaut and be one of the people to go Mars".Staying on her goal, she is currently on her way to be an astronaut with her ultimate goal to go to Mars.

                                                                                                                 

                                                                 ALYSSA  CARSON
              Among a longlisted candidates, Alyssa was selected for this mission.NASA is on track for orbiting and possibly landing on Mars in late 2030.In 2033 there is expected to be a dimming in the sun's  radiation output and the distance between earth and mars likely to be shorter.So this got be the perfect timimg to send human to Mars.

             The possibility of coming back to earth is less, so Alyssa has signed in to not to be married or involved in any kind of meaningful relationships.It's really hard to think What people can do for their dreams. Her father has a mixed feeling about this. On one hand he is happy for his daughter pursuing her dream and on other hand She is commiting her entire life to a possibly one way trip to the red planet.

             Undoubtedly,this mission will create a whole new chapter for the mankind whether it's succesful or not.Parhaps one day we will end up living in mars but no one never gonna forget the pioneer of this whole new chapter Mrs Alyssa Carson.  

Theory of Relativity

Theory of Relativity:

1. Special Theory of Relativity:

In 1905 Einstein published his paper on this theory. In this theory he simply took the fact that speed of light is constant as explained by michaleson and morley in late 1800.By tooking this fact he simply explained that time is not constant every where as told by Newton.This phenomenon is called "Time Dilation". He also came to this point that when you are travelling in speed of light every thing around you contracted in a single point. It's called "Length Contraction". Later he proved that any particle which has mass can't travel in speed of light.

          2. General Theory of Relativity:

In 1915 Einstein came up with another theory simply named as General Theory of Relativity.This theory is a massive example of his imaginational power. This theory not only put einstein in global recognization but with this he simply destroyed the question that what's the source of Gravity.This theory says that Space is a fabric of space-time and Gravity is the curvature of that space-time. As famous American Theoretical Physicist John Wheeler told" SPACE-TIME SAYS MATTER HOW TO MOVE AND MATTER SAYS SPACE-TIME HOW TO CURVE".This curvature depends on the mass of the matter. The more it has mass the more it will curve the space. And with this curvature, time will also vary. Time with slows down near massive objects.  

General Relativity predictions

Albert Einstein, simply named as "Genius" is one of the most influencial physicists of all time. He got his "Genius" tag because of his imaginational power. With his imagination he thought this world in a different way that no one never could and based on this he gave us some ground breaking theories.One of them is "The theory of relativity" which consists of  two parts - Special Theory of Relativity and General Theory of Relativity. Among them General Theory of Relativity predicts about some bizarre kinds of things in the universe.This predictions  remain a fiction until 2016 when we first detect Gravitational wave and 10th  april 2019 when we first got the image of Black Hole. Other predictions have not been approved yet. But hopefully in the near future we can detect them too. In the following you can understand this quite easily:  

physics

From the origin of science there are so many questions that worry us.One of them is who governs our world. After many years of researching and finding out the fundamental  secrets of the universe , scientists have finally discovered that there are four forces that governs the world.