How Stars are formed?

Have you ever question yourself, how these "bulbs of universe" (Stars) formed?

They are present in number of millions and billions hence, they are forming each and every second because the process of star formation is time consuming. Star formation is the process in which the dense region of interstellar space which is also referred as "stellar nurseries" collapses and form stars.

Lets know more about interstellar clouds first:

In the universe, lots of stellar remnants, and diffuse interstellar medium of gases and dusts are present. Our milky way galaxy is composed of about 70% of hydrogen gas and in rest 30% a huge amount of helium is present. But our interstellar medium is also rich in heavy elements released from stars.

These regions of heavy density take a shape of cloud which is further referred as diffuse nebulae which later converts into nebulas with high density and this is the site for formation of a star.

These dense nebulas are also called molecular nebula because most of the Hydrogen content in these nebulas exist in molecular form(H2).
The main reason of star formation is, cloud collapse.

But the question rises in mind is, what lead these cloud to collapse?

This question can be answered by using virial theorem. This theorem states that to maintain equilibrium, the gravitational potential energy must equal twice the internal thermal energy.

In large clouds, the kinetic energy of gas pressure is insufficient to support it then the phenomenon of gravitational collapse takes place. The mass above which a cloud will go under such gravitational collapse is known as jeans mass which depends on the temperature and density of cloud.

Also read:-

•what exist before nothing?

•What is dark matter and dark energy?

•The String Theory!

During cloud collapse dozens to ten thousands of stars form more or less simultaneously which is observable in so-called embedded clusters.

The end product of a core collapse is an open cluster of stars. As the cloud collapses, the material at the centre begins to heat up, Known as a protost, it is this hot core at the heart of the collarapsing cloud that will one day become a star.

Molecular clouds may collide with each other, or a nearby supernova explosion can be a trigger, sending shocked matter into the cloud at very high speeds. (The resulting new stars may themselves soon produce supernovae, producing self-propagating star formation).

Alternatively, galactic collisions can trigger massive starbursts of star formation as the gas clouds in each galaxy are compressed and agitated by tidal forces.

The black holes present in the centre of the galaxy also show its effects on star formation.

In newly formed galaxies, the black hole is small hence the process of star formation is faster as compare to those old galaxies in which a huge black hole is sitting in the centre of the galaxy ejecting radio-frequency-emitting particles at near-light speed can also block the formation.

Star formation takes approximately a billion years and between this time that start goes into different phases. One of the most longest and famous phase is formation of a protostar.

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• Chandrayaan 2: Full mission report

• International Space Station!

• "Hubble Telescope" Our First Eye In The Space!

A protostellar cloud will continue to collapse as long as the gravitational binding energy can be eliminated. This excess energy is primarily lost through radiation.

However, the collapsing cloud will eventually become opaque to its own radiation, and the energy must be removed through some other means.

The dust within the cloud becomes heated to temperatures of 60–100 K, and these particles radiate at wavelengths in the far infrared where the cloud is transparent. Thus the dust mediates the further collapse of the cloud.

Here one noticeable point is that the mechanism of formation of low mass and high mass star is totally different in comparison.

Major discoveries about star formation in the far reaches of the Universe. This is important as far away galaxies are seen far back in time, because of the huge distances their light has needed to reach us.

Studying starlight from the most distant objects Hubble has observed gives clues about how stars formed in the early years of the Universe, and how they have changed over time.

Nowadays, scientists are trying to find the oldest star of universe because by studying these oldest star we can predict the early time of our universe.

Today we are capable to see the formation of stars with the help of evolved telescopes and hence we can know anything about Stars now.

It’s a great news for all that we've found the location of the Vikram Lander on lunar surface & orbiter has clicked a thermal image of Lander. But there is no communication yet.

ISRO scientists are trying to have contact and they have said that it will be communicated soon.

After losing communication from lander as after the altitude of 2.1 km ISRO chairman K Sivan said that they will  trying to establish communication with Vikram lander and will keep trying for next 14 days.

And here we have latest updates from ISRO about finding the exact location of Lander on lunar surface also the orbiter has clicked the thermal image of Vikram lander said ISRO chairman.

ISRO Chief K Sivan said that “ We've found the location of the Vikram Lander on lunar surface & orbiter has clicked a thermal image of Lander. But there is no communication yet. We are trying to have contact. It will be communicated soon.”

ISRO will keep trying to establish contact with the Vikram lander for the next 14 days, and that information coming in from the Orbiter would be crucial.

Chandrayaan 2: Why moon landing failed?

Is there any hope for re-establishing the communication with lander?

Although according to scientists the Vikram lander was programmed in such a way that at the stage when communication was lost at altitude of 2.1 km Lander was on self operator mode. So, it is hoped that lander could be landed safely.

According to ex-ISRO Chief Lander may not have crash-landed.
While there is no official verdict about the lander's condition, not everyone is convinced that the landing ended in a crash.

ISRO Director D Sasikumar had this to say: "We have to find out from the communication data whether it is a soft landing or it is a crash landing.

In my opinion, it is not a crash landing because the communication channel is on between the lander and the orbiter. It should be intact. So, let us hope after the analysis done, we may be able to get the final figure."

If the lander has landed safely without any damage and in the proper angle then there is very much chances to re-establish communication with Vikram lander.

Chandrayaan 2: Why moon landing failed?

And if communication will establish again then the Pragyan rover which is housed inside the Vikram lander will also perform its job properly.
Isro further said that the success criteria was defined for each and every phase of the mission and till date 90 to 95 per cent of the mission objectives have been accomplished and will continue to contribute to lunar science, notwithstanding the loss of communication with the lander.

What Was The Purpose Of Vikram Lander?

The lander of Chandrayaan-2   is named Vikram after Dr Vikram A Sarabhai, the father of the Indian space programme. It is designed to function for one lunar day.

Vikram has the capability to communicate with IDSN at Byalalu near Bengaluru, as well as with the Orbiter and Rover. The Lander is designed to execute a soft landing on moon.

Lander's Payload Includes :-

1. Lander’s instrument for Lunar seismic activity will examine the earthquake movement on the sight;

2. Surface thermo- physical experiment will study the thermal conductivity of the moon; and
3. Langmuir probe will study the surface of the Moon

Although the lander also has a Rover which was to be operated after landing safely. Rover named Pragyan also has to perform several tasks .

Read full article on Chandrayaan 2

Chandrayaan-2  rover is a six-wheeled robotic vehicle Pragyan can travel up to 500 metres and leverages solar energy for its functioning. It can only communicate with the Lander. Pragyan weights just 27 kg.

Rover's Payload Includes :-

1. Rover’s Alpha particle x-ray spectrometer will do detail analysis of Moon’s surface; and

2. Leaser induced breakdown spectroscope will test the surface composition of moon near the landing sight.

Read full article on Chandrayaan 2

"The last part of the operation was not executed in the right manner. It was in that phase that we lost link with the lander, and could not establish contact subsequently," said K Sivan.

The ISRO chief had earlier said the final minutes of the soft landing were the most tricky, calling them "15 minutes of terror".


"This is a very complex process and it is new for us. It is a complex process even for those who have already done it. We are doing this for the first time, so it will be fifteen minutes of terror for us," he said.

The Indian Space Research Organisation (Isro) has lost contact with Vikram Lander of Chandrayaan-2  due to a technical glitch moments before Vikram's scheduled landing on Moon's surface.

On 7 September at 1.37 am, Isro tweeted that the final descent of Vikram Lander has started. It said Vikram Lander has started its powered descent. "Rough braking of Vikram Lander begins," the tweet said.

Read full article on Chandrayaan 2

And for the next few minutes everything went right according to plan. Jubilant Isro scientists at the Mission Operations Complex cheered and clapped as Vikram aced the various stages of descent on to the lunar surface.

At 1.49am, Isro tweeted, "Rough breaking of Vikram Lander ends and fine braking phase starts." Soon, scientists clapped and cheered as Vikram Lander completed the rough braking phase before the fine braking phase started.
It was then that the scientists started becoming tense and went into a huddle.

Isro Chairman K Sivan was seen engaged in intense discussions with some scientists.
Soon the ISRO chairman K Sivan announced that the Vikram lander descent was as planned and normal performance observed up to altitude of 2.1 km.

Subsequently communications from Vikram Lander to ground station was lost, he said, adding the data was being analysed.

Isro has a number of data sets to go over -- those sent back by Vikram before it went incommunicado as well as those possibly captured by various Earth-based space communications devices. Isro is also making constant attempts to re-establish communication with the Vikram lander.

Also read:-

•what exist before nothing?

•What is dark matter and dark energy?

•The String Theory!

What was the purpose of Vikram lander?

The lander of Chandrayaan-2  is named Vikram after Dr Vikram A Sarabhai, the father of the Indian space programme. It is designed to function for one lunar day.

Vikram has the capability to communicate with IDSN at Byalalu near Bengaluru, as well as with the Orbiter and Rover. The Lander is designed to execute a soft landing on the lunar surface. Lander weights 1,471 kg.

Read full article on Chandrayaan 2

Lander's payload includes :-

1. Lander’s instrument for Lunar seismic activity will examine the earthquake movement on the sight;

2. Surface thermo- physical experiment will study the thermal conductivity of the moon; and
3. Langmuir probe will study the surface of the Moon

Although the lander also has a Rover which was to be operated after landing safely. Rover named Pragyan also has to perform several tasks .

Chandrayaan-2  rover is a six-wheeled robotic vehicle Pragyan can travel up to 500 metres and leverages solar energy for its functioning. It can only communicate with the Lander. Pragyan weights just 27 kg.

Rover's payload includes :-

1. Rover’s Alpha particle x-ray spectrometer will do detail analysis of Moon’s surface; and

2. Leaser induced breakdown spectroscope will test the surface composition of moon near the landing sight.

Also Read:-

• Chandrayaan 2: Full mission report

• International Space Station!

• "Hubble Telescope" Our First Eye In The Space!

SO, HAS CHANDRAYAAN-2 FAILED?

Not at all. Landing a rover on the Moon was just one, no matter how ambitious part of the Chandrayaan-2  mission. In fact, the lander Vikram and rover Pragyaan combined carried lesser number of experiments (five) than the Chandrayaan-2 orbiter, which has on-board eight scientific payloads.

Even if the worst was to be assumed that Vikram and Pragyaan perished in the attempt to land on the Moon most of the Chandrayaan-2 mission's experiments will remain on course.

The orbiter, over the course of its one-year mission life, will perform these experiments and beam the results back to Earth. And ISRO chairman recently said that the orbiter has enough fuel to continue the mission of orbiter for seven and half years.

In fact, the one experiment that is most associated with Chandrayaan-2 estimating the quantity of iced water present in the south polar region of the Moon is to be performed by the orbiter and not Vikram or Pragyaan.

The mission life of the Orbiter is one  which should be extended upto seven and half years and it has been placed in a 100X100 km lunar polar orbit. Orbiter weights 2,379 kg.

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Orbiter’s payloads include:-

1. Terrain mapping camera will make digital elevation model of whole Moon;
2. Large area soft x-ray spectrometer will examine the composition of surface of the Moon;

3.  Solar x-ray monitor will provide the input of solar x-ray spectrum;
4.  Imaging IR spectrometer will find the evidence of presence of ice and minerals;
5. Orbiter will examine the polar region of moon for finding the evidence of ice under the surface;
6. Atmospheric composition explorer-2 will study the environment of Moon;

7. Orbiter high resolution camera will take pictures of the surface the Moon; and
8. Its dual frequency radio science experiment will study the Ionosphere of the Moon.

Although we have still hope as ISRO chairman recently said that their scientists are still trying to establish communication with Vikram lander and will keep trying for next 14 days.

In the interview to DD News, K Sivan also said that all Isro missions including Gaganyaan will take place as per schedule.

Meanwhile, the space agency said in a statement that Chandrayaan-2  mission was a highly complex mission, which represented a significant technological leap compared to the previous missions of Isro, which brought together an orbiter, lander and rover to explore the unexplored South Pole of the Moon.

Isro further said that the success criteria was defined for each and every phase of the mission and till date 90 to 95 per cent of the mission objectives have been accomplished and will continue to contribute to lunar science, notwithstanding the loss of communication with the lander.

Chandrayaan-2 mission is conducted by Indian space agency ISRO and has been launched on 22 July 2019, at 14:43 IST using GSLV MK III rocket from Satish Dhawan space centre located at Sriharikota at Andhra Pradesh.

Read full article on Chandrayaan 2

Total journey time of Chandrayaan-2 will be of 48 days. Chandrayaan 2 will first orbit the Earth for 17 days, then the Chandrayaan will be separated. It will take 5 days to reach in Moon’s orbit after escaping from Earths orbit. After entering the Moon’s orbit it will orbit it for 28 days and finally will land on Moon’s surface.

In the first week of August, Chandrayaan-2 sent first pictures of Earth as viewed in space as it was moving away from the planet.




In a series , Isro shared the Earth's pictures clicked by LI4 Camera of Chandrayaan-2's Vikram lander on August 3, 2019.
The pictures show the Earth in different hues.

Chandrayaan has sent 5 images of Earth from different altitude. 

(See here).
(See full images)

On August 22, Isro announced on Twitter that Chandrayaan-2 shot an image of the Moon from a height of over 2,000 km as it flies around the satellite, preparing to land a rover on the lunar surface.

The image was shot on August 21 and was taken from a height of 2,650 km, Isro said.

In the photo, Isro highlighted two significant lunar landmarks -- the Apollo crater and the Mare Orientale basin.

Chandrayaan has released total 4 images of moon from different altitude. 

(See here)

(See full images)

Chandrayaan-2 reached the Moon on August 20, when it entered the lunar orbit. On August 21, Chandrayaan-2 performed a manoeuvre to lower its orbit around the Moon.

The spacecraft will perform several such manoeuvres over the next two weeks to bring itself closer and closer to the Moon.

The Chandrayaan-2 mission's D-Day is September 2, when the lander Vikram will separate from the spacecraft and get into a lunar orbit of its own.

Early morning on September 7, Vikram will begin a 15-minute powered descent at the end of which it will land near the south pole of the Moon, making India the only country in the world to perform a 'soft landing' near the lunar south pole.

All images taken by Chandrayaan 2!

In the first week of August, Chandrayaan-2 sent first pictures of Earth as viewed in space as it was moving away from the planet.

In a series , Isro shared the Earth's pictures clicked by LI4 Camera of Chandrayaan-2's Vikram lander on August 3, 2019.

The pictures show the Earth in different hues.

3rd image of Earth from altitude of 4100 km

4th image of Earth from the altitude of 4700 km

5th image of Earth from the altitude of 5000 km

Images of Moon taken by Chandrayaan 2

Images of Moon taken by Chandrayaan 2 from the altitude of 2650 km

"The great void" | The largest and most suspicious empty space in the Universe

Our universe is extremely big, bigger than our consciousness. Researchers still aren't able to see whole universe as they have been able to se a limited area of universe known as observable universe.

Now the fact is, our observable universe also covers a tremendous area of 46.508 billion light years with density of objects.

These objects are stars, planets, galaxies or Space dust which make universe a filled and compacted space.

Now, let's imagine if you are travelling in universe with the speed of light (hypothetical in present time) and watching millions of stars, planets and moons passing in front of you.

Suddenly you see a black area in universe which is totally black and cold and of course it is not a black hole because black hole is not totally black.

After entering in this black area you aren't able to see anything because there is nothing and you are hoping that this void is going to end now, but actually it will never end in your life even speed of light is along with you.

This void is Bootes void (also called 'The great void') which is spread in the region of 1.8 billion light years. Our universe is full of voids.

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•What happens if you falls into a Black Hole?

Now, take some look at 'what actually a void is' :-

* A void is a region of space time where matter lacks and in case of some void dark matter also.

* Void is not totally empty space in universe, it contains some galaxies but in very less amount than usual.

* The temperature of voids is extremely low(0.00027 degree Fahrenheit in case of great void). background.


In 1965, two researchers, Arno penzias and robert wilson were viewing the space with their radio telescope, suddenly their radio telescope starts receiving a special microwave signals which should not come according to two of them.

They do not have any idea about the fact that they accidentally discovered cosmic microwave background which is going to prove the big bang theory of George Gamow and Georges Lemaitre.

This discovery not only gave us the proof of big bang but with its help we also got to see a big hole in our universe. Cosmic microwave background radiation is actually the oldest electromagnetic radiation surrounds us.

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•What latest image of black hole tells us?

•What happens if you falls into a Black Hole?

•Black hole can be formed without Stars, resent study suggests!

In 2001, NASA launched Milkinson microwave Anisotropy probe (WMAP spacecraft) for detail study of cosmic microwave background radiation. After the mission of more than 9 years this spacecraft provided the clear map of cosmic microwave background radiation which is actually the of ancient universe.

Simply we can say that the map of Cosmic microwave background is a temperature anisotropy or temperature difference in universe.

The average temperature of cosmic microwave background is - 2.725K where the hot region are shown by red colour and colder region are with blue colours and the temperature difference between these two regions is 0.0002K which shows the sensitiveness of WMAP.

In this map, the hotter regions contain more amount of matter than colder regions, hence in present time there more galaxies will be present respectively.

During the study of cosmic microwave background scientists were observed something weird, they observed a large area where negligible matter is present. And this is the discovery of bootes void.

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•What is dark matter and dark energy?

•The String Theory!

Scientist named this spot "CMB cold spot" because this spot is colder than 0.00007K than normal temperature. Firstly scientists take it as a error in measurement but after re-confirmation scientists also starts believing that this is a void.

It is impossible for us to see this void with any Telescope because this void is 70 billion light years away from us in bootes constellation.

This void is not totally empty, researchers have found 60 galaxies in bootes void but the fact is this is negligible number in comparison with normal areas of universe. It should contain minimum 2000 galaxies.

After the discovery of this void some scientists propose their ideas and theories about this void. Some says this is a hole in our universe from where all the matter escaped our from our universe to any other one.

Some says this void formed due to the collision between two universes hence it promotes the theory of multiverse and it also sounds quite interesting.

Many other theories related to the great void is present but we can't confirm any of until we will able see it.

Quantum field theory : Fundamental and History

Quantum field theory:- a field theory that obeys the principles of quantum theory.

String theory could be starting point for theory of everything which would define all of our universe's physical laws in one simple mathematical formula.

Read: what is string theory.



* All the matter in universe consist of vibrations of this strings.
* All physical theories are expressed in language of mathematics.

* String theory is a quantum field theory that describes the particles and forces in our universe based on the way that special extra dimensions.

Within the theory are wrapped up into a very small size (a processor called compactification).

Also read:-

•what exist before nothing?

•What is dark matter and dark energy?

•The String Theory!

This is the power of string theory to use the fundamental strings and way extra dimensions are compactified to prove a geometric description of all the particles and forces known to modern physics.

Among the forces needed to be described is of course, gravity because string theory is a quantum field theory which means that string theory is a theory of gravity and this special gravity is known as quantum gravity.

The established theory of gravity, general relativity, has a fluid dynamic space time and one aspect of string theory that's still beings on is getting this sort of a space time emerge out of the theory.

String theory uses no experiments that provides new insights, but it has revealed profound mathematical relationship within the equations, which led physicists to believe that it must be true.

A quick look at where string theory has been based. 
          
* String theory was originally derived in 1962 as a theory that attempted to explore the behaviour of hadrons (such as protons and neutrons) inside particle accelerator. It was abandoned because it requires a large no of extra unseen dimensions.

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•Are we traveling in time?

•"Time travel" a possible phenomenon!

•Time travel in past is possible or not?

It rise again when physicists were able to prove it as a mathematical consistent theory.

In mid-1990s, string theory was updated to become most complex theory known M theory. This contains more objects than just strings.
This new objects were called branes and they could have anywhere from 0 to 9D. The earlier string theory were seems approximation to the more complete M theory.

Key ideas:-

* String theory predicts that all objects in our universe are composed of vibrating filaments of energy.
* String theory attempts to reconcile general relativity (gravity) with its quantum ideas.
* String theory provides a way to unify all the four fundamental forces of universe.

* String theory predicts a new connection (called super symmetry) between two fundamentally different types of particles, Bozons and Fermions.
* String theory predicts a number of extra (usually unobservable) dimensions in the universe.

In 1970s, the filaments of energy in strings were considered as unidimesional object. These strings came in two forms, closed strings and open strings.

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• Chandrayaan 2: Full mission report

• International Space Station!

• "Hubble Telescope" Our First Eye In The Space!

An open end has string that don't touch each other, while a closed string is a loop with no open end. It was eventually found that these early strings are called Type 1 strings, could go through five basic type of interactions as shown below:-



The interactions are based on strings ability to have ends join and split apart because the ends of open strings can join to form closed strings. You can't imagine a string theory without closed strings.
Closed strings can describe gravity. It can explain behaviour of particles.