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Saturday, 22 June 2019

What is universe?

        

                        What is universe?


The universe is all planets, moons, minor planets, stars, galaxies, the content of intergalactic space and all matter and energy.

what is Universe?
The universe is all of space and the stars, the planets, and all other forms of matter and energy in it.
                           
      The Universe in physical science suggests everything, everywhere, all the space. In different words, all of space, time, and their content is the universe. It includes all the galaxies, black holes, stars, planets, and moons. It additionally includes all kinds of energy and matter.

what is Universe?
The Universe is all we can touch, feel, sense, measure or detect. It consists of living things, planets, stars, galaxies, dust clouds, light, and even time.

 Stephen Hawking                              

                     Stephen Hawking (1942-2018) once said: “Look up at the stars and not down at your feet, try to be of what you see, and wonder about what makes the Universe exist. Be curious.”

Stephen Hawking | What is universe?
Stephen William Hawking CH CBE FRS FRSA was an English theoretical physicist, cosmologist, and author who was the director of research at the Centre for Theoretical Cosmology at the University of Cambridge at the time of his death.

        Professor Hawking was a British theoretical scientist, cosmologist, author, and director of research at the Centre for Theoretical Cosmology. In 2016, Prof. Hawking advised that black holes could be portals to different universes, maybe black holes aren't ‘eternal prisons’ from that something their gravity captures ne'er escapes. He puzzled whether or not there could be the way out. 

      Greek and Indian philosophers Scientific models of universes originate to Greek and Indian philosophers. They Drew geocentric models that had our planet Earth in the middle of everything. 

Copernicus and Newton 

           It was not until Nicolaus Copernicus (1473-1543), a Polish astronomer and scientist, those heliocentric models emerged. Copernicus’ model had the Sun in the middle of our scheme. 

       Sir Isaac Newton (1642-1727) designed on Copernicus’ work once he developed the law of universal gravitation. Newton was a British scientist, astronomer, physicist, and theologian. 

       Eventually, models started locating our scheme among the Milky Way galaxy. The Milky Way is one among the cosmos’ roughly one-hundred billion galaxies. Astronomers and astrophysicists say that the Universe has neither middle nor a position. This can be as a result of the distribution of all the galaxies is even and therefore the same all told directions. 

        According to a team of British scientists, the Universe isn't spinning or stretching in any explicit direction. It's increasing uniformly. The universe contains a beginning early within the twentieth century. Scientists discovered that the Universe was expanding and had a starting. Approximately eightieth of the mass within the cosmos seems to exist in matter. We have a tendency to cannot observe matter, however, we all know it's there.

           The universe was, indeed, isotropic. When the traditional Greeks found in the sky, they accomplished the universe may be one in every of
two things, infinite -- stretching forever in each direction, or finite -- with a position.

        When Newton represented the law of gravity, he considered this too and patterned it must be infinite. As a result of otherwise all the gravity out there would have collapsed the universe by now. Then, Einstein assumed the universe was static -- making a cosmological constant to form his math work. Then, Edwin Hubble came along…

Edwin Hubble

          In 1925, Edwin Hubble was looking at galaxies. He got time on a telescope in California and began measuring the Doppler shift of the light coming from galaxies.

        Doppler shift is why an ambulance or train sounds different coming at you than after it passes. That frequency shift is measurable, and he found each galaxy we have a tendency to might see was flying away from us. He realized space is expanding! He published his findings in the Proceedings of the National Academy of Sciences in 1929.

        Einstein called his cosmological constant his "greatest blunder."
Mathematician Georges cosmologist resolved Einstein's equations during this expanding universe, and once we accomplished it had been expanding, we tend to might assume it started somewhere and therefore, the Big Bang was conceived!
This was (and is) huge, and only getting bigger.

Revolver map

                          Revolver Map


RevolverMaps Plain displays the locations of visitors from the time of the installation on the site. Recent visitor locations are animated, new visitor locations appear live on the map. A click on the map opens the public live statistics page providing detailed information on the visitors.
Revlover map
Revolver map

Tuesday, 29 January 2019

How old is the universe?

How old is the universe?


How old is the universe?
A 2013 map of the background radiation left over from the Big Bang, taken by the ESA's Planck spacecraft, captured the oldest light in the universe. This information helps astronomers determine the age of the universe.
Credit: ESA and the Planck Collaboration.
         Do you know how old is the universe? Some people may know a little about how old is the universe and some might not. Those little people who know might have some doubts. This information was used by astronomers to determine the age of the universe i.e. how old is the universe? Age may only be a number, but when it comes to the age of the universe, it's a pretty important one. 
         As per research, the universe is approximately 13.8 billion years old. We know age is just a number but when we talk about the age of the universe, it becomes hard to guess. As per the research till now, the universe is 13.8 billion years old in approximate. But how come the scientists are able to determine the age of the universe? The universe must be older than the oldest thing that exists in the universe itself. By studying the oldest objects in the universe and measuring how fast the universe is expanding, we can guesstimate the age of the universe. Thus to measure the age of the universe, we should go for ancient stars in the universe.

Age limits

          The universe is a huge bubble of space and time that is continuously expanding in volume. If we go far and far enough years back when everything was a compact mass of incomprehensible density, there comes a moment in time the universe began. That’s the moment which should be the birth date of the universe.

So how old is the Universe? How long has it been expanding for? How do we know the age of the universe?


            Mass is the basis of a star’s life cycle. Greater the mass, faster is the burn rate of stars in space than the stars having the lesser mass. A 10 times more massive star than the sun will burn through in 20 million years, while a star having half the mass of the sun’s mass will burn more than 20 million years. The mass is also affecting the brightness i.e. luminosity of a star. Clearly, massive stars are brighter.  [Related: The Brightest Stars: Luminosity & Magnitude]


           The first stars known as Population III stars were great in mass but lived a very short life, contained only hydrogen and helium. After the fusion, they created the other elements which helped in building the next generation of stars i.e. other types of stars.


          “The detection of dust in the early universe yields new data on when the first supernovae exploded and henceforth when the first hot stars showered the universe in light,” European Southern Observatory officials uttered in a statement.” Finding out the timing of this ‘cosmic dawn’ is the most sought after thing in modern astronomy.


          The early stars are not the only object to put limits on the age of the universe. The thickset of stars called as globular clusters have much the same attributes. The oldest familiar globular clusters have stars of age between 11 and 14 billion years old. There comes a wide range in the precise measurement of the distances to the clusters that affect the estimates of brightness and henceforth the mass. If the cluster is farther than the measured distances, the stars in that clusters would be brighter and hence more massive that means they are younger than what the scientists have calculated.


          Archaeologists use fossils to build up the history of the Earth. Likewise, astronomers use globular clusters to build up the history of the galaxy. About 150 globular clusters are known in the milky way galaxy, out of which each globular cluster is a tracer of the galactic halo and the formation of the Milky Way Galaxy. This uncertainty puts limits on the age of the universe. It must b at least 11 billion years old. It should be older but can’t be younger for sure.


How fast is the universe expanding?

How old is the universe? How fast is the universe expanding?
How the universe is expanding
           The universe is not flat and is continuously expanding. Scientists can guestimate the age of the universe if they can determine how fast is the universe expanding? The rate of expansion of the universe is a number known as the Hubble constant.

             Many factors determine the value of this constant. First of all, the type of matter that dominates the universe. Secondly, density is also a key to determine the Hubble constant. The low density of matter is older than a dense-matter.

             
           Now how to determine density as well composition of the universe? We have to rely on missions by NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) and The European Space Agency’s Planck spacecraft. The thermal radiation left after the Big Bang enables these missions to measure the density, composition and the rate of expansion of the universe. These radiations left after the Big Bang is known as the cosmic microwave background. The two missions have mapped it. [INFOGRAPHIC: Cosmic Microwave Background: Big Bang Relic Explained]

           The age of the universe estimated by WMAP in 2012, is to be at least 13.77 billion years with 59 million years of uncertainty. Planck’s result measured the age of the universe at 13.82 billion years. The two measurements fall within the limit of 11 billion years. They had independently derived these numbers from the globular clusters with smaller uncertainties.

        NASA used Spitzer Space Telescope to narrow down the age of the universe reducing the uncertainty of the Hubble constant. The combined results of NASA and WMAP measurements enabled the scientists to determine the size and age of the universe.

Sunday, 12 August 2018

Stars in universe greater or the sand grains in the world deserts?

Stars in the Universe? Which Is Greater, the Number of Sand Grains in the world's deserts and beaches, Or stars in the universe?



           
      Here's an old question— which are there more grains of sand in the world's deserts and beaches, or stars in the Universe? American astrophysicist Carl Edward Sagan had told that there are much more and more stars in the universe than the sand grains in the world's deserts and beaches.

Is he right in his claim? Can the stars in the Universe be counted?
                      


                               
       
           Obviously, grains and stars can't be counted, but you can estimate. Being well-versed in all these things, Gerry Gilmore, professor of astronomy at Cambridge University, tried to calculate the number of stars in our galaxy. He said about 2 trillion stars are there in just our galaxy considering the distance, size and the light they reflect as the factors. Rather than counting the stars one by one, count all the galaxies in one small region of the universe close to the Earth. By measuring the brightness of each galaxy, estimate how many stars it contained and extrapolate for the entire night sky. The number of galaxies in the universe can be guestimated on the basis of Hubble's law; a certain way the universe is expanding.

                                 

           About one trillion galaxies are there in the universe each containing two trillion stars.
Now if we multiply these two numbers we get 20,000,000,000,000,000,000,000, i.e. 2 followed by 22 zeroes
           So, how much is the sand on all the beaches, everywhere, on this earth? We’d need to estimate the average volume of a sandy beach and the average amount of the world’s coastlines which are beaches.

                                    

           According to Open Street map; a plan in which data is shared by all the countries throughout the world including America, UK, and Canada, a beach is considered to be 9.1 km long on an average, thus a total of 3 lacs km consist of long sandy beaches. One cubic meter sand contains 10 billion grains. Now to determine the density, it is highly impossible.
           But we can assume that most beaches are 50 meters wide and about 25 meters deep. Then multiply all the beaches and deserts in the world, what we get is a mind-blowing number. It comes to be 3.75 trillion and each cubic meter of a beach, say approximately, consists of 10 billions of grains. Thus multiplying these two enormously large numbers the figure comes out to be 3.75 followed by 21 zeros that is the approximate number of grains of sand on the collective beaches of an entire planet. We can assume 4 followed by 21 zeros.
 4000,000,000,000,000,000,00. That's a lot of grains.

                                   

           Now we compare,
       
           20,000,000,000,000,000,000,000   (20 followed by 21 zeros) stars in the universe and
         
           4,000,000,000,000,000,000,000   (4 followed by 21 zeros) grains of sand on the collective beaches of an entire planet.
         
           This means that Carl Edward Sagan was correct. These are just mathematical estimates and there is no way of confirming this with 100% certainty, but for now that it is at least probably correct.