THE COSMOS

Abstract: An understanding of the universe is a prerequisite to undertstand our Solar System and our Planet the Mother Earth. Its understanding makes our Members of Pure earth Foundation how crucial is the task of saving our planet from pre natural extinction of Mankind. The Article speaks about universe which is an expanding entity consisting of billions of galaxies each consisting of billions of stars , Black holes, Novas, Super Novas, Planets, satellites and other terrestrial objects. It discusses the truth of Space Time Dynamism and death of every Celestial object born in a Space Time continuum one day by un expalined Forces. The Stars burn and vecome Dwarf Stars and Later White Stars which has to happen to our own Sun one day. But that is Millions of years after and we need not bother now for it as much we need to bother for Global Warming. The Article  explains the Origin of our Universe and Galaxy, Cannibalism and Violence occuring in our Universe which has created our Earth and Human Life in this, which is not known to be existing any where else.The ARticle the Author hopes will guide each and every reader to work for purity of our Earth essential for Human Existence.

 Introduction– The ancient Greek philosopher Pythagoras in 6th century BC used the term Cosmos  for the Universe, but there was not much knowledge as it exists today about the plethora of galaxies and stars existing in it. There are billions of galaxies each with billions of stars in it.  Our own galaxy is called the Milky Way, which has nearly 200 billion stars. Stars often have large number of planets and planets may have satellites. To quote the great Carl Sagan, the great American Cosmologist,  the total number of Stars in the Universe is greater than all the grains of sand on all the beaches of planet Earth. The Universe size can be gauged from the fact that distance to Proxima Centauri, the nearest star after the Sun is about 4.23 light years and distance to the Andromeda Galaxy, the nearest galaxy to our own  is 2.36 million light years.

  The Universe as described in Webster’s dictionary consist of all existing things; the totality of space, stars, planets and other form of matter and energy including the world. Anyone even remotely interested in the exciting world of Astronomy, Cosmology, Physics etc.  would agree that the above description barely touches on how huge and magnificent the UNIVERSE really is. From the tiniest microbe to the vastness of Space and all it holds, the UNIVERSE is a wonder that is dynamic in space and time.

   Up until the early 1920s, most astronomers thought that all of the stars in the Universe were contained inside  the Milky Way. After lot of debates in 1920s , observations by Edwin Hubble, USA showed that the Milky Way is just one of many galaxies—now known to be billions. Thus       beyond our own galaxy lies a vast expanse of galaxies. The deeper we see into space, the more galaxies we discover. There are billions of galaxies, the most distant of which are so far away that the light arriving from them on Earth today was set out from the galaxies billions of years ago. So we see them not as they are today, but as they looked long before there was any life on Earth. Thus may be some of the stars in the Sky we see at night time is illusory, which may not exist today.

    For thousands of years, astronomers wrestled with basic questions about the size and age of the Universe. Does the Universe go on expanding forever, or does it have an edge somewhere? Has it always existed, or did it come to being sometime in the past? In 1929, Edwin Hubble, an astronomer at Caltech, USA, made a critical discovery that soon led to scientific answers for these questions. He discovered that the Universe is expanding.  That the universe is ever expanding was known in 1929 by a phenomenon called Redshift. Redshift happens when light or other electromagnetic radiation from an object is increased in wavelength, or shifted to the red end of the spectrum whether or not the radiation is within the visible spectrum. A redshift occurs whenever a light source moves away from an observer. A common kind of redshift is cosmological redshift, which is due to the expansion of the universe, and sufficiently distant light sources (generally more than a few million light years away) show redshift. In 1929 Edwin Hubble, working at the Carnegie Observatories in Pasadena, California, measured the redshifts of a number of distant Galaxies. He also measured their relative distances by measuring the apparent brightness of a class of variable stars called Cepheids (Pulsating) in each Galaxy. He found that the redshift of distant Galaxies increased as a linear function of their distance. The only explanation for this observation is that the Universe was expanding.

Big Bang Theory

The origin of the Big Bang Theory can be credited to one man…Edwin Hubble. He made the observation that the Universe is continuously expanding, and discovered that a Galaxy’s velocity is proportional to its distance. Galaxies that are twice as far from us move twice as fast. Another observation is that the Universe is expanding in every direction. This observation means that it has taken every Galaxy the same amount of time to move from a common starting position to its current position.

 Once scientists understood that the Universe was expanding, they immediately realized that it would have been smaller in the past. At some point in the past, the entire Universe would have been a single point. This point, later called the big bang, was the beginning of the Universe as we understand it today. The expanding Universe is finite in both time and space. The reason that the Universe did not collapse, as Newton’s and Einstein’s equations said it might, is that it had been expanding from the moment of its creation. The Universe is in a constant state of change. The expanding Universe, a new idea based on modern physics, laid to rest  the paradoxes that troubled astronomers from ancient times until the early 20th Century. The Big bang has happened nearly 13.7 billion years back when the entire material of the present universe was in a highly condensed form at a particular point.

But questions which are not yet answered are many. What was the Universe before the Big Bang ? What really caused the Big bang? Is there a Multi Universe that is large number of Universe ? Will the Universe collapse one day? These questions are still under scientific study and may be answered in future.

The Expanding Universe

   For the last eighty years, astronomers have been making increasingly accurate measurements of two important cosmological parameters I.e. the rate at which the Universe expands and  the average density of matter in the Universe. Finding the distance to these very distant galaxies is challenging, but astronomers can do so by watching for incredibly bright exploding stars called supernovae. Some types of exploding stars have a known brightness. So we can figure out how far they are by measuring how bright they appear to us, and therefore how far away it is to their home galaxy.  

 

The puzzle of the expanding Universe have three possible solutions, each of which predicts a different eventual fate for the Universe as a whole. Which fate will ultimately befall the Universe can be determined by measuring how fast the Universe expands relative to how much matter the Universe contains. The three possible types of expanding Universes are called open, flat, and closed Universes. If the Universe were open, it would expand forever. If the Universe were flat, it would also expand forever, but the expansion rate would slow to zero after an infinite amount of time. If the Universe were closed, it would eventually stop expanding and re collapse on itself, possibly leading to another big bang. In all three cases, the expansion slows, and the force that causes the slowing is gravity.          A simple analogy to understand these three types of Universes is to consider a spaceship launched from the surface of the Earth. If the spaceship does not have enough speed to escape the Earth’s gravity, it will eventually fall back to Earth. This is analogous with a closed Universe that re collapses. If the spaceship is given enough speed so that it has just enough energy to escape, then at an infinite distance away from the Earth, it will come to a stop and this is the flat Universe. And lastly, if the ship is launched with more than enough energy to escape, it will always have some speed, even when it is an infinite distance away and this is the open Universe.

Is there other Intelligent Life in the Universe?

That is the huge question that we all want answered. But the truth is that no-one knows whether or not there is other intelligent (by our standards) life in the Universe. There is no reason there shouldn’t be though.

 We know by our very own existence that the Universe is conducive to Life. But there are many hurdles to overcome for intelligent Life to form, and many threats to its continued existence once it does form. Life constantly faces the prospect of extinction. For instance Life (as we know it) requires water, any environmental disaster that removes water, dooms Life.

But even when Life does arrive other environment disasters threaten Life also. Here on Earth we have had huge meteor impacts that are believed to have   called shooting stars.The famous Cosmologist late Stephen Hawkins believes that there are Alien creatures and they are less intelligent than us.

The Violent Universe

The  Universe from the day of Big bang is in a violent state. Violence is the law of nature from the beginning of the Big bang  13.7 billion years ago. Sometimes galaxies collide resulting disintegrations, Stars burn out , disintegrate and merge .Thus  movements of all terrestrial bodies change in space and time with respect to each other. By such movements of bodies in space , Stars, Planets, satellites and other celestial bodies  born and die every day. Our mother earth is born and life has come due to violence in our Solar system. Similarly extinction of many animals and plant life on earth has happened due to violent incidents  in our Solar system. An understanding of Cosmic bodies like Black holes, Neutron stars, Novae and Supernovae, White dwarfs etc is necessary to understand the violent universe.

A black hole is a mathematically defined region of space time exhibiting such a strong gravitational pull that no particle or electromagnetic radiation can escape from it. The theory of general relativity predicts that a sufficiently compact mass can deform space time to form a black hole. The boundary of the region from which no escape is possible is called the event horizon. Although crossing the event horizon has enormous effect on the fate of the object crossing it, it appears to have no locally detectable features. In many ways a black hole acts like an ideal black body, as it reflects no light.

 Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, super massive black holes of millions of solar masses  may form. There is general consensus that super massive black holes exist in the centers of most galaxies.

 Objects whose gravitational fields are too strong for light to escape were first considered in the 18th century by John Michel and Pierre-Simon Laplace. The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958. Long considered a mathematical curiosity, it was during the 1960s that theoretical work showed black holes were a generic prediction of general relativity. The discovery of neutron stars sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality.

Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light. Matter falling onto a black hole can form an accretion disk heated by friction, forming some of the brightest objects in the universe. If there are other stars orbiting a black hole, their orbit can be used to determine its mass and location. In this way, astronomers have identified numerous stellar black hole candidates in binary systems, and established that at the core of our own Milky Way galaxy, contains a super massive black hole .

A nova (plural novae or novas) is a cataclysmic nuclear explosion on a white dwarf, which causes a sudden brightening of the star. Novae are not to be confused with other brightening phenomena such as supernovae or luminous red novae. Novae are thought to occur on the surface of a white dwarf in a binary system. If the two stars of the system are sufficiently near to one another, material can be pulled from the companion star’s surface onto the white dwarf. A nova is caused by the accretion of hydrogen onto the surface of the star, commencing a runaway fusion reaction.

What Is a Supernova? A supernova is the explosion of a star. It is the largest explosion that takes place in space. A supernova is a large explosion that takes place at the end of a star’s life cycle. Where Do Supernovas Take Place? Supernovas are often seen in other galaxies. But supernovas are difficult to see in our own Milky Way galaxy because dust blocks our view. In 1604, Johannes Kepler discovered the last observed supernova in the Milky Way. NASA discovered the remains of a more recent supernova. It exploded in the Milky Way more than a hundred years ago. What Causes a Supernova?.A supernova happens where there is a change in the core, or center, of a star. A change can occur in two different ways, with both resulting in a supernova.

The first type of supernova happens in binary star systems. Binary stars are two stars that orbit the same point. One of the stars, a carbon-oxygen white dwarf, steals matter from its companion star. Eventually, the white dwarf accumulates too much matter. Having too much matter causes the star to explode, resulting in a supernova. The second type of supernova occurs at the end of a single star’s lifetime. As the star runs out of nuclear fuel, some of its mass flows into its core. Eventually, the core is so heavy that it cannot withstand its own gravitational force. The core collapses, which results in the giant explosion of a supernova. The sun is a single star, but it does not have enough mass to become a supernova.

Why Do Scientists Study Supernovas?.A supernova burns for only a short period of time, but it can tell scientists a lot about the universe. One kind of supernova has shown scientists that we live in an expanding universe, one that is growing at an ever increasing rate. Scientists also have determined that supernovas play a key role in distributing elements throughout the universe. When the star explodes, it shoots elements and debris into space. Many of the elements we find here on Earth are made in the core of stars. These elements travel on to form new stars, planets and everything else in the universe.

White Dwarfs are Compact Corpses of Stars after stars burn out . The ancient white dwarfs are 12 to 13 billion years old, only slightly younger than the universe itself. In theory, white dwarfs will eventually stop emitting light and heat and become black dwarfs. The stars in the sky may seem ageless and unchanging, but eventually most of them will turn into white dwarfs, the last observable stage of evolution for low- and medium-mass stars. These dim stellar corpses dot the galaxy, leftovers from brightly burning stars.

The most massive stars, with eight times the mass of the sun or more, will never become white dwarfs. Instead, at the end of their lives, they will explode in a violent supernova, leaving behind a neutron star or black hole. Smaller stars, however, will take a slightly more sedate path. Low- to medium-mass stars, such as the sun, will eventually swell up into red giants, eventually shedding their outer layers into a ring known as a planetary nebula. The core that is left behind will be a white dwarf, a husk of a star in which no hydrogen fusion occurs. When this happens the Earth will escape the Sun’s Gravitational Field and so its orbit around Sun and float in Space and all forms of life without Sun’s light may end.

    A Neutron star is a type of compact star that can result from the gravitational collapse of a massive star after a supernova. Neutron stars are the densest and smallest stars known to exist in the universe; with a radius of only about 12–13 km (7 mi), they can have a mass of about two times that of the Sun. Neutron stars are composed almost entirely of neutrons, which are subatomic particles without net electrical charge and with slightly larger mass than protons. Neutron stars are very hot.  

OUR HOME GALAXY

     The name of our home galaxy is Milky way. A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas and dust, and dark matter. The Milky Way is the galaxy that contains our Solar System. Its name “milky” is derived from its appearance as a dim glowing band arching across the night sky whose individual stars cannot be distinguished by the naked eye. From Earth the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. The Milky Way is a barred spiral galaxy that has a diameter usually considered to be roughly 100,000–180,000 light-years. The Milky Way is estimated to contain 100–400 billion stars although this number may be as high as one trillion. There are probably at least 100 billion planets in the Milky Way. The Solar System is located within the  Milky Way disk, about 27,000 light-years from the Galactic Center. The very center is marked by an intense radio source, named Sagittarius A*, which is likely to be a supermassive black hole. The stars and gases move around the Galactic center and the Galaxy as a whole move around with respect to extra galactic frames at various speeds. The oldest stars in the Milky Way are nearly as old as the Universe itself and thus must have formed shortly after the Big Bang. The Milky Way has several satellite galaxies and is part of the Local Group of galaxies, which is a component of the Virgo Supercluster, which again is a component of the Laniakea Super cluster. The image below is our Milky way Galaxy

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The Sagittarius Dwarf Galaxy is the nearest galaxy to our own. However, it was only discovered as recently as 1994. It lies on the far side of the galaxy from us and is heavily obscured by the intervening gas, dust and stars. It is approximately 78000 light years away and about 10000 light years in diameter. It is orbiting our galaxy in a period of about 1 billion years but it cannot be expected to last much longer, in a few hundred million years it will be ripped apart by our own galaxy. It contains about one hundred million stars. Galaxies show Cannibalism which is called Galactic Cannibalism. The Sagittarius Dwarf Galaxy will probably not be the first galaxy that has been ‘eaten’ by our galaxy. There are  reports that outside of the Galaxy there are huge clumps of stars that appear to be the remains of smaller galaxies that were ripped apart by the Milky Way more than a billion years ago. The distribution of these stars shows at least two clumps that are several thousand light years in size and more than 100 000 light years from the center of the Galaxy.

SOLAR SYSTEM– Our Solar System consists of a star called Sun and 8 planets excluding Pluto, satellites around planets, Asteroids, Comets etc. The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. The dwarf planet Pluto  is the largest known object in the Kuiper belt, a belt of celestial material beyond Neptune. When discovered in 1930, it was considered to be the ninth planet; this changed in 2006 with the adoption of a formal definition of planet. Pluto has a relatively eccentric orbit inclined 17 degrees to the ecliptic plane for which it is deleted from list of planets. The age of our Solar System is 5 billion years and that of earth is roughly 4.6 billion years.

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  Asteroids are small Solar System bodies composed mainly of refractory rocky and metallic minerals, with some ice. The asteroid belt occupies the orbit between Mars and Jupiter . It is thought to be remnants from the Solar System’s formation that failed to coalesce because of the gravitational interference of Jupiter. Asteroids range in size from hundreds of kilometers across to microscopic. The asteroid belt contains tens of thousands, possibly millions, of objects over one kilometer in diameter. Asteroids with diameters between 10 and 10−4 m are called meteoroids.

 Comets are small Solar System bodies, typically only a few kilometers across, composed largely of volatile ices. They have highly eccentric orbits, generally a perihelion within the orbits of the inner planets and an aphelion far beyond Pluto. When a comet enters the inner Solar System, its proximity to the Sun causes its icy surface to sublimate and ionize, creating a coma: a long tail of gas and dust often visible to the naked eye.

THE FUTURE

< p style="text-align:justify"> The Cosmic world is not static in space and time. It has passed through  violence ever since the Big Bang as spoken above. It is believed by scientists that the Universe will collapse one day after billions of years and coalesce into one big unit of matter like what was there before the Big bang by the gravitational forces resulting in no life on earth. Thus the end of present Universe after billions of years by this process cannot be ruled out.

Just like every living being has an end, the celestial objects have also an end. The only difference is the longevities of the celestial objects which are long. The Sun will one day burn out resulting formation of a dwarf star and life on earth shall cease to exist. So the end of Civilization on earth is an unavoidable  scientific truth. But we feel less concerned as it is not in near future.

There are many predictions on Dooms day i.e. when the human life on earth will vanish resulting in end of  civilization. All previous predictions on Dooms day of earth have failed. However few predictions based on some scientific models reported are as follows.  

i)8,000,000th century-According to current models, the Sun is expected to increase in luminosity by 10% in the next 800 million years. This will cause several changes to the climate that will make the continued existence of life on Earth impossible, starting with photosynthetic organisms and eventually killing off all life.

ii)40 millionth century-The galaxy Andromeda (currently 2.5 million light years away) is expected to collide with our galaxy, the Milky Way. This year is going to be eventful for the earth’s existence.

iii)50 millionth century- 5 billion years from now: According to most accepted models of stellar evolution, the Sun will eventually run out of hydrogen fuel to fuse into helium and will expand, becoming a red giant as a result. This red giant might get large enough to swallow the Earth’s orbit, but even if it doesn’t, the Earth will be roasted to a cinder crisp.

iv)200 millionth century-20 billion years from now: Judging from the current rate of universal inflation — the rate at which the expansion of the universe is accelerating — in 20 billion years, the universe will be expanding so rapidly that atoms will no longer be able to hold on to their electrons. This predicted event is known as the “Big Rip.” Blame dark energy.

v)3×1041 st century- 3×1043 years from now: estimated time for all nucleons in the observable universe to decay, if the proton half-life takes the largest possible value . This is the Total Existence Failure of the entire universe. Out of all the above, this is the most likely. ( source-rationalwilki.org)

    One scientifically calculated danger to earth is from the hit of an Asteroid on earth on 16th March 2880 named 1950 DA . The asteroid, named 1950 DA, is a rock two-thirds of a mile in diameter, travelling at about 15 km (nine miles) per second relative to the Earth. It is approximately 3,280ft (1,000 meters) in diameter, but rotates once every two hours and six minutes. At this rate, the rock should break apart and eventually disintegrate, but it is not showing any signs of doing so. In fact, the rotation is so fast that at its equator, 1950 DA effectively experiences negative gravity. If an astronaut were to attempt to stand on this surface, he or she would fly off into space unless he or she were somehow anchored. It is estimated that if 1950 DA were to collide with the planet, it would do so with an force of around 44,800 mega tons of TNT. Although the probability of an impact is only 0.3 per cent, this represents a risk 50 per cent greater than an impact from all other asteroids. Asteroids hitting the earth is nothing uncommon and it is believed that one Asteroid hit has made the Dinosaurs extinct nearly 65 million years ago. Hitting of a big Celestial object has tilted the earth to 66 degrees with respect to its orbital plane. The formation of the moon is also by hitting the earth by  a celestial object nearly 4 billion years back. Thus celestial hitting will continue and the possible hitting in 2880 March 16th may cause terrible impact.

Conclusion– The Earth is the only Celestial object known to have any form of Life as on today. A strange phenomenon has caused our Solar System, Earth and the Environment conducive for different forms of Life sustaining by a conducive atmosphere, Oxygen and Carbon Dioxide level, Temperature and Water with a favourable Climate and Biodiversity. It is in our own interest to save the planet by fighting the Global Warming and Climate Change.

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