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basics of the universe a detail description regarding the development of the universe
Geography Honours
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Basics of the Universe
Technical Report · October 2017 DOI: 10.13140/RG.2.2.
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Basics of the Universe
by
Prof A. Balsubramanian
Centre for Advanced Studies in Earth Science
University of Mysore
Mysore-
- Nicolaus Copernicus (1473-1543).
- Tycho Brahe (1546-1601) Compiled the star catalogue-during pre-telescopic time.
- Johannes Kepler (1571-1630) Planets more around the Sun in Orbits which are not circular but elliptical.
- Galileo Galilei (1564-1642).
- Sir Isaac Newton (1643-1727).
Their findings formed the basis for all present day astronomical and astrophysical studies and applications. Nicolaus Copernicus, the Polish astronomer established three things: i) The earth is a planet of Solar System. ii) The Sun is at the centre of the Solar System iii) There are other planets like Mercury, Venus, Mars, Jupiter and Saturn orbiting with in the same system.
J. Kepler was the first to identify that the path of each planet around the Sun is not circular and is elliptical. Galileo Galilei, the greatest Italian scientist supported the Sun-centred theory of Solar System. His contributions were related to i) Behavior of moving objects. ii) The weight of an object does not affect its rate of fall. iii) Air resistance has a role to play for light object.
Galileo, by using his telescope, made many discoveries like
- Four satellites of Jupiter.
- Planets are circular disc like bodies.
- Venus, has phases like moon.
- Moon's surface has mountains, craters and plains.
- The Sun has both hot high temperature and dark low temperature spots.
Sir Isaac Newton the greatest genius of that time (1643-1727) was the first to explain why the planets move around the Sun. He proved the idea of Galileo that no force was needed to keep an object in motion. Newton’s first Law of motion was an outcome of this time. The force of gravity and the Law of universal gravitation were postulated by Sir Isaac Newton at his age of 23. It states that “Every body in the Universe attracts every other body with a force that is directly proportional to their masses and inversely proportional to the square of the distance between them.” This signifies that, (i) the gravitational force decreases with distance. (ii) The greater the mass of the object, greater is the gravitational force (iii) The mass does not change unlike the weight. It was a thought provoking time during which the theory was formulated about the origin of the Universe called Big Bang Theory (BBT). According to the Big Bang Theory, the Universe came into existence due to a huge explosion called “Big-Bang” occurred between 10 and 20 billion years ago. A very hot dense fireball of expanding cooling gas probably began to condense into localized clumps called Proto galaxies which due to further cooling released galaxies, stars and planets, many of them co-exist under the influence of gravity.
Content of the Universe:
Initially, astronomers thought that the universe was composed entirely of ordinary atoms, or "baryonic matter". During the recently years, more evidences obtained by global scientific bodies suggests that most of the ingredients making up the universe are in some forms which we cannot see. It shows that atoms only make up 4 percent of the universe. Of the remainder, 23 percent is made up of dark matter. This dark matter is composed of one or more species of subatomic particles that interact very weakly with ordinary matter. Almost 72 percent of the Universe is made of dark energy. This is the driving element which is accelerating the unpredictable distribution and expansion of the
universe. According to NASA, hydrogen makes up about 75 percent, while helium makes up about 25 percent, with heavier elements making up only a tiny fraction of the universe's chemical content.
Structure of the Universe:
Scientists thought in the earliest periods, that the universe has no structure and the matter and energy are distributed nearly uniformly throughout. But later studies by NASA confirmed that the gravitational pull of small fluctuations in the density of matter gave rise to the vast web-like structure of stars and emptiness in the universe. The Dense regions pulled in more and more matter through gravity is responsible for the forming stars, galaxies and larger structures known as clusters, super clusters, filaments and walls. This is also responsible for the formation of "great walls" of thousands of galaxies. These are reaching more than a billion light years in length. Due to this reason, we call the universe as vast and dark. The less dense regions did not grow, evolving into an area of seemingly empty space called as voids.
Expanding Universe:
In the 1920s, astronomer Edwin Hubble discovered that the universe was not static but was expanding. This finding revealed that the universe was apparently born in a Big Bang. In 1998, the Hubble Space Telescope's observations of very distant supernovae revealed that a long time ago, the universe was expanding more slowly than it is today. In other words, the expansion of the universe was not slowing due to gravity, but instead inexplicably was accelerating. The name for the unknown force driving this accelerating expansion was called as dark energy.
The universe was born with the Big Bang which was an unimaginably hot, dense mass. When the universe was just 10- 34 of a second in age. It has experienced an incredible burst of expansion known as inflation, in which the space itself got expanded faster than the speed of light. During this period, the universe doubled in its size at least 90 times, going from subatomic-sized mass to a golf-ball- sized mass almost instantaneously. According to NASA (National Aeronautics and Space Agency of the USA), this inflation and growth of the universe were continued but at a slower rate. As the space expanded, the universe cooled and the matter was formed. One second after the Big Bang, the universe was filled with neutrons, protons, electrons, anti-electrons, photons and neutrinos.
First Three Minutes of The Universe:
During the first three minutes of the universe, the light elements were born during a process known as Big Bang nucleosynthesis. Temperatures cooled from 100 nonillion (10 32 ) Kelvin to 1 billion (10 9 ) Kelvin, and protons and neutrons collided each other and made deuterium, an isotope of hydrogen. Most of the deuterium then combined together to form helium, and trace amounts of lithium were also generated. According to France's National Center of Space Research(CNES), for the first 380,000 years or so, the universe was essentially too hot for light to shine.
Era of Recombination:
The heat of creation smashed atoms together with enough force to break them up into a dense plasma, an opaque soup of protons, neutrons and electrons that scattered light like fog all around. This was called as the Era of recombination. Roughly 380,000 years after the Big Bang, the matter got cooled down well enough to form more atoms resulting in a transparent, electrically neutral gas as observed by the NASA. This set the initial flash of light created during the Big Bang, which is detectable today as cosmic microwave background radiation. It was found that after this situation, the universe was found to be plunged into a state of darkness, since no stars or any other bright objects had formed yet.
Composition of the Universe:
According to the latest observational evidence, ordinary matter, including stars, planets, dust and gas,
only make up a tiny fraction of the universe (5%). The rest is the elusive dark matter (25%) and dark
energy(70%).
Dark energy is a mysterious (and as yet hypothetical) form of energy which is spread out uniformly throughout space (and time). It has anti-gravitational properties. It is one of the possible explanations for the current accelerating rate of expansion of the universe.
Dark matter is the matter not visible to us because it emits no radiation that we can observe, but it is detectable gravitationally.
Hydrogen & helium gas: Hydrogen and Helium are the most abundant element in the universe. This element is found in great abundance in stars and gas giant planets. Star: A ball of mostly hydrogen and helium gas that shines extremely bright. Our Sun is a star.
Neutrino: A small particle that has no charge and is thought to have very little mass. Neutrinos are created in energetic collisions between nuclear particles. The universe is filled with them but they rarely collide with anything. The distribution pattern is as follows:
Details Percent
Dark energy 70%
Dark matter 25%
Hydrogen & helium gas 4%
Stars 0%
Neutrinos 0%
Heavy elements 0%
Abundance of elements in the Universe are shown in this table.
Ten most common elements in the Milky Way Galaxy estimated spectroscopically
Z Element Mass fraction in parts per million
1 Hydrogen 739,
2 Helium 240,
8 Oxygen 10,
6 Carbon 4,
10 Neon 1,
26 Iron 1,
7 Nitrogen 960
14 Silicon 650
12 Magnesium 580
16 Sulfur 440
The elements – that is, ordinary (baryonic) matter made of protons, neutrons, and electrons, are only a small part of the content of the Universe. Cosmological observations suggest that only 4% of the universe's energy (including the mass contributed by energy, E = mc² ↔ m = E / c²) comprises the
visible baryonic matter that constitutes stars, planets, and living beings. The rest is made up of dark energy (68%) and dark matter (27%). Hydrogen is the most abundant element in the Universe; helium is second. However, after this, the rank of abundance does not continue to correspond to the atomic number; oxygen has abundance rank 3, but atomic number 8. All others are substantially less common.
The Dark Matter:
Today astronomers believe that around one quarter of the mass-energy of the Universe consists of dark matter. This is a substance quite different from the normal matter that makes up atoms and the familiar world around us. Hubble has played an important part in work intended to establish the amount of dark matter in the Universe and to determine where it is and how it behaves. Dark matter only interacts with gravity, which means it neither reflects, emits or obstructs light (or indeed any other type of electromagnetic radiation). Because of this, it cannot be observed directly. In 2007 an international team of astronomers used Hubble to create the first three-dimensional map of the large-scale distribution of dark matter in the Universe. It was constructed by measuring the shapes of half a million galaxies observed by Hubble.
The Dark energy:
More intriguing still than dark matter is dark energy. Hubble studies of the expansion rate of the Universe have found that the expansion is actually speeding up. Astronomers have explained this using the theory of dark energy, that pushes the Universe apart ever faster, against the pull of gravity. As Einstein's famous equation, E=mc 2 tells us, energy and mass are interchangeable. Studies of the rate of expansion of the cosmos suggests that dark energy is by far the largest part of the Universe’s mass-energy content, far outweighing both normal matter and dark matter: it seems that dark energy makes almost 70% of the known Universe.
Other clustered objects in the Universe:
There are several clustered objects concentrated in the Universe as Galaxies, Nebulae, Stars, Black holes, and Novae.
The Galaxies:
A Galaxy is a huge mass of stars, nebulae and other interstellar objects co-existing as star families under the gravitational attraction of a giant single star. A Galaxy is a giant family of millions of stars. The Scientific observations say that there may be as many as 100 billion galaxies existing in the Universe, a fraction of it is alone known to human knowledge. There are different kinds of Galaxies as i) Spiral Galaxies ii) Elliptical Galaxies iii) Irregular Galaxies
The story of telescopic astronomy began in 1609. The first astronomical observations were made by Thomas Harriott, Galileo and Marius. It was Thomas Harriott has compiled a map of the moon which formed the foundation to Galileo’s contributions. Hans Lippershey of Holland made the first instrument which helped Galileo to invent the refracting telescopes. The year 1609 has shown spectacular discoveries on Moon, Jupiter, Venus and Sun. In 1663, reflecting telescope was invented by J. Gregory, to overcome the problems of rainbow colors in the Prisms used for refracting telescopes.
Throughout 18th century telescopes of various sizes were built. Uranus was identified using the telescope made by William Herschel in 1781. During the 19th Century both spectroscopy and photography were taken as separate schools of studies. Scientists of Astronomy and optics were
Elliptical Galaxy
It is a galaxy that looks round or elliptical. One example is M87, in the constellation Virgo. Elliptical galaxy is a galaxy without spiral arms and with an ellipsoidal shape. Ellipticals have little interstellar matter and no blue giants - the only giants are red, and they give ellipticals a slightly redder color than spirals. The most massive galaxies known (about 1013 M ) as well as some of the least massive known, are ellipticals.
Seyfert Galaxy
Seyfert Galaxy is a type of spiral galaxy first discovered by Karl Seyfert in the 1940s. The central region of a Seyfert galaxy is distinguished by powerful radiation, much of it focused into narrow frequencies. These are one of a small class of galaxies (many of which are spirals) of very high luminosity and very blue continuum radiation with small, intensely bright nuclei whose spectra show strong, broad, high-excitation emission lines probably caused by discrete clouds moving at velocities that are higher than the escape velocity.
Spiral Galaxy
Spiral Galaxy is a galaxy with a prominent nuclear bulge and luminous spiral arms of gas, dust, and young stars that wind out from the nucleus. Masses span the range from 1010 to 1012 M.
Spiral Nebula
Spiral Nebula is a spiral galaxy - not really a nebula at all (although many do appear nebulous).
Interstellar Dust
These are dust particles in the space between the stars. These are responsible for the dark patches of obscuration seen on astronomical photographs. The particles are composed of common heavy elements such as carbon and silicon but there is no agreement about the exact composition of the dust grains. Typically, the particles have size about 1 μm but there must be a wide range of particle sizes present to explain the interstellar extinction curve. The dust plays a key role in giant molecular clouds in protecting the fragile molecules from intense interstellar ionising and dissociating radiation. The energy absorbed by the grains is emitted in the far-infrared waveband, and this form of dust emission is one of the most important energy loss mechanisms for regions of star formation. The particles are polarized, needle-shaped grains. Interstellar dust affects the entire spectrum, and leads to dimming and reddening of starlight.
Nova
Nova is a star that brightens suddenly and to an unprecedented degree, creating the impression that a new star has appeared where none was before. Hence the name, from nova for "new". All known common novae are found in close binary systems with one component a cool red giant and the other a hot, less massive object which is the seat of the instability. A star that undergoes an explosion during which its brightness increases by up to ten magnitudes.
Planetary Nebula
Planetary Nebula is a bubble of gas surrounding a hot, dying star. The star is so hot that it makes the planetary nebula glow, which allows astronomers to see it. The star was once the core of a red giant, which ejected its outer atmosphere and created the planetary. A planetary nebula has nothing to do with a planet, but through a small telescope, it looks like a planet's disk, hence the misleading name. The planetary nebula stage lasts for less than 50,000 years. During the core contraction that terminates
the red-giant stage, the helium-burning shell is ejected at a velocity so high that it becomes separated from the core.
Protogalaxy
Protogalaxy is a galaxy in the process of formation. None are observed nearby, indicating that all or most galaxies formed long ago. A galaxy during the early phase, before it has developed its present shape and mix of stars.
Pulsar
A Pulsar is a fast-spinning neutron star that emits radiation toward Earth every-time it rotates. Neutron stars that spin rapidly and have strong magnetic fields, which produce electromagnetic radiation. All pulsars are characterized by the general properties of dispersion, periodicity, and short duty cycle. Pulsars are believed to be rotating, magnetic neutron stars which are the end products of supernovae.
Black Hole
A Black Hole is a region of space-time which cannot be seen by distant observers because light is trapped by a strong gravitational field. The boundary of this region is called an event horizon because it separates events (i. those in the hole) that cannot be seen from events outside the hole, which can. Black holes might form, for example, from the gravitational collapse of a massive star. When the star shrinks inside an event horizon, it will collapse without known limit, leaving the surrounding space empty, Thus the designation `hole'. Spherical black holes (without electric charge) are known as Schwarzschild black holes. Rotating holes are non-spherical: they are known as Kerr black holes.
A Black hole is an object that is maximally gravitationally collapsed, and from which not even light can escape. An object with such a strong gravitational field that even light cannot escape. Matter can fall into a black hole, but according to classical physics no matter or energy can leave it. It is a mass that is sufficiently compact that not even light can escape its intense gravity. Thus it appears black from the outside.
Light year
The light-year is a unit of length used to express astronomical distances. It is equivalent to the distance that light travels in one year, which is 9 × 1 012 km (nearly 6 million million miles). As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365 days). Because it includes the word "year", the term light-year is sometimes misinterpreted as a unit of time.
The light-year unit appeared a few years after the first successful measurement of the distance to a star other than the Sun, by Friedrich Bessel in 1838. The light-year unit appeared, however, in 1851 in a German popular astronomical article by Otto Ule. The light-year is most often used when expressing distances to stars and other distances on a galactic scale. The abbreviations used for light years and multiples of light years are
"ly" for one light year "kly" for a kilolight-year (1,000 light years) "Mly" for a megalight-year (1,000,000 light years) "Gly" for a gigalight-year (1,000,000,000 light years)
and on his television series Cosmos as a way to conceptualize the vast amounts of time in the history of the universe.
The 13 billion year lifetime of the universe was pictorially mapped onto a single year. At this scale the Big Bang takes place on January 1 at midnight, the current time is December 31 at midnight, and each second is 434 years. The scale was popularized by Carl Sagan in his book The Dragons of Eden.
C o s mi c E vo l u t i o n
The following includes Cosmological time and the start of Geological Time (Chaotian and Hadean).
Date / time bya Event
1 Jan 13 Big Bang, as seen through cosmic background radiation 11 May 8 Milky Way Galaxy formed
1 Sep 4 Sun formed (planets and Earth's moon soon thereafter)
16 Sep 4 Oldest rocks known on Earth
Evolution of life
Date / time bya Event
21 Sep 3 first life (prokaryotes)
12 Oct 3 photosynthesis
29 Oct 2 Oxygenation of atmosphere
8 Nov 2 complex cells (eukaryotes) 5 Dec 1 first multicellular life
14 Dec 0 simple animals
14 Dec 0 arthropods (ancestors of insects, arachnids)
18 Dec 0 fish and proto-amphibians
20 Dec 0 land plants
21 Dec 0 insects and seeds
22 Dec 0 amphibians 23 Dec 0 reptiles
26 Dec 0 mammals
27 Dec 0 birds
28 Dec 0 flowers
30 Dec 0 K-T mass extinction, non-avian dinosaurs die out
Human evolution
The following continues with Geological Time, which then becomes Quaternary Time. Date / time mya Event
30 Dec 65 Primates
31 Dec, 06:05 15 Apes
31 Dec, 14:24 15 hominids
31 Dec, 22:24 2 primitive humans and stone tools
31 Dec, 23:44 0 Domestication of fire
31 Dec, 23:52 0 Anatomically modern humans 31 Dec, 23:55 0 Beginning of most recent glacial period
13
31 Dec, 23:58 0 sculpture and painting 31 Dec, 23:59:32 0 Agriculture
The purpose of Cosmic Calendar
To give us a better idea of the time scale involved in human evolution, it is interesting to compare the numbers involved with something a little more familiar. Here, the history of the universe has been scaled down to one year, That is, one month is equivalent to one billion year, one day to 30 million years, one hour to 1 million year and one minute to 20 000 years.
Importance of studying the universe:
Human beings possess an intrinsic need to explore the world. Through exploration, people have discovered new continents, found treatment methods to cure diseases, advanced in technology, communication and innumerable aspects. Studying the origins of the Universe and exploring it helps us build our civilization. Exploring how our civilization came into existence has evolved our ability of thinking and understanding our surrounding and also the universe in a better way. Our curiosity to get the answer to every query in relation to the origin and existence of universe has helped us to discover and build better technology that we so ungratefully enjoy in all walks of life. Humans have managed to advance in every field of technology, medicines, energy and telecommunication.
The ideas of Space Travel, Rockets, and artificial Satellites got emerged with outstanding contributions. The first sets of Liquid-propellant rockets were launched in 1926 and 1949. Probing the planets really started after the launch of Sputnik-I in 1957 and Lunik-1 in 1959 by the Russians. The first manned space flight was achieved on 12th April 1961, while using Vostok-1, by reaching 203 miles in one hour and 48 minutes. Alan Shepard became the first American in Space. Apollo-II was the first successful landing of man on the moon in 1969.
During this time, two planets, Venus and Mars were concentrated, for various studies. The nearest was Venus. Artificial satellites with sophisticated and sterilized probes were used to explore all the planets and satellites. The Moon is the only satellite of Earth and its closest associate. Moon has a special position in the heart of every human being on earth. Lunar charting, with photographic systems and mapping of Moon Maria, Moonquakes and Moons Mountains, volcanic craters were the efforts of those days, in History.
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basics of the universe a detail description regarding the development of the universe
Course: Geography Honours
University: Creighton University
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