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Though i am not an applied physics /B.S.C physics student ,Science has always been something of my interest :) Presentation during "International School on Astronomy and Space Science organized by Ministry of Environment, Science and Technology and B.P. Koirala Memorial Planetorium, Observatory and Science Museum Development Board "

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  1. 1. FROM BIG BANG TO PRESENT TIME Presented by: Uttam Pudasaini 1
  2. 2. Presentation Online  Big Bang  Timeline of Universe  Hubble's law and the age of Universe  Universe and its composition  Galaxy  Stars  Supernova  Planets  Formation of solar system  Information extraction  Telescopes  Satellites 2
  3. 3. BIG BANG Prevailing cosmological model that describes the early development of the Universe  Universe was once in an extremely hot and dense state  After its initial expansion from a singularity, the Universe cooled sufficiently to allow energy to be converted into various subatomic particles 3
  4. 4. Big Bang contd… The first element produced was hydrogen, along with traces of helium and lithium.  Giant clouds of these elements coalesce through gravity to form stars and galaxies 4
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  6. 6. Hubble's law and age of Universe Edwin Hubble in 1920 discovered the expansion of the universe. Farther galaxies are moving at a higher speed following the law, v=Hod, where v is the velocity in km/s, d is the distance in Mpc, and Ho is the Hubble constant in km/s/Mpc.  Velocity is determined via the redshift in the spectrum and distance to the galaxy determined using observations of stars Up until the 1990's, the best estimates for Ho were between 50 km/s/Mpc and 90 km/s/Mpc, giving a range on the age of the universe between 7 and 20 billion years. 6
  7. 7. UNIVERSE (COMPOSITION) Universe is 13.7 billion years old with an uncertainty of 200 million years. The WMAP value of Ho is 71 ± 4 km/s/Mpc 70% of the energy of the present universe is in the form of dark energy.  26% of the energy is in the form of cold (not thermalized) dark matter, and the remaining 4% of the energy is in the atoms and photons. 7
  8. 8. Dust Particles Size: Few molecules to few microns in size Mass spectrometer in the satellites collect them (They get stuck on Aerogel) Possesses Scattering property Analyzed studying the properties of light emitted by the dust  ISM(Interstellar Matter),IGM(Inter Galactic Matter) and Inter Planetary Dust Particle(IDP) 8
  9. 9. Dust particles contd… Universe was homogenous and there was little-to-no structure in it after Big Bang. As the universe cooled clumps of Dark matter began to condense, and within them gas began to condense. Large scale structure of the cosmos we observe today was formed as a consequence of the growth of the primordial fluctuations. The primordial fluctuations gravitationally attracted gas and dark matter to the denser areas, and thus the seeds that would later become galaxies were formed. 9
  10. 10. Dust particles contd… 40 Tons of extraterrestrial matter falls to Earth everyday What happens to the Earth mass????? Using the isotropic ratio we can differentiate them from the common dust particle in the Earth 10
  11. 11. Formation of Galaxy  At this point the universe was almost exclusively composed of hydrogen, helium, and dark matter.  Soon after the first proto-galaxies formed, the hydrogen and helium gas within them began to condense and make the first stars and finally the first galaxies were formed.  The discovery of a galaxy more than 13 billion years old, which existed only 480 million years after the Big Bang, was reported in January 2011.  A structure distributed in a great cosmic web of filaments throughout the universe which contains the fossil clues to this earlier time
  12. 12. Galaxy contd..  Come in a variety of shapes, from round, featureless elliptical galaxies to the pancake-flat spiral galaxies.  In Milky Way there are an estimated 6,000 molecular clouds, each with more than 100,000 solar masses. 12
  13. 13. STARS Higher density regions of the interstellar medium form clouds or diffuse nebula Much of the hydrogen is in the molecular (H2) form(molecular cloud) The nearest nebula to the Sun where massive stars are being formed is the Orion nebula, 1,300 ly (1.2×1016 km) away. 13
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  15. 15. Stars contd… Another site of star formation is the opaque clouds of dense gas and dust known as Bok globules; so named after the astronomer Bart Bok. These can form in association with collapsing molecular clouds or possibly independently. The Bok globules are typically up to a light year across and contain a few solar masses.  Over half the known Bok globules have been found to contain newly forming stars. By other process: cloud collapse, empty space 15
  16. 16. Supernova The most massive stars end their lives as supernova, the explosive destruction of a star. Occurs when a massive star suddenly becomes unable to sustain the core against its own weight The explosion expels much or all of a star's material at a velocity of up to 30,000 km/s (10% of the speed of light), driving a shock wave into the surrounding interstellar medium. 16
  17. 17. Planets 17
  18. 18. Formation of Solar System  Stars formed by self gravity  Early solar system was a cloud of interstellar gas that had fairly fast rotation so not all of the gas could fall into the star forming at the center  Dust particles stuck by sticking process  Planetecimals grew by sticiking process  Protoplantes were formed  Protoplanets finally formed planets 18
  19. 19. Information extraction Telescope on Earth surface and Satellites in space collects all the possible information Huge amount of data is then systematically processed 19
  20. 20. Telescope :Design and working A segmented mirror telescope with displacement sensors Instead of eye a CCD camera as a detector Wave front distortion is avoided with the help of deformable mirror Fig: Advantage of using a large diameter telescope 20
  21. 21. EELT(42 m diameter Telescopes) 21
  22. 22. Satellites Hubble Space Telescope Fitted with telescopes for images of distant objects Infrared detectors of longer wavelength helps to take pictures of such regions Source:www 22
  23. 23. Satellites contd… Thermal blanket working as a shield Prior to launch subjected to a thermal vacuum testing(temp range:-60 to 60 degree Celsius) Suffers gravity effects, radiations and collision with debris High frequency transmission suffers less attenuation 23
  24. 24. SDSS(Sloan Digital Sky Survey) In February 2003, the WMAP project released an all-sky map of the radiation emitted before there were any stars. Output: 287 million objects 1.3 million spectra 10 TB imaging data 2 TB catalogue data 24
  25. 25. Scope of Geomatics students in Astronomy  For those who want to continue their higher study in the filed of Astronomy and Space science  Site selection project for observation centers at Earth  Satellite communication and Space science  Computer programming and its use in Virtual Obeservatory 25
  26. 26. Some Snapshots 26
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