from big bang to the present time
DESCRIPTION
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 "TRANSCRIPT
FROM BIG BANG TO PRESENT TIME
1Presented by: Uttam Pudasaini
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 extractionTelescopesSatellites
2
BIG BANG
Prevailing cosmological model that describes the early development of the Universe
3
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
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
5
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
UNIVERSE (COMPOSITION)
7
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.
Dust Particles
8
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)
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
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
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
Galaxy contd..
12
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.
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
14
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
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
Planets
17
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
Information extraction
Telescope on Earth surface and Satellites in space collects all the possible information
Huge amount of data is then systematically processed
19
Telescope :Design and workingA 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
20
Fig: Advantage of using a large diameter telescope
EELT(42 m diameter Telescopes)
21
Satellites
Fitted with telescopes for images of distant objects
Infrared detectors of longer wavelength helps to take pictures of such regions
22
Hubble Space Telescope
Source:www
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
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 objects1.3 million spectra10 TB imaging data2 TB catalogue data
24
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
Some Snapshots
26
27
28
29
30
31
32
33
34
35