from big bang to the present time

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