Our Place in the Grand Scheme of Things


 Universe is necessary for our existence but human beings have a tendency to invert this - that universe exists for our benefit, that we mark the centre of the universe, that the whole of creation revolves around us.

Earth is centre of creation

Domination vs. Cohabitation

Anthropocentrism  arrogance

 Where do we really stand?

Spatial Significance

Earth:

A smallish Planet

One of nine planets revolving around the sun

Orbits the sun (V~20km/s)

Sun:

An average G3-type star

One of 100 Billion stars

Sun zipping around galatic centre at V~200km/s

Above~Andromeda (similar to Milky Way)

Milky Way:

Medium-sized galaxy

One of 2 Billion + Galaxies in known universe
 

Zipping thru cosmos at V~600km/s

Spatial Scale

Atom

~1A 

 10^-8 cm 

Man 

~1m 

10^2 cm 

Earth 

 ~10,000 km

10^9 cm 

Sun 

 ~10^6 km 

10^11cm 

Solar System

~10^9 km

 10^14 cm

Galaxy 

~30,000 ly *

10^22 cm 

Observable Universe

 ~10 Billion ly

10^28 

 * {ly = c x (t) year}

    = (3 x 10^10 cm/s) (3 x 10^7 s/yr)

Temporal Scale

THIS LECTURE

 ~1hr

 ~10^3 s

HUMAN LIFETIME

 ~100 yr 

 10^9 s 

HUMAN CIVILIZATION

 10,000 yr

 10^11 s

LIFE ON EARTH

 3 Billion yr

 10^16

EARTH/SOLAR SYSTEM

 5 Billion yr

10^16 

UNIVERSE

 10-15 Billion yr

 10^17


Creation Myths

TOP

Development of Astronomy