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ecology and environmenttoday we hear people from different walks of life using the terms ecology and environment politicians leaders town
anthropological evidencemodern humans arose at a time when the earth was going through a very cold and icy period called the ice age which began
archaeological evidencethe study of human antiquities especially of prehistoric period is known as archaeology the biological and cultural
australopithecus-the transitional human formsby about two million years ago there were several well established hominid ancestors in africa one of
palaeontological evidencepalaeontology is a branch of earth sciences which is essentially a study of plant and animal life in the past
theories of evolution of mantowards the beginning of the nineteenth century scientists had already started doubting the theory of special
chemical evolutionthe question of how life came into being in the first place still remained unanswered to find an answer to this
origin of life on the earthman has always wondered how he came into existence who created him and why he was created curiosity in this
plutoplutos existence was also proposed to account for deviations in the orbit of uranus even after the influence of neptunehad been
neptunethe eigth planet neptune was discoveted in 1846 by astronomer johann gottfried galle we have already told you the story of
the asteroid belt-rubble of the solar systemthere is a gap of 547 million kilometers between the orbits of mars and jupiter in this gap are
solar wind and solar flaremost of the suns family is continually bathed in an outflow of material from the suns atmosphere streams of
evidence favouring the big bangone piece of evidence comes from the expansion of the universe which we have already described the expanding
big bang theorythe most important current theory for the origin of the universe is the big bang theoryaccording to this theory the
life of a stara young star is thought to be composed largely of hydrogen gas hence the most likely place for a star to be born is in one
stellar motionstars are not fixed in the heavens they are moving within the galaxies the speed of a star moving toward or away from
fingerprinting the starsastronomers use various methods to measure the distances to stars for determining the distances to nearby stars the method
ventures in spacesometimes the atmospheric conditions distort the light or radiowaves coming in from space for instance there may be a storm
in pursuit of starlightthe easiest method of studying light from a cosmic object is to collect it through a telescope and record it on a
interstellar and intergalactic spacethe space between the stars and the galaxies looks empty doesnt it but this 1s not true in the great dark
the solar familylet us now take you on a journey across the universe we begin from our planet eqrth it is our home the earth is active
cosmic distancesif we asked you what the distance between delhi and kanyakumari is you would say that it is roughly 3000 km another way of
physical universethe universe is vast the earth we live on appears to be just a speck of dust circling a small star in a remote corner of
rejection of heliocentrismthis happened in the year 1918 when the astronomer harlow shapley 1885-1972 first surveyed the size and shape of
stars in the limelightamong galilees my discoveries with the telescope was his observation that the white nebulous band in the sky