as for heliocentrism being originally propounded by arybhatta,
your most revered source of knowledge 'wiki'pedia, says
Development of the idea
To anyone who stands and looks at the sky, it seems clear that the
earth stays in one place while everything in the sky goes around
once every day. Observing over a longer time, one sees more
complicated movements. The Sun makes a slower circle over the
course of a year; the planets have similar motions, but they
sometimes turn around and move in the reverse direction for a while
(retrograde motion). As these motions became better understood,
they required more and more elaborate descriptions, the most famous
of which was the Ptolemaic system, formulated in
the 2nd century.
The counter-intuitive idea of heliocentrism, that it is the Earth,
not the heavens, that is actually moving, was suggested at least as
early as the 4th century BC. In Chapter 13 of Book
Two of his On the Heavens, Aristotle wrote that
"At the centre, they [the Pythagoreans ] say, is fire, and the
earth is one of the stars, creating night and day by its circular
motion about the centre." The reasons for this placement were
philosophic based on the classical elements rather than scientific-
fire was more precious than earth in the opinion of the
Pythagoreans, and for this reason the sun
(representing fire) should be central. Aristotle dismissed this
argument and advocated geocentrism.
Later, heliocentrism was again proposed by
Aristarchus (c. 270 BC). By the
time he was writing, the size of the Earth had been calculated
accurately by Eratosthenes, and he himself
measured the size and distance of the Moon and Sun; while his
figures for the Moon were fairly decent, those he obtained for the
Sun were quite far off by modern standards, but a serious start.
Perhaps, as many people have suggested, paying attention to these
numbers led him to think that it made more sense for the Earth to
be moving than for the huge Sun to be moving around it.
Aristarchus' original work on heliocentrism has not survived and is
known only from others' accounts; hence the uncertainty as to his
arguments on its behalf. It appears, though, that he understood the
problem of stellar parallax: if the Earth moves over huge distances
in circling the Sun, then the nearer of the fixed stars should be
seen to move relative to the farther ones, as nearby hills move
relative to distant mountains when one is traveling. Aristarchus
explained the lack of any such visible effect by saying that the
stars were at extremely large distances: the sphere of the fixed
stars was to the Earth's orbit as the surface of a sphere is to its
center. That would make the stars infinitely distant; whether he
meant that literally, or just meant to convey an extremely large
ratio, is not possible to determine now. (In the event his
explanation turned out to be right, though the distances are
finite; stellar parallax was observed in the 19th century.)
Aristarchus' heliocentric model was considered by
Archimedes in The Sand Reckoner. The purpose of
this work was to prove that extremely large numbers, even the
number of grains of sand that it would take to fill the universe,
could be expressed mathematically and did not have to treated
vaguely as "infinite". To this end, he took the largest existing
model of the universe, which was that of Aristarchus, to calculate
the amount of sand that would fill even that universe. Pointing out
that mathematically it made no sense to talk of a ratio between the
surface of a sphere and its center, which has no magnitude,
Archimedes made the working assumption that the distance of the
fixed stars was in the same relation to the radius of the Earth's
orbit as that orbit was in relation to the Earth itself. Under
these conditions stellar parallax would be beyond current
observers' ability to detect, as it was in fact. [1] This treatment
shows that the problem of stellar parallax was well understood,
though it produces no information on whether the Earth's motion was
a reality.
In the 5th century AD (apparently independently of
Aristarchus) the Indian astronomer Aryabhata also
proposed a heliocentric Universe. As his work was not translated
into Latin until after Copernicus had written De
revolutionibus orbium coelestium, his theories were apparently
unknown in the West.
Copernicus also drew on the ideas of the (possibly semi-mythical)
Egyptian philosopher Hermes Trismegistus in De revolutionibus
orbium coelestium but it is not clear to what extent Trismegistus
was actually proposing a heliocentric world view. Accurate dating
is impossible, but Trismegistus probably lived in pharaonic Egypt,
although actual texts we have that constitute the hermetic
tradition probably date from about the time of Christ.
For many centuries, Heliocentrism was countered with the apparent
common sense view that, if the Earth were spinning and moving
around the Sun, people and objects would tend to fall off or spin
out into space; an object dropped from a tower would fall behind
the tower as the latter rotated with the Earth and would land to
the West; and so on. A response to these objections required much
better understanding of physics.
In the 16th century the theory was revived by
Nicolaus Copernicus, in a form consistent with
then-current observations. This theory resolved the issue of
planetary retrograde motion by arguing that such motion was only
perceived and apparent, rather than real: it was a parallax effect,
as a car that one is passing seems to move backwards against the
horizon. This issue was also resolved in the geocentric Tychonian
system; the latter, however, while eliminating the major epicycles,
retained as a physical reality the irregular back-and-forth motion
of the planets, which Kepler characterized as a "pretzel." In
developing his theories of planetary motion, Copernicus was
probably indebted to the earlier work of the Arabic astronomer Ibn
al-Shatir and the Persian Nasir al-Din al-Tusi; they had resolved
significant problems in the Ptolemaic system,
though retaining an essentially geocentric arrangement
http://en.wikipedia.org/wiki/Heliocentric
