The Mauni Amavasya is a day when sun, moon, Venus and Mercury are in the zodiac of Capricorn, a rare but perfect alignment of planets, devotees believe.

BBC: Spiritual cleansing at Mela Bathers at Mela

These upheavals will, supposedly, be the result of a planetary alignment, as the combined gravitational influences of the moon, Mercury, Venus, Mars, Jupiter and Saturn wreak havoc on the earth.

ECONOMIST: Not the end of the world

That means only Mercury and Venus (and our moon) can cause eclipses from a vantage point on the Earth.

CNN: A transit of Venus, an age of wondrous science

The Maya used their mathematical knowledge along with celestial observations to finesse a calendar created by the Olmec which is a culture from the Mexican Gulf Coast and to create monuments to observe and commemorate movements of the moon, the sun, and Venus.

UNESCO: Culture

Of course Galileo made great use of the telescope, and his discoveries--that Jupiter has its own moons, that the Milky Way is made of stars, that Venus has phases just like the moon--were turning points.

FORBES: The Universe and Mrs. Ferguson

Hubble will focus its cameras on the moon for the full six hours of the transit of Venus.

CNN: A transit of Venus, an age of wondrous science

Although Mercury and the Moon never progressed beyond the planetary-congealing stage, volcanic activity on Mars, Venus and Earth created powerful forces that caused further mineral diversification.

ECONOMIST: Minerals