The law of conservation of mass, also known as the principle of mass/matter conservation, states that the mass of an isolated system (closed to all matter and energy) will remain constant over time.
But
Mass is also not generally conserved in open systems (even if only open to heat and work), when various forms of energy are allowed into, or out of, the system .
The Earth gains mass each day, as a result of incoming debris from space. This occurs in the forms of "falling stars", or meteors, on a dark night. The actual amount of added material depends on each study, though it is estimated that 10 to the 8th power kilograms of in-falling matter accumulates every day. The seemingly large amount, however, is insignificant to the Earth's total mass. The Earth adds an estimated one quadrillionth of one percent to its weight each day.
Extracted from a book by
Dr D.Venkat Reddy
Experience in the area
20years texhing and reserch expireience in geology,enginnering geology for graduate and undergraduate students-reserch guidance,10years field exoireience conducting field camps for geology students=Presently Assistant professor in geolog
Hope this will throw some light