Not including living things, does the earth weigh more now than a billion years ago, as all the elements to make things, such as cars and buildings, must have been here already?

Baloo55th

Weight is dependent on gravity, mass isn't. As the question is worded, one has to take into account the difference in weight (we can use the term here rather than mass as the gravity will not be very much different) of the living things now, and then. Living things derive their bodies from the Earth just as much as cars do. About a billion years ago, the majority of life was still in the seas, with bacteria bravely advancing into the hostile air world (possibly) http://news.bbc.co.uk/2/hi/science/nature/2246831.stm I would say that the weight of living things is far greater now than it was then. Now for the incoming. Between 1740 and 1990 4946.25 tonnes of meteorites were known to have fallen. http://www.nineplanets.org/meteorites.html There is also dust from space and burned out meteors to take into account. The amount falling per annum may well have decreased over the last billion years, as the Solar System tidies its bedroom up and puts the loose rocks away. I will leave it to a better mathematician to calculate the weight of land life, and to extract an annual figure fron that meteorite total and to multiply it by a billion. And then compare the two figures. Aug 18 08, 5:21 AM