Every day, babies are born and people grow, which makes their respective masses greater. However, this change in mass (should) come out of the food that they consume - it is used as energy and thus converted into this growth. Likewise, building new structures is just a redistribution of mass already on Earth.

Thus, the only way I can see the actual mass of the Earth changing is by meteors that have landed here (increase in mass) and things that leave Earth such as space shuttles and rockets which would be a decrease in mass.

But have I missed anything out? If no meteors crashed into Earth, and we had not yet figured out how to make machines that could fly, would the mass of the Earth remain constant? Or is it somehow loosing or gaining mass? Am I wrong in assuming that the growth of animals doesn't affect the mass?

Thanks, Toastrackenigma.

EDIT: Mass includes atmosphere :)

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    $\begingroup$ Probably the most significant factor of Earth's mass change is atmospheric escape into space. But it's not clear to me why you consider the atmosphere as not part of this issue, since you set airplanes apart for some reason. $\endgroup$
    – Stan Liou
    Nov 25 '15 at 2:26
  • $\begingroup$ Earth loses a little atmosphere to space every day: en.wikipedia.org/wiki/Atmospheric_escape It also picks up a little through the solar wind, although our magnetic field blocks most of that: en.wikipedia.org/wiki/Atmospheric_escape Cosmic rays, which can be quite massive, also account for a small daily weight gain. $\endgroup$ Nov 25 '15 at 2:28
  • $\begingroup$ @StanLiou I wasn't sure if the atmosphere normally got included with the weight or not, which is why I wrote a question mark next to planes. After checking on Google re your comment, yes it is, so yes, I think that I can consider atmosphere a part of the problem. Thanks! $\endgroup$ Nov 25 '15 at 5:29
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    $\begingroup$ Question answered here $\endgroup$ Nov 25 '15 at 7:44
  • $\begingroup$ Atmosphere doesn't get included with the "weight", which is a fairly meaningless concept in the context of this question, but is of course included in the mass. $\endgroup$
    – ProfRob
    Apr 10 '16 at 16:48

Earth gains mass through the impact dust from space, we see the meteors that form as this material impacts the atmosphere. We gain 40000 to 80000 tonnes a year. Even if ut "burns up" the mass is still added to the atmosphere. However, hydrogen is lost from the atmosphere, and this amounts for rather more, about 100000 tonnes a year.

The resjult is a net loss of about 20000 to 60000 tonnes per year. This is miniscule compared to the mass of the Earth. It is many order of magnitude less than the uncertainty in the mass. There are no direct consequences of this loss if mass.

Other thing that could change the mass od the earth (eg space probes or cosmic rays) have even less effect.


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