Mass: Creation & Destruction - What Does it Mean?

[ThomasFuhlery]

this might be a physics question, but...

I don't understand something about thermodynamics. About how mass cannot be destroyed or created, really. They say that the Earth gains mass every year from meteorites, right? And more people are born every year, and grow, etc., adding mass to the planet as well (and I understand that this is just the movement of mass from, say, the food they eat and what-not), but does that mean that the rate of death and decay of life is exactly proportional to the rate of birth, growth, and consumption of living things, or are we consantly gaining (or losing) mass, on earth? And if so, what does this mean for the future?

 

[HallsofIvy]

this might be a physics question, but...

I don't understand something about thermodynamics. About how mass cannot be destroyed or created, really. They say that the Earth gains mass every year from meteorites, right? And more people are born every year, and grow, etc., adding mass to the planet as well (and I understand that this is just the movement of mass from, say, the food they eat and what-not), but does that mean that the rate of death and decay of life is exactly proportional to the rate of birth, growth, and consumption of living things, or are we consantly gaining (or losing) mass, on earth? And if so, what does this mean for the future?

Yes, it is true that the Earth gains mass every year from meteorites- not very much compared to the mass of the Earth itself. No, "more people born every year" (not to mention animals, plants, etc.) do not add mass. As you say, that's just recycling: a baby's mass comes from the food it's mother eats. While growing a person (or animal, plant, etc.) gains mass because the food it eats has mass (and the oxygen taken in, etc.). Except for the small amount of mass added by meteorites (and I guess we now ought to subtract the mass of space probes sent out) the mass of the Earth is a constant. What does that mean for the future? Basically that it is "steady state" and things (well, the mass of the earth) will stay about the same. Of course, it also means that the Earth's "biosphere" is a closed system and very bad things can happen if you pollute a closed system.

 

[sir-pinski]

Mass cannot be created or destroyed, but it can be transformed from one form to another. This is known as the Law of Conservation of Mass in physics. This means that the total mass of a closed system (such as the Earth) remains constant over time, even if there are changes in the forms of mass within the system.

In the case of the Earth, as you mentioned, mass is constantly being added in the form of meteorites and living organisms. At the same time, mass is also being lost through processes such as decay and decomposition. This balance between creation and destruction of mass is what keeps the total mass of the Earth relatively constant.

As for the rate of birth and death of living things, it is not exactly proportional to the rate of growth and consumption. There are many factors at play, such as natural disasters, disease, and human intervention, that can affect the rates of birth and death. However, the overall balance of mass on Earth remains relatively constant.

Looking towards the future, it is difficult to predict what changes may occur in terms of mass on Earth. However, as long as the Law of Conservation of Mass holds true, we can expect that the total mass of the Earth will remain stable. It is important for us to be mindful of our impact on the planet and strive to maintain this delicate balance of mass.