Is the Earth slowly getting larger? (Beginner)

Is the earth very slowly getting larger and why? P.S I stand to win 20 quid off me mate if the answer is yes !!!!

I am not aware that this is happening and I can think of no physical reason why it might. Sorry about your bet.

There are things about the Earth which are changing that are somewhat surprising, for example, the Earth's rotation is slowing down and the Moon is slowly getting further away because of tidal interactions between the two. Also, the Earth is cooling down (ie. the molten rock inside is cooling down) very slowly and the magnetic poles switch occasionally. (The reversal is probably caused by random fluctuations in the process that creates the magnetic field. This process is called dynamo action, and it is produced in Earth's liquid outer core.)

Further to my question "is the earth getting larger", I'm a bit puzzled? as living matter dies i.e. plants, animals, humans, surely this matter would break down and add to the earth's mass, is it me or am I being a bit thick?

I mean most of the fossilised remains of animals, plants etc are rarely found on the surface now are they, they are mostly found beneath the earth's surface, so where has all the earth come from that is above them. You must be thinking oh! my god we've got a right one here!!! Ya see what I can't get my head around is, think of how many billions of people there are in the world, when they die they will add to the earth's mass surely! If you were to weigh them all the actual weight would be enormous. Now I know that all you have left is bone but even so the weight would be huge!!!! Are ya still with me!!!

Now I know what you're going to say is ok but where did these people come from, and I would say a woman's womb and you say ok the woman has to eat to make the child grow, and where does the food come from: the ground, plants and animals, etc.

Do you reckon you could solve this mystery for me please or at least try to explain, otherwise I'm gonna lose twenty quid!!!! And a hell of a lot of pride !!!

I'm afraid that this would not do it. All the raw materials to make living things come from the Earth in the first place and then go back to it when the thing dies. That's why it's called the CYCLE of life!

However, after thinking about it some more I think that I have come up with a way that you can win you bet. I apologize for not thinking of this earlier. I guess you are in fact right, the Earth is slowly (very slowly!) getting bigger. Particles of solar system debris are continuously bombarding us. Usually this isn't noticed too much (since the fragements are like dust), sometimes larger things hit (I'm sure you've seen Deep Impact....) and all in all it's probably not very much a year, but enough to slowly make the Earth larger.

January 2003 Update: Thanks to a curious reader for this comment:

I just wanted to point out the mass lost from satellites, probes, international space station, stuff left on moon, etc...?

To figure out if the earth is truly gaining mass, one would have to figure it out based on the average debris the earth gets, average number of satellites that fall, average number of satellites and probes launched, etc...

There's also the slow loss of the atmosphere as a small fraction of the molcules have speeds above the escape velocity of the Earth.


This page was last updated on June 27, 2015.

About the Author

Karen Masters

Karen Masters

Karen was a graduate student at Cornell from 2000-2005. She went on to work as a researcher in galaxy redshift surveys at Harvard University, and is now on the Faculty at the University of Portsmouth back in her home country of the UK. Her research lately has focused on using the morphology of galaxies to give clues to their formation and evolution. She is the Project Scientist for the Galaxy Zoo project.

Twitter:  @KarenLMasters

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