Weight of the earth getting lighter?

[bobclean]

As we burn millions and millions of tons of oil, does this mean that the planet is getting lighter? At first glance, this seems silly, but after thinking about it, we are converting the mass of oil into gases and heat, so are we losing mass and weight? Any thoughts?

[zzxxee]

does that mean we get lighter if so bring it on lol

[Clanad]

There appears to be a misconception that burning of fossil fuels somehow lightens the mass of the Earth. In fact, the burning of the fuels simply redistributes the weight inherent in the original fuel. The gasses and particulates released in the process are reabsorbed eitheir directly to the Earth or through plant life.
Fact is, according to an article in Science Now "estimates the annual gain (from meteorites and other space debris) to be about 40,000 metric tons"...

[Rev. Green]

The answer is not as obvious as it seems.

The products of nuclear fusion and nuclear fission do have a different mass from the fuel. The difference is the "mass" of the energy expelled. If some of the energy is in the form of radiation which excapes the Earth then there will be a loss of mass of the planet.

Burning oil is a chemical reaction, not a nuclear reaction, but the energy expelled will also have an equivalent mass. So I wouldn't be surprised if there was a small loss of mass from burning oil.

jake-the-peg would know. Let's hope he/she reads this thread.

[Teddio]

12 tons of carbon requires 32 tons of oxygen for complete combustion, forming 44 tons of carbon dioxide gas. There is no overall loss in mass. As the Rev says, any exothermic process will convert mass to energy but the effect globally is negligible.
Fusion and fission reactions (exothermic ones) convert mass into energy. Producing 9 X 10 to the power of 16 Joules of energy (a huge amount) will result in a mass loss of only 1 kg.

[wildwood]

The Earth doesn't really weight anything.

[jake-the-peg]

The energy released from burning fossil fuels was never stored as mass and so burning it and releasing energy does not make it lighter.

Energy converted from nuclear reactions was originally staored as mass and so can be lost in that way but the amount of mass that we actually use in this way is in the order of Kg rather than tonnes.

The other way we can lose mass to compensate for Clanad's 40,000 tonnes of meteorites is by Hydrogen or Helium escaping from our atmosphere.

I haven't had time to find the figures for this but I doubt it's enough to compensate

[beso]

Rev Green is partly correct. Einstein's equasion (E=mc^2)does apply universally not just to nuclear reactions. The products of an exothermic chemical reaction do have less mass than the input.

However the energy released is absorbed by the surroundings. And believe it or not, hot things weight slightly more becasue of that energy. Same law.

Just don't expect to find a scale that can measure it.

[beso]

Incidentally Jake is (on this rare occasion) wrong about chemical energy not being stored as mass.

All energy obeys Einstein's relationship with mass.

[jake-the-peg]

They do but the mass equivilence in a chemical reaction is pretty negliable.

Especially in comparison to thousands of tonnes of meteorites

[R1Geezer]

Jake, can you clarify. We know the energy in fossil fuels is from the sun, so how is it actually stored if not in "mass", I mean when we burn some coal we get the energy and the ash has less mass than the original peice of coal. Perhaps I've mis understood some where.

[bobclean]

Thanks for the answers, everybody, but along with R1Geezer, I too don't fully understand. Are we saying that the weight and mass of the oil, once burnt, equals the weight of the gases produced after combustion?

[Rev. Green]

We are saying that the mass of ash, gas, smoke etc. is 99.99999...9 per cent of the mass of the fuel. There is an unmeasurably small amount of mass which could still be retained on Earth e.g. by making something hot, or it could be radiated into space.

[Teddio]

In an exothermic nuclear reaction, eg. the fission of Uranium-235, the binding energy (per nucleon) in the uranium nucleus is lower than the binding energy (per nucleon) in the fission product nuclei.
Similarly, in an exothermic chemical reaction, the average bond strength in the reactants is lower than that of the products. In both cases mass is lost.
When stronger nuclear or chemical bonds are formed, energy is released and mass is lost.

[brunods]

I totally object!!

Earth will fart all those gases to the solar system and intoxicate other planets, eventually the galaxy and someday the entire universe!! You see now how bad this pollution problem is don't you? ;-)

By farting away all those gases it slowly loses mass and someday there will be no earth left and we'll be all floating in space... the melting of the icebergs is just the begining!!

[BillyBB]

I thought the energy released in the chemical reaction of burning was due changing the bonds between individual atoms.
Acetylene has a triple carbon bond and so burns hotter than propane due to the additional energy released.

[jno]

so does the earth with 6 billion people on it weigh the same as with none?