[chris (OP)]

Since Dave and I did some calculations for the programme More or Less regarding the annual mass change of Earth we have received a considerable amount of correspondence from people regarding our suggestion that Earth is gaining about 160 tonnes per year in mass owing to global warming.

Therefore I would like the input and opinions of you forum visitors in relation to this suggestion.

Chris

[CliffordK]

The explanation by Chris has gotten posted here.

http://www.thenakedscientists.com/forum/index.php?topic=42905.msg379502#msg379502

It is an interesting hypothesis, and perhaps should be considered as part of Earth's mass balance.  However, it would certainly be overwhelmed by other influences.

Loss of mass from Hydrogen/Helium escape.
Gain of mass from Absorption of Cosmic Rays, Meteorites, & Micrometeorites. 
Loss of mass through Fission.
Loss of mass through radioactive decay of naturally occurring radioactive materials (as well as that produced by humans).
Also the few interplanetary probes that Humans have launched.

[lightarrow]

It is an interesting hypothesis, and perhaps should be considered as part of Earth's mass balance.  However, it would certainly be overwhelmed by other influences.

Loss of mass from Hydrogen/Helium escape.
Gain of mass from Absorption of Cosmic Rays, Meteorites, & Micrometeorites. 
Loss of mass through Fission.
Loss of mass through radioactive decay of naturally occurring radioactive materials (as well as that produced by humans).
Also the few interplanetary probes that Humans have launched.

Ok, but I haven't understood the third. What do you mean?
However, to be nitpicking, you could add the loss of mass by radio waves escaped from the ionosphere    :-)

[CliffordK]

Fission, of course, is what all of our Nuke Plants use to generate electricity.

I'm seeing that we use about 66,000 tons of Uranium each year.  Of course, that is just raw materials, and not directly the matter consumed.

About 370 Gigawatts of nuclear power is produced each year.

A while ago I made some calculations that all the nuclear power in the world is dwarfed by a fraction of a watt per square meter of a change in solar energy.

Half the surface area of the Earth (exposed to the sun) is about
255,000,000,000,000 sq m
Considering a conservative 0.1 W per sq M difference in warming, that still leaves.
25,500,000,000,000 W, or over 25,500 GW, or about 100x our nuclear power generation.

Loss of energy via natural geothermal sources, though may be a much more significant contributor to mass loss in the Earth.

[CZARCAR]

if fotons are massless & co2 greenhouse traps fotons to warm globe, i'd think earth would be losing mass as a result?

[simplified]

if fotons are massless & co2 greenhouse traps fotons to warm globe, i'd think earth would be losing mass as a result?

Thermal energy has mass.Thermal energy,losing itself, radiates photons.Methane & co2 can return some photons which turn again into thermal energy.

[CliffordK]

Has anybody ever indisputably proven that Thermal Energy has mass?

I was thinking one could build a 2-arm balance in a large NASA vacuum chamber and do an experiment with selectively heating one mass, but I think one would need an accuracy on the order of a few nanograms per ton, and I'm not sure if one could get that high of accuracy, especially with a lot of natural movement of the Earth.

According to this, the Earth's rotation has been speeding up over the last few decades.
http://en.wikipedia.org/wiki/Leap_second


Tidal theories indicate that the Earth should be slowing down, I think (need to add more leap seconds, rather than fewer leap seconds).

Could Earth be loosing mass?  Moving mass from equator to poles?  Shrinking in diameter?

Or, could it be caused by the moon getting more distant from Earth, and thus causing lower tides?

Or, is it all inaccuracies in the clocks?

[simplified]

Has anybody ever indisputably proven that Thermal Energy has mass?

I forgot the topic,but there lightarrow was speaking about it.
And at all co2 is useful for plants and seaweeds.They have much work,and we should help them.In my region weather is cold in february...

[Geezer]

Has anybody ever indisputably proven that Thermal Energy has mass?

Einstein did a pretty good job of establishing the connection, and subsequent brutal experiments confirmed that he was right. It's difficult to imagine a more indisputable proof.

[simplified]

Has anybody ever indisputably proven that Thermal Energy has mass?

I was thinking one could build a 2-arm balance in a large NASA vacuum chamber and do an experiment with selectively heating one mass, but I think one would need an accuracy on the order of a few nanograms per ton, and I'm not sure if one could get that high of accuracy, especially with a lot of natural movement of the Earth.

Thermal energy has gravitational mass,but I don't know  does thermal energy have kinematic mass of Earth's motion.Photon has kinematic mass,but has not any gravitational mass.Maybe thermal energy has gravitational mass,but has not kinematic mass as kinematic mass of Earth.

[Michalec]

If the Earth is gaining mass due to global warming (which seems to be in question,) then wouldn't it lose mass during global cooling?  If so,the Earth's mass would always be in a state of flux.  Either way, what are the ramifications of this?  Would it matter?

[chris (OP)]

Michalec - that would indeed be true, if the world were cooling; but the NASA data we used in the calculation shows that the Earth is in fact warming at the rate cited. This we used to calculate the net mass increase.

[Michalec]

I understand that the Earth is warming right now but I also understand that the temperatures have been going up and down all the time throughout the history of the planet and was curious if the planet was actually getting larger or if it just fluctuates.  From your reply I have to believe it fluctuates.  I am also curious what sort of effect gaining or losing mass would have on the planet.  Does gravity get stronger and weaker?  Does the rotation of the planet slow down and speed up?  Or is 160 tonnes a year not enough to make a difference?

[CliffordK]

I think the answer is that 160 tons is not a lot of difference for a relativistic effect, either with warming or cooling.

There is also linear expansion and contraction of materials with heating and cooling (including atmospheric density). 

Of course, there is also the redistribution of water.

All of which can effect the speed of rotation of the planet, and could be detected on the surface of the planet.

If the Earth's rotation sped up or slowed down by even a second a day, I'm doubtful that it would have been noticed by the Animal Kingdom.  Likewise fluctuations in the atmospheric density would be hard to notice, although the effects of changes in dissolved gasses in the ocean might be more noticeable.

[Jim Grozier]

Has anybody ever indisputably proven that Thermal Energy has mass?

Einstein did a pretty good job of establishing the connection, and subsequent brutal experiments confirmed that he was right. It's difficult to imagine a more indisputable proof.

Einstein actually distanced himself from the concept of relativistic mass (and therefore of energy having mass) in later life (1948) and it is not taught nowadays, except as a historical curiosity. We are a long, long way short of establishing experimentally whether energy has mass, but most physicists would say it doesn't. See my post in the other thread for more details.

[acecharly]

Is it not futile trying to answer this question? There are so many variables such as matter falling from space, which we can only make an estimate at best. Somebody mentioned the earth may rotate slighty faster if the Earths mass increased, well one day is never the same legnth as the last anyway, simply by the direction of the wind blowing over the Andes mountain range making it act as a sail. Id imagine to prove this gain in mass you would need a control taking away any variables apart from those attributed to global warming and there arn't many Earths in our solar system.

Maybe one possible way would be to work out the change in the mass of Venus, which having global warming in overdrive should show around the same quantity of matter raining down from meteorites and space dust but a significantly higher increase due to global warming, should this argument hold any weight.

[CliffordK]

I said that the Earth does seem to be rotating faster over the last few decades. 
I didn't say the cause was more mass.  I would anticipate more mass would in fact slow it down.

There seems to be a rather odd seasonal fluctuation in the speed of rotation, with the Earth rotating slower during the northern hemisphere winter, and faster in the northern hemisphere summer based on UTC/UT1 differences.

Greenhouse effect or not, I presume that the temperatures on Venus have reached a point of equilibrium. 

[JP]

You'd be hard pressed to argue that energy can't give rise to mass, since most of the mass we see every day is due to energy. 
Matter gets most of its mass from protons and neutrons, which in turn are made up of quarks. 
The quark rest/invariant mass accounts for only a tiny fraction of the total mass of a proton/neutron, while much of the rest comes
from the kinetic energy of the quarks and the energy of the strong nuclear force that binds them together. 

Most of the mass we see every day is in fact due to energy!

[yor_on]

JP, I know you're perfectly correct, and it is very interesting.

But...

"The derivation, above, of the equation E = mc2 from E2 = p2c2 + m2c4 (note that that is the correct form of the equation – the slightly different version quoted is dimensionally inconsistent) has one very important caveat – that “the object is not moving”. As such it will only work in the rest frame of the object, and cannot be used to model situations where a body gains energy by, say, absorbing or scattering a photon. In fact the interpretation of E = mc2 used by Einstein was somewhat different since he redefined mass as mγ – the “relativistic mass” – although he later regretted this. Relativistic mass is not used today, although some physicists still hold onto the concept.

Using this latter interpretation does indeed compel one to say that energy has mass. This is what is known as the “concomitance” view. Those who take this view will say that both energy and mass are conserved at all times, and they would not agree with the statement that by “measuring the mass of a radioactive atom, and all of its decay products, you will find that the decay products are slightly too light, by the amount of energy released divided by c2”. They would say instead that the mass of the system, and its energy, are the same before and after the decay, they are just “rearranged”.

Taking the more modern line, that mass is Lorentz invariant, one arrives at the “interconvertibility” view, which is at odds with the idea of energy having mass. Which line you take depends on how you define momentum, and it is to some extent a free choice. The one sure thing is that you can’t have it both ways – you cannot say that energy and mass are interconvertible whilst simultaneously holding that energy has mass. Yet such confusion is widespread – not only on this forum but in the press, popular books and even textbooks.

One of the problems with the interpretation of special relativity is that Einstein’s models, from which he derived his equations, were incredibly simple. They were based on “rigid bodies” with no internal structure; they therefore had no capacity to heat up, and so one should not expect to be able to use them to model a situation where something is being heated. You only get out of a model what you put in. We might hope to be able to use SR to approximately model a simple collision between, say, a single photon and a single atom (although even a single atom is more complex than Einstein’s model allows, since it can absorb energy by excitation to a higher energy state, which again is not provided for in the model). But if we apply E2 = p2c2 + m2c4 to such a collision, then whichever reference frame we use, there will be motion, and hence momentum; so you can never say that “the object is not moving”, even at this simple level." By Jim G.

So, could you call that the 'relativistic mass' of the quarks?
Or just 'Energy'?

But that 'energy' must then be everywhere in our geometry, mustn't it? The expansion for example, isn't that a rearrangement of 'energy' in SpaceTime too? Why shouldn't that too show up as 'mass' somewhere?

Or maybe it does? 
Heh

And then that strong nuclear force?
'Energy' too?