13 replies to this topic

[Bah.]

I only just recently started think that maybe the earth may be growing, ever slowly, but still. I've heard the shrinking theory involving the core and I've also read a couple things on the tectonic plate theory which looks to be the most solid, however it doesn't seem to account for the water, the oceans that is. It seems like they expect that it just derived from nowhere. Besides, if the sea-floor is slowly splitting, wouldn't that mean that the ocean level is slowly receding? Given that school has led me to believe we have a set amount of water on earth and it just gets recycle continuously, this seems to be a logical conclusion to me. Anyway, I digress.

My question is "does gravity increase the earths mass?" My thought is that gravity pulls things toward the surface of the earth, obvious. I realize that there is a point where it stops doing this and I also realize other factors may be included to this, such is why the moon is in the orbit and doesn't crash into us. But surely even the smallest particles of space debris would get sucked in were it that they got close enough, would they not? Maybe they might even make it past the ozone layer. I'd also like to note that we are moving through space and probably collide with things more than they collide with us, if you know what I mean. So after trillions of years of this, did the earth get bigger, or is this just a silly thought?

[Euphorbia]

Bah., on 15 January 2013 - 11:27 PM, said:

I only just recently started think that maybe the earth may be growing, ever slowly, but still. I've heard the shrinking theory involving the core and I've also read a couple things on the tectonic plate theory which looks to be the most solid, however it doesn't seem to account for the water, the oceans that is. It seems like they expect that it just derived from nowhere. Besides, if the sea-floor is slowly splitting, wouldn't that mean that the ocean level is slowly receding? Given that school has led me to believe we have a set amount of water on earth and it just gets recycle continuously, this seems to be a logical conclusion to me. Anyway, I digress.

My question is "does gravity increase the earths mass?" My thought is that gravity pulls things toward the surface of the earth, obvious. I realize that there is a point where it stops doing this and I also realize other factors may be included to this, such is why the moon is in the orbit and doesn't crash into us. But surely even the smallest particles of space debris would get sucked in were it that they got close enough, would they not? Maybe they might even make it past the ozone layer. I'd also like to note that we are moving through space and probably collide with things more than they collide with us, if you know what I mean. So after trillions of years of this, did the earth get bigger, or is this just a silly thought?

Earth is certainly gaining mass. It is being constantly bombarded with meteorites and space dust (tiny meteorites).

Gravity does not increase mass.......mass increases gravity!

[The Id3al Experience]

To the best of my knowledge( I could be wrong) that there is no 'set' amount of water. The atompshere creates a green house effect, heat vapurates water, which in turn, turns into clouds and rain back to the earth. I could be wrong, but I beleive there is no one set amount fo water at any given time, this logically must vary depending on weather conditions and geological conditions.

To your second point, again this is best to my knowledge and could be wrong, but most of the space debris burns up in our atomsphere so never really hits earth, however some do so I would assume it is getting bigger. However volcanic and techtonic activity I beleive also recycle materials of the earth and convert them to magma which in turn creates land.

This is from my school education and could be filling in the gaps with blank rambles haha.... Hope someone can clarify further.

Kind Regards,

[Euphorbia]

The moon, by the way is moving away from us at a rate of about 1.5 inches per year due to the direction it rotates.

There is a mirror on the moon that they shine a laser off of to make this measurement.

[The Id3al Experience]

Euphorbia, on 15 January 2013 - 11:50 PM, said:

The moon, by the way is moving away from us at a rate of about 1.5 inches per year due to the direction it rotates.

There is a mirror on the moon that they shine a laser off of to make this measurement.

I knew the moon is moving away from us, However didnt know how they measured it. Thanks for that.

Kind Regards,

[Waspie_Dwarf]

Bah., on 15 January 2013 - 11:27 PM, said:

I only just recently started think that maybe the earth may be growing, ever slowly, but still. I've heard the shrinking theory involving the core and I've also read a couple things on the tectonic plate theory which looks to be the most solid, however it doesn't seem to account for the water, the oceans that is.

Why would tectonic theory account for water? It is a theory which describes the motion of the continents, not one which describes how various chemicals, including water, got here.

Bah., on 15 January 2013 - 11:27 PM, said:

It seems like they expect that it just derived from nowhere.

Who is this "they". If you mean scientists, then no they don't expect it just derived from nothing. Water was brought to earth by comets very early in it's existence.

Bah., on 15 January 2013 - 11:27 PM, said:

Besides, if the sea-floor is slowly splitting, wouldn't that mean that the ocean level is slowly receding? Given that school has led me to believe we have a set amount of water on earth and it just gets recycle continuously, this seems to be a logical conclusion to me. Anyway, I digress.

You have a very incomplete understanding of tectonic theory.

As the tectonic plates move some oceans get larger whilst other get smaller. Since there is the same amount of land, it is just moving, the ocean levels will not change.

Bah., on 15 January 2013 - 11:27 PM, said:

My question is "does gravity increase the earths mass?"

If I take this question literally then no. The gravity of any object is determined by its mass, in other words gravity is caused by mass, hence the one can not make the other increase.

Bah., on 15 January 2013 - 11:27 PM, said:

My thought is that gravity pulls things toward the surface of the earth, obvious.

To be pedantic: wrong. Gravity pulls things towards the centre of the Earth. Because the surface is solid things can fall no further.

Bah., on 15 January 2013 - 11:27 PM, said:

I realize that there is a point where it stops doing this and I also realize other factors may be included to this, such is why the moon is in the orbit and doesn't crash into us.

In theory gravity extends outwards for ever, but it diminishes with distance. As it obeys an inverse square law (ie if you double the distance you only experience 1/4 the gravity, triple the distance you feel 1/9 the gravity and so on) it soon reaches a point where you can no longer detect it, but every object in the universe is exerting a tiny gravitational influence over every other object.

The whole reason that the moon does remain in orbit is because Earth's gravity stops it escaping.

Bah., on 15 January 2013 - 11:27 PM, said:

But surely even the smallest particles of space debris would get sucked in were it that they got close enough, would they not? Maybe they might even make it past the ozone layer.

What is special about the ozone layer? It makes up an insignificant part of the atmosphere in terms of a re-entering object.

Bah., on 15 January 2013 - 11:27 PM, said:

I'd also like to note that we are moving through space and probably collide with things more than they collide with us, if you know what I mean.

Every thing in the solar system (in fact in the entire universe) is moving so it is illogical to say that we collide with them more than they collide with us. The collision is a mutual thing, the objects collide with each other.

Bah., on 15 January 2013 - 11:27 PM, said:

So after trillions of years of this, did the earth get bigger, or is this just a silly thought?

The universe hasn't existed for trillions of years, it is around 14 billion years old. The Earth is about 4.5 billion years old.

To answer what I Think it is you are asking:

The process you are describing is called accretion. This is the process where small objects stick to each other forming larger and larger ones. It is how the sun and the planets were formed 4.5 billions years ago. There is relatively little dust, gas and other debris left for the earth to accrete now, but meteors and meteorites still hit the earth every day. In all this amounts to between 37,000 and 78,000 tons per year. That may sound a lot but as the earth has a mass of 6,583,212,590,000,000,000,000 tons it is an insignificant amount.

[Waspie_Dwarf]

The Id3al Experience, on 15 January 2013 - 11:48 PM, said:

To the best of my knowledge( I could be wrong) that there is no 'set' amount of water. The atompshere creates a green house effect, heat vapurates water, which in turn, turns into clouds and rain back to the earth. I could be wrong, but I beleive there is no one set amount fo water at any given time, this logically must vary depending on weather conditions and geological conditions.

The water may change state from liquid to solid (ice) or gas (vapour) but it is still water, hence there is always the same amount.

[Waspie_Dwarf]

Euphorbia, on 15 January 2013 - 11:50 PM, said:

There is a mirror on the moon that they shine a laser off of to make this measurement.

There are actually 5. Three were left by US astronauts on Apollo's 11, 14 & 15 and the two Soviet Lunokhod rovers also carried one.

[The Id3al Experience]

Waspie_Dwarf, on 16 January 2013 - 12:16 AM, said:

The water may change state from liquid to solid (ice) or gas (vapour) but it is still water, hence there is always the same amount.

Ahhh, Of course. Cheers Waspie.

Can you please clarify also, Does energy from the Sun contribute to the mass of the planet? E=MC^2. Albeit a TINY TINY TINY not even worth considering amount but still contributes?

Thank you in Advance.

[Waspie_Dwarf]

The Id3al Experience, on 16 January 2013 - 12:24 AM, said:

Can you please clarify also, Does energy from the Sun contribute to the mass of the planet? E=MC^2. Albeit a TINY TINY TINY not even worth considering amount but still contributes?

It would take someone with a much better understanding of the physics than me to give a definitive answer but on the whole I would think not. The vast amount of energy we receive from the sun is simply reflected back. That which is absorbed during the day is radiated back at night. So basically the energy gained and the energy lost are in equilibrium.

[The Id3al Experience]

Waspie_Dwarf, on 16 January 2013 - 12:29 AM, said:

It would take someone with a much better understanding of the physics than me to give a definitive answer but on the whole I would think not. The vast amount of energy we receive from the sun is simply reflected back. That which is absorbed during the day is radiated back at night. So basically the energy gained and the energy lost are in equilibrium.

Makes sence.

Thanks,

Kind Regards,
Me

[sepulchrave]

In addition to the absorption and emission of radiation that Waspie_Dwarf mentioned, the Earth is also gaining mass from the Sun due to the solar wind (the flow of ionized particles from the Sun, some of them hit the Earth).

However the Earth is also losing mass as atoms and molecules in the upper atmosphere are gradually lost to space.

I am not sure that anyone knows whether or not the net effect is a gain, a loss, or a balance for the mass of the Earth, since the amounts of mass gained or lost is so small and distributed over the entire surface of the Earth.

[Uncle Sam]

The Id3al Experience, on 16 January 2013 - 12:24 AM, said:

Ahhh, Of course. Cheers Waspie.

Can you please clarify also, Does energy from the Sun contribute to the mass of the planet? E=MC^2. Albeit a TINY TINY TINY not even worth considering amount but still contributes?

Thank you in Advance.

There is no way to converse the energy into a solid state at the moment, natural or unnatural, so no the sunlight from the sun doesn't contribute to the mass Earth. E=MC^2 is merely mathematical description how mass can be converted into energy, not mainly associated with the atomic bomb. Atomic bombs are rapid release of the energy stored in mass, which creates a blinding flash of light and large amounts of radiation. Let's put it this way, if we had enough understanding and can release all the energy stored in mass, we be able to level whole city block in New York with a bomb the size of a pencil. We barely have begun to tap into the amounts of energy heavy elements can produce.

Edited by Uncle Sam, 20 January 2013 - 06:35 PM.

[sepulchrave]

Uncle Sam, on 20 January 2013 - 06:29 PM, said:

There is no way to converse the energy into a solid state at the moment, natural or unnatural, so no the sunlight from the sun doesn't contribute to the mass Earth.

Not true. Absorbed electromagnetic radiation increases the mass of an object, and emitted electromagnetic radiation decreases it.

Uncle Sam, on 20 January 2013 - 06:29 PM, said:

E=MC^2 is merely mathematical description how mass can be converted into energy, not mainly associated with the atomic bomb.

Precisely. If an object absorbs a photon of frequency v (and energy hv) then the object will increase in mass by hvc^-2.

Of course this is a trivially small amount of mass, but the principle is sound.

See (an english translation of) Einstein's original paper on the subject.