PDA

View Full Version : the earth - heavier or lighter



Pages : [1] 2

iain
12-08-2004, 08:59 AM
Since the point at which the earth came into existance (note: carefully worded to avoid big bang Vs creation :) )

has it increased in mass
decreased in mass
stayed the same

Perspective
12-08-2004, 09:03 AM
Increased. If you want to know why, explanations start a $5 a piece :p

Clyde
12-08-2004, 09:15 AM
We will have lost some atmosphere but have been hit by quite a few meteors/comets, intuitively you would expect the meteors to outweigh the loss of atmosphere by quite a lot, so i'd guess an increase.

Nyda
12-08-2004, 09:17 AM
On the plus-side we have metroids, comets, dust, solar wind and all kinds of other stuff raining down on us. On the minus-side we have... yeah, right, man-made satellites which left the earth. Whooooho. :-)

edit: no, honestly I believe she's getting lighter each day. :D

B0bDole
12-08-2004, 09:21 AM
Planets start as planetismals then accrete into larger and larger planets, Terrestrial planets accrete rock/metal from surrending planetary nebula, while Jovian planets accrete frozen H compounds beyond the frost line (between Mars and Jupiter). Everything in the solar system is getting larger, even the Sun. Since the Sun is a Main Sequence star, and fuses Hydrogen into Helium, the outer surfarce will continue to expand, and the core will shrink, until it turns into a White Dwarf (cold solid rock of Carbon).

Does thate explain it?

Clyde
12-08-2004, 09:32 AM
Presumeably the sun is losing mass though, even if it is expanding.

Govtcheez
12-08-2004, 09:34 AM
It's around the holidays, so I'm going to say it's a little heavier. Gaia's never been one to turn down planetoid drumsticks or the stuffing nebula.

hk_mp5kpdw
12-08-2004, 09:57 AM
Wasn't personally interested in the earth mass loss/gain issue but I did find a couple websites dealing with the sun. They all said the sun is lossing mass. Here is one of them (http://www.newton.dep.anl.gov/askasci/ast99/ast99441.htm).

Sang-drax
12-08-2004, 10:15 AM
has it increased in mass
decreased in mass
stayed the same
It has increased in mass.
Here (http://www.imdb.com/title/tt0390521/)'s recent movie that looks in to some of the aspects of the problem.

iain
12-08-2004, 10:56 AM
All the material we have burned would decrease the mass
All the births would increase the mass

Clyde
12-08-2004, 11:06 AM
All the material we have burned would decrease the mass
All the births would increase the mass


I'm afraid both those statements are basically wrong.

Burning stuff doesn't decrease mass, it just moves it around a bit.

The earth will lose mass by radiating it, but on average we will probably be gaining pretty much the same amount through absorption as we're losing through emmision.

Edit: Though on reflection (hah) we've probably emitted more than absorbed since the Earth has cooled down.

ober
12-08-2004, 12:12 PM
Ok, so either the board hates me or someone didn't like my reply and deleted it.

Brian
12-08-2004, 02:03 PM
Ok, so either the board hates me or someone didn't like my reply and deleted it.

A little from column a, a little from column b.

;)

ober
12-08-2004, 02:22 PM
I see. :: shrugs :: Oh well.

B0bDole
12-08-2004, 03:49 PM
>Presumeably the sun is losing mass though, even if it is expanding.

I don't have an A in AST 2002, I did catch a little info though.

Sang-drax
12-08-2004, 06:17 PM
Energy is mass. The sun is radiating a lot of heat, so of course it's losing mass.

CornedBee
12-08-2004, 06:38 PM
If you're not a creationist, the question is still imprecise, because the earth gradually came into existence by cosmic dust clumping together.

But taking the end of this process as a starting point, I'm pretty sure the mass has decreased. Why? Well, while asteroids hitting the earth generally increase its weight, at one point it was hit by one so large that it broke off a very large chunk: the moon. I don't think the combined weight of all the asteroid dust that remained on earth can make up for that loss.
So I think the mass has decreased overall, although it is increasing gradually.

Perspective
12-08-2004, 07:15 PM
>at one point it was hit by one so large that it broke off a very large chunk: the moon.

i took a full year of astronomy courses and ive never even heard that mentioned as a theory. I was told the moon was most likely a large asteroid that was caught by the earths gravity and pulled into orbit.

+1 increasionalists.

Zach L.
12-08-2004, 08:15 PM
I've heard of it. Seen computer models too (or rather, videos or computer screens running the simulations). Seems like a viable theory.

At any rate, it is probably increasing, but at a truly, remarkably negligible rate (barring any large meteor strikes, of course :) ).

anonytmouse
12-08-2004, 08:35 PM
>at one point it was hit by one so large that it broke off a very large chunk: the moon.

i took a full year of astronomy courses and ive never even heard that mentioned as a theory. I was told the moon was most likely a large asteroid that was caught by the earths gravity and pulled into orbit.

In other news, thirty seconds with Google trumps a year of education. :p


http://www.psi.edu/projects/moon/moon.html

At the time Earth formed 4.5 billion years ago, other smaller planetary bodies were also growing. One of these hit earth late in Earth's growth process, blowing out rocky debris. A fraction of that debris went into orbit around the Earth and aggregated into the moon.
...
Thus, the giant impact hypothesis continues to be the leading hypothesis on how the moon formed. Is it right? Can it be disproven by more careful research? Only time will tell, but so far it has stood up to 25 years of scrutiny.




24 Hours of Chaos: The Day The Moon Was Made (http://www.space.com/scienceastronomy/solarsystem/moon_making_010815-1.html)

For 25 years, scientists have pondered a theory that the Moon was created when an object the size of Mars crashed into Earth less than 100 million years after the Sun was born, some 4.6 billion years ago. The general idea has been run through the paces and massaged into shape and is now the favored explanation.

Perspective
12-08-2004, 08:46 PM
>In other news, thirty seconds with Google trumps a year of education. :p

hey, i said i was in the classes, i didnt say anything about being awake... :p

edit: but i actually hadnt heard that once in either course, though we didnt talk all that much about earth. Next thing you'll be telling me that man has actually visited the moon :rolleyes:

jwenting
12-09-2004, 09:35 AM
The earth slowly leaks air into outer space.
It also picks up a small amount of material from falling rocks (meteorites).
But that's offset by the material we sent out into space on rockets.

The earth picks up some radiation from the sun (which as has been stated is mass), but also radiates itself.

There's probably a slight net loss in mass/energy but it may take geological timespans to see any significant amount.

Perspective
12-09-2004, 10:22 AM
oh, oh. this one im sure about ;)

>>It also picks up a small amount of material from falling rocks (meteorites).

This is incorrect. A meteroite is a meteor (or piece of meteor) that resides on earth. The falling rock that hits the earth is a meteor, the resulting peice of rock on earth is a meteorite ;)


Meteorite Me"te*or*ite, n. Cf. F. m'et'eorite. (Min.)
A mass of stone or iron which has fallen to the earth from
space


oh yeah, that year of astronomy wasnt wasted after all, it helped me point out a grammer error :rolleyes:

PJYelton
12-09-2004, 11:57 AM
So, if we send a meteorite back out into space, does it become a meteor again? Or are our top scientists still working on this one?

Perspective
12-09-2004, 01:23 PM
So, if we send a meteorite back out into space, does it become a meteor again? Or are our top scientists still working on this one?

it becomes a meteroriteor. then if it comes back to earth its a meteoriteorite, and so on... :p

B0bDole
12-09-2004, 04:45 PM
I have a good elementary Astronomy question.

If our Sun was replaced with a 1 solar-mass Black Hole, How would this change Earth's orbit?

hk_mp5kpdw
12-09-2004, 05:03 PM
I have a good elementary Astronomy question.

If our Sun was replaced with a 1 solar-mass Black Hole, How would this change Earth's orbit?


Since the mass is the same, the gravitational forces it would exert would be the same so I would say that it wouldn't. At the current distance, the sun can be considered a gravitational point source and just replacing it with a true gravitational point source wouldn't seem to have any impact on us. That's my guess anyway, I could be wrong.

PJYelton
12-09-2004, 05:16 PM
Shouldn't change the orbit at all. Might get a little dark though.

Perspective
12-09-2004, 05:28 PM
I have a good elementary Astronomy question.

If our Sun was replaced with a 1 solar-mass Black Hole, How would this change Earth's orbit?

well, considering a black hole is a star that becomes so massive it collapses on itself, id say this isnt feasable. Not just the replacement but the existance of the entity itself. Now, if our sun was replaced by a one solar mass fork, it would have no effect on our orbit.

Govtcheez
12-09-2004, 05:39 PM
To be totally pedantic, would the lack of heat change the orbit?

Sang-drax
12-09-2004, 05:55 PM
well, considering a black hole is a star that becomes so massive it collapses on itself, id say this isnt feasable. Not just the replacement but the existance of the entity itself.
It is theoretically feasible. Black holes can be of any size and mass. The existance doesn't depend on mass, but on density. Scientists hope to be able to create extremly tiny black holes within particle accelerators in the future.
If you build and blow up a really large hydrogen bomb (but possible to construct on earth) the extreme pressure would create a black hole.

But for a star to turn into a black hole by its own gravity, it takes a lot more mass than the sun.

-KEN-
12-09-2004, 05:58 PM
To be totally pedantic, would the lack of heat change the orbit?

I don't think so; I don't imagine that heat has much to do with our orbit.

B0bDole
12-09-2004, 07:30 PM
>To be totally pedantic, would the lack of heat change the orbit?
Not at all. Orbits are solely based on gravity and (rare) collisions.

And of course everyone got the answer right, pretty simple question.
The theory of Black Holes has a lot of evidence supporting it, with no evidence defeating it. But like a lot of astronomy, it can't be proven for sure, so it's just a really respected theory.

B0bDole
12-09-2004, 07:31 PM
>But for a star to turn into a black hole by its own gravity, it takes a lot more mass than the sun.

It takes a totally different type of star. The Sun will eventually turn into a White Dwarf.

Zach L.
12-09-2004, 08:19 PM
But the difference is still mass. Although the larger star will have heavier elements in it, its initial composition could have been quite nearly identical to that of the Sun, and it would still form a black hole. The cutoffs, if I remember them correctly (absolutely no guarantee there) are:
M < 3S(olar Masses) -> White Dwarf
3S < M < 10S -> Neutron Star
M > 10S -> Black Hole

B0bDole
12-09-2004, 09:44 PM
>M < 3S(olar Masses) -> White Dwarf
3S < M < 10S -> Neutron Star
M > 10S -> Black Hole


you're pretty close

>different type of star.

This should read- "different classification of star."

Finals have me running on caffeine, nicotine, sugar & no sleep. Errors will insue.

Zach L.
12-09-2004, 09:49 PM
Ah... that makes sense... Yeah, those numbers were dragged out of my head from two years ago, so there is bound to be a bit of error. :)

B0bDole
12-09-2004, 10:11 PM
it's no the absolute number that matters, we can get the point from using relative numbers.

Perspective
12-09-2004, 10:48 PM
>>The existance [of black holes] doesn't depend on mass
agreed, but the creation does.

Apathy
12-09-2004, 10:51 PM
I voted that it has increased. Because all the matter on the earth has stayed on the earth. But we have brought stuff back from the moon.

But then, I think, We have alot of man made satelites in space now. So it has most probably decreased..

*curses click happy finger*


Edit:

People are using math to figure out.

Ap is afraid

Zach L.
12-09-2004, 11:08 PM
Of course, this question is a bit ambiguous unless you specify a reference frame. :)

Sang-drax
12-13-2004, 07:53 AM
>>The existance [of black holes] doesn't depend on mass
agreed, but the creation does.
Not on mass, but pressure. A lot of mass means high pressure, but the high pressure can come from other sources, for example a hydrogen bomb detonating, or a particle accelerator.

Perspective
12-13-2004, 11:48 AM
Not on mass, but pressure. A lot of mass means high pressure, but the high pressure can come from other sources, for example a hydrogen bomb detonating, or a particle accelerator.

i think we're on different wavelengths here. Im refering to the [natural] creation of a black hole from a star, a star has to exceed a certain mass to be a candidate for a black hole.

B0bDole
12-13-2004, 02:54 PM
You're both right. Lamens terms, it depends on the stars mass, if it's going to become a black hole, but technically the process is pressure (that's how they're close to creating a very very small black hole in a particle accelerator).

Darkness
12-17-2004, 09:30 AM
Mass is directly proportional to the amount of heat (energy) in an object. Any substantial increase in heat to a given body yields an equivalent increase in mass (although inversely proportional to the speed of light squared). With respect to a reference frame where the big bang is assumed to be t=0, if the earth has increased in heat energy it is more massive, else it is less massive. Although I think the earth has actually cooled significantly, and I don't know what role organisms play in this matter.

edit:
How did you think of this question? It's intriguing nonetheless

Clyde
12-17-2004, 09:46 AM
Mass is directly proportional to the amount of heat (energy) in an object


If you double the temperature of an object you do not double its mass.

There is a mass associated with the K.E of an object, (or the sum of kinetic energies of its constituent parts) but that mass is almost always miniscule compared to the rest mass.

Darkness
12-17-2004, 01:41 PM
an increase of 10 degrees celsius would increase the weight of a one pound cube of gold by about a millionth of a billionth of a pound.

Therefore the kinetic energy difference between a 'hot' and 'cold' earth might actually have a substantial mass contribution

Clyde
12-17-2004, 02:51 PM
Hmm fair point, i'm estimating a 10 degree loss in the temperature of the Earth translating into a loss of 10^11 Kg!

Now having said that i can't seem to find any info on what kind of total temperature change is likely to have occured since the core appears to be self-heating through radioactive decay.

B0bDole
12-17-2004, 03:52 PM
http://www.expanding-earth.org/

the main claim is that it's expanding, but in the proof it shows the mass is increasing also.

Clyde
12-17-2004, 04:18 PM
Some scientists may dispute the notion that additional solid matter is created from solar energy by photosynthesis in plants and other living organisms, but they should consider coal beds that were formed in the Carboniferous (~360 to ~290 Ma) from living trees, and, on today’s surface, piles of leaves and wood chips are rapidly converted to soil by nematodes. They should also consider the massive deposits of limestone created by marine fauna (fish, coral, bivalves, microfossils, etc.) in earlier epochs


This seems horribly confused.