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Dunash
2002-Jan-20, 07:16 PM
What is the Earth's average density in g/cc? Does it have the highest average density in the Solar System?

Chip
2002-Jan-20, 08:11 PM
On 2002-01-20 14:16, Dunash wrote:
What is the Earth's average density in g/cc? Does it have the highest average density in the Solar System?

Here are some examples I found by writing "Earth average desity g/cc" in a search engine:

Average density of the entire earth = c.5.5 g/cc.

Earth's mantle probably consists of very dense (average c.3.9)

Average density of Venus
is 5.2 g/cc, which is slightly less than that of the Earth or Mercury. (Venus is very close to being the same size as Earth.)

Average density of Mars is 3.9 g/cc.

Jupiter is massive because it has a large diameter (11.2 times that of Earth). However its density is only 1.33 g/cc, which is 1/4 that of Earth.

The other gas giants are probably less dense than Earth.

(Of course if you're talking mental density Earth might still be No. 1.) (-;

2002-Jan-20, 09:15 PM
Try here (http://www.seds.org/nineplanets/nineplanets/data1.html). Earth just edges out Mercury.

Donnie B.
2002-Jan-20, 09:47 PM
I would assume that nickel-iron meteoroids would be considerably higher than Earth's average density. Or were you limiting the question to the major planets?

aurorae
2002-Jan-21, 06:19 PM
On 2002-01-20 16:15, The Bad Astronomer wrote:
Try here (http://www.seds.org/nineplanets/nineplanets/data1.html). Earth just edges out Mercury.

Interesting. My guess would have been Mercury, since all the light elements would have been driven off during formation.

I suppose that Earth is dense because it contains the iron cores of two planets -- the proto Earth and the Mars size impactor. If we add the Earth and Moon together, and compute a combined density, I'll bet a nickel it would be less dense than Mercury.

SeanF
2002-Jan-21, 07:05 PM
On 2002-01-21 13:19, aurorae wrote:

On 2002-01-20 16:15, The Bad Astronomer wrote:
Try here (http://www.seds.org/nineplanets/nineplanets/data1.html). Earth just edges out Mercury.

Interesting. My guess would have been Mercury, since all the light elements would have been driven off during formation.

I suppose that Earth is dense because it contains the iron cores of two planets -- the proto Earth and the Mars size impactor. If we add the Earth and Moon together, and compute a combined density, I'll bet a nickel it would be less dense than Mercury.

Well, I did some quick math using the numbers from that link, and it looks to me like the Moon's got about 1.23% of the Earth's mass and about 2.02% of the Earth's volume. Combined, you get 101.23% mass and 102.02% volume, which would give you 99.23% of the density, right? That takes the Earth-Moon density from the Earth's 5.52 down to about 5.48, which is still slightly denser than Mercury's 5.43.

Unless I did something wrong . . . if not, Aurorae, I'll send you my address for you to send my nickel. /phpBB/images/smiles/icon_wink.gif

Valiant Dancer
2002-Jan-21, 07:39 PM
On 2002-01-20 15:11, Chip wrote:

On 2002-01-20 14:16, Dunash wrote:
What is the Earth's average density in g/cc? Does it have the highest average density in the Solar System?

Here are some examples I found by writing "Earth average desity g/cc" in a search engine:

Average density of the entire earth = c.5.5 g/cc.

Earth's mantle probably consists of very dense (average c.3.9)

Average density of Venus
is 5.2 g/cc, which is slightly less than that of the Earth or Mercury. (Venus is very close to being the same size as Earth.)

Average density of Mars is 3.9 g/cc.

Jupiter is massive because it has a large diameter (11.2 times that of Earth). However its density is only 1.33 g/cc, which is 1/4 that of Earth.

The other gas giants are probably less dense than Earth.

(Of course if you're talking mental density Earth might still be No. 1.) (-;

Gee, when I think up a really good Earth mental density joke, Chip has to beat me to it. /phpBB/images/smiles/icon_smile.gif Good job Chip.

GrapesOfWrath
2002-Jan-22, 01:18 PM
On 2002-01-20 16:15, The Bad Astronomer wrote:
Try here (http://www.seds.org/nineplanets/nineplanets/data1.html). Earth just edges out Mercury.

Earth may be most dense, but Phoebe floats.

And Saturn, and others of its moons. That seems to be unique amongst the planets of the solar system. I imagine that that condition might contribute to maintaining such a prominent ring system.

2002-Jan-22, 01:31 PM
On 2002-01-21 14:05, SeanF wrote:
[quote]
Well, I did some quick math using the numbers from that link, and it looks to me like the Moon's got about 1.23% of the Earth's mass and about 2.02% of the Earth's volume. Combined, you get 101.23% mass and 102.02% volume, which would give you 99.23% of the density, right? That takes the Earth-Moon density from the Earth's 5.52 down to about 5.48, which is still slightly denser than Mercury's 5.43.

I also think that the moon material would be compressed due to the larger gravity of earth, increasing the density a bit more.

Kaptain K
2002-Jan-22, 03:52 PM
Mercury would be the densest planet due to the absence of light volitile elements except for the compression of the Earth's core. Although the normal density of iron is just under 8 g/cc, the density of the Earth's core is ~ 14 g/cc.

aurorae
2002-Jan-22, 05:47 PM
On 2002-01-22 10:52, Kaptain K wrote:
Mercury would be the densest planet due to the absence of light volitile elements except for the compression of the Earth's core. Although the normal density of iron is just under 8 g/cc, the density of the Earth's core is ~ 14 g/cc.

Ah, that explanation sounds like the information that I missed up above.

And thanks for the math, SeanF.