Charting nearby stars by their density

[Dan Dixon]

This image was created with the upcoming version Universe Sandbox. It demonstrates some new enhancements to the Chart Mode feature.

"Density is a measurement that compares the amount of matter an object has to its volume."
http://simple.wikipedia.org/wiki/Density

Water has a density of 1.0.
Our planet Earth has a density of 5.5.

The nearby stars are charted from least dense (Arcturus | 0.00009) to most dense (Luyten 726-8 A | 51.3). Can you find our Sun? It's density is 1.4.

Density is measured in g/cm^3.

[FGFG]

Very nice! Arcturus and other stars are shifted for their dimensions right?

[atomic7732]

yes i found it by EZ aquarii a nice red star. 

[Naru523]

Water has a density of 1.0.
Our planet Earth has a density of 5.5.

Doesn't the Earth has more denisty since it has a lot of water [Oceans, Lakes, etc.]

[Bla]

Water is only a tiny bit of the mass I think. It's only a few kilometers on the surface, nothing compared to the thousands of kilometers there are to the core.
Also, solid materials have a higher density than most liquid materials (though water expands when it freezes ), so I don't think water has any influence on our density at all, not on a big scale.

[Dan Dixon]

Earth is the most dense planet in our solar system, in part, because of its iron core.

Density of Materials
(in g/cm³)
Space = 0.000000000000000000001
Air = 0.0012
Water = 1.0
Earth = 5.5
Iron = 7.8
Gold = 19.3
Core of Sun = 150
Black Hole = 400000000000000

http://en.wikipedia.org/wiki/Density#Densities_of_various_materials

Universe Sandbox show density in g/cm³ so water's density = 1. The Wikipedia chart uses kg/m³ so water = 1000.

You can also look up the density of things with Wolfram Alpha:
http://www.wolframalpha.com/input/?i=density+of+iron

[hbmp88]

Speaking of density I had a question that I did not know how to answer funny thing I thought of it earlier today:

Is there any liquid when heated is less dense than air, but still maintains its liquid form?

[Chaotic Cow]

Very interesting. I learn stuff coming to these forums.

[Dan Dixon]

Is there any liquid when heated is less dense than air, but still maintains its liquid form?

All densities in g/cm³

I don't think so...
http://www.google.com/search?hl=en&q=least+dense+liquid

Again, the density of Air = 0.0012

Someone said it was rubbing alcohol, which isn't right.
Isopropyl alcohol = 0.078
http://en.wikipedia.org/wiki/Isopropyl_alcohol

But I think it's liquid hydrogen. It comes close, but it's still not as light as air.
Liquid Hydrogen = 0.0071
http://en.wikipedia.org/wiki/Liquid_hydrogen

[hbmp88]

Well I wouldn't want to do an experiment with that! Talk about third degree burns .

[Dan Dixon]

Earth is the most dense planet in our solar system, in part, because of its iron core.

Here's a list of the masses of the different parts of the Earth:

Total Mass   = 5.9736 x 10^24 kg
Mass layers:
atmos          = 0.0000051 x 10^24 kg
oceans         = 0.0014 x 10^24 kg
crust            = 0.026 x 10^24 kg
mantle         = 4.043 x 10^24 kg
outer core   = 1.835 x 10^24 kg
inner core    = 0.09675 x 10^24 kg

Source: JPL's Horizon system - Data on Earth

[hbmp88]

Interesting how the core is less dense than the mantle

[Dan Dixon]

Be careful that you're not confusing density and mass. The Earth's core is about 3 times denser than the mantle.

Here's a great post that talks about the layers of the earth in detail:
http://www.madsci.org/posts/archives/1999-11/943288749.Es.r.html

The Earth's core is
=   27.5 % of earth's mass
=   9.25 % of earth's volume
= 10 g/cm³

The Earth's mantle is
=   68.4 % of earth's mass
=   49.5 % of earth's volume 
= 3.3 g/cm³ (upper mantle) to 6.0 g/cm3 (lower mantle)

[hbmp88]

Woops but at least I thought it was contradicting.

[Dan Dixon]

Yeah. I though the numbers looked strange too. I would have thought the inner core would be more massive. (but if you combine the inner and outer core, then the numbers look right.)