Whats the heaviest substance on Earth?

the heaviest naturally occurring substance would be "depleted" Uranium. but if ur talking the heaviest thing on earth, it would be the core of the earth

By firing atoms of metal at another metal, Russian and American scientists have discovered a new element -- No. 118 on the periodic table -- that is the heaviest substance known and probably hasn't existed since the universe was in its infancy.Ununoctium, as the new element is temporarily named, has no known use but inspired almost a decadelong pursuit by scientists on four continents.

It's a common misconception but I think you are talking about density, not weight

In physics, density is defined as mass m per unit volume V. Mathematically, it is expressed as

ρ = m/V

where, in SI units:

ρ (rho) is the density of the substance, measured in kg·m-3

m is the mass of the substance, measured in kg

V is the volume of the substance, measured in m3

It's the old 'which is heavier - a Kg of feathers or a Kg of Lead'? puzzler.

from http://theodoregray.com/PeriodicTable/Elements/077...

Osmium and Iridium are the two most dense elements in pure form. They are also very pretty metals, iridium particularly. Unlike osmium, iridium does not tarnish in air, and is in fact impervious to many forms of chemical attack, much like platinum. An alloy of 90% platinum and 10% iridium is widely used in both the jewelry and chemical industries, because it is strong, hard, beautiful, and impervious to almost all chemicals even at very high temperatures.

Of course, the most dense sunstance might be me......

Roentgenlum 111/272

Discovered : by Hofmann and co-workers in 1994

Nutrino's passing straight through the Earth

Uranium is quite heavy, but the center core of earth probably beats that.

Ununoctium.

Isn't it the most heavy, naturally occuring metal? I don't know about manufactured heavy metals, which are too unstable to exist naturally.

Hmmm, I'm very sure it's uranium, with the lightest being hydrogen

possibly me at the moment