Could a Giant Iron Planet Form a Black Hole?

[Nexus555]

While I know iron isn't the most common element in the universe, is it possible that there is a Jupiter + size planet made primarly of iron? Also, when it comes to black holes - would a massive iron planet form a black hole due to it's immense mass? What would be the minimum mass to form a black hole, or is black holes reserved strictly for dying stars and centers of galaxies?

 

[kmarinas86]

While I know iron isn't the most common element in the universe, is it possible that there is a Jupiter + size planet made primarly of iron? Also, when it comes to black holes - would a massive iron planet form a black hole due to it's immense mass? What would be the minimum mass to form a black hole, or is black holes reserved strictly for dying stars and centers of galaxies?

A planet of that size would likely attract lots of gas and dust coming its way, so that it would end up no longer being naked. Perhaps it is possible.

The Earth is mostly of iron, so we can consider a black hole of the same density (5515 kg/m^3).

Since a black hole must have 6.73426629 * 10^26 kilograms for every meter of radius, the iron sphere (incapable of fusion) would have to be 1.14978957 * 10^38 kilograms (i.e. 58 million solar masses) with a radius of 170,737,170 kilometers, much more hefty than the sun is. I really doubt a black hole could be formed this way, or the existence of such an object. I really really doubt that my understanding of this is complete, so let's someone else pitch in...

http://www.google.com/search?q=1.14...2+*+G*+1.14978957+*+10^38+kilograms+/+c^2)^3)

 

[Flatland]

Why would the iron sphere need to be that massive? All it needs to be is dense enough to form a black hole.

 

[DaveFaz]

Why would the iron sphere need to be that massive? All it needs to be is dense enough to form a black hole.

It takes a massive amount of force to generate the density necessary for the creation of a black hole.