What is the STRONGEST most Impenetrable thing on earth? Is it STEEL or something stronger than that? Something that NOTHING can penetrate?

Actually the solid inner core is considerably harder and less penetrable than the mantle, even seismic waves can't get through it (they go around it or bounce off of it, through the liquid outer core). Temperature much higher than the melting point of the iron/nickel alloy that it consists, but under such extreme pressure that it remains solid. This post was edited by Slartibartfast at January 16, 2021 7:52 AM MST

Pardon my butting in. How is that determinable? How far in or down is the core and was penetrating ever attempted? I always wonder how we KNOW things like that?

Seismologists can measure the way earthquake shock waves behave - and they don't penetrate the inner core, they behave in a way that indicates that they reflect off of it.

Oh so then that's kind of second-hand? Like sonar or something? How do they verify or certify the correctness of the readings of the instruments? How do they KNOW that the readings are accurate? Thank you for your reply R. It always amazes me how we find out what we find out. It takes brains and curiosity and creativity and dedication! I think you know if I'd have the brains I would have wanted to be a quantum physicist. For me the mystery and excitement of things like quantum entanglement and parallel universes and black holes and and and is never-ending. IF ONLY!  Maybe in the next lifetime? This post was edited by RosieG at January 16, 2021 7:53 AM MST

Thanks, professor.

:):):)

1. So it would burn up before it got through the mantle?
2. Hahahahahahahahahaha. True.

Thank you for your reply E and Happy Saturday to thee and thine! :)

Melt.

At first glance I thought "what's the difference?". But then I visualized chocolate melting and a piece of paper burning. So it would just melt then. Okay. Either way it ends existence. Thank you for your reply E! :)