how do you now thers solid iron in the midle of the earth

Question: how do you now thers solid iron in the midle of the earth
- Keywords:
  core,
  earth,
  metal
Asked by to Andrei, Ekbal, Gemma, Helen, Ruth on 17 Jun 2014. This question was also asked by .
- Ekbal Hussain answered on 17 Jun 2014:
  
  Hi,
  Another great question. The solid core of the Earth is about 5200 kilmetres below our feet, that’s like the distance from here to New York straight down!
  
  So obviously we can never directly see the core. We need to use indirect methods to tell what the core is made of.
  
  The method we use the most is to use seismic waves made by big earthquakes. These waves travel through the earth and we can measure them as they come out on the other side. And by measuring how long it took and the type of wave that comes out compared to what went in, we can tell all kinds of things about the inside of the Earth. Like the fact that we have a solid iron inner core and liquid iron outer core for example.
  
  Hope that answers your question!
  Ekbal

Question: how do you now thers solid iron in the midle of the earth