how big is the earths core?

Question: how big is the earths core?
- Keywords:
  core,
  crust,
  earth,
  how big,
  magma,
  molten,
  planet,
  size
Asked by mrlawlor to Charlie, Eoin, Jemma, Julian, Steve on 21 Mar 2011.
- Eoin Lettice answered on 21 Mar 2011:
  
  Hi mrlawlor,
  Thanks for the question. It’s not the kind of thing I’d be able to remember straight away so I’ve looked it up:
  Apparently the earth’s core is divided up into an inner and outer core. The inner core is solid iron and has a radius of 1,220 kilometres and the outer core surrounds this and is liquid. It has a radius of 3,400 kilometres.
  
  Eoin
- Julian Rayner answered on 21 Mar 2011:
  
  Hi mrlawlor. Sorry, no astophysicist or geologist, so I would just look up Wikipedia like you (which says the outer and inner cores together are about 7,000 km wide).
- Stephen Moss answered on 21 Mar 2011:
  
  Hi Mrlawlor
  I don’t know where the ‘official’ boundary lies between the core and the outer layers of the Earth. Perhaps one of the other scientists can help.
- Charlie Ryan answered on 21 Mar 2011:
  
  well it seems it is about 3800km thick, which is very thick really! You’d have better luck asking a geologist though!

Question: how big is the earths core?