article_snippet.sent: The dramatic event could explain why our planet has a hot core that gives our planet our planet magnetic field.
article_snippet.sent: And our planet could also explain why certain rare-earth elements in the young Earth’s mantle do not seem to originate from our planet’s other building blocks - meteorites.
article_snippet.sent: The object would have been the heat source for our planet's core.
article_snippet.sent: The object also explains where some rare-the young Earth elements came from .
article_snippet.sent: However, this model cannot explain where the heat source for the young Earth’s core - and ultimately Earth’s magnetic field - came from.
article_snippet.sent: In addition, the young Earth’s crust and mantle appear to have a higher ratio of the rare-earth elements samarium and neodymium than most meteorites - suggesting there was more at play in the young Earth’s formation than first thought.
article_snippet.sent: This would have been rich in sulphur but very poor in oxygen - just like Mercury.
article_snippet.sent: As Mercury collided with the young Earth, Mercury would have produced radioactive uranium and thorium, generating the heat needed to drive the ‘dynamo’ of molten iron in the young Earth’s core.
highlights_snippet.sent: The Mars-sized object would have been the heat source for our planet .
  
highlights_snippet.sent: The Mars-sized object also explains where some rare-Earth elements came from .