what materials make up the inner core?
Earth’s inner core is made mostly of iron , with a smaller amount of nickel , plus tiny amounts of lighter elements like sulfur, oxygen, silicon, and possibly other “iron-loving” metals such as gold and platinum.
Quick Scoop
- The inner core is a solid metal ball at Earth’s center.
- It is composed primarily of iron (about 80% by mass) and nickel making up most of the rest.
- Scientists think there are small amounts of lighter elements (such as sulfur, oxygen, silicon, and carbon) mixed in.
- There may also be trace “siderophile” elements (iron-loving metals) like gold, cobalt, and platinum.
Main materials
- Iron (Fe): Dominant element, roughly four-fifths of the inner core.
- Nickel (Ni): Second most abundant, likely up to around 10–20% combined with iron in an iron–nickel alloy.
- Lighter elements: Small percentages of sulfur, oxygen, silicon, and possibly carbon help explain why the core is slightly less dense than pure iron.
- Trace metals: Very small amounts of siderophiles such as gold, cobalt, and platinum are inferred from how these elements behave with iron.
How sure are scientists?
Scientists cannot drill to the inner core, so they infer its composition using:
- Seismic waves from earthquakes, which change speed and direction depending on what they pass through.
- Experiments on iron and iron–nickel alloys at very high pressure and temperature.
- Models of how Earth formed and how elements separated early in its history.
All of these lines of evidence strongly support an inner core made mainly of solid iron–nickel alloy with a small mix of lighter and trace elements.
Information gathered from public forums or data available on the internet and portrayed here.