Chuck Darwin<p>Earth’s innermost region is separated into two major components: a solid <a href="https://c.im/tags/inner" class="mention hashtag" rel="tag">#<span>inner</span></a> <a href="https://c.im/tags/core" class="mention hashtag" rel="tag">#<span>core</span></a> that measures about 750 miles in radius and sits within the <a href="https://c.im/tags/outer" class="mention hashtag" rel="tag">#<span>outer</span></a> <a href="https://c.im/tags/core" class="mention hashtag" rel="tag">#<span>core</span></a>, which is a 1,300-mile-thick layer of liquid metal. <br />Due to its remote location 1,800 miles under our feet, the core has long evaded easy observation, though scientists can peer at some of its hidden features by recording seismic waves from earthquakes that pass through this enigmatic area.<br />Past studies with seismic waves have offered tantalizing hints that the inner core might itself contain a distinct core, though the size and nature of this potential “fifth layer” of Earth has remained a matter of debate. <br />Now, Thanh-Son Phạm and Hrvoje Tkalčić, a pair of researchers at The Australian National University, have used “a previously unobserved and unutilized class of seismological observations” to expose the <a href="https://c.im/tags/IMIC" class="mention hashtag" rel="tag">#<span>IMIC</span></a>, which they say “could be a fossilized record of a significant global event from the past,” according to a study published on Tuesday in Nature Communications.<br />“Earth’s <a href="https://c.im/tags/inner" class="mention hashtag" rel="tag">#<span>inner</span></a> <a href="https://c.im/tags/core" class="mention hashtag" rel="tag">#<span>core</span></a> ( <a href="https://c.im/tags/IC" class="mention hashtag" rel="tag">#<span>IC</span></a> ), which accounts for less than 1% of the Earth’s volume, is a time capsule of our planet’s history,” said Phạm and Tkalčić in the study. <br />“As the IC grows, the latent heat and light elements released by the solidification process drive the convection of the liquid <a href="https://c.im/tags/outer" class="mention hashtag" rel="tag">#<span>outer</span></a> core, which, in turn, maintains the <a href="https://c.im/tags/geodynamo" class="mention hashtag" rel="tag">#<span>geodynamo</span></a>,” referring to the mechanism that generates Earth’s <a href="https://c.im/tags/magnetic" class="mention hashtag" rel="tag">#<span>magnetic</span></a> field.  </p><p><a href="https://www.vice.com/en/article/4axkwj/earth-core-discovery-scientists" target="_blank" rel="nofollow noopener noreferrer" translate="no"><span class="invisible">https://www.</span><span class="ellipsis">vice.com/en/article/4axkwj/ear</span><span class="invisible">th-core-discovery-scientists</span></a></p>