ScienceActually<p>Buried beneath the Greenland Ice Sheet is one of the oldest known craters on Earth, the Hiawatha Crater. This massive impact crater is about 31 km (19 mi) wide and is estimated to have formed over 58 million years ago.</p><p><a href="https://sfba.social/tags/science" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>science</span></a> <a href="https://sfba.social/tags/sciencefacts" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>sciencefacts</span></a> <a href="https://sfba.social/tags/GreenlandIceSheet" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>GreenlandIceSheet</span></a> <a href="https://sfba.social/tags/craters" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>craters</span></a> <a href="https://sfba.social/tags/HiawathaCrater" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>HiawathaCrater</span></a></p>