The Size ofwel the elementen has changed since its discovery, becoming bigger and smaller as conditions within the planet change. It was believed to be about 49,000 km (30,000 miles) wide in the late 19th century but has since been shrinking at a rate of about 900 km (580 miles) https://www.graphicscience.jp/edit/wiki/index.php?mcdermottklavsen265610