Research press release


Nature Geoscience

Mercury painted black by cometary carbon



Megan Bruck Syalたちは、おそらく彗星が起源である微隕石により水星や月の表面に運ばれる炭素の全質量を計算した。彼らは、月と比べて水星には単位面積あたり50倍の炭素に富む物質が保持されると見積もっている。高速度の衝突実験では、微隕石による炭素の輸送は水星の表面と同じような色をもたらし得ることが確認されており、観測とも一致する。

The planet Mercury’s puzzlingly dark colour could result from its bombardment with carbon-rich micrometeorites, reports a study published online in Nature Geoscience. This may explain why the Moon is lighter in colour than Mercury, even though the Moon’s surface contains more darkening iron.

Observations of Mercury reveal a planet that reflects little light and also has a low surface iron content, suggesting that another material is probably responsible for its observed dark surface. Comets are rich sources of carbon and they more frequently impact planets closer to the Sun.

Megan Bruck Syal and colleagues calculated the total mass of carbon delivered by micrometeorites, which likely originated from comets, to the surfaces of Mercury and the Moon. They estimate that about 50 times as much carbon-rich material per unit area is retained on Mercury, compared with the Moon. Impact experiments at high velocities confirm that delivery of carbon by micrometeorites can lead to a surface colour similar to that of Mercury, in agreement with observations.

doi: 10.1038/ngeo2397


メールマガジンリストの「Nature 関連誌今週のハイライト」にチェックをいれていただきますと、毎週各ジャーナルからの最新の「注目のハイライト」をまとめて皆様にお届けいたします。