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Magnetopause

/mæɡˈniːtoʊpɔːz/noun

The boundary where Earth's magnetic field holds off the solar wind.

The Greek roots

μαγνῆτις λίθος
magnêtis líthos
stone of Magnesia
+
παῦσις
paûsis
a stopping, ceasing

Literally: where the magnet stops

The story of the word

The magnet half goes back to Μαγνησία, a district in Thessaly whose ore pulled at iron; the same place-name also produced magnesium and manganese, two elements that have nothing magnetic about them. The compound was made in the 1960s once spacecraft could find the boundary. It is not fixed: a strong gust of solar wind can push it inside the orbit of a geostationary satellite.

How it travelled
Ancient Greek → scientific coinage → English
First recorded
1960s

Same family

magnetmagnesiummanganeseheliopause

In a sentence

The storm compressed the magnetopause and left several satellites outside it.

Built on the same root

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