Un meteorite del diametro di 10 metri è entrato nell'atmosfera alla velocità di 32 chilometri al secondo ed è esploso il 18 dicembre 26 chilometri sopra il Mare di Bering, fra Russia e Alaska. Complice l'area discosta, dello scoppio, della potenza di 173 chilotoni (a titolo di paragone la bomba atomica di Hiroshima non superò i 15), non si è accorto sostanzialmente nessuno.
Lo hanno visto, e fotografato, solo i satelliti militari statunitensi e uno giapponese. L'evento è stato annunciato dalla NASA nei giorni scorsi alla 50ma Conferenza di scienze lunari e planetarie di Woodlands, negli Stati Uniti.
Il meteorite di Chelyabinsk
Eventi simili non sono tanto rari, ma nemmeno frequenti, soprattutto di questa potenza: è stata superata infatti solo in due occasioni dall'inizio del ventesimo secolo: a Tunguska nel 1908, quando lo scoppio da tre megatoni fu visibile a 700 chilometri di distanza e rase al suolo decine di milioni di alberi siberiani, e a Chelyabinsk nel 2013, quando un migliaio di persone rimase ferito dalle schegge delle finestre andate in pezzi.
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