Sono oltre 350 mila nel cielo sopra di noi, ma solo qualche migliaio di essi ha un nome. Il primo - scoperto il 1. gennaio del 1801 - si chiama Cerere . Tra i più famosi - e più minacciosi - c’è invece Apophis , scoperto molto più recentemente nel 2004. Per un certo periodi si temuto che gravitando vicino alla Terra potesse colpirla nel 2029. Oggi i calcoli astronomici escludono questa catastrofica possibilità. È però utile e necessario studiare questi corpi celesti che sono sfuggenti per loro stessa natura. Le loro traiettorie sono sovente imprevedibili, ma c’è chi – come il nostro esperto – li osserva da anni per carpirne i più impercettibili segreti e anticiparne le traiettorie nel grande gioco del biliardo cosmico del cielo sopra di noi.
Con Stefano Sposetti, docente di fisica al Liceo di Bellinzona, esperto di asteroidi e corpi minori, presidente della Società Astronomica Ticinese.
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