Apophis is some 350 metres across, considerably larger than the object that is thought to have flattened 2, 000 square kilometres of Siberian forest as it vaporised in the atmosphere above Tunguska in 1908.

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That asteroid entered the atmosphere and exploded, leveling trees over an area of 820 square miles -- about two-thirds the size of Rhode Island.

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For sky watchers, the reports bring to mind the famous Tunguska event of 1908 in remote Siberia, in which an asteroid entered the atmosphere and exploded, leveling trees over an area of 820 square miles -- about two-thirds the size of Rhode Island.

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In that incident, an asteroid entered the atmosphere and exploded, leveling about 80 million trees over an area of 820 square miles -- about two-thirds the size of Rhode Island -- but leaving no crater.

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"The atmosphere is unbelievable, " Capitals captain Alex Ovechkin said Saturday of playing at Madison Square Garden.

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The fact that only a few weeks after the Alexandria attack, Egyptian Copts could hold public prayers in the streets of Cairo, in an overwhelmingly Muslim crowd of protesters, protected by ranks of volunteers from the Muslim Brotherhood at the entrances to the square, may indicate a shift in the atmosphere in Egypt.

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