杏吧原创

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Why do some flowers close up at night but others stay open?

This timing will depend on what pollinators the flowers are hoping to attract, say our readers 鈥� and there are some flowers that open at night, rather than during the day

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F6YK0A Weltzeituhr on Alexanderplatz in Berlin

How do you check the accuracy of an atomic clock?

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ROTHBURY, NEWCASTLE UPON TYNE, ENGLAND, UK - JULY 06, 2019: Two cyclists peddling hard up a steep hill at the cyclone race event from Newcastle to Northumberland.; Shutterstock ID 1539510248; purchase_order: -; job: -; client: -; other: -

This week鈥檚 new questions

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HUD Matrix particles grid. Virtual reality. Grid core. Magic explosion star with particles. Acceleration race. Glow lines. Colorful flash. Big bang. Light trails. Glitch effect. Deep space.; Shutterstock ID 1590869041; purchase_order: -; job: -; client: -; other: -

Did abstract mathematics exist before the big bang?

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2RXK2EN Catford Local Area Photography

This week鈥檚 new questions

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2GFT7TJ Ichthyosaur swimming in the ocean, extinct marine reptile from Early Triassic to Late Cretaceous, 3d paleoart rendering

How did marine reptiles such as ichthyosaurs breathe?

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R1D8PY Silverback western lowland gorilla sitting down to eat at Zoo Atlanta in Atlanta, Georgia. (USA)

Could aliens work out if a human or an ape built the tomb they lie in?

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Kecskemet, Hungary - August 28, 2021: Leonardo C-27J Spartan. Military transport plane at air base. Air force flight operation. Aviation and aircraft. Air lift. Military industry. Fly and flying.; Shutterstock ID 2126430722; purchase_order: -; job: -; client: -; other: -

This week鈥檚 new questions

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Close up of glass of a freshly prepared gin and tonic with lemon slices and spoon on the counter.; Shutterstock ID 482388439; purchase_order: -; job: -; client: -; other: -

Why do ice cubes for my gin and tonic often shatter in the mould?

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2HMRRGF Madrid, Spain - March 6th, 2021: Isidore of Seville statue at National Library of Spain, Madrid. Medieval Spanish scholar

Once life is established, is intelligence inevitable? Part 2

Our readers continue to pick over this question, pointing to the Fermi paradox and slime mould as they grapple (intelligently) with it

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This week鈥檚 new questions

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Why didn鈥檛 green fur evolve among mammals?

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Would your brain run out of storage space if you could live forever?

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This week鈥檚 new questions

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