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2EXM9NK Hand Knuckle Finger Joint Crack. Fingers Snap

How can popped knuckles be so exceptionally loud? Part 2

A retired orthopaedic surgeon explains what is going on when we crack our knuckles, and says he has never seen evidence the habit is harmful to joints (he won鈥檛 vouch for relationships)

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PEWCN3 Relaxed senior couple on picnic sitting on park bench talking and having coffee. Old man and woman relaxing at park having coffee.

Why do older people seem to find that time passes more quickly? Part 2

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close up the fly on the window, on the glass, the concept of sanitation, dangerous insects, insect repellent, copy space; Shutterstock ID 1168097506; purchase_order: -; job: -; client: -; other: -

This week鈥檚 new questions

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Kudzu ( Pueraria lobata ) flowers. Fabbaceae perennial vine. Dark blue-purple fragrant butterfly-shaped flowers bloom in racemes from July to September. The roots are edible and medicinal.; Shutterstock ID 2360739029; purchase_order: -; job: -; client: -; other: -

Why do the climbing plants in my garden all twine anticlockwise?

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HFRCEK Knife slicing wholegrain bread

What is the best way to minimise crumbs when slicing bread?

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HYMJ79 The famous prehistoric stone circle at Stonehenge on a bright spring day.

This week鈥檚 new questions

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Asteroid impact event. Lateral sectioned view of an asteroid impact, similar to that which is thought to have caused the extinction of the dinosaurs around 65 million years ago. The impact took place at sea near the coast of the Yucatan Peninsula in Mexico, forming the Chicxulub crater (around 200 kilometres across). The impact threw trillions of tons of dust into the atmosphere and sent tsunamis (massive waves) around the globe, destroying coastal areas. Dust and water vapour in the atmosphere lowered global temperatures. Plant and then animal life began to die off. The dinosaurs never recovered, and mammals rose to become the dominant form of life.

Could Earth sustain life without having been hit by a dwarf planet?

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Watling Street, a Roman road in Great Britain, stretching to the horizon between green fields under a clear blue sky.; Shutterstock ID 666223486; purchase_order: -; job: -; client: -; other: -

How did Roman road builders know which way to go? Part 2

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Brachiosaurus dinosaur in water next to islands with palm trees. This is a 3d render illustration; Shutterstock ID 2218581533; purchase_order: -; job: -; client: -; other: -

What is the earliest period in which I could survive on Earth? Part 2

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It's raining heavily, wearing an umbrella during the rainy season

This week鈥檚 new questions

While sheltering from a huge storm, I wondered whether there is a limit to how hard it can rain. Nigel Stace, Charlestown, New South Wales, Australia

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What鈥檚 the earliest era on Earth in which I could comfortably survive?

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How did the Romans know which way to go to build their straight roads?

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This week鈥檚 new questions

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What happens to electrons, protons and neutrons when we die?

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