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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: -

What is the best option to save energy when cycling on hilly roads?

Our readers are sure that the best option is to freewheel downhill, rather than waste your energy pedalling 鈥� and they have the science to back this up

2F959A7 Cabazon, CA, USA: June 18th, 2010: A 65-foot-tall Tyrannosaurus rex known as Mr. Rex is part of a roadside attraction that stands near the freeway in

Where is 180 million years鈥� worth of dinosaur poo?

AY65GM 10 97 Australia Queensland Beauty Spot sign Photo c Simon Grosset

This week鈥檚 new questions

2CG262A Old fashioned street clock with Roman numerals without arrows on blue slightly cloudy sky background. Real view of street clock in city. Stopped time

What would happen if time stopped?

J773YF Kitchenware on shelves with stainless steel sink in 17th century Kintyre stone cottage

What happens to the stains in my sink when I clean it with bleach?

2H6020J Few pedestrians on the rather busy street in metaverse conceptual reality

This week鈥檚 new questions

2RXK2EN Catford Local Area Photography

What is the largest size an animal can be?

2DBWHRA A Atom with electrons and protons moving in the microcosmos.

Is there the same number of electrons as protons in the universe?

2JF72KW Digital hands reaching each other, artificial intelligence creativity concept

Will we ever be able to tell if an AI gains consciousness? Part 2

hot Jupiter class exoplanet, gas giant planet lit by an alien sun (3d space rendering); Shutterstock ID 1150780133; purchase_order: -; job: -; client: -; other: -

This week鈥檚 new questions

If an Earth-sized rogue planet passed through our solar system, missing the planets, how much disruption would it cause? And would it be possible for an intelligent species to develop an advanced technological civilisation without the wheel?

How do I know if what I see is actually there?

Could aliens work out if a human or an ape built a tomb? Part 2

This week鈥檚 new questions

Do cells in an astronaut鈥檚 body multiply at the same rate as on Earth?