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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?

There are lots of ideas about how life got started on Earth, say our readers, but if an object hadn鈥檛 crashed into Earth to form the moon, as per the giant-impact hypothesis, life may not have begun

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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

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

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

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grass lawn with yellow daffodils in dutch garden 'Keukenhof', Holland; Shutterstock ID 172603808; purchase_order: -; job: -; client: -; other: -

This week鈥檚 new questions

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Subatomic particles and atoms, conceptual illustration.

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

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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 experience time passing more quickly?

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The two interacting galaxies making up the pair known as Arp-Madore 608-333 seem to float side by side in this image from the NASA/ESA Hubble Space Telescope. Though they appear serene and unperturbed, the two are subtly warping one another through a mutual gravitational interaction that is disrupting and distorting both galaxies. This drawn-out galactic interaction was captured by Hubble???s Advanced Camera for Surveys. The interacting galaxies in Arp-Madore 608-333 were captured as part of an effort to build up an archive of interesting targets for more detailed future study with Hubble, ground-based telescopes, and the NASA/ESA/CSA James Webb Space Telescope. To build up this archive, astronomers scoured existing astronomical catalogues for a list of targets spread throughout the night sky. By so doing, they hoped to include objects that had already been identified as interesting and that would be easy for Hubble to observe no matter which direction it was pointing. Deciding how to award Hubble observing time is a drawn-out, competitive and difficult process, and the observations are allocated so as to use every last second of Hubble time available. However, there is a small but persistent fraction of time ??? around 2???3% ??? that goes unused as Hubble turns to point at new targets. Snapshot programmes, such as the one which captured Arp-Madore 608-333, exist to fill this gap and take advantage of the moments between longer observations. As well as creating beautiful images such as this, these snapshot programs enable astronomers to gather as much data as possible with Hubble. Links Video of A Snapshot of Interacting Galaxies

This week鈥檚 new questions

If the Milky Way were to collide with another galaxy, how would it affect day-to-day life on Earth? And is there any prospect of using machine learning to converse with whales and dolphins?

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How heavy is Earth and how much weight could it take before caving in?

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What are the chances of my remote car key fob unlocking another car?

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This week鈥檚 new questions

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Does a cyclist with a rider behind use more energy than a solo rider?

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