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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?

Even without compasses, the Romans devised some clever ways to build straight roads - sometimes a bit too straight

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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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Analysis of cats during a cat show reveals they mostly lazed around

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Tom Gauld on UFOs

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Twisteddoodles on group research

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Protecting the pruned branch of the fruit tree - plum - with garden paste

Life

Painting a tree’s pruning wounds may be useful after all

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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

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Coast Mountains #16, British Columbia, Canada, 2023 "Recent reports on the world's remaining glaciers provide sobering news. Estimates are that most of Western Canada's glaciers will be lost to melting within the next 80 years. By the end of this century, they could all be gone. My daughters, who are in their 20s, will not be looking at the same world when they are my age. These images are a reminder of what's being lost - relics of ancient ice and an essential resource for ecosystems and freshwater in these parts of the world

Earth

Stark mountain landscapes exposed in Canada as glaciers shrink

Global warming means many of the world鈥檚 ancient rivers of ice will be gone within decades, threatening ecosystems that rely on their meltwater, a looming crisis that photographer Edward Burtynsky highlights in his work

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Just add sugar for an almost death-defying study on tea and coffee

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Tom Gauld on the professor’s naps

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Twisteddoodles on mating calls

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Mathematics

How the maths behind honeycombs can help you work a jigsaw puzzle

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