91色情片

2K6A82T Artist's concept of astronauts and human habitats on Mars.

This week鈥檚 new questions

What is the minimum number of working individuals that would be necessary for the survival of a settlement on Mars? And why aren't we equally capable with our left and right sides? Wouldn't this have given us a clear survival advantage?

Why do fallen trees grow stems vertically from a horizontal trunk?

B1PP5G Spiral Galaxy M74 i. Image shot 2008. Exact date unknown.

What makes galaxies spin in a certain direction?

Various disco, soul and funk, seven inch records at second hand store.

Why can鈥檛 we conjure up smell and touch in our heads? Part 3

Yellow wash scrub sponge placed on wet blue background covered with drops of water in light room during household chores; Shutterstock ID 2167323189; purchase_order: -; job: -; client: -; other: -

This week鈥檚 new questions

Motion Speed Light in London City; Shutterstock ID 1093994570; purchase_order: -; job: -; client: -; other: -

Is the speed of light in high gravity different from in low gravity?

2REAK4A world map of african countries and arabian sea, madagascar island and zambia in close up focus

Why is the east coast of Madagascar so straight?

BNYGBG Astronaut Ed White the First American to Conduct a Spacewalk on Gemini 4 Mission June 3rd 1965 - Manuevering gun in his Right hand and Tether Cable

This week鈥檚 new questions

Middle-aged woman in glasses fell asleep while reading book at home, female sleeping with open mouth on sofa near coffee table with houseplant in living room. Sleep deprivation; Shutterstock ID 2122133960; purchase_order: -; job: -; client: -; other: -

Are we conscious when we are asleep?

The surface of Venus, the irregularities of the planet. Elements of this image furnished by NASA. High quality photo; Shutterstock ID 2157724597; purchase_order: -; job: -; client: -; other: -

Could we build a habitable dome on the surface of Venus? (continued)

One reader brings up the idea of building permanent 鈥渃loud cities鈥� in the Venusian atmosphere, a concept developed by the NASA engineer Geoffrey Landis

This week鈥檚 new questions

When was it first realised that moonlight must be reflected sunlight?

Would a northern hemisphere 鈥渋ce age鈥� trigger one in the south too?

How do dogs recognise that another animal is also a dog? (continued)