BRAINDUMP
Why doesn’t NASA take parts into Earth orbit and build a spaceship to go to Mars up there, like the ISS?
Amazing answers to your curious questions
There are a few reasons why we haven’t sent a manned flight to a planet like Mars yet. The distance is one. At their closest Mars and Earth are still 50 million miles away, or about seven months travel time. They’ll need supplies on board for all that time. Even if advances in rocketry can reduce the time, once on Mars astronauts will have to wait up to a year and a half to return, when the orbits of the planets align just so. A spaceship big enough to contain all the necessary supplies would be too big to launch from Earth’s gravity given our current technology, so we could theoretically build on the Moon or in orbit. But launching parts up over time like that could get expensive. Beyond these issues, astronauts going to Mars would be exposed to high levels of radiation, as well as suffering the effects of microgravity, losing about one per cent of their bone mass each month. There would be psychological fallout from being so far from home too.
WHY DO PERSIAN CATS HAVE FLAT FACES?
Not all Persian cats do – the doll-faced Persian actually has a muzzle. In the late 1950s, some cat fanciers decided a spontaneous mutation was a desirable trait, and began breeding Persians to have shorter muzzles until they had high noses and flat faces. This ultra-typed cat became the breed standard. At its most extreme, a Persian cat with these features runs the risk of having deformed tear ducts and perpetually runny eyes, so some are calling for a return to the traditional breed.
WHAT MAKES THE WIND BLOW?
Wind is the movement of large bodies of air. Air is made up of gas molecules, and those molecules are already whizzing around – that’s what makes air a gas instead of a solid. But the motion of individual molecules is chaotic. They are constantly bouncing off one another and changing direction. When you add all the trillions of tiny collisions together, you get an overall pressure that increases as the temperature rises, because the molecules are moving faster. Air at the equator gets heated by the Sun more than air at the poles, so it exerts a greater pressure and pushes the colder air out of the way. Because Earth is also rotating, the atmosphere gets pulled into huge vortices. These rotating pressure systems move across the planet, and we feel the result as wind. The exact pattern of the wind is further complicated by differences between the temperature of the land and sea, obstructions from mountains and buildings and even the energy released when water vapour condenses as rain. This is why predicting weather is so hard.