Could robots be programmed to evolve?

Yes. In research that was published in some time ago, teams in Cambridge and Zurich built robots that evolve through successive generations.

The ‘mother’ is a robotic arm that builds ‘baby’ robots out of small cubes. Each cube has a mechanism where one side can waggle. When you place it on a surface, it clumsily drags itself around. The mother glues these moveable cubes together in various arrangements. Some combination move further and faster than others. The mother robot builds each arrangement using assembly instructions in the form of a ‘genome’ that is passed between successive generations of robots.

The mother is programmed to insert random mutation into each generation. Some offspring move around better than their forerunners, but others do worse. The mother rejects deficient generations but uses the genetic blueprints of successful ones to build subsequent offspring. In the lab, after only 10 generations, the robots performed twice as well as those at the start of the process.

How does earth maintain a constant level of oxygen?

It doesn’t! the oxygen level of the planet has varied quite dramatically in the last 500 million years ago; as the climate cooled and the land plants died off, oxygen level fell to as low as 12 percent by the beginning of the triassic. Back then, the air at sea level would have felt thinner than at the top of the Alps today.

Burning fossil fuels has reduced oxygen levels very slightly  - about 0.057 percent over the last 30 years. Deforestation only has a small effect because when rainforest is cut down, other plants are usually grown in its place. But it’s marine plankton, rather than trees, that produces about 70 percent of atmospheric oxygen. Global warming will have a significant impact on plankton, which is a much more serious threat to oxygen levels.

Is crying good for you?

Many people would say yes. Crying is said to be cathartic, relieve stress and even remove toxins from the body, and most therapists claim it’s beneficial. There is evidence that blood pressure and heart rate fall after crying, while some allergic reactions are reduced after watching weepy films, and sufferers from rheumatoid arthritis who cry have less pain than those who don’t.

Yet the experimental evidence is mixed. Benefits are more likely when the reason for crying is a resolvable problem and the person crying is comfortable expressing their emotions and not otherwise depressed. One function of crying may be to show our distress, which can help build relationships, and this may be why crying helps.

Could we exist on earth under a red giant star?

About five billion years from now, the sun’s usual source of nuclear energy will be depleted. It will begin to expand and cool significantly, becoming a ‘red giant’. Its outer layers will be thrown off into space. As the sun loses mass, its gravitational pull will weaken and the planets’ orbit will widen. We know that mercury and venus will not be able to outrun the expanding sun, and will be engulfed and incinerated.

Earth may just outrun the swelling red giant but its proximity, and the resulting rise in temperature, will probably destroy all life on Earth, and possibly the planet itself. However, there’s no reason that life could not survive on another planet (or moon) sufficiently far out from the sun, as long as it lies within the sun’s expanded ‘habitable zone’. Life could also survive on suitably hospitable planets around other Red Giants.

Can a yacht ever travel faster than the wind ?

This seems like defiance of laws of physics, but it needs the right shape and size of sail to trap enough of the air-mass blowing in the wind. The resulting transfer of momentum can propel yachts to impressive speeds. Especially if friction is minimized – some sleek catamarans can achieve 80km/h using 35km/h winds.

If humans became extinct, how long would it take for all traces of us to vanish?

Stonehenge is at least 4,000 years old and still visible today, old and still visible today, and monuments buried nearby could be even older. Most modern buildings aren’t that robust, but some traces would likely remain for at least 10,000 years, even if it was just the magnetic trace of the steel bars inside concrete blocks. When Hong Kong airport was constructed in the 1990s, the island of Chek Lap Kok was flattened and extended, and the straight edge of its northern coastline will be a clue to our civilization for tens of thousands of years. Our atmosphere also has high level of plutonium-239 due to nuclear weapons testing during cold war. This isotope only occurs in nature in incredibly small amounts, and will be detectable as a pollutant for at least 250,000 years.

But the most enduring signs of civilization will probably be deep mines in hard rock, such as South African gold mines Australian lead mines. Here, visiting aliens would be able to see signs of our civilization for millions of years, as the tunnels fill up with sediment washed down by rainwater to create massive industrial ‘fossils’.

Why do people cheat?

Because they want to win the easy way. As competitive animals, we human beings constantly seek out opportunities to gain money, food and sex, or simply to look good. Doing all this the hard way requires expenditure of time,efforts and energy, so cheating can obviously be very tempting.

Evolutionary game theory has helped to explain how altruism can exist alongside cheating. Generally, cheats do well when they are rare, but less well when they are many and have fewer non-cheaters they can exploit. So groups tend towards an equilibrium, with few enough cheats that it’s not worth the cost of stopping them. Sadly, this basic biological principle means we are unlikely ever to be completely free of cheats.