Six famous thought experiments explained quickly

A paradox is something that cannot be true but also cannot be false. For example:

What if money was no object?

Ask yourself. What would you do with your life if money was no object? An amazing lecture from the late Alan Watts.

Space travel is bad for your health

From blackout-inducing g forces to withered muscles and bones, there aren’t many tougher physical challenges than going into space.

This has been highlighted by the release of medical records from astronauts who worked on board the Russian space station Mir, which detail the gruelling effects space travel has on human health before, during and after a mission.

The astronauts experience motion sickness on take off. The real problems began when the astronauts returned home. Their bodies had adapted to weightless conditions, so returning to Earth was a shock to the system. For example, in space, the heart adapts to low gravity, no longer having to work as hard to pump blood to the upper body. Returning to Earth put extra strain on the astronauts’ hearts: all had low haemoglobin levels and blood pressure, which made it difficult for them to stand up without fainting.

Even more worrying were the effects of microgravity on bone and muscle, which are known to break down when not bearing the body’s weight. In an effort to combat this, the astronauts exercised on treadmills and bikes, but they still lost up to 2 per cent of their bone mass each month.

Such problems would pose a serious hazard to astronauts travelling to other planets. It would take around nine months to travel to Mars, for example, and once in the Martian gravity astronauts would be too weak to work, and susceptible to blackouts and broken bones. Read more here.

12 Events That Will Change Everything

What would happen if:

• The polar ice caps melted?
• We found extra dimensions?
• We discovered extra-terrestrial intelligence?
• The was a nuclear war?
• Humans created artificial life?
• We created room-temperature superconductors?
• We created a self-aware machine?
• We managed to start cloning humans?
• There was a large pacific earthquake?
• We managed to control nuclear fusion and use it as a source of power?
• An asteroid collided with Earth?
• There was a worldwide deadly pandemic?

To learn the answers to all these questions, check out a great interactive here.

Solving the problems of time travel

Physicists know that time travel is more than just a compelling plot device in movies — it’s a serious prediction of Einstein’s general relativity equations.

Any theory of time travel has to confront the devastating “grandfather paradox,” in which a traveler jumps back in time and kills his grandfather, which prevents his own existence, which then prevents the murder in the first place, and so on.

Scientists have come up with a model of time travel that explicitly forbids these inconsistencies.

For instance, a bullet-maker would be inordinately more likely to produce a defective bullet if that very bullet was going to be used later to kill a time traveler’s grandfather, or the gun would misfire, or some little quantum fluctuation has to whisk the bullet away at the last moment. In this version of time travel, the grandfather is “a tough guy to kill”.

Deciding which theory of time travel is best is largely a matter of taste. Until someone figures out how to build a time machine, no one will know the answer. Read more here.

The chicken came first, not the egg!

It’s an age-old puzzle that’s stumped generations of scientists. But now they believe they have cracked the conundrum of what came first: the chicken or the egg.

It had long been suspected that the egg came first but now we have the scientific proof that shows that in fact the chicken came first.

Researchers say the chicken must have come first as the formation of eggs is only possible thanks to a protein found in the chicken’s ovaries.

The protein – called ovocledidin-17 (OC-17) – acts as a catalyst to speed up the development of the shell. The protein coverts calcium carbonate into calcite crystals which makes up the egg shell, creating six grammes of shell every 24 hours. Read more here.

The Pinocchio Paradox

A paradox is something that cannot be true but also cannot be false.

For example:

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The Hardest Logic Puzzle Ever

This is an easy puzzle:

John and Bill are standing at a fork in the road. You know that one of them always tells the truth and the other one always lies, but you don’t know which. You also know that one road leads to Death, and the other leads to Freedom. By asking one yes/no question, can you determine the road to Freedom?

The answer is easy!

This is the hardest logic puzzle ever:

Three gods A, B, and C are called, in some order, True, False, and Random. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a completely random matter. Your task is to determine the identities of A, B, and C by asking three yes-no questions; each question must be put to exactly one god. The gods understand English, but will answer all questions in their own language, in which the words for yes and no are ‘da’ and ‘ja’, in some order. You do not know which word means which.

And the answer, well it’s extremely difficult to understand too!

I wanna live forever, or 1,000 years

The first person to live to be 1,000 years old is certainly alive today …whether they realize it or not, barring accidents and suicide, most people now 40 years or younger can expect to live for centuries. Wooo hooo !!! I’m 33.

A growing number of scientists, doctors, geneticists and nanotech experts—many with impeccable academic credentials—are insisting that there is no hard reason why ageing can’t be dramatically slowed or prevented altogether. Not only is it theoretically possible, they argue, but a scientifically achievable goal that can and should be reached in time to benefit those alive today. Read more here.

But what if the aliens get sick?

Our planet is chock full of bacteria. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. In total there are approximately five nonillion bacteria on Earth and the total biomass of bacteria is estimated to be equal to that of plants.

It is estimated that 500 to 100,000 different species of bacteria live in the human body and there are about ten times as many bacteria as human cells in the body. So you’ve got about 1000 trillion bacteria in and on you right now!

Humans are also a curious bunch, and one day we will probably have the technology to be able to visit other planets with living occupants. So what if when we do visit another planet we contaminate it and make all the aliens sick, or worse still, our hitchhiking microbes kill them?

Fortunately scientists have started thinking about ways to avoid this. After all humans probably have an ethical responsibility to avoid harming life in other solar systems. Read more here.