#Five things we would need for people to go to Mars

Are there really more stars in our universe than there are grains of sand on all the beaches on Earth?

Do trees communicate with each other? And if so, how?

When you turn on a torch, does the light instantly reach the speed of light? Or does it accelerate up to that speed very quickly?

How do antibiotics work, and how do bacteria develop resistance?

Why do some creatures lose their sight? And how does this fit with Darwin's theory of natural selection?

How do you know when a tsunami occurs? How does the warning system work? When is a warning issued?

What causes a tsunami? Do all underwater earthquakes cause tsunamis? And what was the biggest tsunami ever?

Australia is blessed with many beautiful examples of Aboriginal cave paintings and engravings but what does science tell us about how old they are?

There's been a lot in the news lately about diseases such as MERS, Ebola, anthrax and the bubonic plague. How often do diseases jump from animals to humans, and why do they seem so deadly?