5 science "facts" that are completely wrong

SinceEinstein, we’ve known that nothing goes faster than the speed of light -- roughly 300,000 km every second. But this is only true in a vacuum, or near-vacuum like space. Under the right circumstances, your neighbour’s tortoise can out-pace light. It all depends on the medium.

When light shines through glass or water, it slows down by about a third. That’s still too speedy to be caught. But use still-more exotic materials and you can hobble the speed of light down to walking pace. Recently, scientists even managed to stop light completely, and then release it at a later time. Pretty much anything can move faster than light, so long as you have a world-class laboratory to clip its heels.

Sputnik 1, launched by the Soviet Union on 4 October 1957, changed the world. It circled the globe for three months, as the first human-made object to enter orbit. But it was not the first to reach space. Hundreds of earlier rockets had shot well beyond the recognised boundary, only to fall immediately back to Earth on a ballistic trajectory. These were the German V-2 missiles, which rained devastation on England, France and Belgium in the final years of the Second World War. It was not an auspicious start for the conquest of space.

Read more incredible facts:

• Everything you know about space is wrong
• Solar System facts: 5 things everyone should know about our cosmic neighbourhood
• Sugar cattle, chocolate and giant sperm: 10 extraordinary insect facts

Walk around an old building with a know-it-all friend, and they’re sure to refer you to the ancient windows. ‘See how the glass is thicker at the bottom?’, they’ll say. ‘It’s becauseglassis a liquid, not a solid. Over centuries, gravity has caused the glass to flow downwards’. Sounds convincing, right? It’s actually an urban myth.

Old glass is thicker at the bottom because it was made that way. Early glassmaking technology could only produce small panes, and these were of variable thickness and transparency. It made sense to install these imperfect panels so that the heavier edges were at the bottom. This is the reason that old windows appear thicker at the base.

We’ve all seen the illustrations. Millions of years ago, a particularly plucky fish learnt how to venture onto land for short periods. Over time, its kind spent increasingly lengthy stays ashore. Gradually, gills gave way to lungs to produce the first amphibians, and then reptiles, birds and mammals. Then us. But that venturesome fish was not a true pioneer. The land was already teeming with life, including insects, millipedes, plants and funguses. This fact often gets overlooked in a human-centric history of life.

Here’s a creepy thought. About half the cells in your body are not human. The rogue agents are bacteria, fungi and archaea. Your body is teeming with these tiny intruders. Anywhere between 500 and 1,000 species have made a home within your folds, ducts, flaps and chambers, and they’re each present in their billions. Even your human cells are not entirely your own. Many mothers retain cells from their babies in a process known as microchimerism. These cells function and divide alongside the mother’s native cells, yet remain genetically distinct.

Such remnants can be passed on to further babies, and even linger into the next generation. Cells from your grandmother might loiter in your abdomen; a tincture of your uncle may sequester in your spleen.