Physics

How Strong Is The Force Of Gravity On Earth?

Gravity is a pretty awesome fundamental force. If it wasn’t for the Earth’s comfortable 1 g, which causes objects to fall towards the Earth at a speed of 9.8 m/s², we’d all float off into space. And without it, all us terrestrial species would slowly wither and die as our muscles degenerated, our bones became brittle and weak, and our organs ceased to function properly.

What Is A Magnetic Field?

What Is A Magnetic Field?

Everyone knows just how fun magnets can be. As a child, who among us didn’t love to see if we could make our silverware stick together? And how about those little magnetic rocks that we could arrange to form just about any shape because they stuck together? Well, magnetism is not just an endless source of fun or good for scientific experiments; it’s also one of basic physical laws upon which the universe is based.

What exactly does ‘instantaneous’ mean?

What exactly does ‘instantaneous’ mean?

How short is an “instant”? Is it a second? A tenth of a second? A microsecond? You might think all of these qualify. What about 100 years? That certainly doesn’t seem like an instant, and to a human being, it isn’t, since we’d be lucky to have a lifespan that long. But to a giant sequoia, say, 100 years is no big deal. And in geological terms it’s practically nothing.

The maths behind ‘impossible’ never-repeating patterns

The maths behind ‘impossible’ never-repeating patterns

Remember the graph paper you used at school, the kind that’s covered with tiny squares? It’s the perfect illustration of what mathematicians call a “periodic tiling of space”, with shapes covering an entire area with no overlap or gap. If we moved the whole pattern by the length of a tile (translated it) or rotated it by 90 degrees, we will get the same pattern. That’s because in this case, the whole tiling has the same symmetry as a single tile. But imagine tiling a bathroom with pentagons instead of squares – it’s impossible, because the pentagons won’t fit together without leaving gaps or overlapping one another.

Graphene isn’t the only Lego in the materials-science toy box

Graphene isn’t the only Lego in the materials-science toy box

You may have heard of graphene, a sheet of pure carbon, one atom thick, that’s all the rage in materials-science circles, and getting plenty of media hype as well. Reports have trumpeted graphene as an ultra-thin, super-strong, super-conductive, super-flexible material. You could be excused for thinking it might even save all of humanity from certain doom.

Why lightsabers would be far more lethal than George Lucas envisioned

Why lightsabers would be far more lethal than George Lucas envisioned

Research is an unpredictable process. Sometimes you end up making a really cool discovery that you didn’t see coming. I recently uncovered a fundamental property of lightsabers (that’s right – the awesome weapons from Star Wars) while doing my regular plasma physics research. I found that, while it is in theory possible to build a lightsaber, it’s likely it would be the most dangerous weapon ever created – both for the perpetrator and the victim.

What is time – and why does it move forward?

Imagine time running backwards. People would grow younger instead of older and, after a long life of gradual rejuvenation – unlearning everything they know – they would end as a twinkle in their parents' eyes. That’s time as represented in a novel by science fiction writer Philip K Dick but, surprisingly, time’s direction is also an issue that cosmologists are grappling with.

Corals, crochet and the cosmos: how hyperbolic geometry pervades the universe

Corals, crochet and the cosmos: how hyperbolic geometry pervades the universe

We have built a world of largely straight lines – the houses we live in, the skyscrapers we work in and the streets we drive on our daily commutes. Yet outside our boxes, nature teams with frilly, crenellated forms, from the fluted surfaces of lettuces and fungi to the frilled skirts of sea slugs and the gorgeous undulations of corals.