## Orbits

Going back to my comments on the Karman line (100 km about the earth’s surface), I think it’s worth commenting a bit ‘being in orbit’ means. We are familiar with the fact that if we drop something it accelerates downwards and hits the ground. If we throw something away from us, it will still accelerate […]

## The final frontier

New Zealand is, hopefully, just a few days away from becoming a space-nation. The private company Rocket Lab  (what a great name – I like names that describe what a business actually does) aims to put up its Atea-1 rocket from Great Mercury Island sometime around November 30th. The payload will reach an altitude of […]

## Random use of the word ‘exponential’

One of the things I find mildly amusing is the way that physics and maths words get taken up into everyday vocabulary, where they take on a slightly different meaning from the original. The word ‘random’ seems to be a favourite in NZ at present, as in "I bumped into this random guy and he […]

## Anti-gravity

There are some lovely physics demonstrations that get repeatedly wheeled-out for things like Open Day and visits from school groups. Things like holding a spinning bike wheel on a rotating chair (flip it over and you start rotating – conservation of angular momentum) and levitating a piece of superconductor above a magnet at liquid nitrogen […]

## Monopoles, Dipoles, Quadrupoles and the like

The alternate stretching and squashing casued by a gravitational wave is an example of a quadrupole oscillation. This is another word that probably means very little to most readers, and, unless you like maths, Wikipedia isn’t going to help you, so I’ll explain.  Let’s start with a monopole. You get a monopole when you put ‘stuff’ […]

## Gravitational Waves

One of my undergraduate students has been researching gravitational waves this year. Last Friday, he gave a nice presentation on the subject. Gravitational waves are one of the many examples of waves in physics. We are perhaps more used to waves on the surface of water, or waves along a guitar string, or electromagnetic waves […]

## Approximately speaking

Physicists are notorious for making approximations.  This character trait is the subject of many jokes – for example, one rather rambling one involving a physicist advising a punter on which horse to put his money ends with the line "Oh, didn’t I tell you – my calculations assumed a spherical horse rolling through a vacuum." […]

## Fishics

Eco-systems are of course very complex things – the success of one species is linked to the success of another, which is linked to another, and all of which are linked to outside factors such as climate etc etc.  Now there is direct evidence of another degree of complexity in the ocean eco-system, namely that […]