SOLOMON HUGHES recommends Sunjeev Sahota’s recent novel set in a trade union election campaign for its fresh approach to what unites and divides workers, but wishes the union backdrop was truer to life
How small is light?
Understanding how light can be fused with matter is the key to a major new technology — but researchers in Southampton have found a limit to how small you can go, write ROX MIDDLETON, LIAM SHAW and JOEL HELLEWELL
Waves of light are surprisingly big, only a very tiny bit smaller than the smallest thing we can see — a good gauge for imagining the size of light is a thread in a spider web
Morning Star international editor ROGER McKENZIE says Trump’s ceaseless belligerence is a desperate effort to prevent the emergence of a multilateral world
Don’t dismiss Lebanon as a side theatre of this war, warns SEVIM DAGDELEN — there are signs Israel has expansion in mind, and it has demonstrated its willingness to expel and kill whole populations
The media present Starmer as staying out of Trump’s war — but we’re already deeply involved in a conflict that sees the US and Israel kill civilians on a huge scale, argues IAN SINCLAIR
LINDA PENTZ GUNTER reports on this week’s conference unveiling the findings of the Gaza Tribunal established by Jeremy Corbyn
CHRISTOPHE IMMER of the Morning Star’s German sister paper Junge Welt reports on a Berlin conference on the politics of art and the legacy of Marxist critic Hans Hess
LIGHT is a wave. But what is doing the waving? The abstract idea of a disembodied wave is extremely hard to conceive of. Just as you can’t imagine a wave in the ocean without the ocean, or a wave of a hand without a hand, it’s confusing that we would ever try to imagine a light wave without thinking about what the wave is travelling through.
In order to answer “what is waving,” the physicists who invented our modern description of light constructed the idea of the electromagnetic field. The field permeates every point of space in the universe, whether there is any matter or light at that point or not. The field at any point describes the amount and direction of electrical and magnetic force that is present at that place.
The wave that is light is a pulse of energy that passes in a straight line, carried as fluctuations in the electromagnetic field. Any point on the line undergoes a very quick change back and forth in the electric and magnetic forces as the light passes through. In fact the changing back and forth of the field is itself the light moving. Just like the way that water at the surface of a lake moves up and down as a ripple passes through the surface, and the movement up and down of the water is actually the ripple itself.
Why is it helpful to think about the wave-like nature of light? There are many effects that are easier to explain once you have the idea that light acts like a wave passing through a field.
One particularly striking feature is that when you imagine the light wave that passes through the field, it necessarily means that the wave takes up a certain amount of physical space.
The light wave has a length over which the light at any time is spread. To think about the water waves again, if you are on a boat bobbing up and down as waves pass underneath the boat, then the length of the wave is the distance between the peak of the wave you have reached the top of, and the next wave that you can see coming.
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