What alien plants would look like

We must first understand how plants work here on Earth.

As everyone knows, plants use photons from the sun to break down water molecules, producing oxygen and energy in the form of electrons, which are then used to turn carbon dioxide into glucose.

As you can see from the diagram, the sun emits a lot of light with a wavelength that corresponds to the color green, so why not use it? And again, why not use all available electromagnetic radiation? Why are plants not black?

The answer lies in the fact that photons of different wavelengths (and therefore color) carry different amounts of energy.

To perform photosynthesis, plants need a very specific amount of energy: if they used even a few photons in the ultraviolet, they would get much more than they need, overloading and damaging the photosynthetic complex.

Conversely, even if they used many photons in the infrared, the plants would still not obtain the necessary energy and would only get overheated.

The light they use is therefore the red and blue light of the visible spectrum.

Red light does not carry much energy, although more than infrared. But because it is very abundant in the atmosphere, plants have learned to use lots of photons to achieve the energy they need.