James Turrell, Gagosian, Britannia Street, London

We never tire of watching the sun set, of seeing light bleeding its last over the sky, surprising us with warm oranges, violets and mauves. The American artist James Turrell has been working for decades on his explorations of the human experience of colour and light, using both natural and scientific means of creating atmospheres, and his current exhibition, at Gagosian's Britannia Street gallery, provides several illuminating examples of the latter.

Sustaining Light (2010) looks like a tall window. In fact, it's a programming of light behind glass that gently allows colours to effloresce in soft, yet bright shades. One can sit in front of this work for hours on a small bench, in appreciation of all the many hues of colour that we have the luxury of experiencing in our little world. This might make you think of lava lamps and mind-expanding drugs, but also of faith or belief, and Turrell is concerned with all of this. He's the kind of artist who nudges the divine, but he also wants to expand our minds by allowing us to experience the natural beauty of light – the property that is most readily associated with gods and deities.

You will probably have to queue to see Dhatu (avoid Saturdays if you can), but the experience is both dazzling and calming. You will enter a smooth white space full of light and changing colour, so abundant with light and softness that you can't tell where the walls are. The space appears to change shape. The colour swamps you at some points; at others it seems like fog. It is an experience of colour as physical shape. Flickering lights create the experience of seeing that happens at the backs of the eyes, complex patterns that flare from your own wildly complex brain.

Bindu Shards (2010), which looks rather like an MRI scanner, is a hollow metal sphere which only one person can go into at a time. Unfortunately, it's booked up for the rest of the exhibition's run so I won't spend long on it here, but it involves an intense burst of the kinds of experience described above – magnified to the power of ten. Patterns like spinning chequered wheels in an intense array of colours spin and whip before your eyes, created by your brain's response to certain lights. Like drugs and dreams, it's an experience beyond the limits of language.

Even without this work, however, the exhibition maintains its power, giving you the chance to experience an intense variant of what Turrell has so eloquently described as "the wordless thought that comes from looking into a fire". At Gagosian you can also see some models and plans for the building Turrell has been constructing inside the Roden Crater in the Arizona Desert since the early 1970s, as well as some beautifully produced photographs of the site. Turrell is transforming the inner cone of the crater into a massive naked-eye observatory, designed specifically for the viewing and experiencing sky-light, solar and celestial phenomena. If he ever manages to complete it, one can only imagine the experiences of natural wonder that it will hold.

Though his artificial experiments with light are sublime, I tend to prefer Turrell's use of sun, moon and starlight, and I wonder whether he too might prefer working with these.

To 10 December (020 7841 9960)