The Eagle Nebula, seen in the infrared

Almost everyone has seen the Pillars of Creation: three towering columns of
dust and gas, photographed by Hubble in 1995 and again by the James Webb Space
Telescope, and reproduced ever since on posters and book covers. What almost
nobody has seen is the thing the pillars are part of.

A famous detail of a much larger object

The pillars sit inside the Eagle Nebula, a star-forming region about
5,700 light years from Earth. In visible light the pillars dominate, because
visible light does not travel through dust — you see the silhouettes of the
densest columns against the bright gas behind them, and the rest of the nebula
is simply dark.

Infrared changes the picture. NASA's Wide Field Infrared Survey Explorer
(WISE) observes at wavelengths longer than the eye can detect, and those
wavelengths pass through dust that stops visible light entirely. In the WISE
view the pillars are still there — a faint yellow-green structure near the
centre — but they are no longer the subject. They are a small feature inside a
much larger, much more complicated cloud.

What the infrared actually shows

Different wavelengths pick out different things, which is why an infrared
image of a nebula is not simply a clearer version of the visible one:

• Warm dust glows in the infrared, so the clouds that block visible light
  become the brightest thing in the frame.
• Young stars still inside their cocoons show up. They are invisible in
  visible light, because the dust they formed from surrounds them.
• The shape of the whole region becomes legible — the cavities carved out
  by massive stars, the shells where their radiation has pushed the gas back.

Why the pillars have that shape

The shape is not accidental, and it is not permanent. Massive young stars
nearby pour out ultraviolet radiation and stellar wind, and that erodes the
surrounding gas cloud from outside in. Where a pocket of gas is dense enough
to resist, the material behind it is shielded — and a column is left standing,
pointing back at the stars doing the eroding.

They are, in other words, the astronomical equivalent of the rock spires left
in a desert after softer stone has weathered away. And like those spires, they
are temporary: the erosion continues, and the pillars are being worn back even
as we photograph them.

The image

This view comes from WISE, which surveyed the entire sky in four infrared
bands. Its strength is not resolution — Hubble and Webb both see finer detail —
but coverage: it can show an object of this size in one frame, in a band of
light where the dust is transparent.