Nebulae · star-forming

The Orion Nebula: where stars are born

The Orion Nebula, a green-white glow with pink clouds round it, seen from inside in Exo-View

The Orion Nebula is the nearest great nursery of stars, 1,344 light-years away, and you can see it with no telescope at all: the fuzzy middle 'star' of the three in the sword that hangs below Orion's belt. It is a cloud of gas 24 light-years across, lit from inside by four newborn stars, and Exo-View lets you fly into it.

Fly into the Orion Nebula Watch Betelgeuse explode

Distance: 1,344 light-years
Width: About 24 light-years
Kind: Emission nebula: gas glowing with the light of stars inside it
Mass: About 2,000 Suns of gas and dust
Light source: The Trapezium, four hot young stars at its heart
Seen from: The naked eye, as a hazy patch, on winter evenings in the north

How a nebula makes stars

A cloud of gas and dust, mostly hydrogen, collapses under its own weight into dense knots, and each knot grows hot enough at its centre to ignite and become a star. The four stars of the Trapezium formed in the last few million years, and their ultraviolet light makes the surrounding hydrogen glow pink. The stars are so young, and still so deep in dust, that many of the youngest were only revealed by infrared telescopes.

Planets in the making

The Hubble Space Telescope found many young stars in the nebula each wrapped in a disc of gas and dust, the same stuff our own planets formed from, some of them being slowly eroded by the glare of the Trapezium. These 'proplyds' are a view of what the Sun's own surroundings looked like some 4.6 billion years ago.

Finding it

Look for Orion's Belt, the line of three bright stars, and below it a short, fainter line of stars running down: Orion's sword. The middle 'star' of the sword looks slightly fuzzy, and binoculars show a pale cloud round it. It is best on winter evenings in the northern hemisphere, from December to February. Nearby on the sky, in the same great cloud, are the Flame and Horsehead Nebulae.

In Exo-View

The key below flies from the Sun to the nebula. Seen from here it is a smudge about two Moons wide; flown to, it fills the screen. Its drawn shape is made from photographs of the nebula, so it is an artist's impression, and the plate says so.