NARRATOR Is there, somewhere out there, a star like our sun, orbited by habitable planets that are teeming with life? There are billions of stars just like our sun within our galaxy. And the odds suggest that tens of billions of planets are orbiting around them. If there is life out there, can we find it?

Astronomer Mario Livio, is at the forefront of the search. He's using the Hubble space telescope to look deep into space, to where new stars, like our sun, are bursting into life.

This is the Orion nebula, as seen by Hubble.

Here, 1,500 light years beyond our solar system, new stars are being born inside a vast cloud of dust and gas.

MARIO LIVIO (ASTROPHYSICIST, SPACE TELESCOPE SCIENCE INSTITUTE) So when we look at the nebula now, it's almost like looking into a cave. We see this hollow part, where gas and dust has been blown away, and inside, where these stars are being born.

NARRATOR And right inside, among all the shining stars, is what looks like a small dark smudge.

In fact, it is a young sun surrounded by a dense disk of dust and gas, more than 50 billion miles across. This smudge represents the dawn of a new solar system.

MARIO LIVIO In this case, we see the disk edge-on, and, therefore, the disk completely obscures the light from the star. This is why you don't see the star.

NARRATOR Other images show similar disks, tilted to reveal the star at the center.

These spinning clouds of matter may, one day, form planets and moons, as particles of dust, ice and gas collide and clump together. This is the same process that is thought to have created the planets of our solar system.

Hubble has revealed that swirling disks like this are extremely common.

MARIO LIVIO The fact that we see these very often tells us that these raw materials from which planets form are very, very common, and, so, that planetary systems form, probably, around most stars.

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