Scientists using a telescope based in Chile have taken a picture which gives us greater insight than ever before into how planets are formed.
The Atacama Large Millimeter/submillimeter Array, or ALMA, has captured an amazing image from its position in the Chilean desert. A young star known as HL Tauri can be seen surrounded by a disk of dust 4 times the size of Neptune’s orbit, with a diameter of 22 billion miles. The star is part of the constellation of Taurus, around 450 light-years from Earth.
The formation of planets
Scientists believe that they have captured this stardust in the process of turning into planets, a conclusion they reached after observing that the disk contained dark rings like those of Saturn. Catherine Vlahakis, an astronomer at ALMA, explained that the dark rings are formed as dust accumulates into planets around the star, leaving clear and dark rings as they clean up the dust in their path.
The process of forming stars and planets is an incredibly long one, which begins in galactic nurseries such as the Orion nebula. Primordial elements, remnants of the Big Bang, mix with material left over from stars that have died and exploded, forming clouds which later collapse under their own weight due to explosions, radiation and winds.
The next stage is the formation of clumps of gas and dust which are a breeding ground for new stars and planets. For a solar system a similar size as ours to form, the process can take around a million years, with the system collapsing in on itself to form protostars surrounded by spinning layers of protoplanetary dust.
A delicate balancing act
Many such systems form, but they need to be of a certain size for gravity to be strong enough to compress material sufficiently to cause the ignition of thermonuclear reactions, which signals the birth of a star. For planets to form, these reactions need to burn off the cocoon of material around the star faster than radiation from other nearby stars, otherwise this radiation will also destroy the stardust disk around the new star.
HL Tauri is special because scientists did not expect such a young star to have planets large enough to carve out the aforementioned grooves. It seems that planets might form faster than scientists previously thought.
With this process happening billions of times throughout the Milky Way, what are the chances that Life could have formed on another planet as well as on Earth?