ALMA discovers that planets are born quicker than thought
It takes nine months for a human baby to grow and 22-months for a baby elephant. But how long does it take to grow a planet? It turns out, it takes much less time than we thought.
Previously, it was believed to take tens of millions of years for a planet to form. But baby planets have just been discovered growing around a young star that is only one million years old!
The picture shows the young star surrounded by a ring of cosmic gas and dust called a ‘protoplanetary disc’. These discs are common around young stars and contain all the ingredients for making the planets and moons in a solar system.
In 2014, scientists discovered two large gaps in the disc around one young star. The dotted lines on the picture mark where the two gaps are located.
At the time no-one knew what was creating these gaps. Some people believed the most likely culprits were baby planets. As young planets grow, they collect up the cosmic gas and dust in their path and create gaps in the disc surrounding them.
However, many other people believed the star was too young to already have planets. More data was needed to solve the mystery once and for all.
So for the last two years, scientists have been taking detailed pictures of the star and disc. To many people’s surprise, they’ve found that the gaps are indeed the footprints left by baby planets!
But this exciting answer has led to another question – how did these planets form so quickly? Watch this space as we search for the answer.
The first gap is about the same distance from its star as Pluto is from the Sun. The second lies twice as far away!