Researchers have found out that giant planets grew from pebbles in space. This could also be the case of giants like Saturn or Jupiter.
It is suspected that even the biggest planets have grown from tiny round space rocks. The rocks are believed to have been about a foot round when they first appeared.
Scientists have always manifested interest in the history of huge planets like Jupiter or Saturn, because their growth represents a mystery, taking into account the fact that the planetary models we have today don’t include the time it takes for giant planets to form.
Researchers have analysed younger star systems and they got to the conclusion that the gas discs forming around planets and helping their growth only exist for about one to ten million years.
While Earth is estimated to have needed around approximately 30 million years to 100 million years to form, bigger planets like Jupiter and Saturn need even more time.
The core accretion model is a theory that tries to explain how massive planets were able to form and become what they are right now. According to this theory, planets start as a core of ice and rock that forms first. After that, the interstellar dust and gas from the planet’s disk gets attached to it and helps the planet grow.
In order for discs of space dust to form around it, the core would have to be at least ten times bigger than Earth. Because the core is considered to be the size of a planet, researchers were not able to explain how this core would be able to form in only a few million years.
The formation of the core was explained by the accretion process. This means that rocks attract and assimilate other rocks and they get bigger. Still this theory seems irrelevant when explaining the formation of giant planets as they would need larger cores that couldn’t form through accretion.
Recent research has led to better answers and scientists were eventually able to find the explanation for the formation of giant planets. They concluded that the planets were able to grow so fast, taking them just ten million years to look like they do today, because they accumulated round planetary pebbles that were about one foot in diameter. The pebbles spiral onto the planet’s core with a bit of help from the gas that was proven to boost the efficiency of accretion.
Photo credits: Jpl.nasa.gov
