New evidence gathered on the edge of our solar system has NASA scientists completely rewriting how they believe planets are created.
Rather than material violently crashing together to eventually form new worlds, researchers believe the process is more slow and gentle, according to BBC News.
The study, which appears in the Science journal, was presented at a meeting with the American Association for the Advancement of Science in Seattle yesterday.
Lead researcher Dr Alan Stern said the discovery has helped “settle the matter” of planetary formation.
"There was the prevailing theory from the late 1960s of violent collisions and a more recent emerging theory of gentle accumulation. One is dust and the other is the only one standing. This rarely happens in planetary science, but today we have settled the matter," Mr Stern told BBC News.
It follows an extensive study of a snowman-shaped primordial cosmic body, since named Arrokoth, located more than 6 billion kilometres from the sun in a region called the Kuiper belt.
The Arrokoth, believed to date back to the formation of the solar system 4.5 billion years ago, was likely created by two separate bodies slowly merging into a larger one, scientists said.
Researchers obtained high-resolution images of the cosmic body six years after it was discovered when NASA’s New Horizons spacecraft flew near it one year ago.
An analysis by Dr Stern and his team found no evidence of a violent impact between the two objects forming the Arrokoth, with researchers failing to locate stress fractures or flattening.
"This is completely decisive," said Dr Stern. "In one fell swoop, the flyby of Arrokoth was able to decide between the two theories."
Objects from the Kuiper belt have largely stayed the same, he said.
The theory was first developed by Professor Anders Johansen as a PhD student at Sweden’s Lund University 15 years ago.
"It is a special moment … I was worried that there was an error in my code or that I had made a calculation error,” Dr Johansen said.
"And then when you see these results confirmed from actual observations it is a real relief."