How Mars and Jupiter Formed from Space Rock Crashes
The violent space rock collisions that gave birth to Mars appear to be surprisingly different from those thought to form the rocky core of Jupiter, scientists say.
The difference comes from variations in the disc of dust, ice and other particles that swirled around the sun in the early years of the solar system.
Researchers said there was a “gradient” in the size of planetesimals — an early stage of planet formation — that orbited the young sun. Planets that were further away from the sun were more likely to grow larger than worlds closer in, they added.
"This difference can be explained by the snow line,” said Hiroshi Kobayashi, a researcher at Nagoya University in Japan, referring to the zone in the solar system where it was cold enough for icy compounds to condense 4.5 billion years ago.
"If we consider terrestrial planets, this is close to the sun, this means the temperature was very high, and the main component of the solid was rock, or something like that," Kobayashi added. "But if we consider the outer disc — in this case, the main component is ice — it probably was ice planetesimals [that formed Jupiter]."
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