Cosmic Renegades : Lurking between Mars and Jupiter, two visitors from beyond Neptune.

Two red things are hiding in a part of the solar system where they shouldn't be. Scientists led by Sunao Hasegawa from JAXA, the Japanese space agency, are reporting that two objects spotted in the asteroid belt between Mars and Jupiter appear to have originated beyond Neptune.

The findings could one day provide direct evidence of the chaos that existed in the early solar system.

Earth's stellar neighborhood is fairly stable today. But four billion years ago, chaos reigned as the orbits of Jupiter and other giant planets beyond it may have shifted. The gravitational havoc caused by this planetary dance most likely threw pieces of rock and ice all over the place.

Some of those rocks settled into the gap between Mars and Jupiter and became the asteroid belt. Most of the material is believed to be hunks of inactive rock that failed to form planets. Then there are two objects called 203 Pompeja and 269 Justitia, orbiting at about 2.7 and 2.6 times the Earth-sun distance, well within the asteroid belt.

At 70 miles across, 203 Pompeja looks to be structurally intact, whereas 269 Justitia, only 35 miles or so, seems to be a fragment of previous collision.

Both have an unusual color. Objects in the inner solar system tend to reflect more blue light because they are devoid of organic material, whereas objects in the outer solar system are redder because they have a lot of organics, perhaps the building blocks of life on Earth. [Jonathan O' Callaghan]


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