JAXA: Discover new rocks on “Ryugu”: “Hayabusa2”
-The theory of evolution of the solar system swells delusions-
JAXA:
We found a rock with little alteration on the asteroid “Ryugu”.
This rock preserves the “early state of formation of the parent body of the asteroid Ryugu.”
“Hayabusa2”:
Analysis of images taken when the asteroid explorer “Hayabusa2” descended.
It turned out that “the rock is light enough to float on water and has a low density.”
It may also be contained in the sample collected by Hayabusa2.
This will lead to the origin of Ryugu and the development of planet formation and evolution in the solar system.
Joint research with Rikkyo University:
The results were published in the English scientific journal Nature Astronomy on May 25th.
Crater on Ryugu:
Pay attention to two craters with a diameter of 20 meters or less on Ryugu.
In the center of the crater, the daytime temperature is higher than the surroundings.
It turned out that “there is an aggregate of 10 cm black rocks”.
This place has strong heat insulation
Easy to warm up in the daytime
It has the characteristic that it easily gets cold at night.
Ryugu Rock:
Until now, the porosity of Ryugu rock was thought to be 30-40%.
However, he found that the rock he found was “a light substance with a high porosity of 70%.”
Rock discovered this time:
It is thought that “the state of the surface layer of the parent celestial body is preserved.”
It is likely that it is a substance with early information formed by the parent body of Ryugu.
New switch
Anomalously porous boulders on (162173) Ryugu as primordial materials from its parent body
Abstract
Planetesimals—the initial stage of the planetary formation process—are considered to be initially very porous aggregates of dusts1,2, and subsequent thermal and compaction processes reduce their porosity3.
The Hayabusa2 spacecraft found that
boulders on the surface of asteroid (162173) Ryugu have an average porosity of 30–50% (refs. 4,5,6), higher than meteorites but lower than cometary nuclei7, which are considered to be remnants of the original planetesimals8.
Here, using high-resolution thermal and optical imaging of Ryugu’s surface,
we discovered, on the floor of fresh small craters (<20 m in diameter), boulders with reflectance (~0.015) lower than the Ryugu average6 and porosity >70%, which is as high as in cometary bodies.
The artificial crater formed by Hayabusa2’s impact experiment9 is similar to these craters in size but does not have such high-porosity boulders.
Thus,
we argue that the observed high porosity is intrinsic and not created by subsequent impact comminution and/or cracking.We propose that these boulders are the least processed material on Ryugu and represent remnants of porous planetesimals that did not undergo a high degree of heating and compaction3.
Our multi-instrumental analysis
suggests that fragments of the highly porous boulders are mixed within the surface regolith globally, implying that they might be captured within collected samples by touch-down operations10,11.
Nature Astronomy
https://www.nature.com/articles/s41550-021-01371-7