Last edited on Sept. 1, 2015
Science Magazine reports: “67P is nonmagnetized on a scale of less than a meter, with its surface layers composed of both sintered ices, which are hard in nature, and fluffy grains and pebbles of organic materials, possible remnants from the era of comet formation itself.” (quoted from the last paragraph in http://www.sciencemag.org/content/349/6247/493.short )
Added on Aug. 29, 2015: Detailed reasons for the above claim
1. Earth has no “pebbles of organic materials” that are not life or remains of life.
2. Mars was formed at the same time as Earth was formed, after our Sun had been formed.
3. Like Earth, Mars has a lot of remains of advanced life, as proven in http://wretchfossil.blogspot.tw/2014/09/most-amazing-photos-from-mars-prove-our.html?q=our+past+life+on+mars
Like Earth, Mars has no “pebbles of organic materials” that are not life or remains of life.
4. Comet 67P originated from Mars (see note 1 above), so the comet has no “pebbles of organic materials” that are not life or remains of life. That’s why the “pebbles of organic materials” are pebble-sized fossils.
5. Some people may object, as only small and simple organic molecules have been found on Comet 67P. Explanations: a. Many other research results are not yet published. b. The instruments on Rosetta and Philae spacecraft were designed to detect small organic molecules no larger than 300 daltons. c. Large fossils often break down into small fossil cells, which are rarely broken into indiscernible structure. However, solar radiation can break down the structures of proteins and large molecules within fossil cells into small organic molecules, which are smaller than 1,000 daltons. d. Even small organic molecules, simple or complex,are remains of life, not precursors to life (see http://wretchfossil.blogspot.tw/2015/07/imaginary-production-of-organic.html?q=organic+molecules+originated+from+life )