Volcanic rocks are usually fine-grained or aphanitic to glass in texture. They often contain clasts of other rocks and phenocrysts. Phenocrysts are crystals that are larger than the matrix and are identifiable with the unaided eye.Rhomb porphyry is an example with large rhomb shaped phenocrysts embedded in a very fine grained matrix.Volcanic rocks often have a vesicular texture caused by voids left by volatiles trapped in the molten lava.henocrysts are crystals that are larger than the matrix and are identifiable with the unaided eye. Rhomb porphyry is an example with large rhomb shaped phenocrysts embedded in a very fine grained matrix. Volcanic rocks often have a vesicular texture caused by voids left by volatiles trapped in the molten lava.
The actual temperature in space is about 3Â°K (-270Â°C or three degrees Celsius above Absolute Zero). There are still molecules in space, just very few of them, and this is their temperature. Absolute zero is a theoretical temperature where the thermal kinetic energy of the molecules in a body goes to zero.
NASAâs global temperature data is measured from a 1951-1980 baseline, about 0.3 degrees warmer than pre-industrial levels. That means February 2016 was the first month in history that global average temperatures passed the 1.5 degree Celsius mark.