For most terrestrial life on Earth, oxygen is necessary for survival. But the planet's atmosphere did not always contain this life-sustaining substance, and one of science's greatest mysteries is how and when oxygenic photosynthesis—the process responsible for producing oxygen on Earth through the splitting of water molecules—first began. Now, a team led by geobiologists at the California Institute of Technology (Caltech) has found evidence of a precursor photosystem involving manganese that predates cyanobacteria, the first group of organisms to release oxygen into the environment via photosynthesis.
Continue reading ""Great Oxidation Event" --A New Discovery of Evolutionary Singularity that Transformed the Planet" »
A galaxy already known to have one enormous black hole at its core is actually home to two of these scary giants. Astronomers discovered the second monster black hole at the center of the galaxy Markarian 739, which is about 425 million light-years from Earth in observations by NASA's Swift satellite and the Chandra X-Ray Observatory.
The two black holes are separated by about 11,000 light years, which is about one-third the distance between our solar system and the center of the Milky Way. One light-year is about 6 trillion miles.
Continue reading "Image of the Day: Twin Gigantic Black Holes Found at Galaxy Center" »