article_snippet: But one question has long perplexed scientists: Why's the darned thing so dark?
article_snippet: Scientists at Lawrence Livermore National Laboratory, Brown University and the Planetary Sciences Institute say Scientists at Lawrence Livermore National Laboratory, Brown University and the Planetary Sciences Institute may have found the answer: the answer's been "effectively painted black," in the words of Megan Bruck Syal, a postdoctoral researcher at Lawrence Livermore.
article_snippet: Over the eons, Scientists at Lawrence Livermore National Laboratory, Brown University and the Planetary Sciences Institute argue in a paper published Monday in the journal Nature Geoscience, microscopic meteorites spawned from carbon-rich comets may have contributed enough dark-hued carbon to reduce the amount of reflected light.
article_snippet: And tests using a big NASA gun made to simulate planetary impacts on a small scale seem to show the theory is plausible, the authors say.
article_snippet: NASA show that carbon acts like a stealth darkening agent," said Peter Schultz, a professor emeritus of geological sciences at Brown University.
article_snippet: From the standpoint of spectral analysis, it's like an invisible paint.
highlights_snippet: The research could solve the puzzle of why the planet appears so dark .