An anonymous reader writes "If you're a fan of gigantic volcanoes you'll be happy to know that the biggest volcano on Earth, and one of the biggest in the solar system, has just been discovered under the Pacific Ocean, about 1,000 miles east of Japan. From the article: 'Called Tamu Massif, the giant shield volcano had been thought to be a composite of smaller structures, but now scientists say they must rethink long-held beliefs about marine geology. "This finding goes against what we thought, because we found that it's one huge volcano," said William Sager, a geology professor at the University of Houston in Texas. Sager is lead author in a study about the find that was published this week in the peer-reviewed journal Nature Geoscience. "It is in the same league as Olympus Mons on Mars, which had been considered to be the largest volcano in the solar system," Sager told National Geographic.'"