The most ancient spiral galaxy yet | | Swirly and beautiful, spiral galaxies are what we often think of when someone mentions the word galaxy. Our own Milky Way is a spiral galaxy. These galaxies are pretty common in the nearby universe. But the farther back in time and distance astronomers look, the fewer spiral galaxies they see. Instead, as we peer out into space - and back in time - galaxies appear more irregular in shape. And thus how and when spiral galaxies formed is one of astronomy's classic questions. So it was with some excitement that astronomers reported the most ancient spiral galaxy yet found. Read more and watch a movie on how spiral galaxies form. | | |
How old is the Earth? | | Humans have likely pondered the question of the age of the Earth since we first developed a sense of time. The best scientific research to date suggests that our planet formed about 4.54 billion years ago. Researchers studied the most ancient rock samples, not just from Earth but also from the moon, as well as meteorites formed in the early solar system. All that data, taken together, is how they determined Earth's age. Read more. | | |
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