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The Shape of the Milky Way Is Warped and Twisted (abc.net.au)
Necroloth writes: You probably thought that if you were looking at our galaxy from the outside and at a distance, you would see a thin disc of stars that orbit around a central region, but the further away from the inner regions of the Milky Way you are, the less the pull of gravity. At the outer disc, the hydrogen atoms that make up the Milky Way's gas disc are, as a consequence, warped into an S-like shape, no longer pulled together in a thin plane. A group of astronomers from Australia and China have built their "intuitive and accurate three-dimensional picture" by mapping 1339 classical Cepheids. There's a quick animation of the galaxy on the @NatureAstronomy twitter here. The study has been published in the journal Nature Astronomy.
On a planet with an ocean, you have an environment free from ionizing radiation: under water. On Earth, Life doesn't seem to have moved on land until enough free oxygen was in the atmosphere to create an ozone layer about 400 mio years ago. There has been another period on Earth with at least 10% of oxygen in the atmosphere about 2.1 billion years ago, causing iron in the Earth's crust to oxide and create large layers of reddish stone. It could have give rise to a first development of multicellular life, albeit the nature of the fossils is still in dispute.