Big stuff seen in space

…yeah, I know, right up there with ‘Pope seen in Vatican’, but bear with me…

Two interesting tweets came my way today (well more, but two with relevance to this post). The second linked to a blog post talking about the largest observed stars. I won’t reveal which stellar body has the largest paunch, but it extends 2,200 times or so the radius of the Sun, out to the orbits of Jupiter and Saturn. This isn’t a measure of the heaviest stars, simply those that extend out a bit more than others. The post is here.

The first was something even bigger – the highest mass galaxy ever recorded. ESO 146-IG 005 lies in the Abell 3827 cluster some 1.4 billion light years away. Measurements of x-rays emitted by matter in the jets and accretion discs of the supermassive black hole candidate inside the galaxy suggested something a massive 3 trillion solar masses in size. Then the Gemini South Telescope turned its eye onto the monster and saw something quite amazing. The galaxy has multiple remnant cores of galaxies it has been sweeping up in space and it also is surrounded by more galactic snacks within easy reach, the monster grows. As well as this, within the data gathered by the telescope lay the images of galaxies behind the main target. Due to a process called gravitational lensing, which was first described by Albert Einstein in the General Theory of Relativity and shown to be in operation by Arthur Eddington, measuring the displacement of the apparent positions of bright stars in the Hyades cluster close to the Sun during the 1919 eclipse, light from the more distant galaxies was warped and bent around the massive galaxy like light through a concave lens. The amount that the galaxies were bent (one of which is 2.7 billion light years away, the other 5.1 billion) is directly related to the mass of the galaxy and so a way of measuring how much mass there is in the body. The result was an immense 30 trillion solar masses worth of material, by far the largest known single galaxy. Full story here.


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