侧视星系NGC 5866

侧视星系NGC 5866

2020年11月15日 Edge-On Galaxy NGC 5866 Image Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA); Acknowledgment: W. Keel (U. Alabama) Explanation: Why is this galaxy so thin? Many disk galaxies are just as thin as NGC 5866, pictured here, but are not seen edge-on from our vantage point. One galaxy that is situated edge-on is our own Milky Way Galaxy. Classified as a lenticular galaxy, NGC 5866 has numerous and complex dust lanes appearing dark and red, while many of the bright stars in the disk give it a more blue underlying hue. The blue disk of young stars can be seen extending past the dust in the extremely thin galactic plane, while the bulge in the disk center appears tinged more orange from the…

超快速自旋的旋涡星系

超快速自旋的旋涡星系

2019 November 5 Spiral Galaxies Spinning Super-Fast Image Credit: Top row: NASA, ESA, Hubble, P. Ogle & J. DePasquale (STScI); Bottom row: SDSS, P. Ogle & J. DePasquale (STScI) Explanation: Why are these galaxies spinning so fast? If you estimated each spiral’s mass by how much light it emits, their fast rotations should break them apart. The leading hypothesis as to why these galaxies don’t break apart is dark matter — mass so dark we can’t see it. But these galaxies are even out-spinning this break-up limit — they are the fastest rotating disk galaxies known. It is therefore further hypothesized that their dark matter halos are so massive — and their spins so fast — that it is harder for them to form stars…