At least 125 billion galaxies fill the known universe, but most are so distant that they only appear as faint smudgy dots through our best telescopes — assuming they’re even visible at all. Only one out of every 100,000 is cataloged or given a reference number.
Nearer galaxies offer more detail. Three million large galaxies float within a billion light-years of Earth, although most of these still appear tiny and virtually featureless. But when we turn our telescopes within 100 million light-years of wherever you call home — a volume of space that contains 2,500 major galaxies and 50,000 dwarf galaxies — well, this is the realm we can seriously study. Here alone, galaxies are near enough to show stunning detail.
Sometimes we hit the jackpot and find a peculiar galaxy — astronomers love anything “peculiar” — in the very closest volume of space, within 30 million light-years. That’s the case with Centaurus A. At 12 million light-years, it competes with the equally strange M82 (number 47 on our list) as the nearest galaxy emitting oddly intense radio waves.
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Discovered by James Dunlop in 1826 from Australia, Centaurus A is one of the most peculiar galaxies in the cosmos. Despite being the fifth-brightest galaxy in the heavens, its location in far Southern Hemisphere skies hampered investigations for a long time. It simply never rises high for those in Europe and throughout most of the United States. In the late 1800s, however, it finally earned entry into the New General Catalogue as NGC 5128. But, despite its odd appearance, it never acquired a popular name like its photogenic cousins the Whirlpool (M51) and Pinwheel (M33) galaxies.