Astronomers using the NASA/ESA Hubble Space Telescope have produced a spectacularly detailed image of a pair of overlapping galaxies called NGC 4496.
NGC 4496 was discovered on February 23, 1784, by the German-born British astronomer William Herschel.
Otherwise known as NGC 4505, it consists of the barred spiral galaxy NGC 4496A and the spiral galaxy NGC 4496B.
Both galaxies lie in the constellation of Virgo, but despite appearing side-by-side in the new Hubble image they are at vastly different distances from both Earth and one another.
NGC 4496A is 47 million light-years from Earth while NGC 4496B is 212 million light-years away.
“The enormous distances between the two galaxies mean that the two cannot interact, and they only appear to overlap owing to a chance alignment,” Hubble astronomers said.
“Chance galactic alignments such as this provide us with the opportunity to delve into the distribution of dust in these galaxies.”
“Galactic dust adds to the beauty of astronomical images — it can be seen in this image as the dark tendrils threading through both NGC 4496A and NGC 4496B — but it also complicates astronomers’ observations.”
“Dust absorbs starlight, making stars seem dimmer and shifting their light towards longer wavelengths, a process that astronomers refer to as reddening.”
“By carefully measuring how starlight from background galaxies is affected by dust in intervening galaxies, we can map out where the dust is in the foreground galaxy’s spiral arms,” they added.
“The resulting dust maps help us calibrate measurements of everything from cosmological distances to the types of stars populating galaxies.”
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