In the 1780s, while sweeping the heavens with his state-of-the-art telescope outside London, astronomer William Herschel first noticed dark regions that appeared to be devoid of stars. One night he was heard to exclaim in his native German, "Hier ist wahrhaftig ein Lock im Himmel! [Here is truly a hole in the heavens], at the sight of a void in the Ophiuchus constellation (image below).
By the early 1900s, though, superb photographs by astronomer E. E. Barnard at the Yerkes Observatory began to prove that such shadowy regions, including the famous Horsehead Nebula and the black spots scattered along the Milky Way, were actually dark absorption clouds, too opaque for starlight to shine through.
And that's been the standard wisdom....until now. In the ESA's infrared image (above) can be seen an actual hole. It's the dark spot in the green-tinged cloud at the top of the picture. Astronomers speculate that it opened up when narrow jets of gas, emanating from some of the young stars in the region, punched through the dust and gas of the glowing nebula known as NGC 1999. The spot is not a black cloud but rather a window on distant space―a true hole in the heavens.
William Herschel had the right idea but was just looking in the wrong spot. How appropriate that the infrared telescope that made this observation is named "Herschel."
Image Credits: B. Wallis and R. Provin (top); ESA/HOPS Consortium (bottom)
No comments:
Post a Comment