With the VISTA (Invisible and Infrared Survey Telescope for Astronomy) terrestrial telescope, ESO (European Southern Observatory) staff put together an impressive image with a total of 9 gigapixels showing the center of the Milky Way – and you can zoom in by clicking here, to see an incredible amount of detail, including almost 100 million stars.
The image was released in 2012, but recently the astrophysicist Ethan Siegel, from the blog Starts With A Bang, analyzed it with a clinical eye and brought some interesting insights and explanations about the galactic center that we see in the ESO disclosure. First, it evaluates the general image, without zooming, and details some things that you can already see at first sight.
In the image above, we see the central part of the Milky Way in infrared, with some markings showing where are some nebulae and clusters around it. We see exactly where the Lagoon Nebula (Messier 8), the Trifid Nebula (Messier 20), the War and Peace Nebula (NGC 6357) and the Cat’s Paw Nebula (NGC 6334), for example, are visible even in low resolution. The other points, on the other hand, require the zoom in the image to be identified.
Images like this are only possible thanks to observatories capable of seeing the infrared region of the electromagnetic spectrum, as they can see what is behind clouds of gas and dust that prevent direct visualization through the visible spectrum.
In this other image (above), we see details of the Lagoon Nebula, after zooming in on the ESO assembly. It focuses on the upper right corner of the photo. The region is a nursery of stars and, in the infrared, it appears quite different from how we are used to seeing it in photos of visible light (below), in which it appears in red and intense tones.
The Trifid Nebula combines beautiful shades of blue and red when seen by visible light, as you can see below.
However, in the infrared image, it appears blue and more dusty on the side where its stars are born. On the left side of the image, we see very bright stars, which can be giants or red supergiants.
And, by focusing on the exact center of the galaxy, we see millions of stars that are completely invisible in the visible light observations, being possible to see them only with instruments that “read” the infrared.
However, not even infrared light can penetrate places where the dust is extremely dense and thick, and much of what’s inside remains a mystery. One more zoom in the innermost part of the center of the galaxy shows dust streaks that continue to hide what is there behind, as you can see in the image below.