In February, the European Southern Observatory released this absolutely stunning 187-megapixel image of the entire Milky Way as seen from the Southern Hemisphere. It's one of the most beautiful, intricately detailed images of the sky I've seen. It's something to marvel at on this Astronomy Day, a biannual celebration of the cosmos taking place May 14.
The image marked the completion of the APEX Telescope Large Area Survey of the Galaxy (or ATLASGAL), which has been mapping the coldest regions of the universe for the past several years.
The survey uses a special telescope, APEX, which has a photosensor chilled to near absolute zero. The extreme cold allows the telescope to be sensitive to the slightest changes in temperature caused by incoming cosmic radiation.
Conventional telescopes can only observe very hot, bright things like stars. But APEX is sensitive to the much dimmer light in the submillimeter range (between infrared radiation and radio waves). This allows APEX to see the dark, cold clouds of cosmic dust where stars are born.
Marvel at them in the full image above.