APOD: 2022 March 15

The road to the stars is very scenic. The road leads to La Silla Observatory, which has a 3.6-meter telescope. There are some futuristic-looking support structures for the planned BlackGEM telescopes, an array of optical telescopes that will help locate optical counterparts to LIGO and other detectors. There is more. The night sky is lit up by red airglow, while the central band of the Milky Way is seen across the image center. Jupiter is visible just above the band near the image center, while Saturn is visible just above the dome. The LMC and SMC are the two largest satellites of the Milky Way. Multiple 15-second exposures were taken on June 30 to create the featured image panorama. La Silla experienced a total eclipse of the Sun.

Page 2

How far can you see? Everything you can see, and everything you could possibly see, right now, assuming your eyes could detect all types of radiations around you, is the observable universe. The farthest we can see is from the microwave background, which was 13.8 billion years ago. Humans do not yet have the technology to detect the waves that surround us. The image shows the observable universe on an increasingly compact scale, with the Earth and Sun at the center surrounded by our Solar System, nearby stars, nearby galaxies, distant galaxies, and the Cosmic Microwave Background. Our observable universe is assumed to be the nearby part of a larger entity known as the universe where the same physics applies. There are several lines of popular but speculative reasoning that claim that our universe is part of a greater multiverse where either different physical constants occur, different physical laws apply, higher dimensions operate, or slightly different-by-chance versions of our standard universe exist.