Hyperion: Largest Known Galaxy Proto-Supercluster
Visualization Credit: ESO, L. Calçada & Olga Cucciati et al.

Explanation: How did galaxies form in the early universe? To help find out, astronomers surveyed a patch of dark night sky with the Very Large Telescope array in Chile to find and count galaxies that formed when our universe was very young. Analysis of the distribution of some distant galaxies (redshifts near 2.5) found an enormous conglomeration of galaxies that spanned 300 million light years and contained about 5,000 times the mass of our Milky Way Galaxy. Dubbed Hyperion, it is currently the largest and most massive proto-supercluster yet discovered in the early universe. A proto-supercluster is a group of young galaxies that is gravitationally collapsing to create a supercluster, which itself a group of several galaxy clusters, which itself is a group of hundreds of galaxies, which itself is a group of billions of stars. In the featured visualization, massive galaxies are depicted in white, while regions containing a large amount of smaller galaxies are shaded blue. Identifying and understanding such large groups of early galaxies contributes to humanity’s understanding of the composition and evolution of the universe as a whole.

Tomorrow’s picture: floating light pillars

Apollo 12 Visits Surveyor 3
Image Credit: Apollo 12 Crew, NASA

Explanation: Apollo 12 was the second mission to land humans on the Moon. The landing site was picked to be near the location of Surveyor 3, a robot spacecraft that had landed on the Moon three years earlier. In the featured photograph, taken by lunar module pilot Alan Bean, mission commander Pete Conrad jiggles the Surveyor spacecraft to see how firmly it is situated. The lunar module is visible in the distance. Apollo 12 brought back many photographs and moon rocks. Among the milestones achieved by Apollo 12 was the deployment of the Apollo Lunar Surface Experiments Package, which carried out many experiments including one that measured the solar wind.

Tomorrow’s picture: super cluster

Meteor, Comet, and Seagull (Nebula)
Image Credit & Copyright: Takao Sambommatsu

Explanation: A meteor, a comet, and a photogenic nebula have all been captured in this single image. The closest and most fleeting is the streaking meteor on the upper right — it was visible for less than a second. The meteor, which disintegrated in Earth’s atmosphere, was likely a small bit of debris from the nucleus of Comet 21P/Giacobini-Zinner, coincidentally the comet captured in the same image. Comet 21P, pictured across the inner Solar System from Earth, is distinctive for its long dust tail spread horizontally across the image center. This comet has been visible with binoculars for the past few months but is now fading as it heads back out to the orbit of Jupiter. Farthest out at 3,500 light years distant is the IC 2177, the Seagull Nebula, visible on the left. The comparatively vast Seagull Nebula, with a wingspan on order 250 light-years, will likely remain visible for hundreds of thousands of years. Long exposures, taken about two weeks ago from Iwaki-City in Japan, were combined to capture the image’s faintest elements. You, too, could see a meteor like this — and perhaps sooner than you might think: tonight is the peak of the Orionids meteor shower.

Tomorrow’s picture: lunar shake down