SN Requiem: A Supernova Seen Three Times So Far

We've seen this same supernova three times -- when will we see it a fourth? When a distant star explodes in a supernova, we're lucky if we see it even once. In the case of AT 2016jka ("SN Requiem"), because the exploding star happened to be lined up behind the center of a galaxy cluster (MACS J0138 in this case), a comparison of Hubble Space Telescope images demonstrate that we saw it three times. These three supernova images are highlighted in circles near the bottom of the left frame taken in 2016. On the right frame, taken in 2019, the circles are empty because all three images of the single supernova had faded. Computer modeling of the cluster lens, however, indicates that a fourth image of the same supernova should eventually appear in the upper circle on the right image. But when? The best models predict this will happen in 2037, but this date is uncertain by about two years because of ambiguities in the mass distribution of the cluster lens and the brightness history of the stellar explosion. With refined predictions and vigilant monitoring, Earthlings living 16 years from now may be able to catch this fourth image -- and perhaps learn more about both galaxy clusters and supernovas at once.

from NASA https://ift.tt/3CD5CaC

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Lightning and Orion Beyond Uluru

What's happening behind Uluru? A United Nations World Heritage Site , Uluru is an extraordinary 350-meter high mountain in central Australia that rises sharply from nearly flat surroundings. Composed of sandstone , Uluru has slowly formed over the past 300 million years as softer rock eroded away. In the background of the featured image taken in mid-May, a raging thunderstorm is visible. Far behind both Uluru and the thunderstorm is a star-filled sky highlighted by the constellation of Orion. The Uluru region has been a home to humans for over 22,000 years. Local indigenous people have long noted that when the stars that compose the modern constellation of Orion first appear in the night sky, a hot season involving lightning storm s will soon be arriving. from NASA https://ift.tt/3uy2PLM

A Phoenix Aurora over Iceland

All of the other aurora watchers had gone home. By 3:30 am in Iceland , on a quiet September night, much of that night's auroras had died down. Suddenly, unexpectedly, a new burst of particles streamed down from space, lighting up the Earth's atmosphere once again. This time, surprisingly, pareidolia cally, the night lit up with an amazing shape reminiscent of a giant phoenix . With camera equipment at the ready, two quick sky images were taken, followed immediately by a third of the land. The mountain in the background is Helgafell , while the small foreground river is called Kald��, both located about 30 kilometers north of Iceland's capital Reykjav��k . Seasoned skywatchers will note that just above the mountain, toward the left, is the constellation of Orion , while the Pleiades star cluster is also visible just above the frame center. The 2016 aurora , which lasted only a minute and was soon gone forever -- would possibly be dismissed as an fanciful fable -

What's happening in the night sky? To help find out, telescopes all over the globe will be pointing into deep space. Investigations will include trying to understand the early universe , finding and tracking Earth-menacing asteroids , searching for planets that might contain extra-terrestrial life , and monitoring stars to help better understand our Sun. The featured composite includes foreground and background images taken in April from a mountaintop on La Palma island in the Canary Islands of Spain . Pictured, several telescopes from the Roque de los Muchachos Observatory are shown in front of a dark night sky. Telescopes in the foreground include, left to right, Magic 1, Galileo , Magic 2, Gran Canarian , and LST . Sky highlights in the background include the central band of our Milky Way Galaxy , the constellations of Sagittarius , Ophiuchus and Scorpius , the red-glowing Eagle and Lagoon Nebulas , and the stars Alrami and Antares . Due to observatories like this

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