Garden-variety stars like the Sun live fairly placid lives in their galactic neighborhoods, casually churning out heat and light for billions of years. When these stars reach retirement age, however, they transform into unique and often psychedelic works of art. This Hubble Space Telescope image of the Saturn Nebula shows the result, called a planetary nebula. While it looks like a piece of wrapped cosmic candy, what we see is actually the outer layers of a dying star.
Stars are powered by nuclear fusion, but each one comes with a limited supply of fuel. When a medium-mass star exhausts its nuclear fuel, it will swell up and shrug off its outer layers until only a small, hot core remains. The leftover core, called a white dwarf, is a lot like a hot coal that glows after a barbecue — eventually it will fade out. Until then, the gaseous debris fluoresces as it expands out into the cosmos, possibly destined to be recycled into later generations of stars and planets.
Using Hubble’s observations, scientists have characterized the nebula’s composition, structure, temperature and the way it interacts with surrounding material. Studying planetary nebulas is particularly interesting since our Sun will experience a similar fate around five billion years down the road.
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Journey ahead
Methane ice dunes found on Pluto
The findings come after images from NASA’s New Horizon mission have been analysed from travelling the system for nearly a decade. As well as having a diameter of only 2,377km and surface temperatures of -230C; Pluto’s atmosphere was thought to be too thin for the formation of features similar to those found in deserts on earth. The dunes formed next to a major mountain range of water ice 5km high where wind is generated as air flows downhill. It can get as high as 10m/s which is enough to carry the tiny particles. Scientists can’t see everything from the images but they were able to discern the dunes are 0.4-1km apart and the methane crystals 200-300 micrometers in diameter (roughly a grain of sand).
The grains of methane (and maybe nitrogen) are thought to be produced through a process known as sublimation. This is where a solid transitions directly to a gas skipping the liquid phase. This essentially transports it into the atmosphere where the tiny crystals form then the Pluto’s winds move them around the dwarf planet.
Alex Schomburg cover art for Science-Fiction Plus, April 1953.
animation test part 2, now with actual hair movement lol
//the universe is with you\
credit: https://giphy.com/gifs/QrobePGCYqNcA
Practicing hair on my favorite space queen 👑