astronomnomy

Binary Words: Halo

We have halos in astronomy, though they’re not golden disks hovering above the righteous! Instead of light, they’re made of dark matter, which cannot be directly seen. In addition they’re not very ringed-shaped, more large, blobby masses surrounding galaxies. It is supposed that when the dark matter formed in at the beginning of the Universe, the self-gravitation of the dark matter caused it to start to clump together. These clumps and filaments of dark matter, like in the image, became the backbone of the Universe that all gas and dust fell onto, which then went on to form stars and galaxies.

A dark matter halo is far bigger than the galaxy it may host, and much rounder. Why so? Well, gas and dust particles can collide and so slow down. They can fall into a gravitational well to create a small, compact galaxy. Dark matter is thought to only interact gravitationally so it cannot collide with other dark matter particles, cannot slow down and fall in the way normal matter does so the halos stay larger for much longer.

Halos are used to explain why we see stars on the edge of galaxies moving so quickly they should be flung off into deep space, yet remain gravitationally tethered to the galaxy. If the galaxy has a lot more invisible matter inside and surrounding it, contributing to the gravitational pull of the galaxy, it could hold on to the stars. Dark matter halos fit the bill. 

All this means that there is more to a galaxy than meets the eye, quite literally!

(image credit: Virgo Consortium, the Millennium Run is one of the most well-used simulations of dark matter. Fly through here to see halos!)

astronemma:

ESO’s Very Large Telescope Celebrates 15 Years of Success

With this new view of a spectacular stellar nursery ESO is celebrating 15 years of the Very Large Telescope — the world’s most advanced optical instrument. This picture reveals thick clumps of dust silhouetted against the pink glowing gas cloud known to astronomers as IC 2944. These opaque blobs resemble drops of ink floating in a strawberry cocktail, their whimsical shapes sculpted by powerful radiation coming from the nearby brilliant young stars.

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I have no need of your sass right now Google you impudent little shite. 

distant-traveller:

NYC as seen from different planets

Take a trip around the solar system and bring the entire city of New York with you in these captivating drawings showing how the atmospheres of other planets would interact with the iconic metropolitan skyline.

The images were created by artist Nickolay Lamm of StorageFront.com, who employed the help of astrobiologist Marilyn Browning Vogel to get the details right. Lamm said the idea came to him while looking at pictures that NASA’s Curiosity rover took of Mount Sharp.

Image credit: Nickolay Lamm