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Monte Fitz Roy, Argentina | Photographer: Vicki Mar

Blue Pool Bay, Gower  |  by Liam Tandy

Interacting galaxy

Interacting galaxies (colliding galaxies) are galaxies whose gravitational fields result in a disturbance of one another. An example of a minor interaction is a satellite galaxy’s disturbing the primary galaxy’s spiral arms. An example of a major interaction is a galactic collision, which may lead to a galaxy merger.

A giant galaxy interacting with its satellites is common. A satellite’s gravity could attract one of the primary’s spiral arms, or the secondary satellite’s path could coincide with the position of the primary satellite’s and so would dive into the primary galaxy (the Sagittarius Dwarf Elliptical Galaxy into the Milky Way being an example of the latter). That can possibly trigger a small amount of star formation. Such orphaned clusters of stars were sometimes referred to as “blue blobs” before they were recognized as stars.

Colliding galaxies are common during galaxy evolution. The extremely tenuous distribution of matter in galaxies means these are not collisions in the traditional sense of the word, but rather gravitational interactions.

Colliding may lead to merging if two galaxies collide and do not have enough momentum to continue traveling after the collision. In that case, they fall back into each other and eventually merge into one galaxy after many passes through each other. If one of the colliding galaxies is much larger than the other, it will remain largely intact after the merger. The larger galaxy will look much the same, while the smaller galaxy will be stripped apart and become part of the larger galaxy. When galaxies pass through each other, unlike during mergers, they largely retain their material and shape after the pass.

Galactic collisions are now frequently simulated on computers, which use realistic physics principles, including the simulation of gravitational forces, gas dissipation phenomena, star formation, and feedback. Dynamical friction slows the relative motion galaxy pairs, which may possibly merge at some point, according to the initial relative energy of the orbits.

Astronomers have estimated the Milky Way galaxy, will collide with the Andromeda galaxy in about 4.5 billion years. It is thought that the two spiral galaxies will eventually merge to become an elliptical galaxy or perhaps a large disk galaxy.

Source

Image credit: NASA/ESA & Hubble (procesed by:  Steve Byrne & Judy Schmidt)

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20 Gorgeous Hubble Photos That Showcase The Universe’s Beauty

“Galaxy clusters: The most massive bound structures in the Universe, these contain anywhere from a handful up to thousands of Milky Way-sized galaxies. From incredibly deep views in space to bent light by their gravity, to individual galaxies speeding through them, Hubble offers views like no other.”

It might be Christmas day here on Earth, but thanks to the Hubble Space Telescope, these views of the distant Universe are ours to treasure for all-time. The individual stars in our sky all have a glorious origin story, and will all someday die in their own spectacular fashion. These stars are formed in the most incredible nebulae, where gas races to collapse while the surrounding environs work to evaporate it away. All of this takes place inside individual galaxies, which themselves can clump and cluster together in the most massive structures the Universe has ever seen. Because of Hubble, we get to view them all.

Come explore these 20 gorgeous photos, courtesy of Hubble, that show us the Universe as we’ve never seen it before!

Rho Ophiuchi Cloud Complex Found here

forces of nature … | uwhe-arts

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