Happy Fun Fact Friday!

4/2/25: We'll be closed tonight due to clouds and rain. We'll try again next week.

The Dragon's Egg Nebula, NGC 6164 // Daniel Stern

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)

Animation

2023 October 18

Dust and the Western Veil Nebula Image Credit & Copyright: Jiang Wu

Explanation: It’s so big it is easy to miss. The entire Veil Nebula spans six times the diameter of the full moon, but is so dim you need binoculars to see it. The nebula was created about 15,000 years ago when a star in the constellation of the Swan (Cygnus) exploded. The spectacular explosion would have appeared brighter than even Venus for a week - but there is no known record of it. Pictured is the western edge of the still-expanding gas cloud. Notable gas filaments include the Witch’s Broom Nebula on the upper left near the bright foreground star 52 Cygni, and Fleming’s Triangular Wisp (formerly known as Pickering’s Triangle) running diagonally up the image middle. What is rarely imaged – but seen in the featured long exposure across many color bands – is the reflecting brown dust that runs vertically up the image left, dust likely created in the cool atmospheres of massive stars.

∞ Source: apod.nasa.gov/apod/ap231018.html

Did you know that there are 5 known dwarf planets in our solar system? Everyone knows Pluto, but there is also Ceres, Haumea, Makemake and Eris.

Info from: https://www.iau.org/public/themes/pluto/#n6

Our first public event this Fall occurs Sept. 27, 7:30 - 9:00 pm, weather allowing! (Check the day of the event to see if we're on).

A lot will be happening in the eastern sky! The nearly-full Moon, Saturn, the Double Cluster, and the Andromeda Galaxy will be rising in the east. High in the southwestern sky we'll have the Ring Nebula and globular cluster M13. We'll also have the Big Dipper and the double star Mizar, the central star in its handle.

The bright Moon will wash out dimmer, fuzzier objects, but the Moon itself will be lovely!

The 2023 Partial (Annular) Solar Eclipse as seen from Nevada // Brian Fulda

Follow this link to learn more about the BSU Center for the Advancement of Stem Education!

I see an angry fox about to breathe fire.

Hind's Variable Nebula, NGC 1555 // Rocco Sung

Wed. Nov. 15 - We will be closed tonight due to cloud cover.

Yuck: