Andromeda is a galaxy also known as M31 and NGC224. It is a spiral formation located approximately 780 kp (2.5 million light years) from Earth.
Andromeda is the closest galaxy to the Milky Way. It is named after the mythical princess of the same name. Observations in 2006 led to the conclusion that there are about a trillion stars here - at least twice as many as in the Milky Way, where there are about 200 - 400 billion of them. Scientists believe that the collision of the Milky Way and the Andromeda galaxy will happen in about 3, 75 billion years, and as a result, a giant elliptical or disk galaxy will be formed. But more on that later. First, let's find out what the "mythical princess" looks like.
The picture shows Andromeda. The galaxy has blue and white stripes. They form rings around it and shelter hot red-hot giant stars. Dark blue-gray bands contrast sharply against these bright rings and show regions where star formation is just beginning in dense cloud cocoons. When observed in the visible part of the spectrum, the Andromeda ring is largerlooks like spiral arms. In the ultraviolet range, these formations rather resemble ring structures. They were previously discovered by the NASA telescope. Astronomers believe that these rings indicate the formation of a galaxy as a result of a collision with a neighboring one more than 200 million years ago.
Andromeda Moons
Like the Milky Way, Andromeda has a number of dwarf satellites, 14 of which have already been discovered. The most famous are M32 and M110. Of course, it is unlikely that the stars of each of the galaxies will collide with each other, since the distances between them are very large. About what will actually happen, scientists still have a rather vague idea. But a name has already been invented for the future newborn. Mlekomed is the name given to the unborn giant galaxy by scientists.
Star Collisions
Andromeda is a galaxy with 1 trillion stars (1012) and the Milky Way is 1 billion (31011). However, the chance of a collision of celestial bodies is negligible, since there is a huge distance between them. For example, the closest star to the Sun, Proxima Centauri, is 4.2 light-years away (41013km), or 30 million (3107) diameters of the Sun. Imagine that our star is a table tennis ball. Then Proxima Centauri will look like a pea, located at a distance of 1100 km from it, and the Milky Way itself will extend in breadth for 30 million km. Even the stars in the center of the galaxy (namely, where their largest cluster) are located at intervalsin 160 billion (1.61011) km. It's like one table tennis ball for every 3.2 km. Therefore, the chance that any two stars will collide in a galaxy merger is extremely small.
Black hole collision
The Andromeda Galaxy and the Milky Way have central supermassive black holes: Sagittarius A (3.6106 solar masses) and an object inside the P2 Cluster of the Galactic Core. These black holes will converge at a point near the center of the newly formed galaxy, transferring orbital energy to the stars, which will move to higher trajectories over time. The above process can take millions of years. When the black holes come within one light year of each other, they will start emitting gravitational waves. Orbital energy will become even more powerful until the fusion is complete. Based on simulation data from 2006, the Earth could first be thrown almost to the very center of the newly formed galaxy, then pass near one of the black holes and be erupted outside of Mlecomeda.
Confirmation of the theory
The Andromeda Galaxy is approaching us at a speed of approximately 110 km per second. Up until 2012, there was no way to know if a collision would occur or not. To conclude that it is almost inevitable, the Hubble Space Telescope helped scientists. After tracking the movements of Andromeda from 2002 to 2010, it was concluded that the collision will occur in about 4 billion years.
Such phenomena are widespread in space. For example, Andromeda is believed to have interacted with at least one galaxy in the past. And some dwarf galaxies, such as SagDEG, continue to collide with the Milky Way, creating a single formation.
Research also indicates that M33, or the Triangulum Galaxy, the third largest and brightest member of the Local Group, will also participate in this event. Its most likely fate will be the entry into orbit of the object formed after the merger, and in the distant future - the final merger. However, a collision of M33 with the Milky Way before Andromeda approaches, or our Solar System is thrown outside the Local Group, is ruled out.
The Fate of the Solar System
Scientists from Harvard argue that the timing of the unification of galaxies will depend on the tangential speed of Andromeda. Based on the calculations, they concluded that there is a 50% chance that during the merger the Solar System will be thrown back to a distance three times the current distance to the center of the Milky Way. It is not known exactly how the Andromeda galaxy will behave. Planet Earth is also under threat. Scientists say there is a 12% chance that we will be thrown out of our former "home" some time after the collision. But this event, most likely, will not produce strong adverse effects on the Solar System, and celestial bodies will not be destroyed.
If we exclude planetary engineering, then by the timecollision of galaxies, the surface of the Earth will become very hot and there will be no liquid water left on it, and hence no life.
Possible side effects
When two spiral galaxies merge, the hydrogen present in their disks shrinks. The formation of new stars begins. For example, this can be observed in the interacting galaxy NGC 4039, otherwise known as "Antennas". In the event of a merger between Andromeda and the Milky Way, it is believed that there will be little gas left on their disks. Star formation will not be as intense, although the birth of a quasar is likely.
Merge result
The galaxy formed by the merger is tentatively called Mlekomed by scientists. The simulation result shows that the resulting object will have an elliptical shape. Its center will have a lower density of stars than modern elliptical galaxies. But a disk form is also likely. Much will depend on how much gas remains within the Milky Way and Andromeda. In the near future, the remaining galaxies of the Local Group will merge into one object, and this will mean the beginning of a new evolutionary stage.
Andromeda Facts
- Andromeda is the largest galaxy in the Local Group. But probably not the most massive. Scientists suggest that more dark matter is concentrated in the Milky Way, and this is what makes our galaxy more massive.
- Scientists exploreAndromeda in order to understand the origin and evolution of formations like it, because this is the closest spiral galaxy to us.
- Andromeda looks amazing from Earth. Many even manage to take a picture of her.
- Andromeda has a very dense galactic core. Not only are huge stars located at its center, but there is also at least one supermassive black hole hidden in the core.
- Its spiral arms have twisted as a result of gravitational interaction with two neighboring galaxies: M32 and M110.
- At least 450 globular star clusters orbit inside Andromeda. Among them are some of the densest that have been found.
- The Andromeda Galaxy is the most distant object that can be seen with the naked eye. You will need a good vantage point and a minimum of bright light.
In conclusion, I would like to advise readers to raise their eyes to the starry sky more often. It keeps a lot of new and unknown. Find some free time to watch space this weekend. The Andromeda Galaxy in the sky is a sight to behold.
