Andromeda and Milky Way Collision

The Andromeda galaxy is the brightest galaxy in the neighborhood of the Milky Way. With the help of proper instruments, you can easily spot this galaxy in the night sky. This galaxy can even be seen with the naked eye if you live in a really dark sky area. The galaxy is 2.5 million light-years away and is a subject of curiosity for all scientists and astronomers. Previously we have seen what are all the planets in the Andromeda Galaxy. Today we will see all the details of this collision.

Andromeda galaxy’s history and first discovery

Given the fact that this galaxy is popular among every single astronomer. The discovery of this galaxy might seem very recent to you. In reality, the first discovery of the Andromeda galaxy dates back to even before the discovery of the telescope.

In 965 CE, the Persian astronomer Abd Al-Rahman Al Sufi described this galaxy as a “small cloud” in his book Fixed Stars. A look at the sky charts from that time period confirms this. After the discovery of the telescope in 1612, German astronomer Simon Marius described Andromeda as a candle seen through the horn. In 1764, when Charles Messier cataloged Andromeda as an M31, he was unaware of the work of ‘Abd Al-Rahman Al Sufi’ and he incorrectly credited the discoverer of Andromeda as Simon Marius.

In 1785, the astronomer William Herschel noticed a faint blue hue in the core region of this galaxy. At the time, he believed that it was the nearest nebula. This led to the belief that Andromeda was a nebula. In 1865, astronomer William Huggins observed the spectra of Andromeda and concluded that it was different from a gaseous nebula. There was a supernova in the Andromeda galaxy in 1885. Until now, this galaxy has seen only one supernova.

Andromeda Galaxy’s first photo

In 1887, astronomer Isaac Roberts took the first photograph of the Andromeda galaxy from his private observatory.

As of this time, it was believed that it was a nebula. So, Isaac Roberts mistakenly believed that M31 and similar spiral nebulae were actually solar systems being formed in the Milky Way itself.

In 1917, astronomer Heber Curtis studied the supernova that happened in 1885 and came to the conclusion that the distance was 500,000 light years. He also believed that it was not a nebula but a different spiral globular form known as the “island of universes.”

The Great Debate happened in 1920 as a result of this, where Heber Curtis and Harlow Shapley debated the nature of the spiral nebulas. This debate was finally settled by Edwin Hubble in 1925. He identified extragalactic Cepheid variable stars for the first time on astronomical photos of the andromeda galaxy. Hubble concluded that it is not a cluster of stars or a gaseous nebula in the Milky way but a completely separate galaxy that is located at a significant distance.

Why the galaxy’s name is Andromeda?

The most simple answer to this is that, from Earth’s sky, the galaxy is in the Andromeda constellation. So the name is Andromeda galaxy. Andromeda’s constellation is named after the princess of Ethiopia. Whom, according to Greek mythology, the hero Perseus was saved from sacrifice to the sea monster Cetus.

Andromeda galaxy characteristics

• Andromeda is twice the size of the Milky Way. It has a diameter of 220,000 light years.
• Despite being twice the size of the Milky Way, the Andromeda galaxy has the same mass.
• The distance from Earth to Andromeda is about 2.5 million light years.
• It is about twice as bright as the Milky Way.
• The Andromeda Galaxy is closing in on the Milky Way at a speed of about 110 kilometers per second.
• In 4.5 billion years, Andromeda and the Milky Way will collide and form a new galaxy.

Andromeda galaxy’s past collisions

As mentioned earlier and discovered by scientists, the Andromeda galaxy is approaching the Milky Way at a speed of 110 km/sec. It is inevitable that in 4.5 billion years these two galaxies will collide, but has the Andromeda galaxy collided with any other galaxy so far?

Check out the full article in detail here.