Andromeda galaxy spiral

The Andromeda Galaxy is a giant spiral galaxy, neighbor to the Milky Way, located about 2.5 million light-years away.

About this subject

The Andromeda Galaxy, also known as Messier 31 or NGC 224, is the largest galaxy in the Local Group, the cluster of galaxies that includes the Milky Way. Spanning approximately 220,000 light-years in diameter, it contains about one trillion stars, twice the estimated number in our own galaxy. Its spiral structure, visible in long-exposure images, consists of arms hosting intense star formation regions, interstellar dust, and young star clusters.

Andromeda is on a collision course with the Milky Way, predicted to merge in about 4.5 billion years. This event, simulated countless times, will form a new giant elliptical galaxy, sometimes nicknamed Milkomeda. The approach is already underway, with the galaxies moving toward each other at roughly 110 kilometers per second.

Visible to the naked eye on dark nights as a faint smudge in the constellation Andromeda, it was first cataloged by Persian astronomer Al-Sufi in the 10th century. In 1923, Edwin Hubble determined that Andromeda lies beyond the Milky Way, proving that the universe extends far beyond our galaxy. Today, telescopes like Hubble and the James Webb Space Telescope continue to study its stellar population and central supermassive black hole, which has a mass of about 100 million suns.

Frequently Asked Questions

How far away is the Andromeda Galaxy from Earth?

The Andromeda Galaxy is located about 2.5 million light-years from Earth.

Will Andromeda collide with the Milky Way?

Yes, the two galaxies are approaching each other and are expected to collide in about 4.5 billion years, forming a new galaxy.

How many stars does the Andromeda Galaxy contain?

Andromeda is estimated to contain about 1 trillion stars, twice the number estimated in the Milky Way.