Night Sky Special: What Is The Distance Of The Andromeda Galaxy From Earth?

Adekunle Olanrewaju Jason
Jan 24, 2024 By Adekunle Olanrewaju Jason
Originally Published on Dec 06, 2021
Andromeda Galaxy is the biggest member
Age: 3-18
Read time: 5.3 Min

The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224, and formerly known as the Andromeda Nebula, is a barred spiral galaxy located 2.5 million light-years (770 kiloparsecs) from Earth and the Milky Way's closest big galaxy.

The galaxy's name comes from the constellation Andromeda, which is named after the Ethiopian (or Phoenician) princess who was Perseus's wife in Greek mythology. The Andromeda Galaxy has a virial mass of 1 trillion solar masses which is similar to that of the Milky Way.

The mass of either galaxy is impossible to measure with any precision, although it has long been assumed that the Andromeda Galaxy is 25 percent to 50 percent more massive than the Milky Way. A 2018 research citing a lower estimate of the mass of the Andromeda Galaxy, paired with preliminary reports on a 2019 study indicating a larger mass of the Milky Way, has thrown this into doubt. The Andromeda Galaxy is the biggest member of the local group in terms of extension, with a diameter of around 220,000 ly (67 kps).

It was first recorded by the Islamic astronomer Al-Farabi in the 'Book of the Fixed Stars' in 965 CE and was rediscovered in 1612, shortly after the creation of the telescope, by the German astronomer Simon Marius, who described it as being like the light of a candle viewed through a horn. For years, astronomers thought of the Andromeda Galaxy as a component of the Milky Way Galaxy—that is, as a spiral nebula similar to other brilliant gaseous masses in the local galactic system (hence the misnomer Andromeda Nebula). Only in the '20s did American astronomer Edwin Powell Hubble establish clearly that the Andromeda Galaxy existed in addition to the Milky Way.

The Andromeda Galaxy And Importance

There are numerous smaller galaxies that are present in the vicinity of our Milky Way Galaxy but the Andromeda is the closest spiral galaxy which is around 2.53 million years away from our galaxy. It happens to the most bright galaxy which is visible from the southern hemisphere of Earth.

We may look up at the night sky, but what goes in the night sky behind what we can see is very incredible. Just as we are in a solar system where our galaxy is called the Milky Way, there are many other galaxies. There are even instances where galaxies collide but they are at such a radial velocity and are a million light-years away, so we cannot see them.

The great Andromeda Nebula is a larger galaxy with different star clusters, a constellation, and individual stars that are right near the central region. Compared to the Sun which is around 3.75 billion years away, this galaxy is the closest to the Milky Way Galaxy. A constellation is a group of star formations we may see in the night sky, just like we can see the full moon.

Stars In The Andromeda Galaxy

According to some estimations, the Andromeda Galaxy has one trillion stars. It has a diameter of more than 200,000 light years.

That's a lot larger than the Milky Way, which is estimated to be 150,000 light years across by more recent estimations. Astronomers are indeed trying to figure out how many stars our galaxy contains, but it appears to have a quarter to half the number of stars as Andromeda.

It has been estimated by scientists that the star formation process in the Andromeda Galaxy is similar to the way stars are formed in the Milky Way Galaxy. Several papers have been published wherein researchers have highlighted that not only star formation but planet formation process is likely to be going on in the Andromeda Galaxy.

When the James Webb telescope is finally launched and successfully deployed, we will be able to locate several more galaxies and observe even exoplanets directly. This will mark a new era in space science and would usher in a new era of discoveries in space.

In spiral galaxies, star formation usually completes within five billion years.

How can you locate the Andromeda Galaxy from Earth?

Take a night’s drive to a dark sky location to discover the magnificent Andromeda Galaxy. It's the huge spiral galaxy next door to our Milky Way, and it's the furthest object visible to the naked eye. This time of year, it's best seen in the evening.

The galaxy is most commonly found via star-hopping from Cassiopeia the Queen, a prominent M- or W-shaped pattern on the sky's dome. The Andromeda Galaxy can also be found by star-hopping from the star Alpheratz in Pegasus' Great Square.

Both techniques will take you to the center of the universe. Andromeda — M31 – may be seen for at least part of every night, all year long, from mid-northern latitudes. However, most people first view the galaxy in August or September, when it is high enough in the sky to be visible from dusk to dawn.

Begin looking for the galaxy in late August and early September, about mid-evening, around halfway between your local dusk and midnight.

Does the Andromeda galaxy have planets?

In 2009, astronomers revealed the discovery of a putative planet in the neighboring Andromeda galaxy, although its existence was not confirmed for some time.

With the rapid progress of technology and various ground-based and space-based telescopes, we have been able to analyze the Andromeda Galaxy better. The distance of 2.53 million light years is staggering even in astronomical terms but scientists have now been able to analyze the galaxy better.

As of now, one extremely potent planetary candidate has been identified in the Andromeda Galaxy. This planet has been named PA-99-N2 and was identified after a microlensing event that took place during the year 1999. Scientists are still performing various experiments to confirm the presence of this planet as this will be one of the first times an exoplanet has been identified directly in another galaxy.

There are very high chances that there are millions of exoplanets that are present in the Andromeda Galaxy completing their orbits around parent stars but their presence is yet to be confirmed.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for night sky special: what is the distance of the Andromeda Galaxy from Earth then why not take a look at how many months are cats pregnant or how many cat breeds are there.

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Written by Adekunle Olanrewaju Jason

Bachelor of Science specializing in Mass Communication.

Adekunle Olanrewaju Jason picture

Adekunle Olanrewaju JasonBachelor of Science specializing in Mass Communication.

With over 3+ years of professional experience, Olanrewaju is a certified SEO Specialist and Content Writer. He holds a BSc in Mass Communication from the University of Lagos. Throughout his dynamic career, Olanrewaju has successfully taken on various roles with startups and established organizations. He has served as a Technical Writer, Blogger, SEO Specialist, Social Media Manager, and Digital Marketing Manager. Known for his hardworking nature and insightful approach, Olanrewaju is dedicated to continuous learning and improvement.
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