Galaxies are nothing more than massive groups of stars, planets, and gas clouds. According to one estimate, there might be up to 2 trillion of them spread over the observable universe.
Each of these galaxies, including the Milky Way, may contain billions or trillions of stars, as is the case with the Andromeda Galaxy, which is famed for being visible in the night sky and is thought by many to be the nearest to Earth.
However, this is not the case.
Andromeda is located in the constellation of the same name, and it can be seen as a small cloud practically obliterated in the very dark sky.
The galaxy is 2 million light-years away from Earth, which implies that light traveling at 300,000 km/s takes 2 million years to reach us.
Often referred to as our "neighboring galaxy," the word confuses and misleads many people into believing that there are no other nearby galaxies.
Just as the moon orbits the earth and the earth orbits the sun, our Milky Way galaxy contains its natural satellites and they are considerably closer to us than the Andromeda Galaxy.
The closest known galaxy to us is the Canis Major Dwarf Galaxy, at 236,000,000,000,000,000 km (25,000 light years) from the Sun. The Canis Major Dwarf Galaxy is just 25,000 light years away from the Sun and 42,000 light years away from the Galactic Center. It, too, is well-hidden by dust in the plane of the Milky Way, which is why it was just recently identified.
The Sagittarius Dwarf Elliptical Galaxy is the next closest , at 662,000,000,000,000,000 km (70,000 light years) from the Sun.
The most well-known satellite galaxies are the Large and Small Magellanic Clouds, which are only 200,000 light-years years away. Much closer, don't you think?
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| Large and Small Magellanic Cloud Galaxies |
Even in suburban areas, the Large Magellanic Cloud may be seen as a pale bluish cloud.
It is estimated to be 155,000 light-years away from Earth, with a diameter of only 14,000 light-years, making it twenty times smaller than our galaxy and containing ten times fewer stars.
The Small Magellanic Cloud, on the other hand, is even more compact, measuring only 7,000 light-years wide. It is also located around 200,000 light-years away.
Its brightness is quite modest, and it is best observed on new moon evenings when there is no light pollution.
In short, yes, Andromeda is the closest spiral galaxy to us in terms of size.
If we disregard adjectives, the Great Magellanic Cloud is the nearest to Earth. The Milky Way contains 51 verified satellites, the most well-known of which are the Big and Small Magellanic Clouds.
Reference(s):
NASA | The Nearest Galaxies