Messier 101 – Pinwheel Galaxy

Messier 101 is a spiral galaxy located about 21 million light-years away and is considered one of the brightest objects in the night sky.

Messier 101, also known as the Pinwheel Galaxy, is a breathtaking sight with its striking spiral arms adorned with bright clusters of stars, interspersed with dark dust lanes and glowing pink regions of active star formation, all set against a backdrop of distant galaxies and a vast expanse of space. Its beauty lies not only in its stunning appearance, but also in the insights it provides into the workings of the universe, as astronomers study its structure, composition, and evolution.

The Position of M101

Messier 101 is a spiral galaxy located near the constellation Ursa Major, about 21 million light-years away from Earth. The galaxy has a diameter of approximately 170,000 light-years and contains billions of stars. In its surroundings, there are numerous other galaxies, including NGC 5474 and NGC 5477, which are grouped together with Messier 101 in a galaxy group called the M101 Group. This group is part of the Virgo Supercluster, a collection of more than 1000 galaxies that includes our own Milky Way.

Messier 101 Pinwheel Galaxy

Unique facts

  • Messier 101 is also known as the Pinwheel Galaxy due to its striking spiral arms that resemble a pinwheel in shape.
  • It is home to a massive black hole with a mass estimated to be about 20-30 million times that of our sun.
  • In 2015, a supernova explosion was discovered in one of the spiral arms of Messier 101, making it the closest supernova to Earth in more than 20 years.
  • The galaxy has an unusually large number of HII regions (pinkish-red areas of ionized gas where new stars are forming) scattered throughout its spiral arms, indicating a high rate of star formation.

Brightness and size

Messier 101 is one of the brightest and largest galaxies visible from Earth, with an apparent magnitude of around 7.9 and an actual diameter of approximately 170,000 light-years. Its size and brightness make it easily visible through telescopes and even binoculars under good observing conditions.

In terms of its apparent size, Messier 101 appears quite large in the night sky. Its angular diameter measures about 28 arcminutes, which is equivalent to approximately half the size of the full moon. This makes it one of the largest and most photogenic galaxies in the sky, with its spiral arms and prominent features easily visible in long-exposure images taken with telescopes. Overall, Messier 101 is a popular target for astronomers and amateur stargazers alike, due to its striking appearance and proximity to Earth.

Apparent size - Messier 101 Pinwheel Galaxy