M 45

The Pleiades (also known as the Seven Sisters and Messier 45) is an open star cluster and asterism located in the northwestern constellation Taurus. At a distance of about 444 light-years from Earth, it is one of the closest and brightest star clusters visible to the naked eye, even in urban skies.

The cluster is named after the Pleiades, a group of nymphs from Greek mythology. The photographs show reflection nebulae surrounding the stars, which were originally thought to be remnants of their formation but are now thought to be a dust cloud from the interstellar medium through which the cluster is passing. The cloud is estimated to be moving at 18 km/s relative to the stars.

Origin of the name

The name Pleiades comes from the ancient Greek Πλειάδες, probably related to the verb πλεῖν ("to sail"), since the cluster was used to mark the navigation season in the Mediterranean Sea. In mythology, the Pleiades came to symbolize the seven sisters, daughters of the nymph Pleione.

Astronomical significance of M45 in ancient times

In ancient times, the Pleiades played an important role in establishing calendars. This is due to two features:

1. Unique and easily recognizable appearance in the sky.

2. In the 3rd millennium BC, the cluster was located at the point of the vernal equinox.

Examples of Significance:

• On the Nebra Sky Disc (c. 1600 BC), the Pleiades are shown in the upper right-hand section between the Sun and the Moon.
• In India, the Pleiades are known as Krittika and were associated with the beginning of the year.
• In Mesopotamia, the list of lunar stations began with this cluster under the name MUL.MUL.

Nomenclature and Mythology

The Pleiades are known to many cultures around the world:

• The ancient Arabs called them al-Turaiya (الثريا).
• The Japanese called them Subaru (昴).
• In Indian mythology, they are Krittika.
• The Greeks mention them in the works of Homer and Hesiod.
• The star cluster is mentioned three times in the Bible.

The earliest depiction of the Pleiades is the Nebra Sky Disk. In Babylon, the cluster was called MULMUL ("star of stars"), and in Ancient Egypt - Followers.

Interesting Facts

• In the future, in 250 million years, gravitational interactions will destroy the cluster.
• Together with another open cluster, the Hyades, the Pleiades form the Golden Gate of the Ecliptic.
• Galileo Galilei in his works drew the Pleiades in detail, highlighting a large number of stars invisible to the naked eye.