
Globular star cluster Messier 5, is drawn by the Grok AI
Messier 5, also known as M5 or NGC 5904, is one of the oldest known globular clusters in our Milky Way galaxy. Here are some key facts about Messier 5:
General Information:
- Type: Globular Cluster
- Constellation: Serpens (specifically in Serpens Caput, the head of the Serpent)
- Distance from Earth: Approximately 24,500 light-years
- Discovery: Discovered by the German astronomer Gottfried Kirch in 1702, but it was later cataloged by Charles Messier in 1764.
Physical Characteristics:
- Age: Estimated to be around 13 billion years old, making it one of the oldest structures in our galaxy.
- Diameter: About 165 light-years across.
- Number of Stars: Contains hundreds of thousands of stars, with estimates ranging from 100,000 to 500,000 or more.
- Magnitude: Apparent visual magnitude is about 5.7, which makes it visible to the naked eye under very dark skies, though it's more commonly observed with binoculars or a telescope.
Notable Features:
- Variable Stars: M5 is known for its large number of variable stars, particularly RR Lyrae variables, which are useful for studying stellar evolution and distances in the universe.
- Core Collapse: Unlike some globular clusters, M5 does not show signs of core collapse, meaning its core has not contracted significantly due to gravitational forces. This makes it an interesting subject for astronomers studying the dynamics of star clusters.
Observation:
- Visibility: Best observed in the northern hemisphere during the summer months. It's located near the border with the constellation Libra, making it somewhat of a treat for summer stargazers.
- Telescopic View: Through a telescope, M5 appears as a dense, bright core with stars spilling out into a halo. With larger telescopes, individual stars can be resolved.
Scientific Significance:
- Study of Stellar Evolution: Due to its age and the variety of star types within it, M5 provides insights into how stars evolve over billions of years.
- Reference for Galactic Studies: As one of the closer globular clusters to Earth, it serves as an important reference for measuring distances and understanding the structure of the Milky Way.
M5 is a beautiful example of how the study of globular clusters can inform us about the history and dynamics of our galaxy. If you're interested in observing M5, ensure you're in a location with minimal light pollution for the best experience.
I will gladly supplement what the artificial intelligence has told me
Indeed, the globular star cluster Messier 5 is a classic for visual amateur astronomy, and it is clearly visible even in the most modest optical instruments. It can be seen with the naked eye as a dim star at the limit of visibility (though for this you need to be far from city lights, and better yet — in the mountains). In binoculars the cluster looks like a clearly visible foggy spot. In medium and small telescopes, the peripheral part of the cluster can be divided into individual stars. But if the telescope has an aperture of 8 inches or more, then even the center of the cluster breaks up into individual stars. The latter observation is precisely what indicates a low stellar density in the core.
The cluster is located on the border of the constellations Serpens and Virgo (AI wrote that it is Libra, but there is no big mistake in this — Libra is also very close).
There is some disagreement in science about the age of the cluster. Of course, globular clusters are the most ancient structural formations in the Universe. And sometimes you want to give them all 13 billion years (which can often be seen in articles about clusters). However, the Messier 5 cluster is apparently much younger — about 10 billion years. Why is it like that? — this is still unknown.
It can also be added that a pair of millisecond pulsars (neutron stars) and a so-called dwarf nova (a close binary star in which a white dwarf "steals" matter from a swollen red giant, and a certain dose of this matter after a period of accumulation produces a noticeable, but still not as large as in classical novas, flare) have been discovered in the cluster.

Globular star cluster Messier 5 by Hubble Space Telescope