As mid-August nights draw in, stargazers across the northern hemisphere are being treated to some of the most striking views of the year. Among the highlights are three prominent star clusters, each offering a window into the dynamic and ancient life of the Milky Way. From dense globular swarms to open formations etched into familiar constellations, these stellar gatherings are visible to the naked eye from dark-sky sites, but reveal their full majesty when observed with binoculars or a telescope.<h2>What are star clusters?</h2>&nbsp;Star clusters are gravitationally bound families of stars born from the same interstellar cloud. They come in two main types: open clusters and globular clusters. Open clusters, such as the Hyades and the Pleiades, are relatively young and often located in the Milky Way’s spiral arms. Their loosely bound nature means they can disperse over millions of years as passing stars tug at their members. Globular clusters, by contrast, are tightly packed spheres containing hundreds of thousands of stars, often among the oldest in the galaxy. These vast systems orbit in the galactic halo, high above and below the Milky Way’s disk, and many shine brightly enough to appear as faint smudges of light to the unaided eye.&nbsp;Roughly 150 globular clusters and more than 1,000 open clusters. Observing them requires patience and technique: allow around 30 minutes for your eyes to adapt to darkness, and use averted vision, looking slightly to the side of the target, to engage the light-sensitive rods of your eyes. While some clusters can be glimpsed without equipment, 10x50 binoculars sharpen the view and begin to resolve brighter stars, and a telescope of six inches or more reveals their intricate structures in detail.&nbsp;<h2>The Great Hercules Cluster</h2>&nbsp;One of the brightest sights of August evenings is the Great Hercules Cluster, also known as Messier 13 (M13). Located about 25,000 light-years away in the constellation Hercules, M13 contains around 100,000 stars bound in a glittering spherical mass. It can be found between the bright stars Vega and Arcturus by locating the Keystone asterism, a diamond-shaped pattern of four stars at Hercules’ centre. Sweeping binoculars between Zeta Herculis and Eta Herculis brings this ancient cluster into view, a highlight of the summer sky.&nbsp;<h2>The Hyades and the Pleiades</h2>&nbsp;In the early hours before dawn, the constellation Taurus rises in the east. At its heart lies the Hyades, the closest open cluster to Earth at just 150 light-years away. Shaped like a sideways ‘V’ marking the bull’s face, its brightest star Aldebaran, the red ‘eye’ of Taurus, is a foreground object, only 65 light-years distant.&nbsp;Above the Hyades sits the Pleiades, one of the most famous open clusters, often called the ‘Seven Sisters’. This cluster hosts more than a thousand hot, young stars, but binoculars reveal the seven brightest that dominate its appearance. Positioned about 10 degrees above the Hyades, roughly a fist’s width at arm’s length, the Pleiades are a dazzling reminder of the Milky Way’s star-forming past.&nbsp;

From dense globular swarms to open formations etched into familiar constellations, these stellar gatherings are visible to the naked eye from dark-sky sites.

As mid-August nights draw in, stargazers across the northern hemisphere are being treated to some of the most striking views of the year. Among the highlights are three prominent star clusters, each offering a window into the dynamic and ancient life of the Milky Way. From dense globular swarms to open formations etched into familiar constellations, these stellar gatherings are visible to the naked eye from dark-sky sites, but reveal their full majesty when observed with binoculars or a telescope. What are star clusters? Star clusters are gravitationally bound families of stars born from the same interstellar cloud. They come in two main types: open clusters and globular clusters. Open clusters, such as the Hyades and the Pleiades, are relatively young and often located in the Milky Way’s spiral arms. Their loosely bound nature means they can disperse over millions of years as passing stars tug at their members. Globular clusters, by contrast, are tightly packed spheres containing hundreds of thousands of stars, often among the oldest in the galaxy. These vast systems orbit in the galactic halo, high above and below the Milky Way’s disk, and many shine brightly enough to appear as faint smudges of light to the unaided eye. Roughly 150 globular clusters and more than 1,000 open clusters. Observing them requires patience and technique: allow around 30 minutes for your eyes to adapt to darkness, and use averted vision, looking slightly to the side of the target, to engage the light-sensitive rods of your eyes. While some clusters can be glimpsed without equipment, 10x50 binoculars sharpen the view and begin to resolve brighter stars, and a telescope of six inches or more reveals their intricate structures in detail. The Great Hercules Cluster One of the brightest sights of August evenings is the Great Hercules Cluster, also known as Messier 13 (M13). Located about 25,000 light-years away in the constellation Hercules, M13 contains around 100,000 stars bound in a glittering spherical mass. It can be found between the bright stars Vega and Arcturus by locating the Keystone asterism, a diamond-shaped pattern of four stars at Hercules’ centre. Sweeping binoculars between Zeta Herculis and Eta Herculis brings this ancient cluster into view, a highlight of the summer sky. The Hyades and the Pleiades In the early hours before dawn, the constellation Taurus rises in the east. At its heart lies the Hyades, the closest open cluster to Earth at just 150 light-years away. Shaped like a sideways ‘V’ marking the bull’s face, its brightest star Aldebaran, the red ‘eye’ of Taurus, is a foreground object, only 65 light-years distant. Above the Hyades sits the Pleiades, one of the most famous open clusters, often called the ‘Seven Sisters’. This cluster hosts more than a thousand hot, young stars, but binoculars reveal the seven brightest that dominate its appearance. Positioned about 10 degrees above the Hyades, roughly a fist’s width at arm’s length, the Pleiades are a dazzling reminder of the Milky Way’s star-forming past.

From dense globular swarms to open formations etched into familiar constellations, these stellar gatherings are visible to the naked eye from dark-sky sites.

See 1,00,000 stars at once: The star clusters set to dazzle skywatchers in August 2025

A star cluster in the universe might be hiding a swarm of over 100 stellar-mass black holes. The cluster is called Palomar 5 and is a stellar stream of stars stretching across 30,000 light-years. It is located around 80,000 light-years away.

Globular clusters such as the Palomar 5 are usually very old and are therefore also called "fossils" of the early universe. They are dense, spherical and contain nearly 100,000 to one&nbsp;million very old stars. All these stars in a cluster are birthed at the same time.

Our galaxy, the Milky Way, has around 150 globular clusters that are known to scientists. Since they are extremely old, they are great to help learn about the history of the Universe and the dark matter content of their galaxies.

Recently, tidal streams of stars, or long rivers of stars that stretch across the sky, have also caught the attention of astronomers. This is because the Gaia space observatory has been mapping our galaxy with high precision.&nbsp;

Also Read:&nbsp;<a href="https://www.wionews.com/science/juice-snaps-earth-with-moon-lurking-on-the-sides-as-uranus-photobombs-760410">JUICE snaps Earth, with moon lurking on the sides, and a photobombing planet</a>

Scientists have been trying to figure out how a stream of stars forms. Initially, they were believed to be "disrupted star clusters," astrophysicist Mark Gieles from the University of Barcelona in Spain said in 2021.&nbsp;

"However, none of the recently discovered streams have a star cluster associated with them, hence we can not be sure. So, to understand how these streams formed, we need to study one with a stellar system associated with it.

Palomar 5 is the only case, making it a Rosetta Stone for understanding stream formation and that is why we studied it in detail."

<h2>Why Palomar 5</h2>

Palomar 5 has both a very wide, loose distribution of stars and a long tidal stream. The researchers recreated the orbits and evolutions of each star in the cluster to understand how they ended up in the cluster.&nbsp;

Black holes were included in some of the simulations since evidence suggests they might exist in the central regions of globular clusters. Besides, any interaction with them can throw them off as well.

They found that the presence of a significant number of stellar-mass black holes within Palomar 5 could have resulted in the current formation.&nbsp;

The stars were likely flung out from the cluster due to orbital interactions and into the tidal stream.&nbsp;

This could have also led to an increase in the proportion of black holes.&nbsp;

"The number of black holes is roughly three times larger than expected from the number of stars in the cluster, and it means that more than 20 per cent of the total cluster mass is made up of black holes," Gieles said.

Researchers suggest the cluster will dissolve completely in around 1 billion years. Right before this happens, all that would be left in the cluster are black holes, orbiting the galactic centre.&nbsp;

A star cluster in the universe might be hiding a swarm of over 100 stellar-mass black holes. The cluster is called Palomar 5 and is a stellar stream of stars stretching across 30,000 light-years.

A star cluster in the universe might be hiding a swarm of over 100 stellar-mass black holes. The cluster is called Palomar 5 and is a stellar stream of stars stretching across 30,000 light-years. It is located around 80,000 light-years away. Globular clusters such as the Palomar 5 are usually very old and are therefore also called "fossils" of the early universe. They are dense, spherical and contain nearly 100,000 to one million very old stars. All these stars in a cluster are birthed at the same time. Our galaxy, the Milky Way, has around 150 globular clusters that are known to scientists. Since they are extremely old, they are great to help learn about the history of the Universe and the dark matter content of their galaxies. Recently, tidal streams of stars, or long rivers of stars that stretch across the sky, have also caught the attention of astronomers. This is because the Gaia space observatory has been mapping our galaxy with high precision. Also Read: JUICE snaps Earth, with moon lurking on the sides, and a photobombing planet Scientists have been trying to figure out how a stream of stars forms. Initially, they were believed to be "disrupted star clusters," astrophysicist Mark Gieles from the University of Barcelona in Spain said in 2021. "However, none of the recently discovered streams have a star cluster associated with them, hence we can not be sure. So, to understand how these streams formed, we need to study one with a stellar system associated with it. Palomar 5 is the only case, making it a Rosetta Stone for understanding stream formation and that is why we studied it in detail." Why Palomar 5 Palomar 5 has both a very wide, loose distribution of stars and a long tidal stream. The researchers recreated the orbits and evolutions of each star in the cluster to understand how they ended up in the cluster. Black holes were included in some of the simulations since evidence suggests they might exist in the central regions of globular clusters. Besides, any interaction with them can throw them off as well. They found that the presence of a significant number of stellar-mass black holes within Palomar 5 could have resulted in the current formation. The stars were likely flung out from the cluster due to orbital interactions and into the tidal stream. This could have also led to an increase in the proportion of black holes. "The number of black holes is roughly three times larger than expected from the number of stars in the cluster, and it means that more than 20 per cent of the total cluster mass is made up of black holes," Gieles said. Researchers suggest the cluster will dissolve completely in around 1 billion years. Right before this happens, all that would be left in the cluster are black holes, orbiting the galactic centre.

Swarm of black holes stretching across 30,000 light-years traversing Milky Way

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