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NASA’s Hubble Spies Stellar Sparkler for July 4th

4 July 2026 at 07:15

3 min read

NASA’s Hubble Spies Stellar Sparkler for July 4th

Hubble image of NGC 6426, a compact grouping of a multitude of stars shine in red, white and blue against the dark background of space. The stars are more densely collected toward the center of the cluster.
Ancient stars shine in red, white and blue from a globular cluster almost as old as the universe itself in this image from NASA’s Hubble Space Telescope.
NASA, ESA, and A. Dotter (Dartmouth College); Processing: Gladys Kober (NASA/Catholic University of America)

Red, white, and blue stars glitter like a sparkler being waved on a dark night in this new image from NASA’s Hubble Space Telescope. NASA released this image to celebrate the United States’ 250th anniversary, as the agency carries forward America’s legacy of exploration.

Located in the outer halo of our Milky Way galaxy, globular cluster NGC 6426 is a spherical collection of stars bound together by their mutual gravity, one of 150 known globular clusters in our galaxy. These groups of stars are thought to form as a unit from the same collapsing cloud of gas, and thus the stars in them typically have similar ages. The stars in globular clusters tend to be ancient. At approximately 13 billion years old, NGC 6426 is one of the Milky Way’s oldest globular clusters and almost as old as the universe itself (13.7 billion years).

In this image, blue indicates the shorter wavelengths that are visible light, while red depicts the longer wavelengths of visible light, as well as some near-infrared light. Colors in Hubble images are chosen based on standard image processing techniques to best represent the wavelengths of light that pass through the filters used in the observation. Because the color and temperature of stars are directly related, we know that the blue stars in this image are hotter and the red stars are cooler.

The stars of NGC 6426 have low metallicity, which means they have fewer elements that are heavier than hydrogen and helium. These conditions resemble those of the early universe, when matter was mostly helium and hydrogen and heavier elements were just beginning to form via nuclear fusion within massive stars.

Researchers have found evidence for two chemically distinct populations of stars in NGC 6426, indicating that the slightly younger and more metallic stars were enriched with material from the explosive deaths of the cluster’s earlier stars. Massive stars that explode as supernovae fling elements heavier than hydrogen and helium into the universe, seeding it with materials to build new stars and planets.

Hubble took this image as part of a study of globular clusters in the Milky Way’s halo intended to determine their ages and shed light on the formation and evolution of the galaxy. Over the past three decades in orbit, Hubble has fundamentally changed our understanding of the universe. Its discoveries are expanded upon and complemented by observations from other NASA missions like the infrared-detecting James Webb Space Telescope and the Nancy Grace Roman Space Telescope, scheduled to launch in late summer.

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Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight CenterGreenbelt, MD
claire.andreoli@nasa.gov

NASA’s Hubble Spots Star-Spangled Cosmic Scene

3 July 2026 at 08:42

3 min read

NASA’s Hubble Spots Star-Spangled Cosmic Scene

A packed, roughly spherical cluster of red, white and blue stars shines against the black background of space. The stars are clustered most densely toward the center of the cluster.
This image from NASA’s Hubble Space Telescope shows Messier 3, a densely packed cluster of stars whose origins may be a merger between globular clusters in the early universe.
NASA, ESA, and A. Sarajedini (Florida Atlantic University); Processing: Gladys Kober (NASA/Catholic University of America)

More than 500,000 stars blaze red, white, and blue in this image from NASA’s Hubble Space Telescope, released in celebration of the United States’ 250th anniversary. The image showcases Messier 3 (M3), one of the Milky Way galaxy’s most massive globular clusters, or spherical collections of gravitationally bound stars. Globular clusters are made up of ancient stars that formed at roughly the same time from the same cloud of gas, giving those stars similar ages. Around 150 known globular clusters are sprinkled around the outer regions of the Milky Way.

In addition to its significant mass, M3 is unusual because it lies relatively far from the galactic center and has more than 240 RR Lyrae variable stars, the most of any globular cluster in our galaxy. RR Lyrae variables are some of the galaxy’s oldest stars and are of special interest to astronomers, due to their age and because their light fluctuates over time in a way that tells us their intrinsic brightness. This true brightness can be used to measure distances in the cosmos, just as knowing the brightness of car headlights on a dark road can help estimate the distance to an oncoming vehicle.

The M3 globular cluster also contains around 70 identified “blue straggler” candidates, which are stars that shine with a bright, blue light that makes them look like younger stars than the typical, redder residents of globular clusters. This was the first cluster in which these oddball stars were located. These stars are thought to have gravitationally pulled mass from companion stars, rejuvenating them and making them appear bluer and younger despite their true age.

The unusual characteristics of M3 may arise from its origins. The globular cluster, which contains two distinct populations of stars, may be the result of a merger of two globular clusters. These two clusters were members of the same dwarf galaxy, which was later swallowed up by the Milky Way.

Hubble has taken several images of M3, also known as NGC 5272, documenting its complicated and intriguing characteristics. In this image, blue indicates the shorter wavelengths that are visible light, while red depicts the longer wavelengths of visible light, as well as some near-infrared light. Colors in Hubble images are chosen based on standard image processing techniques to best represent the wavelengths of light that pass through the filters used in the observation. Because the color and temperature of stars are directly related, we know that the blue stars in this image are hotter and the red stars are cooler.

This image is part of a Hubble Treasury program survey designed to observe approximately half of the Milky Way’s globular clusters to construct a detailed chronology of how the Milky Way galaxy formed. With over 30 years of observations, Hubble is one of NASA’s flagship observatories and works in complement with its sibling space missions, including the infrared-detecting Webb Space Telescope and the upcoming Nancy Grace Roman Space Telescope, to weave together a comprehensive picture of our vast universe.

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Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight CenterGreenbelt, MD
claire.andreoli@nasa.gov

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