New Delhi, May 23: Confusion often arises when observing stars and galaxies in the depths of space. NASA has recently addressed this issue through a special image shared on social media.
The Hubble Space Telescope posted an intriguing question on its official Instagram account: “Star or Galaxy?” The image captured by Hubble showcases a cluster of galaxies, yet some stars are also visible. NASA provided an easy method to differentiate between the two using ‘diffraction spikes.’
The posted image features the galaxy cluster MACS J1141.6-1905. Almost every bright point in this image represents an entire galaxy, containing millions or even billions of stars. However, some bright points are stars relatively close to our Milky Way, leading to natural confusion about which point is a star and which is a galaxy.
According to NASA, when light from a star or other light source passes the edges of the structures supporting Hubble’s secondary mirror, it diffracts, forming sharp rays or ‘spikes’ around it. These diffraction spikes are a key indicator of a star’s identity, while galaxies do not exhibit such clear and sharp rays.
In the lower right part of the image, a star is distinctly shining with diffraction spikes. Meanwhile, various spiral and elliptical galaxies can be seen spreading out on the left side.
The MACS J1141.6-1905 galaxy group is located in the ‘Crater’ constellation and is approximately 4 billion light-years away from Earth. Hubble has captured it in both visible and infrared light. Scientists have studied this cluster to understand gravitational lensing and galaxies that shine in X-rays.
The Hubble Space Telescope’s archive has now become a treasure trove of over 1.7 million observations. This data is proving to be extremely valuable for future astronomers. The image, created in collaboration with NASA and the European Space Agency (ESA), was processed by H. Abeling from the University of Hawaii and NASA’s G. Coburn.
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