Hubble zooms in on a galaxy pair that is in a “long-distance relationship”

An image of Hubble space telescope in orbit (Image source: NASA)

Hubble’s Picture of the Week is a celestial pair known as Arp 4. The two galaxies appear deceptively close. However, in reality, they are not close at all. One of the pair is over ten times farther away from us than the other.

Chibuike Okpara, Published 12/27/2025

Astronomy / Space Science

Arp 4 is a galaxy pair located in the constellation Cetus (The Whale). This pair consists of a larger galaxy, MCG-02-05-050, and its smaller companion, MCG-02-05-050a.

In this image, MCG-02-05-050 is the one with the blue fragmented spiral arms and a dim disk in the middle. Its companion MCG-02-05-050a is at the top left of the image. MCG-02-05-050a has well-defined spiral arms and is much brighter.

When viewed from Earth, the galaxies look like they are close to each other. But in reality, they are far away from each other. MCG-02-05-050 is 65 million light-years away from Earth. Meanwhile, the smaller companion MCG-02-05-050a is 675 million light-years away from Earth.

In essence, MCG-02-05-050a is ten times farther away from Earth than MCG-02-05-050. From those figures, it then becomes likely that the supposed smaller companion MCG-02-05-050a is actually the larger of the two. As for why the galaxies appear close despite their distance, it is simply an unlikely visual coincidence.

The name Arp comes from the Atlas of Peculiar Galaxies. This catalog was compiled by astronomer Halton Arp in the 1960s. Since Hubble started operations, it has revolutionized the study of the galaxies in this catalog.

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Source(s)

ESA

Image source: ESA/Hubble, NASA, J. Dalcanton, Dark Energy Survey, DOE, FNAL, DECam, CTIO, NOIRLab, NSF, and AURA

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Chibuike Okpara - Tech Writer - 336 articles published on Notebookcheck since 2024

I have always been fascinated by technology and digital devices my entire life and even got addicted to it. I have always marveled at the intricacy of even the simplest digital devices and systems around us. I have been writing and publishing articles online for about 6 years now, just about a year ago, I found myself lost in the marvel of smartphones and laptops we have in our hands every day. I developed a passion for learning about new devices and technologies that come with them and at some point, I asked myself, "Why not get into writing tech articles?" It is useless to say I followed up the idea — it is evident. I am an open-minded individual who derives an infinite amount of joy from researching and discovering new information, I believe there is so much to learn and such a short life to live, so I put my time to good use — learning new things. I am a 'bookworm' of the internet and digital devices. When I am not writing, you will find me on my devices still, I do explore and admire the beauty of nature and creatures. I am a fast learner and quickly adapt to changes, always looking forward to new adventures.

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