The Hoag Object is a strange and rare ring galaxy located 600 million light years from Earth. It was discovered in 1950 by astronomer Arthur A. Hoag. What makes this celestial object so special?
Hoag’s object is a strange and extremely rare ring-shaped galaxy, located 600 million light years from Earth and discovered in 1950 by astronomer Arthur A. Hoag (1921-1999). It is slightly larger than our Milky Way and has a diameter of about 120,000 light years. After several decades, this cosmic event captured by the Hubble Space Telescope (NASA) continues to intrigue scientists as to its origin. For what ?
To this day, astronomers do not know how Hoag’s object formed. If you look closely at the Serpent Constellation, you can see a galaxy within a galaxy, which itself is inside another galaxy.
In images captured by NASA’s Hubble Telescope, we can see a bright ring made up of billions of young blue stars that form a perfect circle around a smaller, denser sphere of red stars, probably older. In the dark space between the two circles of stars, another ring-shaped galaxy, much further away from us, also hides.
Amazing! Did you know that chickens can blush?
To this day, astronomers still don’t know what caused this extremely rare cosmic phenomenon. After all, ring galaxies – like Hoag’s object – represent less than 0.1% of all existing galaxies. But what is a ring galaxy?
Actually, ring galaxies are normal disk-shaped galaxies which were distorted after a collision with a small galaxy billions of years ago.
The different theories on the formation of the Hoag object
At the time of its discovery, it was suggested that Hoag’s object might be a planetary nebula, but this hypothesis was quickly ruled out. and it was later confirmed that it was in fact a galaxy.
Arthur Hoag proposed that the formation of the rings is just an optical illusion caused by gravitational lensing, an effect that occurs when bodies of large mass bend and amplify light. However, later studies have refuted this hypothesis.
Alert: Atmospheric CO2 increases the lifespan of viruses!
Another hypothesis suggests that Hoag’s object was once a disk-shaped galaxy, following a collision with a smaller neighboring galaxy, over the last 3 billion years. The collision would have produced a density wave in the disk that would have resulted in a characteristic ring shape (imagine a hole in the “belly” of the disk), permanently distorting its gravitational force.
However, if the collision actually occurred within the last three billion years, astronomers should be able to observe the consequences, but no evidence has been found. If a cosmic collision had really taken place at the center of this galaxy, it would probably have happened much longer ago, making all traces of it disappear.
What is certain is that astronomers have not yet elucidated the origin of this intriguing cosmic phenomenon. Nowadays, The Hoag Object is one of the great mysteries of the Universe, because no one knows for sure how it formed.
