HOW HOAG’S OBJECT COULD HAVE FORMED

The possible steps taken towards creating an odd ring-shaped galaxy

1 A lightweight galaxy approaches a larger one

According to a study headed by François Schweizer in 1987, a lightweight galaxy may have come into close enough proximity to a heavier, elliptical galaxy for a major accretion event to have taken place.

2 Mass is transferred to Hoag’s Object

At some stage – likely some 2 to 3 billion years ago – there would have been some level of interaction between the two galaxies which, short of a merger or collision, caused the mass to transfer to Hoag’s Object.

3 Forming a surrounding ring

As the gravity of the heavier galaxy ripped the lighter one apart, transferred gas from the lightweight galaxy settled into orbit and fuelled the mass formation of stars, which over time formed a distinctive ring.

4 Evidence dissipates over the years

Any leftover detritus was then blown away into the universe over many years, which accounts for why there is no firm observational evidence of the event. Such scientific theory continues to be debated, however.