An analysis of the nearby spiral galaxies suggests that they once might have come into being as lenticulars before becoming gigantic elliptical globs.
Spiral galaxies like the Milky Way are thought to design themselves into lentil-shaped or lenticular masses of cosmic matter, astronomer Alister Graham reported in the July Monthly Notices of the Royal Astronomical Society. If correct, Graham’s proposed change in the galactic evolution would rewrite the history of the Milky Way.
“Lenticulars have always been sort of the abandoned stepchild of [galaxy] morphology,” says astronomer Christopher Conselice of the University of Manchester in England, who wasn’t involved in the study.
The stars in the lenticular galaxies protrude in the middle and thins out towards the edges, just like a lentil.
Unlike lenticular galaxies, spiral galaxies have lots of star-forming gas. Scientists are still unsure why lenticular galaxies don’t follow this phenomenon.
Graham, of Swinburne University of Technology in Hawthorn, Australia, found new clues to this mystery of galaxy evolution by considering black holes.
A supermassive black hole is included in the cosmic matter of most galaxies. At the time when galaxies merge, so do these black holes. This phenomenon makes the mass of a galaxy’s black hole a kind of record of its past collisions.