A few days ago, I went online. The first news popup I saw was an image of our sister galaxy, Andromeda. I’m a fan of cosmology, so I clicked the popup for details. The heading for the article was designed to be sensational: Hubble shows Milky Way destined for head-on collision with Andromeda Galaxy.
In its first sentence the article states:
NASA astronomers announced Thursday [May 31] they can now predict with certainty the next major cosmic event to affect our galaxy, Sun, and solar system: the titanic collision of our Milky Way galaxy with the neighboring Andromeda galaxy.
As though to disclaim the opening hyperbole, the article quickly goes on to assure the reader that:
…our Earth and solar system are in no danger of being destroyed.
True. But, writing with the urgency assigned to breaking news, the author neglects to put the galactic event into cosmological perspective. Further, written in a style held in reserve for climactic narratives, the article contains terms that are similes to violent collisions, e.g., head-on collision, [it will take four billion years] before the strike, and Previously it was unknown whether the far-future encounter will be a miss, glancing blow, or head-on smashup.
The tone of the article implies a catastrophic event. Television news broadcasts explicitly defined the merging of galaxies as a catastrophic event. That is a disservice to readers who are not familiar with elementary cosmology. We all know that every synonym for catastrophe has a severe negative connotation.
I have two friends who do not share my interest in cosmology. They both send me articles on cosmology that happen to appear online. Each of them sent the article to me with humorous references to the remoteness of the event in terms of our lives. They understandably interpreted the article as a portent of doom that is not at the top of our lists for concern. But they were basically misinformed despite mention that stars are so widely spaced that they do not collide. So, exactly what is catastrophic about merging galaxies! You can’t have it both ways.
Colliding galaxies are common. Although the word, ‘colliding,’ is technically correct, merging is a far more accurate description of galactic interaction. You may be interested to know that in addition to the Andromeda galaxy, there are two other galaxies that show signs of merging with our Milky Way galaxy: the Large Magellanic and Small Magellanic Clouds.
Quoting myself from a book I wrote on elementary cosmology, I hope the following will provide you with a better perspective of galactic merging:
The Sagittarius Dwarf galaxy is too close for its own good. It is prey to our galaxy. Cosmologists tell us that The Milky Way galaxy is in the process of ingesting the dwarf galaxy. It is already nibbling on some of the dwarf galaxy’s stars…Galactic cannibalism (if we must call it by that ugly word) is a very slow process. Galactic snacks neither give the larger galaxy indigestion nor do damage to the captured stars of the smaller galaxy. The stars of the smaller galaxy merely assimilate into the larger galaxy. There is plenty of space for stars to blend without violence.
Like so many lovers of cosmology, I discuss the universe whimsically, but not with misleading hyperbole. Cosmology doesn’t need anyone’s help to be sensational.
Reflections and commentaries by the other Mario Martone 