That’s shorthand for “Cardiopulmonary Resuscitation for the Milky Way Galaxy”. Scientists believe that if our galaxy is not already dead it is probably drawing its last gasps. Kevin Schawinski, a Swiss scientist from Switzerland’s Federal Institute of Technology explains that this happens when a galaxy no longer forms new stars. His research claims that we are all living in a zombie galaxy that has been a billion years long since dead.
Schawinski has a color code system for galaxies:
- Blue Cloud – Galaxies that are still forming stars from gases
- Red Sequence – Galaxies that are evolving passively
- Green valley – This is a galaxy that is at the crossroads of evolution, between blue cloud stage and red sequence stage. (An interesting tidbit… the term “green valley” came about after an Arizona University student, attending a lecture on the evolution of galaxies, responded to the speaker’s description of the death phase of a galaxy by yelling, “Green Valley! Where galaxies go to die!” referring to a local retirement community, Green Valley, Arizona.)
Green valley galaxies are at an intermediate state. Stars are still forming but the gas reservoir is running low. However, space time is not like real time on Earth. By the time researchers can get the data that a reservoir is empty, meaning a galaxy is no longer capable of creating stars, that galaxy may have already been dead for billions of years.
Andromeda galaxy, our neighbor, is also a zombie galaxy. It began dying eons ago but still produces stars. That means it’s gas reservoir is empty but the stars that began the creation process billions of years ago are still forming. Kind of like when the gringa’s car runs out of gas but I manage to coast off the freeway with just enough momentum to reach the gas pump at the station on the side of the road.
So, even though the data collected about our own Milky Way galaxy is not complete, what scientists do have indicates that it may be on the precipice of falling into the green valley. Once the zombie period is over and a galaxy actually begins to show signs that it is truly dead, it may take billions of years for a complete death mask to be detectable. The clearest indicator is that they stop expanding. Galaxies grow by making stars so when no new growth is possible, when galactic expansion ceases, the galaxy is dead.
The funny thing about this is that stars are the by-product of a build-up of certain gases. It’s as if a galaxy grows by recycling its waste. If mankind could somehow imitate that model just imagine what that would mean for our pollution problems!
So, if star-making gases are the waste product of galaxies, what is their “food”? Dark matter, that invisible stuff thought to be the fibers that hold galaxies together, provide the hydrogen gas that feeds galaxies so they can make stars and grow larger. When hydrogen gas cools it becomes trapped in the dark matter that forms halos around cosmic objects like planets. As it cools, this disk of gas eventually breaks up to later form stars. Where does the hydrogen come from? From dying stars. So, really, a star is just a cosmic object that is recycled, reborn or reincarnated, depending on the perspective you prefer.
What does that mean for humans living in the Milky Way galaxy? It means that if our Sun ever goes kaput, that’s it for civilization. We will never get a new Sun.
Image Credit: d.ibtimes.co.uk