Ok, so New Scientist is just not making my brain happy this week. I decided to forage around their websiteÂ¬â€ to see what was there (one of their editors, Maggie McKee, is a friendly soul I worked with at Astronomy and I wanted to see what’s she’s up to now a days). While Maggie has been writing a whole series of nice, interesting, valid pieces, I found another cosmology based story that just hurt.
Some background… Many cosmologists believe our universe is one of many parallel or branching universes.Â¬â€ These universe’s, if these theories are right, are boiling and seething side-by-side, and (if these theories are correct) these parallel multiverses may periodically merge like two soap bubbles meeting in the wind. It may, if these theories are correct, be possible that one edge of our universe is rapidly getting eaten away by another cannibalistic universe. (Go read this article by Andrei Linde to learn more. Additional links are on his website.)
Those are the theories. Observationally, until the big rip comes are way, we have no way of knowing if they’re true.
And, the New Scientist article seemed to indicate that we might have found that proof in the from of a giant void. (I talked about the void here). The proof? Well, I couldn’t find a peer reviewed journal article or any related science papers, so I’m a little sketchy on what the proof is other than there is a volume of space with no radio galaxies superimposed in front of a particularly cool section of the CMB.
There are also giant galaxy clusters out there and hot areas of the CMB. I’m not sure any of the big things are as big as the void, but dense things tend to collapse while empty things tend to appear to grow as the things around them collapse. Think of it this way: Imagine you have a crowded show room of people and you drop in 5 people who just finished cleaning barns, eating beans, and haven’t yet showered. An initial small area of nothing – a void – will form around each of these people, but it won’t grow since their smell probably is only noticable within a small radius. Now if you drop in 5 movie stars willing to sign autographs and have their pictures taken, then you’ll see a collapse as people crowd around the movie stars, and one side of effect of that collapse is those voids around our tired smelly people (who’ve opted to just plunk down on the floor and wait out the madness rather than to mob the movie stars) seem to grow. The smelly people aren’t doing a better job pushing people away – they didn’t get smellier – but rather the movie stars attracted all the mass to them making the voids seem to grow.
Until we have optical deep images of the void and spectra to map out any non-radio galaxies or other objects (like gas clouds) in the void, I can’t put much significance on the “It’s the most giant empty thing no one ever imagined could exist” hype. Yes, it is cool. Yes, it needs follow up time to understand. But, shouldn’t there always be 1 spot on the sky that is labled “Here be the lowest density of stuff?”
So, rant about the void hype aside, what about the “Its another universe” hype?
Personally, the idea that another universe merging with our own appearing as nothing more than an empty patch strikes me as rather depressing. No fireworks. No gamma rays. No high energy, low energy, or any energy anything – just a bubble of nothing. I’m not a theoretical cosmologist, but I can’t imagine how to colliding universes, with potentially different physical parameters, could collide and not create cause some sort of event at the surface of merger.
I wish I could find a scientific paper addressing this, but I couldn’t. And New Scientist is read by more people than any science journal (and maybe by more people than all the English astronomy only journals combined). So… What people are going to end up learning is our universe might be getting consumed. And some of them will freak out. And some of them will decide this is another example of scientists scaring people for not reason. And I really wish this type of hype wasn’t something I know will eventually lead to some student saying “Isn’t our universe getting sucked into a giant void?” one day.
Maybe it’s getting sucked into a void. Maybe. But I don’t think it’s getting sucked into that particular void.Â¬â€ Give it a couple years – that’s how long I think it will take to get the telescope time needed to start to understand the void. Once the data is in, please feel free to built as big an observationally based theory as you like.