Taken in part from an email conversation I had with a friend:
Yesterday I received an email from a friend with a link to a rather unremarkable Cracked article, entitled 7 Horrible Ways The Universe Can Destroy Us Without Warning. Done in the typical farcical style of Cracked this list sadly does not contain either the more likely ways of destruction, or the proper perspective on the paths of doom that it does list.
Here is my brief take on it:
- Hyper-velocity Stars – space is HUGE. Even the thousands of such stars that the article talks about don’t pose any remotely probable risk to any of the stars in the Milky Way – much less to us – in any reasonable time span. And like the text says – we’ll see any such star coming. (which puts the lie to “without warning” in the article’s title)
- Rogue Black Holes – the odds are even lower than those for Hyper-velocity stars.
- Galactic Cannibalism – the article gets several things wrong here. Andromeda strictly speaking is not the closest galaxy to us, and it also (almost certainly) has less mass than the Milky Way galaxy, none of which is remotely relevant. Galactic mergers take on the order of billions of years. Probability of this affecting you or any of your descendants for hundreds of generations is zero. Probability of this affecting any of their descendants – also as near zero as really matters, since these are non-violent events. Stars do not hit each other, and clouds of intergalactic and intra-galactic dust and gas do not affect us in any negative way, since these clouds are incredibly thin – quadrillions of times thinner than air. And once again here we have billions of years of warning.
- Vacuum Metastability Event – now this is as bullshit as bullshit gets. Of all these threats, this is the emptiest. They suggest that one possible interpretation of the Quantum Theory is a reason to worry? After the universe has existed without any issues for 13.75 billion years, I won’t hold my breath for it collapsing. Could it happen? Only if this interpretation is correct, and even then the universe has held up pretty well for long enough that it does not matter.
- Cosmic Radiation – well I suppose that this particular danger is real. For astronauts. This means that we need to develop better radiation shielding if we plan to put a base on the moon. All of us Earth-bound folks, on the other hand, have little to worry about.
- Gamma Ray Bursts – these guys actually might be dangerous to life on Earth* – IF they’re close enough and IF they’re pointed at us. Those are big ifs. The chances of these happening are pretty damn low, though not impossible.
- Magnetars are pretty noticeable, so chances are that we know about the majority of them in our galaxy, and they are far enough away to not be dangerous to us*. And if a magnetar was significantly closer? Unless one showed up on our doorstep, we would risk damage to satellites, and possible blackouts. Don’t expect it to vaporize you.
So as a summary, is there anything to worry about? Well, ask yourself when was the last time you’ve heard of anyone dying from a Gamma Ray Burst? What we should be a lot more worried about is asteroids. Those are hundreds, even thousands of times more likely to get us, and a couple have already caused mass extinctions on Earth in the past.
All in all this is a scare piece, and should not be taken seriously. The list even skips the one class of astronomical events most likely to affect humans in any meaningful way – solar flares*, which do happen regularly. For a more comprehensive list of things to worry about I would read “Death From the Skies” by Phil Plait, the Bad Astronomer (in fact I really would gladly read this book which I haven’t yet gotten around to purchasing – expect a review when I do).
I’ll leave you with this awesome summary of things as they stand, courtesy of Phil Plait and George Hrab:
Good night, and don’t let the black holes bite.
* Some of these do pose danger to man-made infrastructure – mostly to satellites, power grids, and in extreme cases sensitive electronics. Health-wise though there’s little to worry about, and the article after all did promise horrible destruction.