Hypervelocity stars, rogue black holes, vacuum metastability events, gamma rays. Set Terror Level to OMYGODWEREGONNADIE!!!! and commence your panicking.
I can think of an eighth: very long period or single-apparition comets, particularly those that don’t come from the plane of the ecliptic. (As they might not if they’re interstellar or from the Oort Cloud). Phil Plait mentions these in his great book Death from the Skies:
While we might have decades of notice for an asteroid impact, we might have only a few years for a comet. Even comet Hale-Bopp, which was one of the brightest ever seen, and which delighted hundreds of millions of people, was only discovered about two years in advance of its passage of Earth. Had it been aimed for us, there wouldn’t have been a damn thing we could have done about it. Hale-Bopp’s nucleus—the solid part of the comet—was twenty-five miles across. Had it hit, it would have made the asteroid impact that wiped out the dinosaurs look like a wet firecracker.
Part of the problem with these interstellar comets is that their average velocities are a great deal higher than your normal asteroid. They carry a huge wallop. And since they could come from anywhere in the sky, they’re hard to pick up. (Most people looking for these sorts of things focus on the ecliptic, since that’s the most likely place to find them).
Part of the problem with these interstellar comets is that their average velocities are a great deal higher than your normal asteroid. They carry a huge wallop. And since they could come from anywhere in the sky, they’re hard to pick up. (Most people looking for these sorts of things focus on the ecliptic, since that’s the most likely place to find them).
I can think of a ninth: strangelets. Of course, there’s no proof those exist, but if they do there’s not a damn thing we can do about it if one contacts the Earth.
Ultimately, we will, but if the cause is some sort of steller event, like a super or hypernova and we’re in the way of the gamma ray burst, there’s diddly squat we can do about it, so I see no point in being worried about it.
I think the likelier outcome, at least for the immidiate future is that we’ll mostly live a normal lifespan before we “sleep with out fathers!”
Equal Opportunity Curmudgeon - 19 April 2011 09:27 AM
Set Terror Level to OMYGODWEREGONNADIE!!!!
Ultimately, we will, but if the cause is some sort of stellar event, like a super or hypernova and we’re in the way of the gamma ray burst, there’s diddly squat we can do about it, so I see no point in being worried about it.
At least a stellar event will be quick… lordie lordie just don’t drag it out.
“strangelets” I hadn’t been familiar with those, now that I’m wiki educated, how very strange.
PS. reading all the stellar threats I couldn’t help but think of that “Jesus: I will survive” YouTube video - I still giggle when I think about that ending.
Even if we count the last major catastropne from outer space as 60,000 years ago, that means that historically there has been a 1/60,000 probability of such an event happening in a given year. And I can live with those odds.
Damn, I always knew the universe was out to get me.
We obviously have to initiate a first strike. Take out the universe before it gets us.
These freewheeling stars are the Hells Angels of the cosmos: They’re big, scary and notoriously difficult to stop, and if they move into your neighborhood, your property values are going straight to hell. Yep, there are sun-size balls of nuclear energy zooming wherever they want at speeds of up to 4,000 kilometers per second, burning everything they come across and fucking up every orbit they pass by. We just thought you should know that, in case you were running low on nebulous dread or something.
Have they been keeping track of the success and failure rate of attempts to stop or redirect these things?
{sorry duplicate ~ weird things going on ~ today my wifi has changing over from ALLTEL to AT&T, and so far it really, really sucks. Seems like I suddenly have half the reception rather than the promised double. go figure… but then again maybe it’ll get better.}
I know Cracked is humor site, but this article is so far-fetched and wrong about everything that it is not close to funny.
Let’s start with hypervelocity stars. Our Sun, a typical G class star, is 1.4 million kilometers in diameter. Cracked describes these hypervelocity stars as “great balls of nuclear fire a million miles across.” This is pure hyperbole. A star that size burn out its nuclear fuel long before it reaches Earth. As for “an average HV star moves at a staggering 1.6 million kilometers an hour,” that sounds fast until you think about interstellar distances. These stars are not moving at us from Alpha Centauri, they are orbiting the outer fringes of the galaxy, which puts them several thousand light years from us, at the closest. How far is a light year? Well, at 300,000 km/s x 31,536,000 s/yr you can that light travels about 9.46 trillion km/yr. Cracked can’t even get their math right. In the first paragraph they tell us hypervelocity stars move at 4000 km/s, then a few paragraphs later they tell us these stars move at 1.6 million km/hr. 4000km/s x 3600s/hr = 14.4 million km/hr. Which is it dudes? At the higher speed a hypervelocity star would take 675 years to travel one light year. At the lower speed it would take 6075 years. Cracked even tells us these stars are moving between galaxies. Even at the faster speed a hypervelocity star would take more than 170 billion years to get here.
The rest of the article is just as ludicrous. This one is is not funny, it is just stupid.
Thank the gods that the Anthropic principal will protect us because the universe has been tweaked to be just right for us. The gods love us. Sun spots are worrisome, when Ra is displeased then look out people.
The rocks and comets and stuff… the solar system was a shooting gallery, but most of that has been cleaned up by now. The big rocks have been getting less and less likely, not zero chances yet, but getting better every day!
Deteriorata… hummm… With good time Ken’s digits! heh heh. That Sabrina music video too, humm. (Yeah yeah, stop pretending that you didn’t click it and comment on it.)
I hadn’t been familiar with those, now that I’m wiki educated, how very strange.
The gods love us. Sun spots are worrisome, when Ra is displeased then look out people. 
With good time Ken’s digits! 
