Reddit reviews Death from the Skies!: These Are the Ways the World Will End . . .
We found 8 Reddit comments about Death from the Skies!: These Are the Ways the World Will End . . .. Here are the top ones, ranked by their Reddit score.
Black holes are sometimes portrayed as something like a cosmic vacuum cleaner, sucking things into them. That's the most important myth to get over. They attract by gravity, the same as stars or planets. The effect on other objects is exactly the same: they're not sucked in, they just go into orbit.
If you want to fall into a black hole, you have to deliberately head straight for it. It's not as easy as you'd think.
Having said that, there are two mechanism by which things that aren't heading directly towards a black hole can end up falling into black holes. The first is friction and collisions within the cloud of material orbiting the black hole, which would tends to result in you gradually dropping into lower and lower orbits until you cross the event horizon. The second is gravitational radiation, which will cause anything to gradually spiral inwards, even without friction.
So the question is: could these mechanisms overwhelm the expansion of the Universe?
That's really easy:
No.
Our Universe is expanding in an accelerating way, ripping apart everything that is not already gravitationally bound together.
But clusters of galaxies are gravitationally bound together... so you could ask: could the black hole have enough attraction to eventually consume all mass in our local cluster of galaxies?
Still no, because of Hawking radiation.
The inspiralling of matter towards a black hole from a large distance is ridiculously slow. If you look at the largest supermassive black holes (which are billions of times the mass of the Sun), you can compare the rate at which stars are spiralling inwards towards them to the rate at which the black holes themselves would evaporate - which is also ridiculously slow. It turns out that the evaporation would happen first, by a long long way.
If you waited for all stars to die and turn to cold cinders, and then waited a few trillions of times longer than that, they still wouldn't be falling into black holes. But the black holes would be evaporating, and given 10^100 years or so even the most massive of them would have gone, long before the rest of the galaxy had a chance to fall into it.
This book is the classic for this kind of deep time stuff. Worth a look. Also this one - very readable and very highly recommended.
There is no way Phil Plait said the asteroid "is going to hit us in 2029". I think you may have misheard or misunderstood the show and I highly suggest reading Death from the skies! where he explains the different probabilities of different doomsday scenarios occurring.
According to Dr. Phil Plait in his book Death From the Skies, a powerful enough solar flare has the capability to overload power lines and transformers, which is why I said essentially. Because obviously if every power line and transformer is blown out or snapped it's not going to be a simple repair.
Death From the Skies is an awesome book, btw.
http://www.amazon.com/Death-Skies-These-Ways-World/dp/0670019976/ref=sr_1_1?ie=UTF8&s=books&qid=1240177223&sr=8-1
https://www.amazon.com/Death-Skies-These-Ways-World/dp/0670019976/
(Waits for Phil Plait to post, because he covered the real meaning of eternity so well in "Death from the Skies." (Hint: start with trillions of years, then proceed exponentially from there.) Highly recommended, two thumbs up, I am not related to the Bad Astronomer in any way, shape or form.)
Buy this book: http://www.amazon.com/Death-Skies-These-Ways-World/dp/0670019976/ref=sr_1_8?ie=UTF8&s=books&qid=1220913560&sr=8-8/badastronomy
This. Easily written for people with basic science backgrounds, builds on itself, and explains some more advanced scientific principles along the way.