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Two Asteroids Zipping Past Earth Today

26 points by toni 16y ago

rkowalick 16y ago
In general there is one major impact every million years -a mere blink of the eye in geological time. If the universe is only a few billion years old, how is a million years a "blink of the eye"?
- jat850 16y ago
  Just a convenient turn of phrase, probably. Assuming the universe is around 14 billion years old, a million years is like comparing a blink to about 70 minutes (average speed of a blink being somewhere between 300ms and 400ms). Does a blink feel short in comparison to 70 minutes? That's a matter of perception, I guess...
  - hugh3 16y ago
    Wow, I can't believe we both replied in exactly the same way, including the same damn approximations, simultaneously.
    - jat850 16y ago
      Indeed. At least I feel better about my math now :)
    - jonsen 16y ago
      Happens once in a million years ;-) A little spooky it happened on this post, isn't it.
- hugh3 16y ago
  The universe is about 14 billion years old, so a million years is one fourteen-thousandth of the age of the universe. Now, an actual eyeblink takes about 300 milliseconds, so a million years is to the age of the universe as the blink of an eye is to 70 minutes. So the metaphor seems reasonable to me.
moron4hire 16y ago
"Keeping an eye on NEO is extremely important, given the large number of unknown space rocks that lurk in outer space." So it's important to keep track of the few that we know of, because of the unknown numbers of ones we don't know of? And what if we do track them? What do we do with this information? It's not like we're going to move the things or move the planet out of the way. Tracking NEOs does nothing for us, with maybe the exception of mapping trajectories for deep space probes. How many of those do we launch in a year? And given that we don't know the full implications such an impact would have, isn't the psychological effect on hysterical populations enough of a reason to heed "ignorance is bliss"?
- rbanffy 16y ago
  > Tracking NEOs does nothing for us The dinosaurs would agree with you.
- mike-cardwell 16y ago
  If we don't track them, we wont develop better technology to track more of them. The more we track, the more information we have about what's out there. The more information we have, the better decisions we can make about the risks and how to reduce them. What's the alternative. Ignore the issue until the inevitable happens?
- ugh 16y ago
  You obviously want to track known objects as well as discover new ones. That has happened at a pretty quick pace in the last few years, thanks to increased professional effort (while amateur astronomers discovered most asteroids only a few years ago nowadays most are discovered by professionals). Asteroid impacts are one of the few natural disasters (the other probably being floods) that we could actually be able to prevent from happening. It’s a good idea to be on the lookout. Oh, and even if we can’t prevent the rock from falling we can still evacuate in a timely manner (e.g. in case of an asteroid hitting the Pacific and causing a Tsunami). Sure, if we discover the asteroid a week before it hits we can’t do much. But if we know a few years in advance that an asteroid will cross paths with Earth we can actually do something about it (since relatively minuscule changes in the asteroid’s trajectory can move it out of the way). One way would be to simply park a spacecraft next to it. The gravitational pull of the spacecraft which keeps its distance with thrusters can move the asteroid ever so slightly. It might also possible to hit the asteroid just right with a kinetic impacter (i.e. a big hunk of heavy metal) and slightly whack it. It’s not expensive. People are actually working on this. And they better be, ask the dinosaurs. (If you can.)
jacquesm 16y ago
I can see why it is fascinating to keep an eye on these things but we 'need' to keep an eye on them just as much as we need to keep an eye out for invading aliens. We'll know it when it happens, trust me on that one. Until then it doesn't matter. If and when it happens we'll be dealing with the aftermath long before we'll be able to have a handle on what we can do about the event itself. You could even argue that this is one of the few cases where foreknowledge would not help at all, especially not in the case of a very near miss (or is that a near hit ;) ).
- rbanffy 16y ago
  > We'll know it when it happens, trust me on that one. But wouldn't it be nice to know it before a giant tsunami wipes out the whole pacific coastline? How costly is it compared to what damage it could generate? How costly would be to avert such a disaster compared to the cost of digging a mile-wide crater in central Europe? If we knew of a mountain-sized rock headed towards Earth we would be able to prevent a disaster, provided we had an early warning system in place. IIRC, a Delta IV heavy can carry a Tsar-bomba-sized device, plus a booster to put in the correct trajectory. It wouldn't take long to assemble a couple devices like this and try a couple approaches, from deflection to blasting it to small pieces (yes, I would prefer a couple hundred airblasts over a single mountain hitting the surface). I think the politics of putting a gigaton device on top of a rocket are much more complicated than the engineering.
  - lmkg 16y ago
    I think you overestimate the effect current technology can have on a meteor large enough to significantly dent the human population. Some of the objects mentioned in the article are on the order of hundreds of kilometers. Mountains aren't even on the same scale as that. It's beyond our ability to even scratch.
    - btilly 16y ago
      I think you underestimate the value of stopping smaller impacts. http://en.wikipedia.org/wiki/Impact_event#Sizes_and_frequencies http://en.wikipedia.org/wiki/Impact_event#Sizes_and_frequenc... claims that an incident on the size of the Tunguska event (would could take out a large city) happens every thousand years, and to prevent it we need to move an object with a diameter of 50 m or so. A object on this scale might be in the 10,000,000 kg range. We'd like to deflect it 6000 km or so (ie make it miss the Earth). We have about 600,000,000 seconds to do so. If we can give it a sideways momentum of 100,000 kg*m/s, we'll be fine. While difficult, this may be within our means. (Tapping it with a nuclear bomb is only the most obvious.)

26 points by toni 16y ago

In general there is one major impact every million years -a mere blink of the eye in geological time. If the universe is only a few billion years old, how is a million years a "blink of the eye"?

jat850 16y ago
Just a convenient turn of phrase, probably. Assuming the universe is around 14 billion years old, a million years is like comparing a blink to about 70 minutes (average speed of a blink being somewhere between 300ms and 400ms). Does a blink feel short in comparison to 70 minutes? That's a matter of perception, I guess...
- hugh3 16y ago
  Wow, I can't believe we both replied in exactly the same way, including the same damn approximations, simultaneously.
  - jat850 16y ago
    Indeed. At least I feel better about my math now :)
  - jonsen 16y ago
    Happens once in a million years ;-) A little spooky it happened on this post, isn't it.
hugh3 16y ago
The universe is about 14 billion years old, so a million years is one fourteen-thousandth of the age of the universe. Now, an actual eyeblink takes about 300 milliseconds, so a million years is to the age of the universe as the blink of an eye is to 70 minutes. So the metaphor seems reasonable to me.

moron4hire 16y ago

"Keeping an eye on NEO is extremely important, given the large number of unknown space rocks that lurk in outer space." So it's important to keep track of the few that we know of, because of the unknown numbers of ones we don't know of? And what if we do track them? What do we do with this information? It's not like we're going to move the things or move the planet out of the way. Tracking NEOs does nothing for us, with maybe the exception of mapping trajectories for deep space probes. How many of those do we launch in a year? And given that we don't know the full implications such an impact would have, isn't the psychological effect on hysterical populations enough of a reason to heed "ignorance is bliss"?

rbanffy 16y ago
> Tracking NEOs does nothing for us The dinosaurs would agree with you.
mike-cardwell 16y ago
If we don't track them, we wont develop better technology to track more of them. The more we track, the more information we have about what's out there. The more information we have, the better decisions we can make about the risks and how to reduce them. What's the alternative. Ignore the issue until the inevitable happens?
ugh 16y ago
You obviously want to track known objects as well as discover new ones. That has happened at a pretty quick pace in the last few years, thanks to increased professional effort (while amateur astronomers discovered most asteroids only a few years ago nowadays most are discovered by professionals). Asteroid impacts are one of the few natural disasters (the other probably being floods) that we could actually be able to prevent from happening. It’s a good idea to be on the lookout. Oh, and even if we can’t prevent the rock from falling we can still evacuate in a timely manner (e.g. in case of an asteroid hitting the Pacific and causing a Tsunami). Sure, if we discover the asteroid a week before it hits we can’t do much. But if we know a few years in advance that an asteroid will cross paths with Earth we can actually do something about it (since relatively minuscule changes in the asteroid’s trajectory can move it out of the way). One way would be to simply park a spacecraft next to it. The gravitational pull of the spacecraft which keeps its distance with thrusters can move the asteroid ever so slightly. It might also possible to hit the asteroid just right with a kinetic impacter (i.e. a big hunk of heavy metal) and slightly whack it. It’s not expensive. People are actually working on this. And they better be, ask the dinosaurs. (If you can.)

jacquesm 16y ago

I can see why it is fascinating to keep an eye on these things but we 'need' to keep an eye on them just as much as we need to keep an eye out for invading aliens. We'll know it when it happens, trust me on that one. Until then it doesn't matter. If and when it happens we'll be dealing with the aftermath long before we'll be able to have a handle on what we can do about the event itself. You could even argue that this is one of the few cases where foreknowledge would not help at all, especially not in the case of a very near miss (or is that a near hit ;) ).

rbanffy 16y ago
> We'll know it when it happens, trust me on that one. But wouldn't it be nice to know it before a giant tsunami wipes out the whole pacific coastline? How costly is it compared to what damage it could generate? How costly would be to avert such a disaster compared to the cost of digging a mile-wide crater in central Europe? If we knew of a mountain-sized rock headed towards Earth we would be able to prevent a disaster, provided we had an early warning system in place. IIRC, a Delta IV heavy can carry a Tsar-bomba-sized device, plus a booster to put in the correct trajectory. It wouldn't take long to assemble a couple devices like this and try a couple approaches, from deflection to blasting it to small pieces (yes, I would prefer a couple hundred airblasts over a single mountain hitting the surface). I think the politics of putting a gigaton device on top of a rocket are much more complicated than the engineering.
- lmkg 16y ago
  I think you overestimate the effect current technology can have on a meteor large enough to significantly dent the human population. Some of the objects mentioned in the article are on the order of hundreds of kilometers. Mountains aren't even on the same scale as that. It's beyond our ability to even scratch.
  - btilly 16y ago
    I think you underestimate the value of stopping smaller impacts. http://en.wikipedia.org/wiki/Impact_event#Sizes_and_frequencies http://en.wikipedia.org/wiki/Impact_event#Sizes_and_frequenc... claims that an incident on the size of the Tunguska event (would could take out a large city) happens every thousand years, and to prevent it we need to move an object with a diameter of 50 m or so. A object on this scale might be in the 10,000,000 kg range. We'd like to deflect it 6000 km or so (ie make it miss the Earth). We have about 600,000,000 seconds to do so. If we can give it a sideways momentum of 100,000 kg*m/s, we'll be fine. While difficult, this may be within our means. (Tapping it with a nuclear bomb is only the most obvious.)