# Thread: The K-T Impact event - How Bright in the Sky??

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## The K-T Impact event - How Bright in the Sky??

If objects the size of sand grains can produce bright meteors and objects a few cm in size can produce a bright fireball - just how bright would an object 10km be as it passed through the atmosphere?? Maybe thousands or hundreds of thousands of times brighter than the Sun.

What would be the unfortunate effects of being close enough to see it streak through the sky. And I wonder what kind of damage it would do before it even hit the ground???

Disaster movies always show a feeble fireball followed by a long smoky trail.

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While it doesn't calculate the effects of going through the atmosphere, this site is a very handy tool for seeing what the effects of an impact would look like to someone standing some distance away. It does give the radius of the produced fireball, but i suppose that would be the fireball created by the impact itself.

A search for something similar for atmospheric entry effects came up negative.
I did find this paper, which examines the Tungunska event. The paper gives all the relevant equations, so plugging in the variables relevant to the K-T event should shed some light on the question.

3. Assuming the equations hold for objects that large - it has to matter than the diameter of the Chicxulub impactor was comparable to the depth of the troposphere!

(The calculator does get hangwire if you imput too big impactors - frex, it's possible to get transient crater depths greater than the Earth's diameter. However, nothing is obviously strange for Chicxulub-class objects.)

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Originally Posted by AndreasJ
Assuming the equations hold for objects that large - it has to matter than the diameter of the Chicxulub impactor was comparable to the depth of the troposphere
Good point. Makes one wonder wether our 'normal' visualizations with a fireball speeding through the sky are even by far realistic.

There also seems to be a great dependence on inclination angle, i'm not sure that has been established for the K-T impactor.
Last edited by caveman1917; 2010-Aug-02 at 03:09 PM.

5. What puzzles me is that the speed of the impacting body relative to the Earth makes the descent through the atmosphere appear overlong. It seems a large body would go right through the atmosphere, top to bottom, in less than a second.

LATER: Oh, maybe not. I see that the reentry speeds are much less than I had believed. Learn something new every day.

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Originally Posted by caveman1917
Good point. Makes one wonder wether our 'normal' visualizations with a fireball speeding through the sky are even by far realistic.

There also seems to be a great dependence on inclination angle, i'm not sure that has been established for the K-T impactor.
IIRC, about a 30 degree above the horizon slope travelling SE to NW. (assuming that chixiclub is the K-T impact)

Assuming a velocity of about 16km/s and that it starts to glow 80km up, it should be visible for about 10 seconds between start of glow and impact.

I am pretty sure that if you could see it you were either dead or about to be.

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Originally Posted by korjik
IIRC, about a 30 degree above the horizon slope travelling SE to NW. (assuming that chixiclub is the K-T impact)

Assuming a velocity of about 16km/s and that it starts to glow 80km up, it should be visible for about 10 seconds between start of glow and impact.

I am pretty sure that if you could see it you were either dead or about to be.
He-he, not if I had a culvert or cave to dive into immediately afterwards.

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Originally Posted by mugaliens
He-he, not if I had a culvert or cave to dive into immediately afterwards.
Except that if you could see it, chances are you are going to be inside the crater when it goes BOOM!

Even if you arent in the crater, the blast front from the impact will make a pyroclastic flow seem like a warm breeze.

Asteroid/Comet impacts fall under the erupting volcano rule: If you can see it with your own eyes, you are waaaay too close.

9. Originally Posted by mugaliens
He-he, not if I had a culvert or cave to dive into immediately afterwards.

There's basically no way to escape it - the seismic effects would make any cave or culvert a very bad place to be, and the fireball and air blast would make anything above the surface a very bad place to be. With an impactor of that size, you might as well relax and enjoy the show, because if you can see it, there's really nothing you can do to avoid it.

10. Originally Posted by cjl
There's basically no way to escape it - the seismic effects would make any cave or culvert a very bad place to be, and the fireball and air blast would make anything above the surface a very bad place to be. With an impactor of that size, you might as well relax and enjoy the show, because if you can see it, there's really nothing you can do to avoid it.
ONLY place more or less safe would be inside a submarine . . . if the impactor , impact land ! Better have a mixed crew if they want to repopulate the Earth after the cataclysm !

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How about an all female submariner crew with a sperm bank and embryo bank? That way, inbreeding of the new population is reduced. Neil

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As the others posted, If you see the 10 kilometer asteroid moving though the atmosphere, it is very unlikely that you have more than seconds to live. Permanent blindness is likely as the disk would appear brighter than the sun, and larger if it was closer than about 900 kilometers. Neil

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Originally Posted by neilzero
As the others posted, If you see the 10 kilometer asteroid moving though the atmosphere, it is very unlikely that you have more than seconds to live. Permanent blindness is likely as the disk would appear brighter than the sun, and larger if it was closer than about 900 kilometers. Neil
Ah, balony. I'd grab my sunglasses and hoof it down to the pool (19 seconds as of a midnight trial and contest race just moments ago). Even if I hit the water burning, I'd still be ok.

It takes a LOT to boil water. That 73 deg water wouldn't be more than 80 (stiill 20 deg below min hot tub) even if all sides were burning at 212 deg F. The fundamental affect of water is that it just takes time to heat it up. A pot with all sides blaring takes a few minutes. A pool takes much, much longer. When that begins to fail, there's always the mad dash to the concrete storm culvert adjacent to our property.

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Originally Posted by mugaliens
Ah, balony. I'd grab my sunglasses and hoof it down to the pool (19 seconds as of a midnight trial and contest race just moments ago). Even if I hit the water burning, I'd still be ok.

It takes a LOT to boil water. That 73 deg water wouldn't be more than 80 (stiill 20 deg below min hot tub) even if all sides were burning at 212 deg F. The fundamental affect of water is that it just takes time to heat it up. A pot with all sides blaring takes a few minutes. A pool takes much, much longer. When that begins to fail, there's always the mad dash to the concrete storm culvert adjacent to our property.
The estimated release of energy of the Chicxulub impact is sufficient to vaporize about 200 trillion tons of water. The crater width is about 180 km. Considering that the maximum range to the horizon, assuming a bit of height, is in the 10s of km range. If you could see the impact site, you may be able to jump into your pool, but your pool is going to get blown off the planet and be vaporized reentering the atmosphere a while after the impact.

15. One of the learning channels did a documentary of what would happen if the K-T event happened today.

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Originally Posted by korjik
The estimated release of energy of the Chicxulub impact is sufficient to vaporize about 200 trillion tons of water. The crater width is about 180 km. Considering that the maximum range to the horizon, assuming a bit of height, is in the 10s of km range. If you could see the impact site, you may be able to jump into your pool, but your pool is going to get blown off the planet and be vaporized reentering the atmosphere a while after the impact.
Terrific. 180 km is 111 miles, which doesn't even cross the Gulf of Mexico, and is more than 10 times further to where I live.

No, Korjik, my pool would not be "blown off the planet."

My largest problem would involve the detonation pressure of the vaporized ocean water involved in the Chicxulub explosion resultant to the meteor in an oceanic basin impact, followd by the very widespread, mostly large-scale shrapnel effects of the ejecta.

Personally, my best location would be a relatively shallow mine not subject to cave-ins, but as those are rare...

My apartment building is gross. It's likely be to be leveled in the shock wave.

Shock waves running transient to the Earth's surface have a funny happet of simply running parallel to that surface, unless generated nearby. Cicxulub isn't neaby. Nevertheless, the shockwave would rapidly approach and raze pretty much everything to the ground. I can dive and leap into the pool in less than thirty seconds; I know what to look for on the horizon with respect to arriving shock waves, and I can hold my breath quite easily for more than a minute to allow for the usual series of over/under-pressure trailing waves, though even from Chic, that would take hardly less than 17 seconds.

My primary concern remains ejecta, which would be common from any land or shallow oceanic strike, hence my idea to hide out in the local concrete and steel washbasin. If I take a direct hit, oh well! Otherwide, I'm alive and am better able to help myself and my fellow man than most.

Meanwhile, I would fully expect to be giving a sorry kick in the pants with respect to s/p waves! In fact, I think they might very well dump me clear out of the pool into the open field well over the adjacent apartment building, while utterly destroying the buildings in the process.

Since the airborne waves would arrive tens of minutes later, if I am even alive by that time, I'd most certainly crawl back into the pool, or most likely, the nearby drainage culvert, for protection from the aerodynamic blast.

Then there's the ejecta. Coming before (likely) as well as after (also likely) the aerodynamic blast, I've refined my guess that the best place I might reside is the very large culvert less than half a mile from here, with the obvious understanding that immediately following the initial results, my best bet would be to head to higher ground.

Should I even be alive at this point, but having outlived several situations which should have buried me deep, I'd like to think I'm pretty good at dodging the death darts, at least so long as to protect my family and ensure I've a reasonable chance of rejoining them in the future, should they have survived.

As to the conditions immediately following survival, I plan to take to the high country and be the predator of other such animals, including deer, elk, bear, cougar, fox, rabbit, beaver, marmot, squirrel, bird, fish, insect, and snake, while eating anything and everything I can off the land (which, surprisingly, we humans can indeed eat, while most of our mammalian cousins cannot).

In the meantime, folks - please let us hope and pray that our diplomatic efforts will ALWAYS result in any sort of situation!???!

Obviously, if it comes from our heavens above, things would be a bit different. Once of the first things I'd attempt is a peaceful and cooperative government for the survivors endeavoring towards the maximum restoration of pre-event water/food capacity. The "clothing" and "shelter" issues would largely involve raiding clothing stores and sheltering in multi-family units.

This is indeed a touchy subject among many, as many have never conceived of the aftermaths of such an event. I am a survivor, though I will endeavor to do much more than just survive, most of which output will be geared towards whatever community I inhabit.

Bottom line - there are actually ways out of this where if everyone keeps their head, cooperates to the maximum extent possible, works their *** to the bone while forgetting any idea of national government help, and continues to plow our (mine too, folks) backsides back into society, we'll do ok. Yes, black summers for years, failing crops... Knock it off. If it happens, it happens. Undermining the people's will to fight before any such event happens is incredibly self-defeating!

We Americans will re-group, and come back. That's what we've always done, from 26,730 to now, and that's what we'll always do.

All of us. Forever.

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If the impactor ended up hitting part of a sea or ocean (I don't know what conditions there were like, at the time), then, even at ~1,000 km distant, you'll likely be hit by a tsunami and/or pyroclastic flow-like wave that'll at least mess with your styled hair (if not kill you instantly). Of course, if you're at a considerable elevation - >500 m, say - the tsunami may not get to you ...

18. The impact site would have been shallow sea at the time.

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Originally Posted by beethovenspiano
If objects the size of sand grains can produce bright meteors and objects a few cm in size can produce a bright fireball - just how bright would an object 10km be as it passed through the atmosphere?? Maybe thousands or hundreds of thousands of times brighter than the Sun.

What would be the unfortunate effects of being close enough to see it streak through the sky. And I wonder what kind of damage it would do before it even hit the ground???

Disaster movies always show a feeble fireball followed by a long smoky trail.
Hi beethovenspiano, Please think this through, a grain of sand travelling at 2280 kph, hitting the earths atmosphere would, and does
vapourise, an object 10 km across would take time to heat up, indeed, it may never reach a temperature that allows it to be seen
before its impact.
Nokton

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Originally Posted by nokton
Hi beethovenspiano, Please think this through, a grain of sand travelling at 2280 kph, hitting the earths atmosphere would, and does
vapourise, an object 10 km across would take time to heat up, indeed, it may never reach a temperature that allows it to be seen
before its impact.
Nokton
While the interior of the body wouldn't heat up the surface layers are a different matter, and the atmosphere it was passing through would definitely heat up in the shockwave produced by it.

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Originally Posted by mugaliens
Terrific. 180 km is 111 miles, which doesn't even cross the Gulf of Mexico, and is more than 10 times further to where I live.

No, Korjik, my pool would not be "blown off the planet."

My largest problem would involve the detonation pressure of the vaporized ocean water involved in the Chicxulub explosion resultant to the meteor in an oceanic basin impact, followd by the very widespread, mostly large-scale shrapnel effects of the ejecta.

Personally, my best location would be a relatively shallow mine not subject to cave-ins, but as those are rare...

My apartment building is gross. It's likely be to be leveled in the shock wave.

Shock waves running transient to the Earth's surface have a funny happet of simply running parallel to that surface, unless generated nearby. Cicxulub isn't neaby. Nevertheless, the shockwave would rapidly approach and raze pretty much everything to the ground. I can dive and leap into the pool in less than thirty seconds; I know what to look for on the horizon with respect to arriving shock waves, and I can hold my breath quite easily for more than a minute to allow for the usual series of over/under-pressure trailing waves, though even from Chic, that would take hardly less than 17 seconds.

My primary concern remains ejecta, which would be common from any land or shallow oceanic strike, hence my idea to hide out in the local concrete and steel washbasin. If I take a direct hit, oh well! Otherwide, I'm alive and am better able to help myself and my fellow man than most.

Meanwhile, I would fully expect to be giving a sorry kick in the pants with respect to s/p waves! In fact, I think they might very well dump me clear out of the pool into the open field well over the adjacent apartment building, while utterly destroying the buildings in the process.

Since the airborne waves would arrive tens of minutes later, if I am even alive by that time, I'd most certainly crawl back into the pool, or most likely, the nearby drainage culvert, for protection from the aerodynamic blast.

Then there's the ejecta. Coming before (likely) as well as after (also likely) the aerodynamic blast, I've refined my guess that the best place I might reside is the very large culvert less than half a mile from here, with the obvious understanding that immediately following the initial results, my best bet would be to head to higher ground.

Should I even be alive at this point, but having outlived several situations which should have buried me deep, I'd like to think I'm pretty good at dodging the death darts, at least so long as to protect my family and ensure I've a reasonable chance of rejoining them in the future, should they have survived.

As to the conditions immediately following survival, I plan to take to the high country and be the predator of other such animals, including deer, elk, bear, cougar, fox, rabbit, beaver, marmot, squirrel, bird, fish, insect, and snake, while eating anything and everything I can off the land (which, surprisingly, we humans can indeed eat, while most of our mammalian cousins cannot).

In the meantime, folks - please let us hope and pray that our diplomatic efforts will ALWAYS result in any sort of situation!???!

Obviously, if it comes from our heavens above, things would be a bit different. Once of the first things I'd attempt is a peaceful and cooperative government for the survivors endeavoring towards the maximum restoration of pre-event water/food capacity. The "clothing" and "shelter" issues would largely involve raiding clothing stores and sheltering in multi-family units.

This is indeed a touchy subject among many, as many have never conceived of the aftermaths of such an event. I am a survivor, though I will endeavor to do much more than just survive, most of which output will be geared towards whatever community I inhabit.

Bottom line - there are actually ways out of this where if everyone keeps their head, cooperates to the maximum extent possible, works their *** to the bone while forgetting any idea of national government help, and continues to plow our (mine too, folks) backsides back into society, we'll do ok. Yes, black summers for years, failing crops... Knock it off. If it happens, it happens. Undermining the people's will to fight before any such event happens is incredibly self-defeating!

We Americans will re-group, and come back. That's what we've always done, from 26,730 to now, and that's what we'll always do.

All of us. Forever.
?

So, you didnt actually see the part where I said 'if you can see it'?

Last time I checked, 'If you can see it' requires you to be withing 10s of km of whatever it is you are seeing. Otherwise it would be over the horizon and not visible.

I thought that was pretty clear.

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Originally Posted by Nereid
If the impactor ended up hitting part of a sea or ocean (I don't know what conditions there were like, at the time), then, even at ~1,000 km distant, you'll likely be hit by a tsunami and/or pyroclastic flow-like wave that'll at least mess with your styled hair (if not kill you instantly). Of course, if you're at a considerable elevation - >500 m, say - the tsunami may not get to you ...
How about 2,000 meters? As in where I live... Seriously, though, a large enough meteor packs enough punch to send the Gulf of Mexico my way, but I don't think the K-T event was that large.

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Originally Posted by mugaliens
I think you mean 2,000 km!

As in where I live... Seriously, though, a large enough meteor packs enough punch to send the Gulf of Mexico my way, but I don't think the K-T event was that large.
I'm not so sure.

IIRC, there were some papers published on the distribution of tsunami (and other) debris from the impact, including some findings that deposits that would have been several metres thick at the time were found up to about that distance (and maybe beyond). Of course, I may have mis-remembered ...

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Originally Posted by Nereid
I think you mean 2,000 km!
No, we're talking about altitude, here. I live around the 6,500 ft level, which is around 2,000 meters.

I'm not so sure. IIRC, there were some papers published on the distribution of tsunami (and other) debris from the impact, including some findings that deposits that would have been several metres thick at the time were found up to about that distance (and maybe beyond). Of course, I may have mis-remembered ...
I think it's more likely that massive quantities of water flashed into steam which resulted in torrential rains. The explosive forces would have carried the salt with it. From what I remember, "thin layers" of sediment marks the K-T boundary.

You know, this section discusses which groups of animals died, and why.

So: "Mammals and birds that survived the extinction fed on insects, worms, and snails, which in turn fed on dead plant and animal matter."

So, get used to eating...

If it came to it, I'd try chewing on anything. And everything. Perhaps that's one of the reasons human's digestive traits are ridiculously wide. Perhaps that's the reason we're currently at the top of the food chain - it's not because we're smarter than the others. It's because we can pretty much eat anything. Except cellulose, and we long since domesticated cellulose eaters years (a few millennia (whatever the spelling) ago).

So, let's save the cows?

25. Originally Posted by nokton
Hi beethovenspiano, Please think this through, a grain of sand travelling at 2280 kph, hitting the earths atmosphere would, and does
vapourise, an object 10 km across would take time to heat up, indeed, it may never reach a temperature that allows it to be seen
before its impact.
Nokton
Apart from what Grashtel said, a 10 km object doesn't need to glow to be visible! It would reach the angular diameter of the Moon at an altitude of well over 1000 km, where the atmospheric density is practically zero.

26. Originally Posted by mugaliens
If it came to it, I'd try chewing on anything. And everything. Perhaps that's one of the reasons human's digestive traits are ridiculously wide. Perhaps that's the reason we're currently at the top of the food chain - it's not because we're smarter than the others. It's because we can pretty much eat anything. Except cellulose, and we long since domesticated cellulose eaters years (a few millennia (whatever the spelling) ago).
Humans basically eat only two things: flesh and the reproductive parts of plants. In the eat anything game, that's distinctly unimpressive.

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## Thankyou Grashtel

Originally Posted by Grashtel
While the interior of the body wouldn't heat up the surface layers are a different matter, and the atmosphere it was passing through would definitely heat up in the shockwave produced by it.
You are of course correct, Grashtel, but my point was, and is, would the surface of such a massive body
heat up to be incandescent to an observer? Would that not depend on the speed and tragectory of the body?
Nokton

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Originally Posted by AndreasJ
Humans basically eat only two things: flesh and the reproductive parts of plants. In the eat anything game, that's distinctly unimpressive.
Ah-hem!

We, of all animals our planet, have perhaps one of the widest diets of all, eating pretty much anything and everything! I dare say there is very little I cannot eat, save for a few readily identifiable berries (blue/black/red/white and non-aggregated) and mushrooms - why bother? - no net gain.

Several times I've hit the trail sans food, only to return rather stuffed!

I know we'd very much like to think our brains are the reason we find ourselves at the top of the current food chain, but I dare say it's not our brains, but our bellies, which allow us such an incredibly powerful non-food leisure during which we think up all the stuff we talk about here on this board as well as many others.

Even in a minimalist/survival situation, I've still conquered the food/clothing/shelter side of the equation. Yes, it's a heck of a lot of work, but far less work than simply staying alive.

On another note, baseball bats weren't invented to hammer little white rawhide obstacles over some fence. They were invented to deal with the howling hounds (coyotes) which to this day keep me awake at night.

Speaking of which...

Don't worry, folks, as I've yet to achieve connection range with any of the several hundred band of folks which keep me awake at night, and yes, I've ventured among them. I have absolutely no doubt that if I fell at their feet they'd devour me in an instant, but there's something earily strange about midnight hiking amongs our pad-footed friends, knowing they all all about, yet unwilling to attack humans.

Why? I dunno. Perhaps coyotes are an offshoot of a formerly domesticated dog.

Meanwhile, I've had the very distinct pleasure to interact with 100% wolves on several occasions recently, and I must say I'm incredibly impressed! Wow! What unbelievably powerful and fascinating animals!

Even so, all of them seem to know (or believe) when I walk into their cage they're no longer in charge, but that I'll have their back and take care of them.

Still, they scare me to no end! Meanwhile, I'd trust my life to my brother's German shepherd or the rather large yet lovable GS/rotweiller/aussie mutt living below me. I'd pit myself and either of them against the natural beasties, but only if I were there to weild a speer!

Yes, and please understand, folks, we're still vulnerable in the wild. Travel in groups and hang your food.

29. Originally Posted by mugaliens
Ah-hem!

We, of all animals our planet, have perhaps one of the widest diets of all, eating pretty much anything and everything! I dare say there is very little I cannot eat, save for a few readily identifiable berries (blue/black/red/white and non-aggregated) and mushrooms - why bother? - no net gain.
Berries? There's that human fixation with reproductive parts again. Tell me there's a only a few plants you can't eat in their entirety and I'll be impressed.

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Originally Posted by AndreasJ
Berries? There's that human fixation with reproductive parts again. Tell me there's a only a few plants you can't eat in their entirety and I'll be impressed.
Actually, it's just some data from SERE, which identified which wild berries were edible, and which were not.

As far as what we can and cannot eat, I'd very much rather not be labled as the next Eull Gibbons, thank you very much! Wow! "Stalking the Wild Asparagus" - ouch!

Back to reality, Euell was right - much of our wild is edible, but only to us. We have perhaps 4 times as much food potential as our best semi-domesticated friend, the wolf.

Lol, I know tons of people who claim our brains are the reason we're where we are today, but for the past couple of years I've thought it has a lot more to do with our digestive systems.

We really can eat most things most animals cannot. That's a very decisive evolutionary advantage.

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