A direct hit by Comet Elenin or Honda would probably not cause human extinction

Using the K-T (Cretaceous-Tertiary) extinction event as a guide to the possible out come of an impact of an Elenin or Honda sized comet, I've come to the conclusion that it would not mean extinction of the human race.

K-T extinction: 65 million years ago, a 10 to 12 km sized asteroid or comet hit the ocean off the Yucatan Peninsula and formed the 200km diameter Chicxulub crater. The prevailing theory proposes that this collision caused an "impact winter" that killed the dinosaurs.

Impact winter: "An impact winter is a period of prolonged cold weather caused by the impact on the Earth of a large asteroid or comet. If such an impact occurred on land or the floor of a shallow sea, it could cause large amounts of dust or ash to be thrown into the Earth's atmosphere, blocking the Sun's light and dramatically lowering the amount of sunlight reaching the Earth's surface. Impact winter is one of the mechanisms proposed for extinction events, such as the asteroid impact at Chicxulub in Mexico which supposedly led to the extinction of the dinosaurs." (Wikipedia)

During the K-T extinction event solar transmission was reduced to 10-20% of normal for a period of 8-13 yr from an impact of 10 to 12 km sized asteroid or comet.

Source - www.ncbi.nlm.nih.gov...

Based on this data a 3km diameter comet would cause about 4 times less damage as the 12km Chicxulub asteroid. This would mean a direct hit by an Elenin or Honda sized comet might produce particulates enough to reduce the sunlight to 80% of normal levels for about 3 years.
The extinction rate might be around 12% to 18%, but would probably be a lot less. A normal summer of 90 to 100 degrees F highs would be in the 70's and a winter low in the teens F would be in the single digits. Humans would certainly survive these conditions.

Of course if a 3km comet struck the earth, the area it hit would determine the level of damage to our environment. The following link provides estimates for different scenarios.

thetruthbehindthescenes.wordpress.com... h/

Disclaimer: I'm not in anyway saying that either of these comets are going to actually hit our planet and this may have been covered before.

reply to post by MichiganSwampBuck


Do your calculations take into account the impact it would have on the already precarious human civilization. Trade, desease, health, transportation? A direct impact of something of this nature might not kill us outright, but would certainly be enough of a disruption that life would be tossed into a complete jumble for a long long time.

Just look at the size of elenin its tiny Id be very surprised if it done anything major to the planet if it hit.

www.abovetopsecret.com...

Originally posted by TerryMcGuire
reply to post by MichiganSwampBuck

 

Do your calculations take into account the impact it would have on the already precarious human civilization. Trade, desease, health, transportation? A direct impact of something of this nature might not kill us outright, but would certainly be enough of a disruption that life would be tossed into a complete jumble for a long long time.

It could destroy our civilization, no doubt, but our species would most likely survive. It would be bad, but no where near as bad as something larger.

reply to post by MichiganSwampBuck


You bring up some good points.

Im not sure if the impact impulse in terms of force to the Earth and surrounding environment would be 4 times less than that of the KT extinction meteor. In fact, many factors would be important to regard other than diameter of the asteroid, including:

-Composition
-Density (part of composition you could say)
-Velocity
-Angle of descent

Among others. You would need to determine the actual momentum of each object, which is near impossible. We could only estimate.

However assuming the comets are roughly the same material (dense dusty snow balls essentially), one thing to highly consider is the effect of the atmosphere on the projectile during entry.

If a 3km diameter comet were to enter our atmosphere, considering it is made of ice and dust tightly packed together, that bad boy is going to shed MANY layers of skin before it makes land fall, if at all. C

However consider also the possibility that a comet traveling at tens of thousands of miles per hour, with a approx. diamater of 3km enters our atmosphere at a steep angle. It degrades rapidly and reduces almost to 2km in diameter, but fully combusts over an ocean or continent at around 55,000 feet. That would be assuming the comet was composed (composition) of enough deuterium.


[1 kilometer diameter or larger
A 10km asteroid strike would create waves in the Earth’s crust higher than houses, and a blast of 500ºC air travelling at 2500 kph. Any creature within 12 million sq km would be wiped out.(1) That’s roughly the size of the USA, Europe or Australia]

Holy #e! So assuming a comet with a diameter of 3km retained it's size, we could assume that the blast radius would be somewhere in the realm of 600-1200 miles in diameter, something close to this:





If a comet of that size were to hit the ocean directly off the coast of a continent, something like mile high waves would crush the coasts of the continent. If, however, the comet were to combust over the ocean, it would effectively incinerate everything within that blast radius, assuming of course.

Originally posted by roughycannon
Just look at the size of elenin its tiny Id be very surprised if it done anything major to the planet if it hit.

www.abovetopsecret.com...

"The size for Elenin has yet to be confirmed by NASA." - elenin.org...

It's coma is 3km and the highest estimated size is 4-6km diameter.

Honda is 1.6km diameter, so I chose 3km as a base size for comparison.

reply to post by xacto


The image you posted, did you create it?

st.

reply to post by xacto


I agree, I left out many factors. I did supply a link that has some estimated damage under different conditions. Please feel free to add more of these types of links.

Edit to Add: The profile pic is one I designed for a deer ranch that never paid me, so I used it here. Opps! That was SatoriTheory talking to Xacto! LOL!

reply to post by MichiganSwampBuck

Regardless of whether you are correct or not, this is just not something that a majority of the fear-craving individuals will want to read. There is no excitement.


This post, taken from right up↑↑ there, now this is something that people will want to read. Hypothetical possibilities of death and destruction is very entertaining to most. It is very easy to remove a couple words here and there, and start repeating it as an absolute fact.

Originally posted by BrokenCircles
reply to post by MichiganSwampBuck

 

Regardless of whether you are correct or not, this is just not something that a majority of the fear-craving individuals will want to read. There is no excitement.


This post, taken from right up↑↑ there, now this is something that people will want to read. Hypothetical possibilities of death and destruction is very entertaining to most. It is very easy to remove a couple words here and there, and start repeating it as an absolute fact.

Broken Circles, it appears that you were correct. Not fear mongering gets you only a little attention, if any. Star on your comment. But hey, if someone happens to live near a 3km Dia. impact, then they would be in for some big time death and destruction.

By the way, I believe the link you meant to post was this - thetruthbehindthescenes.wordpress.com... h/

"The possibility of comet ELENIN being ‘pushed’ into a collision path with earth" is the title. It provides some scenarios and basic data.

The equation is missing a few variables. You can't project impact energy based on the dimensions of a projectile alone. You need it's mass, and core to crust composition. You need velocity. You need geographic point of impact and local conditions at the time of impact, water vs. land impact would have a significant affect on the duration of a debris cloud, as well as it's temperature.

When you consider all of the above unknowns, it's established that you can't simply say because an object is smaller, it will cause less damage.

Which do you think would cause more devastation?
a) a 12 km object consisting of loosely bound rock and ice, traveling at 10k mph.
b) a 3 km solid iron asteroid with an impact velocity of 75,000 mph.

Since (b) likely weighs 10s if not hundreds of times more than (a), and is traveling significantly faster, it's likely that it would also produce a bigger bang.

So, you can't just pick an arbitrary impact event like the KT extinction, and use it as a measuring stick for all future impacts. The only thing the KT has in common with any other impact is the fact that it's an impact. Had the KT event occurred 60 minutes later, humans may have never had an opportunity on this planet.

reply to post by MichiganSwampBuck

In that particular instance, I would have preferred being wrong.
It's sad really.


I did post the correct link though. I was just mainly referring to the last few paragraphs. I suppose the part about 'remove a couple words here and there,' may have been a slight understatement.

reply to post by Unit541

You are absolutely correct Unit 541. But I used the K-T event as an extreme example. Perhaps it was to give hope to those people who actually believe that Elenin and Honda are about to strike the earth. In the end I was thinking out loud for the most part.