> While the scientists think the new study gives a robust picture of how large injections of soot into the atmosphere can affect the climate, they also caution that the study has limitations.
> For example, the simulations were run in a model of modern-day Earth, not a model representing what Earth looked like during the Cretaceous Period, when the continents were in slightly different locations. The atmosphere 66 million years ago also contained somewhat different concentrations of gases, including higher levels of carbon dioxide.
> Additionally, the simulations did not try to account for volcanic eruptions or sulfur released from the Earth's crust at the site of the asteroid impact, which would have resulted in an increase in light-reflecting sulfate aerosols in the atmosphere.
Additionally, the "world-class computer model" in which the simulations were run may or may not have been a Minecraft server.
I think our present space technology research focus should be on these asteroids. Both how to deflect them (peacefully) and how to mine them for rare metals.
If I read this table correctly it seems that only eight days ago a fairly chunky rock passed within 60,000 miles of us:
Really cool link, thank you. I think you are referring to the 2017 QP1 asteroid that was closest to us on 14-Aug. the distance was about a sixth of the distance to the moon, or 38k miles. The speed was 24km/s and the diameter 37-83 meters. Just for fun I ran the Impact Earth calculator to see what would happed if such an asteroid hit Earth. Assuming the worst case scenario (iron meteorite, max diameter, perpendicular hit) the explosion would be equivalent to about 200 MT TNT, and the crater would have a 2 mile diameter and 2000 foot depth.
Speed values in space always seem to omit "relative to what" clarifications. Relative to the earth, the sun, along the earth's orbital path or contra, etc.? It makes a huge difference.
Well, in >4 bn years there have been probably less than 5 such events. Catastrophic yes, but very low possibility. I can understand if any agency even the slightest related to space prioritizes other things.
As far as my understanding goes, space is very unevenly distributed, with lots of debris and asteroids in dense (well, humpf) parts of space, but the vast majority of it is just... empty space with so little matter in between that it is basically negligible. To mine an asteroid likely means going to where it's more probable to find a suitable one, and also more risky. Asteroids around us are few (IIUC).
Death by asteroids is a low risk but high impact type of event. We cannot afford to have even one such event.
It really does only take one and costs little for us to prepare. We want to mine asteroids and further science anyway, so we are going up there already. It's not like the cost of the whole space program is dedicated to defending from this. We just need to have a few plans ready to go when we do find it.
It would cost millions of dollars, compared to the billions already in space and trillions we spend in defense. What is money in the face of a 0.00001% chance of annihilation?
> What is money in the face of a 0.00001% chance of annihilation?
Every day that you commute to work, you have a higher then 0.00001% chance of dying in a traffic accident.
Yet, you still roll the dice, and go to work. Presumably because you get paid.
For a more global catastrophic event, consider that the odds that you will die in a catastrophic nuclear war between Russia and the United States are far, far greater then 0.00001%. Yet, we all carry on as if its business as usual. (When we could take steps to reduce how catastrophic such a war would be, or how likely such a war would be.)
I think you've just pointed out the fallacy here: the false equivalence of a risk affecting one person vs. the entire human race (or planet).
The if the odds of dying in an auto accident for one person are 0.00001%, then the risks of the 7.5 billion souls on this rock dying simultaneously in an auto accident are 0.00001% raised to the power of 7.5 billion. That's basically 1 * 10^-45% odds.
The comparative risk posed by the asteroid is approximately 1 * 10^40 times greater.
Each of us may face that risk, but all off us don't, together.
This is a point at which conventional models of risk start falling apart. There's a meaningful difference between small events randomly distributed, and massive large impacts occurring everywhere all at once. Also between small events with no interconnectedness, and with systemic failure.
Simple incident occurrence rate fails to capture this.
We also invest heavily in preventing such a nuclear exchange.
Of course we continue on, we hope or expect that we will still be here. Rather than just lob missiles or give up, we took a stance and many active and expensive steps costing the equivalent of trillions of modern dollars. We definitely took real action on the Threat of Nuclear war.
We also invest incredibly heavily into making such a nuclear exchange more likely. We've sunk trillions of dollars into building a collective suicide switch.
We don't need more then a hundred nuclear weapons for MAD to work. Meanwhile, Russia and the US are pointing thousands of them at each-other. (And in the US, at least, the minimum number of people required to authorize a launch is tragically small. In a time of escalated tensions, a president can bring about the end of the world, without the consent of anyone else. There is no law or military process that can prevent it.)
Even if the odds of nuclear war were 1% in my lifetime, it would be an unacceptable level of risk. I wouldn't be surprised if it is, in reality, much higher.
>Death by asteroids is a low risk but high impact type of event. We cannot afford to have even one such event.
Depending on how rare and difficult to tackle would be, we probably also cannot afford to do anything about it.
If we have as much as 1% or even 0.1% possibility of one hitting earth in the next 100 years, we would have rallied to build something even if is very costly and difficult.
In 0.00001% chances or less, there's no way any country is gonna's devote any significant resources...
>What is money in the face of a 0.00001% chance of annihilation?
Still very important?
(We have a much more concrete and possible chance of billions of deaths from nuclear arms and/or global warming, but we still don't do anything about it).
Spending in one area does not prevent spending in another. we have many dollars and some problems require more than others. They can even work together, perhaps a tax on CO2 release can fund diplomatic and scientific missions to help mitigate or prevent the other two catastrophes.
> As far as my understanding goes, space is very unevenly distributed, with lots of debris and asteroids in dense (well, humpf) parts of space, but the vast majority of it is just... empty
Even the "asteroid belt" is really empty. It's not like you see in science fiction movies where asteroids are hitting into one another continually.
The ability to deflect asteroids away from Earth also means you can deflect them toward Earth and even aim them at your enemies! You could sneakily aim a meteor strike at anywhere on Earth and make it look like a natural event.
Technically this is something that could be done today with gravity tractor [0] or an ion beam deflection [1] system, both of which are being developed by NASA.
> You could sneakily aim a meteor strike at anywhere on Earth
Can you? Are you sure? My understanding is that it's not possible to predict the trajectory at less than the size of a continent. Much less actually control it.
Well it just so happens that the 3 countries where this would be seen as favorable attack vector against the others happen to be the size of continents. Mainly China, Russia, and The USA.
In principle it's no different from predicting the path of a spaceship, which can be done with great accuracy. The error comes from imprecision in knowledge of the meteor's location and velocity, which would improve greatly once you start pushing it around.
And in fact, the path of an unguided spaceship can not be predicted. Go look for old news stories of satellites crash landing - they can only give general areas, not exact.
That's a completely different scenario. Satellites in decaying orbits are descending due to atmospheric drag. Atmospheric drag is difficult to predict because it depends on the precise shape of the satellite, the precise orientation, and atmospheric conditions at each moment.
If you're dropping an interplanetary asteroid on an enemy, it won't be in a slowly decaying orbit. It'll spend a few seconds within the atmosphere, which won't mess up predictions that much.
It occurs to me that we just had a great example of the ability to predict where big rocks will be in space long in advance. People were able to predict that the Moon's shadow would cross from Oregon to South Carolina decades ago, and of course the predictions were spot on.
You underestimate the difficulty. For example the asteroid could break up, which would move the trajectory. If the asteroid is not round it will tumble and shift. Uneven heating would cause a "jet" of hot air to act like a rocket and move the asteroid.
Don't forget that it's very unlikely you will be able to guide an asteroid perpendicular to the earth (which would give you the most accuracy, and the most velocity, which also helps with accuracy). Most of the asteroids obit more or less in the same plane as the earth, so you will have to settle for a more shallow impact, which will magnify atmospheric effects.
> example ... moon
We have had thousands of years to precisely record the orbits of the moon and earth [sun]. That is the only reason we are able to predict it. And despite that, past a few hundred years accuracy goes down, and past 1 thousand or so it's mostly impossible to predict eclipses.
And that's for bodies we have very accurate data on, and who have no atmospheric drag.
The inaccuracy for eclipses is because we can't predict how fast the earth will turn (to an accuracy of a ppm) more than a few months out, and because of tidal effects changing the orbit of the moon.
Small asteroids have a very small escape velocity, on the order of a few meters per second. I think a mass driver which broke off small chunks of asteroid and hurled them to escape would not take too much power and be able to disassemble the asteroid in less than one orbit. (Advanced detection would be a plus here.) If we aimed the ejecta, to get a momentum change in a given direction, we would not have to completely disassemble the asteroid, because its orbit would change and eventually miss Earth. Complete disassembly would be safer, because small chunks would burn up in Earth's atmosphere.
Graham Hancock dedicates at least 10% of his most recent book "Fingerprints of the Gods" to exploring the recent evidence for a cataclysmic meteor impact that catalyzed the precipitous drop in global temperatures we observe 12900 years ago at the "Younger Dryas Boundary." https://en.wikipedia.org/wiki/Younger_Dryas#Impact_hypothesi...
He has some pretty out there theories but that section is pretty convincing.
My understanding is the duration does not really line up with an impact event also the starting periods don't seem to line up correctly. "In Western Europe and Greenland, the Younger Dryas is a well-defined synchronous cool period.[34] Cooling in the tropical North Atlantic may, however, have preceded it by a few hundred years; South America shows a less well-defined initiation but a sharp termination."
Which is what I find annoying about pet theories in books, you can make plenty of things seem convincing by leaving out other evidence.
Feathers act as insulation, they are warm blooded, and opportunistic eater. My chickens are hardy to -20 degrees outside. So long as they were farther south I could imagine them surviving. Even if they were north, as long as they could eat meat, the coming cold temperatures could keep food (other dead animal) around for quite a while. Even then, I could image ancestors of vultures doing quite well for a good long while.
I do have to wonder how plants could have rebounded from two years without being able to photosynthesize - you'd think lots of species wouldn't have viable seeds kicking around at that point. Which would make for some massive changes to the fossil record for plants. To say nothing of the animals that depend on them...
It would also have to remain viable in the sense that no animals starving in the darkness will try to eatthem, or fungus or bacteria running wild. I think you have to assume that are small burrowing ancestors ate pretty much every seed they could get their tiny paws on. We know that quite a few different organisms survived, and while some of them estivated or hibernated most of them presumably we had to live and eat in a roughly normal way.
Fungi and bacteria don't like the cold. There would be a lot more food to eat for survivors (chickens) as things that they competed with for food (T rex) died off.
66 mn years is plenty of time to diversify a lot from a few, so you might be correct that "lots of species wouldn't have viable seeds". Perhaps they didn't, and just the (relative) few that did are the basis of what we have today.
Interesting point - even though some animals might thrive in the dark, the food chain can also be undermined in a way that it topples the foundation of the members above, thus indirectly destroying it.
Owls consume rodents such as squirrels, rats, and mice, which are nocturnal.
Kiwis eat grubs and worms - only the latter of which I know can be nocturnal.
Seeds can remain viable for significantly longer than a year. My guess is that as it got significantly colder for that same time period, most seeds were too cold to grow until it warmed up after the soot left the atmosphere.
Old seeds had much higher germination rate according to the linked wikipedia article. In addition, cold storage increases the life of seeds. I doubt you would see much of anything in the fossil record.
Fascinating is the feedback loop recovering after the impact. So basically, all that is needed to bring the sood from the atmosphere down is a long enough cooling window, binding ice to the dirt.
Disclaimer: this is proving hard from me to explain via text without the use of visualization.
Mammals did not evolve from dinosaurs. Mammals are synapsids, a branch of tetrapods. Dinosaurs come from a different branch of tetrapods entirely, called sauropsids. (There is a third branch of tetrapods, amphibia.)
Sauropsida is a really diverse branch containing both extinct and extant species. Look at the tree at the bottom of the page here [0]. A fork of interest is Sauria, which splits into lepidosauromorphs (including modern lizards & snakes) and archosauromorphs. Archosauromorphs have many branches as well (one of note being turtles), with one that traces far enough to get to archosaurs [1]. Modern crocodiles come from a branch of archosaurs. Dinosauria are another branch of archosaurs, and birds are descendants of dinosauria. They are the only extant species of dinosauria.
The confusion comes because many of these animals co-existed at the same time, some become extinct, others evolved and change and form new branches (but still belong to the parent group). The word 'Dinosaur' itself is also misapplied by the public - it's not all of the animals that lived 65+ million years ago. It's a very specific group of related animals and all of their descendants.
TLDR: Mammals didn't evolve from dinosaurs, but from a different branch further up the chain that dinosaurs also belong to. Those mammalian ancestors did co-exist with dinosaurs. Like mammals, modern reptiles didn't evolve from dinosaurs, but from ancestors that co-existed with dinosaurs. Reptiles and dinosaurs are more closely related than mammals and dinosaurs. Birds did evolve from dinosaurs, and are the only living dinosaurs today.
> For example, the simulations were run in a model of modern-day Earth, not a model representing what Earth looked like during the Cretaceous Period, when the continents were in slightly different locations. The atmosphere 66 million years ago also contained somewhat different concentrations of gases, including higher levels of carbon dioxide.
> Additionally, the simulations did not try to account for volcanic eruptions or sulfur released from the Earth's crust at the site of the asteroid impact, which would have resulted in an increase in light-reflecting sulfate aerosols in the atmosphere.
Additionally, the "world-class computer model" in which the simulations were run may or may not have been a Minecraft server.