Dinosaur-Killing Asteroid Could Have Caused 2 Years of Darkness

http://astrobiology.com/2017/08/dinosaur-killing-asteroid-could-have-caused-2-years-of-darkness.html

by okket • 9 years ago

91 61 9 years ago

astrobiology.com

QAPereo3• 9 years ago

Naively I would assume that if we really had experienced two years of darkness, avian species would not be here now.

ljf• 9 years ago

Would be interested to hear your thoughts that led you that way (not saying wrong or right, just interested)

cwbrandsma• 9 years ago

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.

Anyway, also a naive set of guesses on my part.

blacksmith_tb2• 9 years ago

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...

retSava2• 9 years ago

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.

colordrops2• 9 years ago

Lots of seeds remain viable for more than 2 years.

mixmastamyk• 9 years ago

Owls and kiwis prefer the dark.

QAPereo3• 9 years ago

Do their food sources?

roceasta• 9 years ago

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:

https://cneos.jpl.nasa.gov/ca/

retSava2• 9 years ago

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).

sqeaky3• 9 years ago

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?

EDIT - Wording and spelling.

bsder• 9 years ago

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.

credit_guy3• 9 years ago

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.

Edit: changed mph to km/s

https://www.purdue.edu/impactearth/

imaginenore• 9 years ago

The speed was 24mph

No way. It was 24 km/second.

WalterBright• 9 years ago

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.

hutzlibu• 9 years ago

.. so 4 times as strong as the biggest men made explosion?

https://en.wikipedia.org/wiki/Tsar_Bomba

Well, thats bad for sure, but far from humanity-threatening, I guess.

ars4• 9 years ago

Both how to deflect them (peacefully)

Curious about your parenthesized addition. How do you deflect an asteroid non-peacefully?

thatcherc• 9 years ago

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.

[0] https://www.nasa.gov/content/asteroid-grand-challenge/mitiga...

[1] https://en.wikipedia.org/wiki/Ion_Beam_Shepherd

gshubert17• 9 years ago

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.

brianbreslin2• 9 years ago

This may be a dumb question, but were all the dinosaurs reptilian and avian? Were there no mammalian dinosaurs pre-66M years ago? like rodents?

rarec• 9 years ago

There were proto-mammals then, similar to possums. https://www.thoughtco.com/the-first-mammals-1093311

kobeya• 9 years ago

Dinosaur is a specific class of animal. Theee were rodents back then, which we evolved from, but they weren't dinosaurs.

thanksforcoming• 9 years ago

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.

[0] https://en.wikipedia.org/wiki/Sauropsida [1] https://en.wikipedia.org/wiki/Archosaur

brianbreslin2• 9 years ago

Thank you for the thoughtful answer.

julienchastang• 9 years ago

"A world without photosynthesis", "photosynthesis would still have been impossible for an entire year"

Clearly, photosynthesis did survive in some capacity. No? Life did not re-evolve photosynthesis in the last 66 million years.

Xeoncross2• 9 years ago

Seeds can germinate after much longer than a year: https://en.wikipedia.org/wiki/Oldest_viable_seed

blacksmith_tb2• 9 years ago

"Some seeds can live for a long time before germination, while others can only survive for a short period after dispersal before they die."[1]

I wasn't suggesting all seeds would fail to germinate after two years, just that some would, and that change would be noticeable in the fossil record.

1: https://en.wikipedia.org/wiki/Seed#Germination

dasil003• 9 years ago

All photosynthesizing plants could die and then re-sprout from seeds without extinction.

pilom• 9 years ago

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.

mrfusion2• 9 years ago

Deciduous trees would just treat it as a long winter.

excalibur• 9 years ago

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.

sogen• 9 years ago

How can they publish something so wrong?

Also: Get off my server

SapphireSun• 9 years ago

Before decrying how wrong it is, try estimating how much those effects matter.

mrfusion2• 9 years ago

I'd be curious how any animals survived.

09bjb• 9 years ago

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.

Retric• 9 years ago

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.

Pica_soO• 9 years ago

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.

Dinosaur-Killing Asteroid Could Have Caused 2 Years of Darkness

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