Ok, we'll change from https://www.earthlymission.com/dinosaur-mummy-science-discov... to https://www.nationalgeographic.com/magazine/2017/06/dinosaur.... Thanks!
This is in the FAQ at https://news.ycombinator.com/newsfaq.html and there's more explanation here:
only to watch it break into countless pieces!! :(
I had seen dinosaur skeletons in museums before but it didn't compare. Also guided tours through the limited access of the park were amazing, almost surreal, with fossils of dinosaur bones just popping out of the ground now and then plus the chance of seeing active digs.
Lots of neat little caves, bones all over. Very awesome place. Especially when you're a dinosaur obsessed 8 year old.
There was one time we were going down the river and there was a cow on the bank stuck in the mud up almost up to its neck. I remember the adults going to find the rancher and a lot of fuss and the cow was eventually saved.
> To give you an idea of how intact the mummified nodosaur is: it still weighs 2,500 pounds!
How does it weight less as a stone fossil than as an organic life form mostly made of water?
Most stone is 2-3 times as dense as water
> Most stone is 2-3 times as dense as water
Presumably because the water was completely filling a volume, whereas the stone is very much not.
Chemical traces of things like pigmentation can remain in fossilized soft tissue, I suppose that counts as "original material", but this thing isn't made out of meat anymore.
Perhaps though it contains some original carbon that can be used to do some very old radiocarbon dating, which could improve geological strata based dating of other fossil finds.
Because you are comparing different things. The fossil comprises only the anterior part of the animal. The tail and posterior legs are missing.
(Am I being too cynical?)
2. There is less pressure to produce right now given oversupply and shipping constraints in Alberta
3.Suncor cares more about its reputation than some of the other players in the tar sands
4. The Royal Tyrell Museum is well known to most Albertans, kids go there on school trips and it would likely seem like the obvious thing to do (stop work) when presented with such a find.
5. I have no idea if there is a finders fee, but that fossil is probably more valuable than anything that loader was processing all day.
6. It's a dinosaur - most folks find them pretty cool. :)
Imagine for example a machine that takes off 1 layer of atoms at a time, painstakingly charting them, and then another layer of software that figures out probabilistically whether the arrangement of atoms means that a decayed strand of DNA was here... and then probabilistically adds together the the billions of decayed shreds of DNA.
Maybe the relative positions of the base pairs are still probabilistically informative despite decaying and many of them breaking apart. I don't know. But it seems like there's a plausible way to try to extract data from fossilized DNA.
Scientists have been working very diligently to try to recover DNA from millions of years ago, but the reality is any DNA found has a very good chance of being from bacteria & other organisms from the more recent past.
Still there are (disputed) claims to have found DNA that's millions of years old:
For this particular mummified dinosaur, if they found lots of somewhat preserved soft tissue, maybe hundreds of pounds, chances are that there could be trillions of DNA segments. Very likely no single gene will be unbroken, but with many fragments broken in different places the theoretical possibility to reconstitute the genetic code is there. You also don't start from zero knowledge. Humans and birds share about 65% of the genetic code , and dinosaurs are closer to birds than humans are.
half life is a general term that is frequently used in biochemistry, enzyme kinetics, chemistry and nuclear physics
as a general term it is converse of doubling time and is simply a measure of stability or observed activity
To be more specific:  is a published article in Current Biology where they state they were able to fully sequence the genome of two mammoths, one of which was 44.8k years old. That would be 86 half-lives according to the meme of 521y half-life for DNA. 2^(-86) is roughly 10^(-26). By the logic of DNA half-life, reconstituting a 44.8k y.o. mammoth genome would be beyond utterly ridiculous. Still, here we are.
I mean it seems like you are implicitly saying that it's a huge exaggeration to claim 120,000 half-lives since the dinosaurs went extinct whereas it might be as little as 47,000. I don't think you're wrong. But raising 2 to either power overflows my calculator, so I don't see how it matters.
*my calculation is very imprecise and ignorant of biology, but I think orders of magnitude are good enough when talking about exponentials.
- the sample was 180 mg
- the number of cells in that size sample might be 8e10.
- they had 17x coverage
- log2(17/8e10) is about -32
- 44,000 years / 32 = 1375
 I got a number for cells/kg by assuming a human weighs 180 lbs and has the number of cells mentioned in this reference: https://pubmed.ncbi.nlm.nih.gov/23829164/
Instead we read fragments and stitch them together. Like you see a "GATACA" and then a "TACACCG" and hypothesize that they were both parts of the longer string "GATACACCG". The longer the intersection string, the most likely the stitching is correct. In the mammoth case, they had fragments longer than 60 letters. Stitching together all these fragments, they were able to produce the full string (of billions of letters) 17 independent times. That gives them a high level of confidence that what they did is correct.
In the case of dinosaurs. Will we ever be able to read fragments of tens of letters and stitch them together? Maybe, maybe not. If the DNA breaks down so much that you won't be able to see even pairs of letters, then we are totally out of luck. If we see pairs of letters, we probably see triplets, quadruplets, etc. Can we stitch together a long string out of quadruplets? Most likely not, but if we have 10-letter strings, probably yes.
Are we going to have a contamination problem? If most of the DNA fragments come from bacteria rather than the original dinosaur, will we be doomed? Most likely we'll be able to come up algorithms that will eliminate bacterial DNA genes out of the reconstituted genome. We are quite smart.
Is Jurassic Park in the near future. Not before we are able to revive mammoths. And a mammoth is difficult to create for the simple reason that it takes a very long time to gestate a baby elephant. If each iteration in your experiment takes one year, you are in danger of shipwrecking your career.
Can we overcome these challenges? You bet. Anytime soon? My guess is that not during my lifetime, at least. But then Bill Gates states that we overestimate what we can do in one week but underestimate what we can do in a decade. So, you never know.
I'm sure it doesn't, but we agree that the recovery of the sequence implies a half life greater than 500 years, right? I was trying to get at how much greater, whether double or 100x or 1,000,000x, etc.
"From this point of view a half-life of 521 years is an astronomic number, and totally false"
Please set aside this point of view, because it wasn't mine. If they got 17x coverage, that's not literally from 17 totally intact cells, of course I know that. But I was interpreting the recoverable DNA in aggregate as being what the half-life refers to, as it were, proportional to 17 cells worth. If that's within a couple orders of magnitude, it's good enough for my point.
If you think the half life could be millions of years, because I don't understand gene sequencing, then it would be really cool if you could do your own estimate and show me why your number is different.
>If you think the half life could be millions of years
I don't think the half life could be millions of years. I simply think half life is not a meaningful concept for DNA.
Books decay. What's the half-life of books? How many books from a hundred years ago are still around nowadays? Let's be generous and say 0.1%, that's a half-life of about 10 years. That means there should be no books older than 300 years, yet I have seen with my own eyes a Gutenberg bible, printed well before 1500.
There are about 49 Gutenberg bibles known to remain of 158-180 copies, I read. log2(49/169) = -1.8; 570/1.8 = 316 years for half of them to disappear. It's very meaningful to say that a number is between 10 and 1000. It's not 10,000; it's not 100,000, or 1,000,000. There are maybe 10^82 atoms in the universe. That's about 2^272 so saying I am confident the half life of even the best preserved, most cherished books is less than 1000 years means that a 300,000 year old book could not exist. Because even if there were 10^82 of them, not one would be left. If you really insist you cannot quantify it, you're saying there's a chance! Aren't you?
With DNA, it's not that I know the half life is 1375 years precisely, or have hardly any biological knowledge, but the little knowledge I have combined with exponential rates of loss constrains it so I can't imagine the upper bound is above 10,000 years.
The thing I am trying to express is that even huge uncertainty and almost total ignorance give you far more to work with than "nothing".
Here's an interesting quote from the wikipedia article on ancient DNA 
"Researchers in 2016 measured chloroplast DNA in marine sediment cores, and found diatom DNA dating back to 1.4 million years. This DNA had a half-life significantly longer than previous research, of up to 15,000 years. Kirkpatrick's team also found that DNA only decayed along a half-life rate until about 100 thousand years, at which point it followed a slower, power-law decay rate"
A DNA molecule consists of two strands.
RNA is single stranded.
Mammoth DNA preserved in permafrost can last longer. Temperature is a variable. But dinosaurs lived in a very warm time, much warmer than the Ice Age the mammoths lived in so there's no possibility of nature somehow preserving Jurassic fossils in ice/permafrost.
I'm not sure if you read this link before but I encourage you to - it includes a nice summary of the issues.
Because we have no certain model of the dinosaur, behaviorally, we can guess at that and ML our way to that, too.
And boom: you have your ersatz sim dino, and it only took like three Matrioshka brains.
The data is thought to be pretty accurate (±5M years) and it's from radiometric dating of the oil sands.
It looks like their site is another on the list that lifts our articles and recirculates them on social media.
Why is that relevant? Tissue has been replaced by minerals which presumably are much denser than flesh.
We've banned this account for now, but if you want to email firstname.lastname@example.org with a better username, we can rename it for you and unban it.