We are time travelers!
No, not in the sense of the teenagers who get 'time yanked' in my sci fi series for young adults: David Brin's Out of Time. Or through space in my other YA series for teens, the High Horizon. (If you know any young folks - or you have a taste for mind-expanding adventure - you'll love these!)
Rather, today I want to discuss a different kind of time travel -- some ways in which we are getting windows into the past via science!
Earlier (recent) examples included Utzi the Iceman, who was discovered when retreating alpine glaciers exposed a neolithinc murder victim. Scientists were able to use the contents of his guts and pollen in his lungs to trace his exact path and meals and the season in which he made his final journey, till he was ambushed by some enemy. Incredible story!
Or the way genetic analysis told us about Chromosome bottlenecks in the past, including Mitochondrial Eve, the apparent mother of us all... and more recently evidence of a similar Y-chromosome bottleneck about 12,000 years ago, almost exactly when people made two technological breakthroughs associated with agriculture... beer and kings. And very likely the latter simply ordered the deaths of many males who couldn't control their use of the former!
But no, let's go even farther back!
== Here come those 'extinctions' again! ==
Ever more, we are using amazing techniques to penetrate what was a darkly hidden past. For example, rhythms and 'cycles' or extinction that were part of Earth's meta-stable equilibrium... but of the sort that may have hobbled life's progress elsewhere. For example...
In EXISTENCE, I talk about how humans appear to have undergone a major cultural – possibly genetic – shift a little over 40,000 years ago, that included cave art, ceremonial burials and a vastly expanded suite of tools. (I assert it was just the earliest known in what would become a series of accelerating reprogrammings of the human operating system.) It’s also a time when many megafauna species... and our Neanderthal cousins... shuffled off the stage.
Now comes a theory that magnetic pole reversals can stress an ecosystem and cause extinctions: “One temporary flip of the poles, known as the Laschamps excursion, happened 42,000 years ago and lasted for about 1,000 years.” Accompanied by a major solar minimum, it may have caused the tipping point. Interestingly, my colleague Rob Sawyer goes with exactly this notion in his HOMINIDS series.
The authors of this study go to the “42” thing, though, to connect with a different sci fi series.
Oh, BTW: “Earth’s magnetic field has weakened by about 9% over the past 170 years, and the researchers say another flip could be on the cards.”
== “Periodic” Extinctions are back on the table ==
In 2015 I re-posted my 1980s era article in Analog: "The Deadly Thing at 2.4 Kiloparsecs" along with updates, referring to theories for what might explain periodicity in Earth's major and intermediate extinctions. Now comes a revised estimate of extinction periodicity led by NYU’s Michael Rampino, who reiterates that widespread die-offs of land-dwelling animals – which include amphibians, reptiles, mammals and birds – appear to follow a cycle of about 27 million years.
The article says the next periodic comet drop isn't due for 20 million years. But track from the end of the Cretacous - 63 million years ago, if the cycle really was 27 M.y, then we would be 9 away from the next.
I've looked at the pattern currently listed here and I don't think the 27M.y thing works at all, except as an average that posits a SINGLE cause. Especially, it doesn't look like a good fit for when our solar system plunges through the galactic "skirt."
But what if the triggers number more than one? Say TWO or THREE objects that pass nearby, disturbing our solar system, each with its own, longer periodicity... AND SOMETIMES THEY MISS, failing to leave a trace in the fossil record? Moreover, Suppose that the two - or 3 or 4 - trigger objects have somewhat different phases?
I have to wonder if someone out there can program a fit to the listed extinctions with two or three different periodic triggers that sometimes fail to leave a trace. Including that latter element could be tricky. But it already looks to me as if some of the sums of adjacent intervals might show better periodicity.
My 'lapping" process (posited in the "Deadly Thing" article) could then be several causal objects in Galactic orbit, or possible brown dwarves in far solar orbit. In the former case, they'd be farther out from Galactic center than my 1st paper supposed, and thus pass sometimes much closer to us.
Of course, some of the extinctions may not have had a foreign cause... and the datings of the intervals gets foggier, farther back in time.
And now a splash of cold water. These other researchers claim to have used deep-learning systems to sift the data and found no clear timing relationship between the extinctions.
In EXISTENCE I posited the resurrection of the Neanderthal species in our near future. Are we already on our way?
Neanderthal mini-brains! Working near UCSD, Dr. Alysson Moutri grown mini ‘organoids’ from both human neurons and others that were genetically altered with Neanderthal DNA. And the results are already so amazing that NASA agreed to fly a version of the experiment aboard the space station. (I was peripherally involved in that aspect of things.) “Organoids with the ancient NOVA1 gene also appear to mature more quickly and remain smaller than their modern counterparts, Muotri says." The neurons start to get more active at very early stages.
These findings are consistent with the hypothesis that modern humans evolved big brains that continue to develop long after birth in order to navigate complex social systems. Of course I have revived Neanderthals as characters in Existence... But see also my own research into the role that neoteny has played in giving humans ever-young and agile minds. Well... some of us.
== And some space stuff! ==
While we’re talking about new tools to look back through time… Gravitational micro-lensing only works when three objects line up, our telescope, a distant star… and the object directly in between that’s doing the lensing by bending the star’s light as predicted by Einstein’s General Theory of Relativity. What’s amazing is… it works! With our new telescopes that can scan tens of thousands of stars at a time, we are spotting these events… and one revealed a small rogue planet, likely no larger than ours but cut loose from its origin system, doing the brief bending bit as it passed brifly through our line of sight! This may be important.
Curious. Is the universe getting… hotter? A team of international scientists compared the temperature of cosmic gas farther away from Earth (and, therefore, farther back in time) to younger gases nearer to our planet and to the present day. According to their calculations, in the past 10 billion years, the mean temperature of these gases has increased by more than 10 times.
Remember that “monolith” discovered in an isolated red rock cove in Utah? Apparently the first published images were deceptive. It's a prism shape with triangular horizontal cross section. Making it much sturdier and less like 2001. But the Interior Dept guys have a sense of humor. Anyway, apparently the “obelisk” discovered in the Utah desert has been there a long time.
Are there others? In my novel EARTH, pyramidal obelisks have been placed to seem like the tips of a single, humungous tetrahedron sculpture embedded in the planet. Only one orientation lets all tips emerge on dry land; one must be on Easter Island... as I depict in the novel. And in real life a sculptor did it!