We didn't know until recently that there were planets orbiting other stars. We suspected that there might be, but we didn't know. The idea that there could be other "earth-like planets" was a hopeful guess.
When the headlines started coming in from Kepler, that was huge. Very exciting and huge.
That is going to be huge news if we find it (I suspect we'll get a lot of other results first though and a ton of new interesting work looking for alternative photosynthetic chemistries).
https://www.jwst.nasa.gov/content/forScientists/faqScientist...
https://en.wikipedia.org/wiki/Timeline_of_knowledge_about_ga....
With such knowledge ready at hand for such a thorough comment on HackerNews, I am curious what your learning lifestyle is (books mostly? What kind? How many hrs a week? How much other media do you consume? Youtube? Netflix docos?). As I get older I'm realizing that life is too damn short to learn all the stuff I want to learn and so am constantly thinking about how best to spend my time.
We should NEVER accept a hypothesis as fact because that makes people stop thinking or searching for answers. And there’s no way we can even definitively say something that happened tens of millions of years ago actually happened.
I personally think it was an asteroid too, but I never want to be arrogant enough to think it’s a closed case now. For example, it could have been the switching of the poles causing cosmic radiation to cause mass extinction, similar to why the Neanderthals disappeared and there would be no way for us to know.
https://phys.org/news/2021-02-asteroid-crater-case-dinosaur-...
1. Such a pandemic (or other calamity) occurring simultaneously with overwhelming evidence a catastrophic asteroid impact is exceedingly unlikely.
2. Cross-species pandemic resulting in mass extinctions are similarly unlikely. Boom-bust population cycles perhaps. Mass cross-species extinction not so much.
3. Patterns of extinction (and survival) far more closely match the presently-accepted conclusion.
4. Precisely because an infectious agent leaves few multimillion-year traces, any defence of such a hypothesis can advance no further than "it might have happened". This is not evidence-based argument. (Traces of pathology might be preserved in fossil or amber substrates.)
Point remains that multiple highly consistent widely-distributed lines of evidence point to the asteroid hypothesis.
One unsubstantiated Hacker News comment points to the epidemic scenario.
One of the books I had growing up was a Patrick Moore juvenile book on astronomy, probably Seeing Stars (1970). That had a ... pretty good ... description of the state of knowledge at the time, but it was published only about five years after the 4.5 billion year figure for the age of the Earth, and plate tectonics as a geological mechanism, were formally adopted.
The Viking missions, Voyager, Mars rovers, New Horizons, the Hubble Space Telescope, Keck observatory, LIGO ... were all in the future.
The degree of development in the field of geology in the 20th century alone has been staggering. Credible scientific estimates of the age of the Earth in 1900 were as little as 30 million years (Lord Kelvin's gravitational collapse/cooling calculation). Interestingly, parallel developments in physics (notably radioactivity) helped give us the clocks we finally needed to measure geological time. We could trace landmass movements, make some determination of interior structures using seismic (and I suspect nuclear blast) waves, and more.
Much of the more interesting physics (and some chemistry) Nobel Prize awards of the past 50 years have been in sensing and detecting, at large and small scales, again, giving tools to measure, detect, and distinguish patterns, structures, and phenomena.
Within my own lifetime notions such as the asteroid hypothesis for the mass extinction of the dinosaurs have passed from wild theory to accepted fact, we've got evidence of 300 million-year snowball Earths, strong evidence concerning early Earth evolution, atmospheric composition, and life. We have detected thousands of extrasolar planets (a value still strongly limited by what sizes, types, orbits, and distances at which such detection is possible). Pluto's been un-planeted, and imaged. We've kissed the face of comets and returned their dust to Earth.
And we're starting to get some idea as what the long-term stability of planetary orbits might be --- the notion that planets may wander not only in the skies but in their orbital characteristics ... would change things markedly.
So it's quite possible that what you didn't pick up wasn't there to pick up when you were learning it.