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.
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.
The wikipedia article is very poor compared to the depth of his work/thought but here it goes anyway for reference: https://en.wikipedia.org/wiki/Charles_Fourier
You can dive in from wherever, and you will be able to know his cohese and wonderful universe of thought - it really doesn't matter, because it's a single entity, so you can start from his thoughts about family, work, slavery, astronomy, architecture, higiene, urbanism, politics, religion, sex, tolerance, women, commerce, law, philosophy, love, etc
I should warn you to beware of the translation because there are bad ones - he's a guy coming up with words and concepts and always playing with language and meaning, so you gotta be able to read between lines. I wish you a good reading, if you can find them because they seem to be kinda rare, and mind = blown! If you'd like to exchange some ideas about it later, feel free to get in touch!
The sheer scale of it makes it hard to perceive, so probably you aren't the only one and probably a lot of the literature has similar blind spots which implicitly signals "this isn't happening" and we pick up on that and it gets implicitly repeated until it's hard to give any kind of push back in our own minds.
A wonderful, easy to read book on this that I recommend is Factfulness.
https://www.ted.com/playlists/474/the_best_hans_rosling_talk...
https://www.amazon.com/Factfulness-Reasons-World-Things-Bett...
If it's a tinkertoy style model or a drawing within a book, it's made up BS. There are no books large enough to actually show it to scale.
Edit: For the pedants of the world, I have added "(Some)" to my sentence. "Not all accurate scale models" of course. Some are even larger than that.
2nd edit: Folding another comment in here as well that I deleted :
https://en.wikipedia.org/wiki/Solar_System_model
The Sweden solar system scale is listed as 1:20,000,000. Others have used a different scale and been fit into less than an entire country. There are several around the world.
In York, it is spread across 6.4 miles:
https://astrocampus.york.ac.uk/cycle-the-solar-system/
There's another in Greater Boston:
https://foursquare.com/eric_odea/list/museum-of-science-bost...
Sweden was, last I checked, larger than a city block.
Imagine what we could accomplish by mining their resources!
This is incorrect. Red dwarfs will end their lives as black dwarfs. However, no black dwarfs are currently expected to exist because the universe is not old enough yet. Red dwarfs, in particular, are expected to have lifespan of trillions of years.
https://www.zooniverse.org/projects/marckuchner/backyard-wor...
Though some might argue that in the changing nature of fusion reactions and body mass, this sorting of sub-stellar bodies is only true for as long as our star is a red dwarf.
Once that's over (thinking in the larger timescale of things) and it becomes a brown dwarf, what then? Wasn't it a solar system at one point in time?
Our sun will never become a brown dwarf. Stars have their life-cycle and nomenclature. You cannot made your own willy-nilly.
The simplistic solar systems and textbooks in grade school are not just misleading when it comes to scale, but they're really really misleading. Few people really comprehend the scale of things in the universe.
> most brown dwarfs are slightly smaller than Jupiter (15–20%)
> Brown dwarfs are all roughly the same radius as Jupiter.
The suggestion that Jupiter is "orders of magnitude too small" to be a brown dwarf is obviously wrong in terms of size, but it's also wrong in terms of mass:
> at the low end of the range (10 [Jupiter masses]), their volume is governed primarily by Coulomb pressure
(But i guess our moon could have moons so it's moons all the way down)
A system the size of our solar system centred on a jupiter-sized object wouldn't be very stable - it'd be quickly disrupted by an encounter with a star.
But it wasn't until recently that I realized that the solar system didn't just form into some static natural state where it largely didn't change until say the sun was finished with it's lifespan.
Rather it evolves, changes, planets are habitable, then not, moons are formed and break up, even frozen planets are geologically active and are changing, Saturn's rings are relatively recent and etc.
Not sure how I didn't pick up on that.