JWST is a narrow-field instrument, so it’s ill suited for survey type tasks; it would take an extremely long time to map some appreciable fraction of the sky, and anyway parts of the sky are out of its reach because of the need to remain behind the sunshade. But the NGRST, due to launch in 2026 or 2027, is designed specifically for surveys in visible light/near infrared. Its field of view is approximately the angular size of the full moon, which is an area about 100x larger than that of Hubble or JWST. Mapping the whole sky at that level of detail would still require a couple hundred thousand separate exposures!

How many grains of sand do you need before it can be called a heap?

Well, theory predicts these reactions and experiments eg. with particle colliders have shown that the predictions match exactly what actually happens, to a high precision.

Indeed the theory (the so-called standard model of particle physics) is so successful that phycisists are frustrated because despite its success, it’s also incomplete, but not even the LHC has found even a hint of any new physics beyond the standard model.

> And yeah its a horrible word. Doesn't make any sense with the normal English definition of specific. Old science terms are often bad science terms in modern English.

I'd guess it's a bit too literal translation from the German spezifisch which means "specific", "particular", but also "intrinsic", which is much closer to the actual meaning. (For a long time, German was the lingua franca of physics.)

Those sorts of events are really extraordinarily rare compared to simply normal everyday gradual subsidence, regular annual floods changing geography and depositing sediment, constructing new buildings on top of the rubble of the old ones…

Whew, got nerd sniped. Wikipedia is a crazy, wonderful thing.

• The two species of gorillas are comfortably over the 100lbs limit on average, but humans, chimps (but not bonobos), and orangutans (three species) should also count if we're talking about average adult weight, remembering that males are generally quite a bit larger than females. So that's seven primates.

• There are eight or nine extant bovine species (genera Bos and Bison), all much heavier than 100lbs, as well as six species of buffalo.

• I think there are maybe ten species of cervids (deer) that are unambiguously over 100lbs on average, with several others that are straddling the limit.

• 94 cetaceans, all of which over the limit except maybe the very smallest dolphin and porpoise species.

• Four species of tapirs in addition to the five rhino and two hippos you mentioned.

• Only one extant horse species, but eight other equines (donkeys and zebras), all weighing several hundred pounds.

• There are 18 extant species of suids (pigs), all or at least almost all of them clearly more than 100lbs on average.

• There are seven species of sheep, at least three or four of them over 100lbs on average.

• Nine species of goats, most of which straddle the 100lbs figure, so let's be conservative and not include them.

• There are 91 antelope species which makes sense given that it's a catch-all group encompassing those bovids that are not cattle, goats, or sheep. There's a huge variation in size, but I'd guesstimate that at least ten of them pass the 100lbs test.

• Of the big cats, three (tigers, lions, and jaguars) are comfortably over the limit, with the others straddling it.

• Eight species of bears, out of which at least four are clearly over 100lbs.

• And finally, there are 34 extant species of pinnipeds, all of which weigh over 100lbs thanks to all the blubber!

I'm probably forgetting something but all the major groups should be accounted for.

(EDIT: forgot giraffes and the okapi, five species in total)

So that adds up to over 200 species quite easily. The 148 figure is possibly still defensible depending on the definition of "over 100lbs" used though. Also, over half of the species are aquatic or semiaquatic.

Well, we did exactly that with the ESA’s Rosetta mission, google it!

It’s not a “magnetic engine” in any relevant sense. It’s a huge rotating ball of iron and nickel and conservation of angular momentum is a thing! Truly ludicrous amounts of momentum would have to be transferred somewhere else for it to stop rotating.

(Now, to be fair, a mechanism does exist that slowly bleeds off Earth’s rotational momentum, and has done so for billions of years: the moon and its tidal forces. In the far future Earth would become tidally locked with the moon, and rotate very slowly, if the sun didn’t become a red giant first. But somehow only slowing down the core? That would require magic.)

Anyway, my use of “absolutely” should be taken in the context of the discussion, just like everything else. There’s no reason to add some sort of an “except via magic” to every other sentence, pedantic Redditors notwithstanding.

You’d have to be gentle enough not to blast away too much of the core in the process. so I’d think many, many smaller bodies over a longer period of time could work better.

What’s there to be skeptical about? The core used to be slightly superrotating, ie. rotating a bit faster than the rest of the planet, now it has slowed down a bit and rotating at about the same rate as everything else, and it seems to be natural variation.

“Reverse” as in start rotating slightly slower than the rest of the Earth, which I guess is “reversing” in a frame corotating with the planet. The same goes for “stopping”, those are really misleading terms to use because the core is very much rotating indeed at about one turn in 24 hours as expected! There’s absolutely nothing that could make it actually stop. Unfortunately, popular media is as clueless as always.

The inside of your eye is a "dark room" like the insides of a camera; your pupils appear black even though they are transparent because the retina is dark and reflects little light. Light bouncing around the eyeball would cause glare and reduction of contrast.

The avian respiratory system is very different from the mammalian system. Bird lungs don't expand and contract like mammals' do; rather birds have several air sacs that expand and contract in an alternating fashion and push air unidirectionally through the lungs; the lungs have millions of narrow "tubes" where gas exchange occurs, whereas the alveoli in mammalian lungs are "bags" with only one opening.

If the force that accelerated you were constant, you could indeed reach a speed arbitrarily close to the speed of light just by starting arbitrarily far away – and escape velocity wouldn't be a thing, either.

But gravity is inversely proportional to distance squared, so if you're very far away (in a toy universe where there are only you plus the object you're falling towards), your initial acceleration will also be very slow and almost all of the speed gain will happen when you're already very close to the object.

Most living things don't have an immune system even today, because almost all living things are single-celled microbes. Of course, all living things have evolved in a constant arms race against parasites, so have all sorts of adaptations against getting infected, and infectious organisms of course are adapting all the time to overcome those defenses. But only complex multicellular organisms have "immune systems" with specialized cells and epigenetic memory and so on.

One of the funniest (but probably really frustrating to figure out) "radio pollution" cases is the story of strange radio spikes that plagued an observatory for years being caused by misuse of a microwave oven…

I'd say it's fine to use the term "light pollution" to refer to any unwanted anthropogenic photons hitting your detector, whether ambient or point sources.

Eh, that's just arguing about semantics, using a different definition of "details" than the GP. And note that many of the details you see in the periphery, your brain simply reconstructs from having previously looked there (and indeed continuously and subconsciously moving your eyes in saccades, collecting a patchwork of detailed information for the brain to stitch into a whole), including colors. You'd be surprised how many of the colors you see in the periphery are entirely filled in by the brain.

From a survival perspective, our peripheral vision mostly needs to do one thing and it indeed does it well: detecting moving things. The moment there's unexpected motion detected, we instinctively shift our gaze there to take a better look with the foveal part of the retina.

Well yes, and many other things like most interior walls and basically all relatively thin non-metallic and non-watery things which let your cellular or wifi signal pass through just fine with just some attenuation. Resolution’s limited by wavelength though, the “pixels” of microwave vision are on the order of 1..10 cm or so at best. And you’d need big “eyes”.

Well, I'm sure you have experienced how something like hand lotion is absorbed quite effectively (and indeed that's its whole purpose)!

In the Finnish case, it's absolutely a glacial erratic, being that there's very little surface geology in Finland that was not shaped, moulded, or moved there by the latest glaciation.

We're talking visible, baryonic matter. Dark matter and energy are irrelevant here.