I’m not sure what you are replying to. Did I say anywhere that large objects fall faster than small objects?
If you are referring to my line “If it’s a big meteorite, it must be further away and be falling much faster,” then this is not a comment on its mass, it is a statement of pure geometry. Read the link to understand more.
Well I think that you’ve completely missed my point, but it does give me an opportunity for sophistry, which I never pass up. Y’see, one way to look at it would be that the probability of a meteorite passing a parachutist in midair is extremely low, while the chance of a parachutist above that person having accidentally released a rock from their chute is higher, therefore it’s most likely (concluded to be) just a rock. And if that’s true for any given parachutist it must be true for every parachutist. Parachutists are also those people more likely to see either a rock or a meteorite before it hits the ground, being that they are higher up. Since we know that parachutists only observe ordinary rocks, not meteorites, then all that falls to the ground is most likely (concluded to be) rocks released from parachutes.
Another way to think about it would be to say that there are thousands of meteorites falling to the ground every day, many of which are detected or even observed. As far as I can tell (and I googled around quite a bit) there has never been a recorded incident of a rock being released from a poorly packed chute. Therefore, the object on the camera is most likely to have been a meteorite, not just an ordinary rock.
Personally I like to think of it as being in both states of being at the same time; it is both a rock and a meteorite at the same time. And a cat.
First, many skydivers have said falling debris is a relatively common event; all manners of small objects can get caught in the parachute when it is packed on the ground before the dive.
I’d wager that the “relatively common event” quoted is of an a priori higher likelihood than the never-before-witnessed meteorite passing a skydiver. Indeed, you say “many [meteorites] are detected and observed,” but the article points out that this is wrong several times: a meteorite has never been observed in it’s “dark flight,” when it is not burning up.
So, on the one hand, an event that parachutists say is relatively common. On the other, an event that has never been observed to happen before, ever.
Like I said, the Bayesian inference in this case simply means that we’d need extraordinary evidence that it’s a meteorite – the “likelihood function.” So a burnt-up iron-filled rock in the ground surrounded by a large crater? That is enough evidence to say that a meteorite has probably fallen. Something that looks maybe like a meteorite (in dark flight) and maybe like a pebble? More likely a pebble.
Yeah, pebble. Anything coming in from outer space will be super-heated, and fragmenting as it re-enters. This is one of those vids that looks cool until you stop and think about it for a bit. I’ve been waiting for a few days before doing a “HOLY COW” Facebook post about it. I expect we’ll get a definitive refutation within a few days.
I was looking for somewhere to drive my truck through and that’ll do nicely! A true statement about one thing need not be true about a million such things. An individual lottery ticket buyer is almost certain to not win the jackpot. But every week or so, someone wins the jackpot. The reason is that a million is not equal to one.
You casually (nb. not causally) diss Bayesian inference in the fashionable backlash style, but the actual core theorem of Bayes is utterly uncontroversial. If it’s false then so is basic arithmetic: if you have two phenomena, A and B, and you want to study their coincidence, there are basically four categories: (1) neither happens, (2) A happens, (3) B happens, (4) both A & B happen. Any observed outcome is in exactly one of these categories. You can count them. They must add up to the total number of observations. The count of observations where both happened divided by the count of observations where A happened is “the probability of B given A”, written as P(B|A). It’s just the answer to the question: “Of the observations where A happened, in what proportion did B also happen?” That’s it. It cannot be wrong. No one who can count thinks it is wrong.
Personally I like to think of it as being in both states of being at the same time; it is both a rock and a meteorite at the same time. And a cat.
You’re joking (of course…?) because a meteorite is a subclass of a rock, so to say “it is both a rock and meteorite” would just be a long-winded way of saying “it’s a meteorite”. A thumb is a finger but a finger is not necessarily a thumb. But sadly there are a lot of artsy folk who think that QM is a physical theory in which everything imaginable is equally likely, so whatever randomly chosen fairytale you prefer is somehow lent credibility by QM.
Actually, though I am also fairly confident it’s a pebble (as if it weren’t obvious from my other 43 posts on the topic…) if it were as simple as that the original Bad Astronomy article would not have ended by concluding that it was probably a meteorite. It turns out that many (most?) meteorites split up and tumble through the air at slower-than-burning speed, during their “dark flight.”
Or, you know, someone in the plane could be really mad at that guy, and happen to have a rock nearby.
Toss a rock out the door a little while after the jumper, they fall in tandem, the parachute pops open, and the rock continues downward at the original speed, past the jumper.