This is just a guess but I fly a _lot_ (~40 flights so far this year). My guess is that the software probably did its job, the gate agents are often just automotons and don't really check anything other than your boarding zone.
Even then, I often board with my coworkers who have higher status than me. If we're sitting next to each other and he's in group 2 but I'm in group 6, I'll generally board with him anyway and no one seems to care.
The system may not be aware of something like boarding groups, especially since every airline does them differently.
It's entirely possible that the "check" is "is this boarding pass checksum valid.", especially given the stories of boarding wrong flights - it doesn't even flash red for "this is not the right pass for this flight".
Depends on an airline and maybe even airport, I guess.
Anecdotally, last time I was flying on a business to Germany with Lufthansa, my cow-orker did the Internet check-in for me without me knowing, and printed out the boarding passes. I later did the check-in for myself again, and picked a different seat. At the airport, the friend gave me the boarding pass he printed (with the old seat number), and so I thought, let's check if it still works on the scanners. I scanned it when boarding, and the scanner threw up an error that the seat on the pass does not agree with the one that's actually booked. I pulled the up-to-date boardin pass on my phone and continued on my way - but it seems that there is some actual checking being done, not just CRC.
I have my friends do this when they travel with me. I tell them that if the gate agent says something, tell them you have a peanut allergy and need extra time to wipe the seat down. That line has worked every time.
"tell them you have a peanut allergy and need extra time to wipe the seat"
Another often overlooked travel tip is that you can park in handicap spaces to save walking 10 extra feet.
That's not a life hack thats deliberately lying to someone whose job requires them to accommodate you to sometimes great degrees. Like not serving peanuts to those around you.
Wait. What? A star more massive than a black hole?
I must be missing something here. Once something reaches the mass of a black hole, it becomes a black hole. No? How is it possible for a mass to be greater than a black hole but not a black hole? Mass over distance?
no, there isn't some set mass that will make a black hole. A black hole is gravity overcoming the other fundamental forces. When a star dies and forms a black hole the force pushing outward from the fusion is overcome by the gravity of the star, but there isn't some threshold of size where this happens.
While true, this answer is a bit misleading. There is a minimum threshold for stellar black holes–the ones created through stellar evolution–it's called the Tolman–Oppenheimer–Volkoff limit.
> There is a minimum threshold for stellar black holes–the ones created through stellar evolution–it's called the Tolman–Oppenheimer–Volkoff limit.
That limit gives the maximum size of a neutron star, but it does not say an object smaller than that cannot form a black hole. In fact, it is considered likely that supernova explosions could cause an implosion that could form a black hole smaller than the limit, simply because it happens too fast for neutron degeneracy pressure to stop it before the implosion reaches the Schwarzschild radius.
I don't know absolutely nothing about black holes, but I think that amount of mass has nothing to do with it. It is the density what matters. Wasn't the LHC trolled about the possibility of creating tiny black holes?
No, stellar black holes have less mass than the stars they came from. When a star goes supernova it ejects much of its mass, the core can collapses into a black hole. Black holes don't form due to mass alone, but density of mass. Collapse the earth to the size of a golf ball and it'll become a black hole, but of course the earth doesn't have the necessary gravity to do that. Neither do stars, until their cores collapse and get dense enough to cross that line and become black holes.
What you're missing is that there's energy potential in nuclear structures, which can be released through nuclear fusion (and in some cases: fission, though that's not materially significant for stars).
What a star is, basically, is gravity and the strong nuclear force duking it out. Eventually, in most cases, the strong nuclear force wins. How long that takes, and where that ends up, depends almost entirely on the initial mass of the star itself.
For low-mass stars ("brown dwarfs"), there's only just barely enough gravitational pressure to stimulate nuclear fusion. The stars may radiate only in the infra-red, and have lifespans of trillions of years, after which they gradually cool to the background temperature of space, having exhausted their hydrogen. These are from a few times the mass of Jupiter to significantly less than the mass of our Sun.
A star such as our Sun has a lifespan of around 10 billion years. Gravity compresses its hydrogen and helium sufficiently that the atoms are no longer distinct, but form a plasma. In that, hydrogen atoms fuse (through several different chains, it can be complicated), producing first helium, then, as lighter elments (or at least their nuclei) are consumed, temperatures rise, and those in turn fuse, through carbon, nitrogen, oxygen, silicon, and finally resulting in iron, with core temperatures increasing all the while.
Iron is at the bottom of the nuclear potential curve -- you cannot release energy by fusing it (as you can lighter nuclei) or fissioning it (as you can heavier nuclei). Which means that gravity at this point wins, and the collapse of the star progresses to its next stage(s).
Incidentally, the rate of energy release by unit mass of the Sun is about 1/5 that of your own body. It's not that the Sun is highly energetic, but that there's so much of it.
Larger stars are fighting a stronger pull of gravity, so must release more energy with time to overcome its pull. They burn faster, and hotter. Basically: the bigger the star, the shorter its life, with some of the largest having a lifespan of only a few tens of millions of years.
There's a maximum star size (through normal formation) given that once a star begins hydrogen fusion the generated pressure drives off any additional potentially in-falling gas. This is roughly 40x a solar mass as I recall.
There may be models in which more massive stars can form through collisions, though I've no specific information on this.
In all of this: the star that forms may have enough mass to form a black hole, but so long as it can undergo fusion it will be able to resist that.
The ability to resist stops when silicon fuses to iron in the star's core. Once the silicon is exhuasted, a life-stage which takes about one Earth day, the core collapses. Depending on total mass, this may result in a white dwarf, a neutron star, or a black hole. It also generates absolutely immense heat (through pressure and kinetic energy) which rips through the rest of the star -- a nova or supernova. Much of the star's mass may be lost, and additional heavy elements (beyond iron) are formed. Which is to say: all of you that isn't hydrogen or helium, was once part of stellar fusion or a supernova (some heavy elements -- gold and platinum-series elements, may come from neutron-star collisions).
Which is how you can have stars more massive than black holes. For a while.
Keep in mind that surface temps could be anywhere from, say, a few low-thousands of K (dull red) to hundreds, possibly even tens. Constitution would likely be roughly 75% hydrogen / 25% helium, and up, with some lithium and possibly higher metalicity constituents.
What you wouldn't have though is a high-silicate crust with a bunch of CNO -- carbon, nitrogen, and oxygen.
Temperature and chemistry can both be ascertained through spectral emissions (wavelength corresponds to temp via blackbody, emission or absorption spectra to chemistry).
I'm not an astronomer though I've got a pretty good lay grasp of the subject. There may well be some literature on dwarf star chemistry and temperature, and Wikpedia is likely a good starting point.
Exactly - when the weather report says "its dangerous to go outside" and "exposed skin will freeze in less than 1 minute", there's no amount of clothes that'll save you.
A friend of mine has been doing this for many years. I have bought a lot from him, and he's not cheap. I know he could make a lot more if he worked on his marketing a little bit, but I'm not sure he wants to.
Agreed. I don't think the problem in winter driving is the speed. It's anticipating what the hazards are and how to avoid them.
You - and the other drivers on the road - have less control at all speeds and are always much closer to the limit of traction. Driving on winter roads is a lot like racing a car on a track with other drivers - everyone is near the limit of traction and a hazard can present itself very quickly. Having the right reaction at the right time helps, but planning ahead is more important. Daily driving in summer months is benign in comparison.
> Driving on winter roads is a lot like racing a car on a track with other drivers - everyone is near the limit of traction and a hazard can present itself very quickly
Don't know where the parent is from but I live in a largish Canadian city. Using a bike for primary travel is not viable except for short leisure/weekend errands. I even live in the part of town where biking would be the most viable.
1) the city isn't built for biking. It's long distances between where people work and their homes. Not many live downtown like other large cities.
2) you can only do it for six months of the year. The other six are too cold.
$1000/year is a very low amount to consider regular use, I would think.
As others have stated making money off of the merchants is part of their business model. At $1k/year I wouldn't be surprised if that puts you into negative territory.
