otto hammar Why? As far as I can tell he didn't play any part in the development of GPS. His STDMA patent was filed a couple of decades after GPS was developed in 1973.
Wow, this is so much more complex than I thought. To be fair, I never really thought about "what is sea level", having lived "right next to" the sea for the majority of my life :).
You should also know that if the glaciers on Greenland melt, the sea level would drop due too: - Rise in land due to release of pressure (caused by Ice) - drop in sea level due to current blockage (the salty and fresh water dont mix, so it kind of pushes water away) - drop in sea level due to redistribution of mass from the poles to the equators - drop in sea level due to the dispersing of mass (ice) from Greenland. And thats just what we know...
@@Azivegu Ten years late, but for context if the glaciers are melting, it's likely ocean temperatures are also increasing, so thermal expansion becomes an issue as well
someone had to spoil it lol. literal sea level is actually 62, 63 is where ur feet are, wich is the block Y coord is defined by. people say 64 cause it's the old measure. happy ?
Wow! I never would have thought how much work has gone into this seemingly intuitively simple concept - sea level! Scientists of all kinds - the uncelebrated heroes of our civilization, just doing their work.
So basically the height of Mt. Everest is defined by a hypothetical sea level influenced by the gravity of himalaya itself? Wouldn´t that also mean that Mt. Everest is even higher than 8848m, measured on an average sea level?
and the mt everest is even taller if you count from the center of the earth! we need the sea level definition to measure something that dont have a real ''starting point''.
Franz Reischl Maybe you mean the ellipsoid? That is an idealization of the geoid. However, if you use the ellipsoid to determine the altitude (the height), the air would be thicker at the Himalayas than it would be at the same altitude at other parts of the earth, which it is not if you use the definition of sea level that is given in the video to determine the altitude. Which is why it is that definition that is used, because it is the definition that is the most useful in practice.
Its only 42 km though, compared to the entirety of Earth its not even noticeable when looking at it(i.e. from Space) but its enough to have to factor it in when it comes to math and science.
I know me too! I came to find out how let's say Jim from Hundreds of years ago or when ever, goes to Mt. Everest and determines how tall it is. I want to know how he did it and came up with that number, what told he used or WHAT!
This all just provides to me evidence that we really have no fucking clue and just make shit up and call it fact until we show ourselves how wrong it is
Fresh from the "You can learn so much fascinating stuff on RU-vid" series is this mind blowing exploration of sea level and what it really means. I'll admit, before watching this, I thought "Seriously, how complicated can sea level be?".
As someone who studied in this field in university for 5 years, I was _very_ happy he made a video about it and that as I type this comment the video is very near [less than 4,000] 1 million views. :D He did quite a fine job explaining this within a 2m50s time frame. I think I know how others must have felt when he uploaded videos specific to their fields of work. I wanted him to keep talking! Haha.
You studied in this field is your claim. I can not find any empirical evidence of living on a sphere/elipsoid/oblate spheroid anywhere. Water is empirically level, used to construct structures plumb and level. Even over several miles structures are built plumb and level with the supposed earth curve not being factored in. Water does not conform to solid spheres or ellipsoids. Unless of course you could show me such a demonstration as you studied in this field. Practical demonstration thanks? I found the video length of 2 minutes and 50 seconds to be full of outrageous assumptions and full of pseudo science. Mainly religious mantras.
@@justinh1433 I'm not sure how you stumbled upon my 7 year old comment with only 18 likes. You're free to believe that the Earth isn't a sphere/ellipsoid/oblate spheroid. I actually work with a guy who believes the Earth is flat. Nice guy.
you are not free to believe whatever you want if you have enough evidences of a reality, you have the moral responsibility to acknowledge its truth. When a kid tells his mom: "I hate you, you are not my mom", while the mom has raised him and he looks like her, the kid is just lying to himself. About gravity, a simple human may not have enough knowledge to prove by himself that earth is spherical, but assuming that they can redefine gravity by themselves is fondamentally wrong. It is not about the shape of the earth, it s about working predictive theories. a gps calculates positions using the fact that earth is spherical assuming the earth is flat you can’t even explain that 2 people in america and europe can have a call and one has the sun under the earth and the other has the sun still up in the sky. You are free to believe some high powered people are manipulating everyone and scheme evil plans against poor people, there are not plenty of evidences it is not the case. You are free to believe some kind of superior intelligence decided to create this world and wants to give everyone love and happiness. You are not free to believe 1 + 1 = 3 because you know 1 apple and 1 banana makes 2 fruits Claiming the opposite is basically lying to other and to yourself, and this is bad, morally bad. The same bad when you say killing people is bad.
@@raphaelnej8387 He's allowed to believe things that aren't factually correct and that go against evidence. Basically, he's free to be wrong. We're all wrong about many things, some more than others. To not be free to be wrong is far worse and is honestly quite a dark path.
I had no idea the gravitational anomalies at the Earth's surface were that big. Neat. I wonder if anything is known about how our anomalies compare to the other planets in the solar system?
Great video! I had never really thought about the matter before I saw this video, and I think it makes this video even better: finding something new to wonder about.
I go into most of these videos with a rough understanding of the scientific principals, some more than others. This one I thought I was understood, and the complexity involved blew my mind.
This is amazing and how these videos should be. Imagine a 10 second video which only says "Seal level is measured by scientists calculating gravity if the mountain is not there. this calculation is programmed into GPS satellites"
If a video said that, and I was still curious enough about the subject, then I would waste 3 minutes of my time to do some more research, like you and many others should do instead of complaining about video durations...
I prefer long over short but short is nice too. I don't care as long as we have the long videos still. I mean why should I complain? I get an extra 10 seconds every day of learning when without the short I would just get 3 min per month here.
When I was about 5 I used to think "sea level" meant that there was water underneath the ground, and you would measure from there. I thought this was like that because when I used to make sand castles near the beach, I'd always find water while digging... Silly me!
It's nice to know people a lot smarter than me are doing extremely complicated things to make my life more convenient, even if it's just the sea level.
Augurk6 Isn't it clear that sandis550 appreciates the videos? I mean they obviously love the videos made by this channel & are wanting longer, more detailed content. Perhaps it is just me.
I do like Henrys videos a lot, but honestly i have only watched one of the 10sek. videos. They are not my cup of tea. They are like a cheap Cheeseburger when you are used to a premium Burger (with Bacon).
That binary pattern at the end is not random. It was clearly written by a human who was TRYING to make it seem random. The number of 0's is matched too evenly with the number of 1's over short distances. It's too well compensated for. This is a common mistake made by humans who are trying to mimic randomness. I've seen it before.
You can never say whether a result is random or not. You can only say whether or not the process by which the result was found actually produces random results. When truly random, all results are equally likely, including ones that, to your mind, do not appear to be random.
I remember my father, a physicist, explaining this to me as a kid. He used the geodetic model in his job, writing targeting programs for intercontinental ballistic missiles.
Walthanar I like to think that because our ICBM's were accurate to within a few meters that the USSR went bankrupt trying to match our technology. In my mind, my father helped win the Cold War.
that was incredably much more complicated than i'd imagined. i love how you completely crush my understanding of sertant things in the universe and then rebuild my understanding to a much deeper degree. :D
Ok. This is first one from 100s I've seen lately on various scientific channels that stands out for me. 1) I didn't know about that at all. And 2) the topic is not scientifically complex. And 3) it is very interesting and counter intuitive I actually was taught in school that whole world when say "see level" is a referencing to one particular see - Baltic sea. I always doubted about it though, but never checked. Now I know
As always: simple things are never simple. But the closer you look, the less simple but the more interesting they become. Thank you for picking this topic and showing it to me. I feel a tiny bit smarter now.
So do mountains get smaller by definition because the sea that's used as a reference point is rising? Or are those measurements referring to sea level at a fixed point in time?
It's actually more complicated than that since earth is not a sphere as this video mentions, so the clumpiness of the crust and other factors accounted the end result is that mountains are large,but relatively.
Pencils Graphite i think he meant would mountains be measured as taller if sea level was measured as if the mountain wasn't there at all, including it's gravity?
***** and the answer to that question is yes. but i think he means sealevel riesing due to global warming. we can only measure to about 1m as he says and it will take a while until sealevel will rise over 1m. at that time we would have to measure again and i think yes mountains would be a little smaler after that.
MeisterHaar Yes, that's exactly what I meant. Projections vary greatly but it's perfectly possible that we are going to see a sea level that's 2m higher than today by the end of the century. The rest of the melting will probably take centuries or millennia so other generations will have to deal with that. But the end of the century, that's something the younger among us are very likely to experience.
I think there was a project to build a bridge from Germany to Switzerland but the two parts of the bridge didn't meet because they both wanted the bridge x meters high, but they realized to late they wee at different sea levels
Wow! That was super informative! Something I had never thought about in depth before. I didn't realize it was so complicated. Thanks for the explanation!
Now this is the MinutePhysics I prefer. Although this was more like MinuteEarth. No matter what channel this video would have been uploaded to I enjoyed it.
I think he's still putting 10 second videos out, as he said in the announcement that "in addition to minute physics, I will be putting out a 10 second video every day."
The thing that is so nice about those videos is that in every video I learn something new because of all of the facts fitted into it, even if you already know the general idea :D Love this channel!
If gravity varies around the world, does the weight of things vary as well? And by how much? For instance, if I buy some gold, would I be paying less for it on Sri Lanka? Or is this negligeble?
That depends on what you mean by weight. If you mean the mass of an object, then no it doesn't vary. If you mean the weight as measured by a scale (which actually measure the force caused by the gravity and converts it to mass), then yes the same object will weigh differently much at different locations, as long as you measure it with the same scale. If you use different scales those may have been calibrated to match the gravitational strength at that location and then you might get still the same weight.
If the scale that you measure the mass with uses the standard gravity ~9.81 to determine the mass of the object, there would be a difference. For example, an object with a mass of 10 kg or 22.05 pounds would measure about 9.97 kg/21.98 pounds at equator and 10.02 kg/22.10 pounds at the North Pole, so obviously the difference is negligible.
Question for Henry: how does the conception of a "flat sea" change when you are in or around one of these bulges/dips in the sea level? Can you sail down a dip easier than you can sail up a bulge?
No, you can't. If flatness is defined as an equal amount of gravitational pull in all directions, then the sea *is* flat. So you can't use gravity to move down those slopes ... if "down" is the right word here.
The geoid is an equipotential surface meaning that at any point on sea level you have the same potential. It also means you're traveling perpendicular to the force of gravity. Simply put: No you can't sail down, because the water has leveled out.
Teodor Georgiev I am not saying that the water has anything to do with it. I am wondering if the same force that is causing the water to dip and bulge (namely, gravity) would also exert "odd" forces on your ship which would appear to help or hinder your ability to sail.
Fantastic video, as always. Can you make a video explaining quantum entanglement? I always thought it was fascinating but a bit confusing. Also, congratulations on passing 2 million subscribers! That is an astounding amount of subscribers, I would be astonished to even reach 1000 on my channel (I also make science videos). Keep it up!
As an analogy for quantum entanglement, say you have one coin in each of your hands. You know that one is a nickle and one is a dime. Without looking at any of the coins, you don't know which coin you have in your left hand or which coin you have in your right hand. But if you look at the coin in one of the hands and sees that it is a nickle, you instantly know that the coin in the other hand is a dime. This is entanglement, when the state of one thing is dependent of the state of another thing. There's no more magic to it than that, and neither is there when it comes to quantum entanglement. If you set one of two entangled particles in a specific state, you break the entanglement. Kind of like if you would replace one of the coins in one of the hands, it doesn't change what coin the other one is. So you can't use it as a way to send information. Sorry. :)
RelatedGiraffe maaaaan thank you...i never got this stuff...can you explain one more thing that just can't get into my mind ? how can something be 2 states at the same time and change under observation ? i think the name is quantum superposition
that's exactly why he did it. this is a physics channel, imagine if he had made the exact same design, but in a lower scale, it'd look like a perfect sphere to the naked eye.
@Cesar Raudales No one knows shit I believe ... we are in 2018 soon in 2019 and people fighting on earth If its flat or glob . And oil and if we went to the moon and if Obama was a clone of Ben laden ... just smoke weed bro because no one knows shit
MinutePhysics I don't know what is more amazing: The fact that I knew nothing about this Or that you were able to explain such a complex topic to quickly You guys rock !
I thought that I had watched every Minute Physics that existed. I am going to school for geodetics, so this was an extra special gem to come across. Thanks!
1- He did not say force. He said centrifugal EFFECTS which means he was just describing it in normal person English, not technical terms. 2- Besides, a certain frame of reference centrifugal force is actually a real thing. 3- xkcd.com/123/ But more importantly, this whole thing was freaking mind blowing. I've thought it must be complicated, but I didn't even have an inkling of the whole variable gravity thing. Yeesh.
I am from Jordan where we have the lowest point on Earth (Dead Sea, 430 meters below sea level) and I never actually thought the concept through. Thank you for such a good video.
And even with such a distorted planet, Neil deGrasse Tyson tells us that the Earth is still proportionately rounder and smoother than any billiard ball on Earth. 42km, is just 0.33% the diameter of Earth, 12,742km, which makes it hardly significant. Also the water vapour when you blow on a billiard ball is proportionately thicker than all of the crust and oceans on Earth.
KS Ng I think that they meant that the 42km is significant compared to the 9km height of the mountains, even if it's just 0.33% of the Earth's diameter.
What if there was an identical version of mount Everest, but made of osmium. Since it would have more of a pull on the water wouldn't that make its sea-level higher, and therefor shorter even though its identical.
Been reading dozens of articles beating around the bush of the this topic for a project in my geodesy class. This video taught me more in just a few minutes
3:10 It's extremely unlikely that this list of 100 ones and zeroes is random. For any given random list of binary states with n elements, there is very likely going to be a run of the same state consecutively, of size log[base 2](n) or greater (round down). For example, in a random list of 32 ones and zeroes, there's likely to be a spot where you see 5 ones or 5 zeros. In a list of 100, you'd expect a run of 6, but the longest run is 4. Of course, it's still possible that it was randomly generated. That's the thing about randomness; you can never really know.
+Manabender It's unlikely, but _extremely_ unlikely is perhaps a bit of an overstatement. To make a very broad estimation, by my calculation the chance of having not a single run of 5 ones or 5 zeroes should be a lot smaller than (30/32)^20 and a lot larger than (30/32)^96, or in other words, it's somewhere between 1 in 3.6 and 1 in 491 but not really close to either. That's a very wide margin, but my point is the chance is definitely significantly larger than 0.2%, which I would not call extreme.
