"The Earth looks flat when..." flat-earther: *say no more*

Well this wouldn't be a problem if Isaac Newton didn't invent gravity

I wish we could just float around like we did before newton discovered gravity

5:00 be careful with that exclamation mark when dealing with a math problem

Now IF ONLY some Hipster could have plucked the Bass while I was learning Physics back in High School... XD

*According to Keeanu Reeves* Gravity is the secret for staying down-to-Earth

Minute Physics: "Hair is actually 2D" Uh excuse you, my hair has VOLUME.

In other words: Newtons law isnt wrong. Its imperfect, specialized, or misses factors that are ignorable in some cases but important in other cases. But thats physics.

still it seems to an excellent estimation by considering 1600's world

I've done many observations, and two sheep definitely attract.

Scientist: How many dimension we need to discover you? Gravity: Yes.

The best part about these videos is that the step-by-step reasoning is always clear and eminently logical, even if how the math works may be hard to grasp for non-specialists and even if the proposed conclusions seem unimaginable. Like following a trusted friend through a jungle on an island, listening to him explain why we're taking a particular route, which all seems very logical until we come to a clearing and somehow we're in the Alps.

you could say we don't really understand the gravity of the situation

ZeptoNewtons. So small you never even heard of it

Who knew you could make an epic depiction of a black hole with just a sharpie and some pencil crayon scribbles?

4:15 I heard this dialogue in the movie *INTERSTELLAR*

Me: *spends years and patience to understand physic laws MinutePhysics: *ding dong what you knew is wrong*

*@minutephysics* Henry, the graph at 3:25 is wonderful. This aspect of science is so poorly understood and I think leads to a large amount of pseudoscience. Could you please make a video with several different concepts showing how certain we are about each concept. This shows the danger of extrapolation so clearly! Excellent video as usual. Thanks, Ben - a mathematician.

Actually there is a very known Experiment "The Cavendish Experiment", where you calculate G just by measuring the attraction of two small lead balls to two big metall balls, with the help of an Torsion-Spring and a laser. I have done this experiment myself and its pretty accurate!

I think the earth looking round, flat or bumpy depending on how close you zoom in is a really good illustration for how physics laws change for different scales

I'm reminded of what Klaatu told Professor Barnhart in The Day the Earth Stood Still. "It (Newtonian gravitation) works well enough to get me from one planet to another."

I'm so strong I can lift the entire earth. *proceeds to do a handstand*

Me: Watching video, pretending to understand everything

At first, the video made me a bit unhappy at 0:31, when he said that for small masses we can't really measure the gravitational force. I was like "Does he not know about the 200 years old Cavendish experiment? What kind of a channel is this?" But as the video progressed, I realized that he does in fact know much more than I do, he just had to make shortcuts in order to make the video flow better. By the end I learned so much about our current understanding of gravity, that I can't help but love this channel :-)

I've got a physics exam tomorrow, and am taking a short break from studying. Aaaaand what do I decide to do in my break? Learn more physics... I think I'm doing this wrong. Honestly though even though I don't understand them half the time, these videos are super engaging and fun and break complex topics down into understandable bits. Keep up the great work!

0:54 for all the Flat-Earth believers, he just cleared it up

All i know is that that stick figure looked pretty exited to have two sheep at the end there.

The most known stuff are the easiest to overlook, its always good to have a lil reminder! nice vid!

*minute physics... 5 minute video* *wait, that’s illegal*

5:00 "it remains pretty crazy to blindly apply newtons law of gravitation to things like protons..." Pardon my ignorance, but does anybody actually do that? Aren't the Strong Nuclear Force and EM Force totally dominant at those scales? Even assuming the gravitational force is not well known at those scales, how much larger than assumed would it have to be to even show up on measurements when compared to the other forces?

I answered and said, "If I have found favor in thy sight, O Lord, show this also to thy servant: whether after death, as soon as every one of us yields up his soul, we shall be kept in rest until those times come when thou wilt renew the creation, or whether we shall be tormented at once?" 76 He answered me and said, "I will show you that also, but do not be associated with those who have shown scorn, nor number yourself among those who are tormented. 77 For you have a treasure of works laid up with the Most High; but it will not be shown to you until the last times. 78 Now, concerning death, the teaching is: When the decisive decree has gone forth from the Most High that a man shall die, as the spirit leaves the body to return again to him who gave it, first of all it adores the glory of the Most High. 79 And if it is one of those who have shown scorn and have not kept the way of the Most High, and who have despised his law, and who have hated those who fear the Most High -- 80 such spirits shall not enter into habitations, but shall immediately wander about in torments, ever grieving and sad, in seven ways. 81 The first way, because they have scorned the law of the Most High. 82 The second way, because they cannot now make a good repentance that they may live. 83 The third way, they shall see the reward laid up for those who have trusted the covenants of the Most High. 84 The fourth way, they shall consider the torment laid up for themselves in the last days. 85 The fifth way, they shall see how the habitations of the others are guarded by angels in profound quiet. 86 The sixth way, they shall see how some of them will pass over into torments. 87 The seventh way, which is worse than all the ways that have been mentioned, because they shall utterly waste away in confusion and be consumed with shame, and shall wither with fear at seeing the glory of the Most High before whom they sinned while they were alive, and before whom they are to be judged in the last times. 88 "Now this is the order of those who have kept the ways of the Most High, when they shall be separated from their mortal body. 89 During the time that they lived in it, they laboriously served the Most High, and withstood danger every hour, that they might keep the law of the Lawgiver perfectly. 90 Therefore this is the teaching concerning them: 91 First of all, they shall see with great joy the glory of him who receives them, for they shall have rest in seven orders. 92 The first order, because they have striven with great effort to overcome the evil thought which was formed with them, that it might not lead them astray from life into death. 93 The second order, because they see the perplexity in which the souls of the unrighteous wander, and the punishment that awaits them. 94 The third order, they see the witness which he who formed them bears concerning them, that while they were alive they kept the law which was given them in trust. 95 The fourth order, they understand the rest which they now enjoy, being gathered into their chambers and guarded by angels in profound quiet, and the glory which awaits them in the last days. 96 The fifth order, they rejoice that they have now escaped what is corruptible, and shall inherit what is to come; and besides they see the straits and toil from which they have been delivered, and the spacious liberty which they are to receive and enjoy in immortality. 97 The sixth order, when it is shown to them how their face is to shine like the sun, and how they are to be made like the light of the stars, being incorruptible from then on. 98 The seventh order, which is greater than all that have been mentioned, because they shall rejoice with boldness, and shall be confident without confusion, and shall be glad without fear, for they hasten to behold the face of him whom they served in life and from whom they are to receive their reward when glorified. 99 This is the order of the souls of the righteous, as henceforth is announced; and the aforesaid are the ways of torment which those who would not give heed shall suffer hereafter." 100 I answered and said, "Will time therefore be given to the souls, after they have been separated from the bodies, to see what you have described to me?" 101 He said to me, "They shall have freedom for seven days, so that during these seven days they may see the things of which you have been told, and afterwards they shall be gathered in their habitations." 102 I answered and said, "If I have found favor in thy sight, show further to me, thy servant, whether on the day of judgment the righteous will be able to intercede for the unrighteous or to entreat the Most High for them, 103 fathers for sons or sons for parents, brothers for brothers, relatives for their kinsmen, or friends for those who are most dear." 104 He answered me and said, "Since you have found favor in my sight, I will show you this also. The day of judgment is decisive and displays to all the seal of truth. Just as now a father does not send his son, or a son his father, or a master his servant, or a friend his dearest friend, to be ill or sleep or eat or be healed in his stead, 105 so no one shall ever pray for another on that day, neither shall any one lay a burden on another; for then every one shall bear his own righteousness and unrighteousness." .....2 Esdras 7:75 //////////////

There is a large difference between knowing there is a potential inaccuracy and having it proven/ replaced. Until it is proven we use what we have. That is the fundamental of science and why it is the study of discovering questions. In this case the question are When does Newtonian gravitational law become provably inaccurate? What is the most accurate way of addressing this? Thank you for the video. I liked it even though I was expecting you to cover more of how we are addressing these 2 questions. It is a good intro into making people question science. Without doing this we cannot improve it.

But... I Googled for a recipe about GRAVY.

seems odd to focus on the Newton equations here when they are just simplified versions of the more complex relativity ones. it doesn't really change the point that we don't know how accurate our model of gravity is on the small scale.

I'm not losing sleep over this. 0.01% precision for small objects 1 meter away is pretty good.

0:57 Flat earthers left the chat.

Does anyone remember the first episode of minute physics Man how time flies

"I think we've underestimated the life on this planet. The people have so much courage. Here they are hurling through space on a molten rock at 67000 miles an hour and the only thing that keeps them from flying out of their shoes is their misplaced faith in gravity." - Dick: 3rd Rock from the Sun

One of the big problems with measuring the gravitational attraction of two small objects (your yarn and tape) is noise or interference. Newton's Law is kind of an approximation, which holds most accurately when two massive objects are near each other within the same gravitational field, because gravity is not really the attraction between two masses, but between on mass and every other mass in the universe. So, the yarn and tape will have such a minimal attraction upon each other because the Earth produces much more gravitational force than them, and they're more attracted to the mass of your hands than to each other due to the larger mass. This confound of noise is part of why we have not and probably will not measure gravity to the same precision of other forces, because the only way to get a truly precise G constant is to measure the attraction between two neutrons in an otherwise massless universe. This is why the small scale is so uncertain, that and Heisenberg's Uncertainty Principle is a factor to consider at distances and masses that small. Adjusting for Gravitational Time Dilation using the Schwartzschild metric (whose effect is negligible at Newtonian Scales), it should be possible to extend Newton's law to relativistic masses.

This explanation just opened my eyes this explanation is so clear much better than others I just don’t know from where such knowledge comes from.

I disagree that physicists are "ignorant" of gravity at short distances. Its not like they just choose to ignore it because they don't know enough about it. As you mentioned, the force is so weak compared to electric forces its a very very very safe assumption to ignore gravity because it has a negligible effect on calculations. The only usefulness to knowing gravity at small scales is to test the theory. But practically speaking, physicists ignore gravitational force between particles for the same reason they dont include the force of gravity from Pluto in their calculations. Its way too weak.

If newton hadn't invented gravity, we would be floating around right now!

THANKYOU. Now I'm both certain and uncertain I know about these gravitational uncertainties.

your channel makes me love the bass

Science experiment : looks pointless, ends up very useful a few centuries later.

Could you please share the papers titles of some of the experiments that appear in the video as figures. I would love to grasp a read on them

You are great! Soon I can make my doctoral degree in Minute Physics. But really, you helped me a lot.

I remember using this equation for atoms in school. Now I'm questioning if my degree is valid?

These are the things that ARE taught when the formulae is explained, but people forget all these other bits and just memorize the formula.

Wait a couple of years Murph and Alfred are working on it

a good, simple, and reasonable explanation, thank you for sharing!

1. Gravity fits into relativity. You can use relativity to solve gravitation problems. 2. The gravitational constant is very small and depends of the mass of the object to provide a force. Boltzmans constant is freaking huge. Because of this, small charge has a noticable force. I'm not sure why that was neglected when making those points.

I have a masters in Engineering and I was unaware of the uncertainty about gravitational measurements wrt scale of distances. Thanks minute physics for enlightened video. I want to go back and study physics again.

Well, I know the gravitational pull between a cheeseburger and my mouth is pretty damned strong.

I always questioned my teachers. “Gravity is when objects pull on eachother” well yeah but WHY? We’re being taught obsolete 17th century information.

This was one of the most informative, interesting and well structured explination videos that I have ever seen. I love it. Thank you! PErmission to use this in High School science classes?

*Gravity* pulled me here

Наконец то подняли такой важный вопрос. Давно стоило в этом разобраться.

Newton: I can predict gravity Mercury: LOOK AT ME!

When I was a kid I imagined gravity as everything expanding in size at the same ever accelerating rate. I think iy was my way of understanding the feather and hammer on the moon experiment.

Regarding distances larger than a light year, don't forget the expansion of space.

"Do you believe in gravity?" - a gay blond vampire

Your videos are great keep it up 😀

You are so smart 😘 Can't wait for the next

Thanks for clarifying our uncertainty about gravity. It's pretty clear how little the everyday person knows about gravity, too. The other day, I was talking to my differential equations teacher after class, and he started spewing conspiracy theories at me about science and physics. I won't bore you with the details (unless someone replies and asks), but he's under the impression that NASA used anti-gravity technology to land on the Moon, and that electrons/protons get their energy from another dimension. When a nutcase doesn't understand something, they come up with wild explanations for it that make Absolutely no sense. Maybe I can show this to him, and maybe it can give him some insight on the fact that No, Gravity Isn't Understood. (... though with my luck, he'd just say "This is just another cover-up. Minutephysics is working for the government and is lying to us about the truth of gravity.")

We don't understand what Gravitation truly is.. So we speculate with formulas that define the relation of it but not the causes of it... It is like magnetism, we had to truly understand electricity to truly understand what Magnetism is... My opinion gravity is some sort of effect that acures like the effect of magnetism acures when electricity (flowing electrons) acures. If we could found a effect where you can convert gravity directly to electricity to measure gravitation then you could probably invert this effect and get gravitation from electricity like a peltier device

Yeah I remember the experiment at college to test out newton's gravitational law, it was bloody hard to get the heavy lead balls to stop moving so I could measure

Great video, I really liked the parts about uncertainty. Still, I feel like a disservice was done to the viewers by not mentioning the unification of spacetime, Lorentz transformations, or the way in which the Lorentz factor scales so as to allow for classical equations to work at the sizes that you've illustrated here. An object's size and the strength of the 'force' of gravity between two black holes are two very different measurements being used to disqualify Newton's classical equations, when all you need is the difference between reference frames to see why the classical equations cease to apply accurately.

I think the short distance gravity problem is very important because we need to know this answer to understand how stars formed in the early universe.

Us: *Is ignorant about gravity* Gravity: Am I a joke to you?

For the first time, I have to say, "Booo!" I mean, confirming things with direct experiment is great, and we should keep trying to do so even when it seems wasteful, but sometimes you have to accept indirect confirmation when direct experiment is infeasible and there isn't at least a plausible mode of failure. General Relativity and Quantum Electrodynamics are both gauge theories and together have been probed to precision of better than 10 decimal places on scales from electrons to neutron stars. That's an absurdly good coverage. So we can say that gauge theory works at all scales at which we can conduct an observation. If we can agree on which degrees of freedom have local symmetries, we can construct a field theory for it that will be correct to the absolute best of our combined scientific knowledge. That leaves two possibilities. Either Poincare symmetries, which lead to General Relativity as a gauge theory, break down at microscopic scale, or we can apply General Relativity until quantum effects kick in. And we would have seen the effects of the former, because it would actually break relativistic effects in QED as well, and these are some of the best measurements we have in physics! And sure, quantum gravity is a thing, so there's certainly a scale at which all of this breaks down. But evidence for universal law of gravity being applicable and correct for something like grains of sand is absolutely overwhelming. The kind of elephant that would have to be hiding in proverbial room for this not to be the case and for us to have not found a thorn in particle physics that indicates it is absolutely unprecedented. And a lot of it, like anisotropies of space that would indicate space-time symmetries being different at microscopic scales, people have been actively looking for with zero success for a long time. Law of Universal Gravity may have started as an empirical formula that required direct experimental verification, but we've gone way past that point. And when viewed as a classical approximation to the effective field theory on the underlying quantum gravity, it has experimental backing of basically the entirety of modern physics.

2:54 Zeptonewtons, Harponewtons, & Grouchonewtons

Just when I thought I was smart, KZfaq sent me this.

That's why I think there is no need for dark matter in the universe. Gravity behaves differently when there are a lot of massive objects (Stars, Black holes, etc.) scattered around - like in galaxies. I know this is no mathematical description. ;)

Very informative and surprising... thanks!

For very small objects, yes the gravitational pull is very small but the reason why they don't move towards one another is that this gravitational pull is smaller than the inertia needed to move the objects. If we were to put them in space with no gravitational fields, they will eventually move towards one another over time

We need to get cloning working, so we can dig up Einstein, clone him a million times, and then get a million Einsteins working on these problems! I think my idea sounds sensible and we should totally do it! NOW! .. who is with me?

sorry if I missed it in the video, how small is small when it comes to the uncertainty of the measurement?

I agree with your explantations and I have also some comments to add as the theory of non dependance of the mass in free falling subjects as Galilio experiments ; So if we implement the this law of gravity on each element macro or micro we will measure the difference on time between the subjects falling with different acceleration and non only the g=10 m/s² and each subject will have its added value on this formula to change the acceleration from 10 m/s² to 10+ni m/s² I think my explanation need some details; if u like I could do in a long description.

This video is basically a variation on the rhetorical question: How long is a piece of string? 1:45 There are no laws per se, only observations made at certain frequencies and densities.

Thanks for this. Gravity is a tougher thing to measure than people give it credit for. Mathematical equations can only go so far, without real testing we cannot verify accuracy of the force of gravity on all scales.

3:50 We can't use these other formulae since they are dimensionally incorrect

Wow this is the first science resource I've EVER seen tackle this.

Gravity is really strong until I lay on my back in the water...

*_I only know that I know nothing_*

I was surprised that photons weren't mentioned at the end. If I'm not mistaken, Newton's law only applied to objects with mass, so on that point, the law is not universal at any scale.

Fascinating. I must say, though, Newton serves me well day-to-day.

Also worth mentioning that we don't even know what gravity is (no known force carrier). If we ever figure out why/how gravity even exists, a lot of these uncertainties will be likely be cleared up.

The problem with gravity is that EVERYTHING attracts everything, we arent just point masses with some acceleration. At the atomic scale, the force of gravity may only extend to within the radius of a nuclei simply BECAUSE everything else is farther away than the earth is from the moon. The other thing we have to remember, is gravity actually isnt newtonian, it is relativistic, the whole reason gravity works is it is a gradient in space-time, applying uneven forces to masses in the T dimension, because it warps space in the normal 3 dimensions. So, we would be better off creating a new rule of universal relativistic gravitation, where the warping of space time is instead taken into account based on mass and distance. Because who knows, maybe the reason gravity doesnt seem to work the same on small and large scales is merely because of the sheer amount of space warp created by black holes, and the sheer amount of space warp caused by atoms in literally every direction. The force of gravity gets smaller the further away you are, so if gravity ITSELF affects space-time and affects how far away something IS, then that would change how much it attracts something. We arent falling down, we are moving in the same direction we always were, but space has warped around us to change the vector angle to point towards the largest nearby mass.

Honestly this is like criticising a hammer for not being suitable for sewing.

Henry: Makes well thought-out, informative, entertaining, great video overall. People in the comments: The earth is flat, gravity is trash, I am gonna speak stupid things that sound sciencey because I have no idea about science.

The Euler Number is approximately: 2.71828... Newton’s law of gravitation: G = 6.67 x 10^-11 N.m^2/kg^2. Golden number: 1.618ɸ (2.71828 ^ 6.67) x 1.618 x 10 = 12,756.23 Earth’s equatorial diameter: 12,756 km. Golden number: 1.618 Golden Angle: 137.5 Earth's equatorial radius: 6,378 Universal Gravitation G = 6.67 x 10^-11 N.m^2/kg^2. (((1.618 ^137.5) / 6,378) / 6.67) x (10^-20) = 12,756.62 Earth’s equatorial diameter: 12,756 km. Earth's equatorial diameter: 12,756 km. Speed of light: 299,792,458 m/s. Universal Gravitation G = 6.67 x 10^-11 N.m^2/kg^2. (12,756 / 299,792,458) / 6.67 x (10^9) - 1 = 6,378.22 Earth's equatorial radius: 6,378 km. Book: Orion: The Connection between Heaven and Earth eBook Kindle

2:54 The sassiest thing I've ever heard

Over the years, minutephysics videos have bloated to over 500% of their original runtimes! I'm kidding of course. I love the longer videos! :)

Frank DiMeglio is RECOGNIZED as having surpassed Newton and Einstein.

Gravitation between two relatively small objects was tested in the Cavendish experiment in 1798.

Here I was thinking uncertainty was confined to the life and social sciences, now you tell me it's in the physical sciences too :P

So whatever I learnt in school was wrong? My future is bright!!

I think the answer is in a 4th spacial dimension. Your focus on scales is apt. I think we’re overlooking the obvious gravity at subatomic scales.

This what I argued the most but no one believed me. And after this video I really can't explain my inner feelings