Michio Kaku: Why Your Head Is Older Than Your Feet | Big Think

Michio Kaku: Why Your Head Is Older Than Your Feet
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Because of relativity, time moves faster the farther away you are from the center of the earth, meaning that your head ages slightly quicker than your feet.
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MICHIO KAKU:

Dr. Michio Kaku is the co-founder of string field theory, and is one of the most widely recognized scientists in the world today. He has written 4 New York Times Best Sellers, is the science correspondent for CBS This Morning and has hosted numerous science specials for BBC-TV, the Discovery/Science Channel. His radio show broadcasts to 100 radio stations every week. Dr. Kaku holds the Henry Semat Chair and Professorship in theoretical physics at the City College of New York (CUNY), where he has taught for over 25 years. He has also been a visiting professor at the Institute for Advanced Study as well as New York University (NYU).
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TRANSCRIPT:

Big Think: How have today’s super-accurate clocks changed the way we understand time?
Michio Kaku: Believe it or not, a clock on your head beats at a different rate than a clock on your foot. We can now measure this and it has practical importance as well. First of all, Einstein said that time is a river. It's a gigantic river were all swept up in the river of time and it can speed up and it slows down. For example, on the moon; did you know, that time beats faster on the moon than it does on the earth and we can measure this? On Jupiter, time beats slower on Jupiter that it does on the Earth. So time beats at different rates. When an object moves very fast, time slows down inside that rocket that is moving very fast. If that rocket is then placed on the Moon, time beats faster. So we have to do competing effects. This has a direct implication with regards to your cell phone.
Your cell phone has GPS which allows you to locate objects on planet Earth by focusing in on satellites orbiting the planet Earth. Satellites travel at 18,000 mph if they’re in lower earth orbit; therefore time slows down for those low-lying satellites. But if satellites go farther and farther away, gravity gets less and less and less so time speeds up. So in outer space we have two competing effects. Fast satellite slowdown in time, very faraway satellites speed up inside and in fact, at one radius you could calculate time beats exactly at the same rate as it does on the planet earth. So what does it mean? Your GPS system would totally fail without Einstein's theory of special and general relativity.
This also means that the top of your head because it is farther from the center of the earth, beats at a faster rate... time beats at a faster rate then your feet. So you can actually show that even within your own body now—our instruments are so accurate—that you could show within your own body the fact that time beats at different rates within your own body.
Directed / Produced by
Jonathan Fowler & Elizabeth Rodd
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[thanthainoitro]

I dont know why but whenever I need a boost in motivation and encouragement, I am back here to find Prof Michio. Thank you a lot

[HueyAT]

I guess the older (bigger) we get the more it seems time goes faster. You always here older people say I can't believe it's nearly Christmas again. Yet when you're little it seems to take forever to come around.

[usapointmileman]

He's also pointed out that when you look at yourself in the mirror, it's not actually "you" it's you as you were 1/billionth of a second before your brain interpreted the image.

[joeshmocoolstuff]

Too bad I walk on my hands Michio Kaku!

[PaganSteve]

Love the videos, but my feet smell like they are going to die before I do... Wait I think they may just have...

[epif]

Yes, you are correct! The time difference would be negligible. Even for satellites it is very, very small, but when you are trying to pinpoint a location to within 3 meters from 400km up then these effects must be adjusted for.

[dumbasffff]

Oh I thought it was because my head came out first

[zorandesign]

(cont.) because it has no mass while not moving, it only has moving mass(not sure if this is clear enough). So, if you want to take gravity into account, then, it only works when we speak about objects with mass. Photons do not have mass if they stop, and they only move at the speed of light...but if the time is slowed down, that speed is not same anymore...one second lasts longer....so that speed is lowered...so if the photon do not exit, either it is infinitely slowed, or the time is stopped.

[techracer]

Yes, but the distance between our head to our feet when compared to us to the center of the Earth should actually provide a very minute difference in time/aging, most likely a very tiny fraction of a second. But perhaps the biggest question remains -

Can time really be qualified as a 4th dimension in physical reality rather than just by mathematics alone? When it is known that it can be relative to the observer's speed and location while being relative to other observers or near/on different size gravitational bodies such as a small planet to a massive blackhole (as in the movie Interstellar), and so far it appears from all the scientific research and understanding that time appears to be unidirectional (within the realm of maximum speed limit of light itself of course) rather than bi- or multi-directional as in 3 dimensional space. All lower dimensions from 1-3 can be measured with one set of unified measurement system that is not relative. An inch is an inch, no matter how fast or where you measure it from (or it may not be true as observable by some red-shifting galaxies that appear to be moving away from us faster than the speed of light, perhaps they are traversing at a speed less than that of light but relative speeds may make them appear to be traversing further within the given time).

Even now some scientists question whether time may be relativistic based on the size of the observer as flies may see the world in slow-mo and is the reason that they might be able to respond quicker to swatters for example. Although this alone does not prove time moves slower in their world since we are able to swat ants and butterflies; however tests on insects draw some conclusions that they have a slightly higher tendency to respond to light quicker than humans. Perhaps we see time flowing normally but the flies see us moving very slowly, while in their world, they feel time is flowing normally. Vice versa, elephants may perceive time flowing normally but seeing us walking and talking much faster than we perceive ourselves.

What this all boils down to and why I pose this beginning question in the first place - If you erase all notions that time can even be conceived as a dimension (since it is relativistic) in the sense of physical reality and it is just the measurement of two occurring events only, then it is actually not time that is moving faster at the head than the toe, , it just means that the events of cellular decay or aging may happen to occur in slightly shorter intervals at the head than toe due to relative sizes, speeds and/or distances to varying sizes of gravitational wells. I admit that it is still all very confusing in the end and perhaps someone with a doctorate degree in theoretical physics can enlighten this subject more..

[askapk]

I always like when they say "this has real world implications" but then never tell us what those are. 😓

[derekonlinenow]

one of the best lecturers and professor of our time...but I just love his videos..they are so full of knowledge and so inspiring.

[MotoRhapsody]

I was searching for a simple explanation of How relativity is used in GPS systems, and Michio Kaku gave the best explanation possible. Thanks Kaku.. once again.

[eclipseslayer]

If you have a stone tied to a string and you take the other end of the string and you swing the string around with the stone on it the string is "straight" the stone moves faster relative to the part of the string that is close to your hand because it has to cover a much larger distance in the same amount of time. So if the stone moves faster and time slows the faster something gets the stone should be younger than your sting close to hand. IE Stone is head and string close to hand is feet.

[dunsel]

thats funny, my clock upstairs is always slower then my clock downstairs ..
at 1:45 on this video, so when I tie my shoes my hands go back in tine to do it, then forward in time to scratch my head?  time travel woo hooo

[TAshifter]

This talk always intrigues me. Admittedly, and unfortunately, I've been out of this for too long, but I was under the impression of the opposite:

Time slows the faster you go. As you approach the speed of light, the speed of time approaches zero. Due to Earth's rotation, your head would experience a faster speed than your feet (t = 0 as you approach celeritas). Therefor your head would age slower than your feet.

Of course, this is a question of whether gravity or speed impact time greater.

[AngeloVicencio]

So less gravity = faster time.... If you move really fast, time slows down in relative to the objects around you, If you run a the quarter of a 100 meters, you would reach the end faster cause time slowed down for you, so the opposite should be true,   if you walk or slow down, time moves faster so it would take you longer to reach the end of 25 meters. What I don't understand yet is how is gravity affecting the flow of time?

[soadfan]

correction* time is inversely proportional to velocity, the faster you travel, the slower you experience time (relatively) and vice versa, also you experience time slower if you're near a larger mass

[alxjones]

@SpartanWolf222
This is a pretty good explanation. Just two things I have to say about it:
1) Rigorous mathematical proofs are the only kind truly accepted by physics, and that's because they reference things which have already been proven. It's not circular, that's how proofs work.
2) We currently have no particles moving faster than the speed of light, with the possible exception of neutrinos, which no one believes anyways and experiments show that it was a miscalculation.

[machbaby]

I just want to know when I'll turn into a "Star Child".

[Cesariono]

And how exactly do you define "backwards"? In order to define "backwards", you have to define a "forwards" but your "forwards" could be any randomly selected direction therefore your "backwards" could be any direction so since "backwards" isn't a specific direction, the rate time beats at is independent of the direction you're travelling in.

It's possible to go faster in time by travelling at lower speeds. It's possible to go backwards in time by going faster than the speed of light.