Physics 62.1 Understanding Space, Time & Relativity (2 of 55) Special & General Relativity

In this video I will explain the difference between special relativity and general relativity. Special relativity is the effects caused by moving very fast (closed to the speed of light. Where as general relativity has to do with the events that happens on Earth due to gravity (9.8m/s^2) are indistinguishable to the same events in a space ship accelerating at 9.8m/s^2.

Next video in this series can be seen at:

[JackBrunsion]

I have graduated from the collage a few months back and I would like to thank you for your great online lectures in vast variety of topics with precise and easy to follow content. Great work, keep it up!

[CuzJesusWould]

I find your videos really helpful. I hope in the coming time you get more exposure to help those who need it - you deserve it. Great job.

[charlesbrightman]

He says 'An object placed in space (bends or warps) space causing gravity'.

Which for me raises some questions:
a. What exactly is 'space'?
b. How exactly does space 'bend or warp'?
c. If this is really true, then why aren't all the individual pieces of matter orbiting Saturn in Saturn's rings in a stable orbit, falling down to Saturn's surface? (As the 'dent' in the fabric of space time would be greater at Saturn's surface versus the 'dent' of the individual pieces of matter in the rings). And once even just one piece of matter fell to Saturn's surface, it's moving 'dent' should cause adjacent individual pieces of matter to follow along with it to Saturn's surface in a spiral fashion, since angular momentum would still have to be taken into account. But yet, that is not what is actually observed. Why exactly is that?
d. Light bending around planets:
Consider the following:
1. Photons (light) are recognized as having an electric component and a magnetic component.
2. Matter is recognized as being quarks, electrons and interacting energy. Moving electrons not only having an electric charge but an associated magnetic field as well.
3. Possibly light bending around planets is due to the interaction of 'em' between photons and matter and not gravity? Or at least a factor in that light bending around planets, not just because of gravity? Or maybe even what is called gravity is a part of what is currently recognized as the 'em' photon and the 'gem' photon is the energy unit in this universe that makes up space, time, and everything in existence in this universe? "GEM" forces interacting with other "GEM" forces causes things to occur in this universe?

[rishi]

Thank you so much for taking time and teaching us.. Im always keen and excited about universe and laws which governs it.. Your videos help me a a lot. :)

[zakirhussain-jsku]

1. Universe is not Observer dependent.
2. For measurement to be closer to reality, time & place of measurement need to coincide. I think measurements made by astronaut on moving spaceship are correct.
3. Observer at rest moves thru. time while observer in motion moves thru. time & space. While both appear to move relative to each other, they are not equivalent. Relativistic effects of slower time & length contraction should occur only for observer on moving spaceship since it is moving thru. time & space.
4. I think increase in mass is not a relativistic effect. Motion of charge induces magnetic field which stores energy. Similarly motion of magnet induces electric field which can also store energy. Likewise motion of mass should induces kinetic field which should store kinetic energy. Due to opposite charges E & M fields are circular. Mass has no opposite counterpart therefore kinetic field should move in the direction of moving mass. E & M fields exist in space around the electric & magnetic charge. Kinetic field should also exist in space surrounding moving mass.

[bakibalcioglu]

this is what I've been waiting for.

[ESSAKS]

this is so helpful and so good to know

[mathstudent]

Does this mean that there are two different effects on an orbiting clock? In its orbit, it is moving faster than the fixed clock on Earth, so it records time slower (Special Relativity). And, because it is farther away from the gravitational effect of the Earth, it moves a bit faster than the fixed clock on the surface of the Earth (General Relativity).

[anbrugm]

Question, if observer A is looking at observer B which is flying through space close to the speed of light, it will appear like things are happening really slow. But what if observer B is looking back at A, would time be moving super fast at A's location?

[RobertoLion]

I know we all understand but he should have said: "If the spaceship is moving very slow then the difference in the perceived time, mass, or length is extremely small", and not that there won't be a difference. 3:49

[chiragjain]

Michael sir upload chapter 12 of astronomy

[منوعات-تف]

Does observer B see the clock, mass and length of observer A slow, increased and contracted ? is it vise versa ?

[barryhughes]

If  events happen at different times between two observers who are in relative motion then how can they share the same ' instant' of time? One observer must either be in the past or present of the other, how then can they communicate?  I am unaware of any mechanism that would allow me to communicate with anyone in my past or future directly, right now, I cannot communicate directly with yesterday's you. Please show me the error in this train of thought.

[bebinashanty]

In the case of special theory of relativity why does the time in the event appears to be slowed down for the observer A

[ptyptypty]

Yeah, that's all interesting, BUT did Einstein Play SOCCER? .. :D

[schifoso]

Special relativity deals with constant velocities, whereas as general relativity deals with acceleration.

[michaelduke]

The light continues on in a straight line---The space-time is warped by the gravity of the massive object. Thus causing the light to appear bent. The attraction of the gravitational field is determine by the inverse of the square of the radius or the distance between objects. Just like Gauss's Law concerning the electric and magnetic fields...

[toolguyslayer]

Does light not have any mass or does light not have any mass that is detectable by today's sensors it would be a ghost A specter in order to not have any Mass and who's to say that it ghost doesn't have mass light May simply be a different type of mass such as a feather compared to a rock in a vacuum there is a different measurement there

[hasanhasn]

light bends, therefore, space can bend.