L=length measured by the observer's own reference frame

v=speed of the object

**Einstein's Theory of Special Relativity**

Thought Experiment

TWIN PARADOX

Eartha and Astra

Eartha stays at home

Astra travels at 80% c to Astra Centauri, which is 4 light-years away. Takes 5 Earth years.

Astra returns to Earth at 80% c. Takes 5 years.

Mass Expansion

Mass at normal speeds is “Rest mass”

Under acceleration at relativistic speeds, object experiences mass expansion.

Electrons gain energy, enabling them to smash through the nuclei of other electrons, creating new particles.

Energy gain can is equivalent to mass gain.

Time Dilation

No such thing as universal time.

Time is different for different observers.

Time “dilates” for moving observers, and thus appears to slow down.

Time Clock: Measures Earth years when an object is moving

At relativistic speeds the time clock will slow down because the photon has to travel a longer distance

Example: Twin Paradox

Length Contraction

The relationship of relativistic speeds on length

Length of an object will contract at relativistic speeds, this will occur in the direction parallel to the objects motion

The shortened, calculated length is measured from the perspective of the outside observer

The Predictions

Special relativity makes predictions that can be verified in an experimental framework, though many of the results are measurable only with highly sophisticated equipment.

Main Predictions:

Time Dilation

Length Contraction

Mass Expansion

Interesting Side-Effect of Predictions:

Time Travel

The Postulates

Postulate 1. The effects of laws of physics are the same to every observer in uniform motion.

Postulate 2. The velocity of light through space is the same to every observer in uniform motion.

Speed of Light is a SPEED LIMIT for the Universe

Nothing can travel faster than approximately c = 3.0x10^8 m/s

No matter what “inertial reference frame”

Background Experiments

Special Relativity is more than just a “thought”, its basis had been supported experimentally countless times before the theory was set.

Kennedy–Thorndike Experiment: Tests the "dependence" of the speed of light on the velocity of an object

Ives–Stilwell Experiment: Provides process to test time dilation

Michelson and Morley Experiment: Showed that regardless of the motion of the Earth, the calculated speed of light is always approximately c=3.0 E 8 m/s.

General Overview

Famous Thought Experiment: What does light look like if it passes you at twice your speed?

Definition of “Special”

Strict assumptions: Motion must be UNIFORM in order for the conclusions on which special relativity calculations are based to be valid. CONSTANT VELOCITY & CONSTANT ACCELERATION

Definition of "Relative”

Theory does not depend on absolute motion but only relative motion of moving objects.

What is Special Relativity?

Einstein originally proposed this theory in 1905 in his paper: “On the Electrodynamics of Moving Bodies”

The theory itself is split into two separate parts:

1. Relativity Principle: The laws of nature are the same in all reference frames

2. Speed of Light, or "c", is a constant

The theory is experimentally supported by time dilation, length contraction, and mass expansion

Einstein's Theory of Special Relativity

Presented by: Larry Suprun and Alex Taub

What is the paradox? What is the resolution?

Is Time Travel Theoretically Possible?

The world we live in is Newtonian based, but theory never lets us forget about Einstein.

The speeds of everyday life is slow in relativistic terms, yet theory proves that faster speeds do create significant results.

Time travel to the future is theoretically easy: just move fast and your clock will tick slower relative to stationary observers.

Is Time Travel Practically Possible?

Yes, but let’s consider the magnitude of time travel that’s possible.

Cosmonaut Valeri Polyakov holds the record for the longest single space flight: 437 days traveling at 28,968 km/h. As a result, the his clock ticked slowly.

He time traveled 15 milliseconds into the future because his clocks moved slower.

T'=time observed in other reference frame

T=time in observer’s own reference frame

v=speed of moving object

M=the mass measured at rest relative to an observer traveling with the same velocity as the mass, the "rest mass"

M'=the mass measured by the observers on the other reference frame.

v=the speed of the object

Bibliography

Concept of Time Traveling Theory of Relativity. Dir. Mukesh Khan. YouTube. YouTube, 21 Jan. 2012. Web. 21 May 2014. <

Faraj, A. A. "The Ives-Stilwell Experiment." Submissions. N.p., n.d. Web. 21 May 2014. <http://www.gsjournal.net/old/physics/faraj7.htm>.

Howell, Elizabeth. "Time Travel: Theories, Paradoxes & Possibilities." Space.com. N.p., n.d. Web. 21 May 2014. <http://www.space.com/21675-time-travel.html>.

"Length Contraction." UMHEP, n.d. Web. 21 May 2014. <http://www.phy.olemiss.edu/HEP/QuarkNet/length.html>.

Marett, Doug. "The Kennedy- Thorndike Experiment." Conspriacy of Light. N.p., n.d. Web. 21 May 2014. <http://www.conspiracyoflight.com/Kennedy/Kennedy.html>.

"Mass Increase." UMHEP, n.d. Web. 21 May 2014. <http://www.phy.olemiss.edu/HEP/QuarkNet/mass.html>.

Motta, Leonardo. "Michelson-Morley Experiment." Scienceworld.wolfram.com. WOLFROM RESEARCH, n.d. Web. 21 May 2014. <www.astro.virginia.edu%2F~jh8h%2FFoundations%2Fchapter7%2Fchapter7.html%20http%3A%2F%2Fscienceworld.wolfram.com%2Fphysics%2FMichelson-MorleyExperiment.html>.

"Special Theory of Relativity." The Physics Of The Universe. N.p., n.d. Web. 21 May 2014. <http://www.physicsoftheuniverse.com/topics_relativity_special.html>.

"Time Dilation and Length Contraction in Special Relativity." EINSTEINLIGHT. The University New South Wales, n.d. Web. 21 May 2014. <http://www.phys.unsw.edu.au/einsteinlight/jw/module4_time_dilation.htm>.

"Time Dilation." UMHEP, n.d. Web. 21 May 2014. <http://www.phy.olemiss.edu/HEP/QuarkNet/time.html>.

Image Bibliography

http://en.wikipedia.org/wiki/File:Hopetoun_falls.jpg

http://www.newsbiscuit.com/2011/09/30/ministers-to-consider-raising-the-speed-of-light/

http://physicalworld.org/restless_universe/html/ru_lrgfig1_26.html

http://shihengcheong.com/blog/einstein-quotes-did-albert-einstein-say-these/

http://www.epola.co.uk/epola_org/michelson.html

http://www.physicsoftheuniverse.com/topics_relativity_special.html

http://www.learner.org/courses/physics/unit/text.html?unit=3&secNum=1