Some of the ideas of the relativity theory have shocked everyone, because our classical concept of time and place were very limited. Einstein’s theory is not a science fiction, but it has been proven right by accurate experiments.

## 1- Speed of light

When you turn on the light, it illuminates the place instantly. In fact light has a specific speed of almost 3 x 10⁸ meter/seconds. The speed of light is constant and it is represented by the letter ”c”. It appears that nothing can travel faster than light. Albert Einstein came with the relativity theory to explain why the laws of Isaac Newton don’t apply to high speed objects. If you could travel at speed of light, time would stop for you and you would live forever. If it was theoretically possible to travel faster than the speed of light, you would even go back in time.

## 2- Time dilation

The classic idea was that time was constant under every circumstances. According to that concept, one minute is one minute everywhere. That is until Albert Einstein introduced his relativity theory, which explains that time slows down for high-speed objects. Let’s assume that it is possible for one of a twin brother at age of * 20* to travel through space at

**0,99**of the speed of light. We further assume that his journey takes almost 10 years.

**When he comes back, his age would be 30 years. However, his twin brother who remained on earth would be almost 91 years old.**The 10 years which passed during the journey was equal to almost 71 years on earth according to the dilation equation.

See below the calculation:

t’ = is the time in the moving spaceship

t = is the time on Earth.

V = speed of the spaceship

c = speed of light

10 = 0.1410t

t = 70.9 years

## 3- Length contraction

The length of any moving object will appear contracted in the direction of motion. We can use the following mathematical formula to calculate that accurately. The faster an object move the shorter it becomes. That will be noticeable when the object’s speed approaches the speed of light. **For example, a length of an object decreases from 20 cm to almost 3 cm if it travels at 0.99 of the speed of light. By applying the contraction equation, we can calculate its length as shown below. **

L = Length

Lo = rest length

v = speed of the object

c = speed of light

L = 20 x 0.1410 = 2.82 cm.

## 4- Relativistic mass

According to the special relativity, objects cannot travel at the speed of light if their rest masses are above zero. By applying the following mathematical formula, the mass of an object increases from 10 gm to almost 80 gm if it moves at 0.99 of the speed of light. Objects which have a mass above zero cannot travel at speed of light because their masses become infinity and that is practically not possible.

Here below is the calculation of the above example:

m = the mass of the moving object

mo = rest mass

v = velocity of the moving object

c = speed of light

m = 70.89 gm

## 5- E = m c²

The famous equation of E = mc² is one of the most important work of Einstein. E represents energy, m is mass and c is the speed of light. According to this formula mass and energy are related. This idea was very important by developing nuclear energy as well as nuclear bombs.

Feel free to leave your opinion beneath the article! It is easy and does not require registration. LoaSite offers simple and practical knowledge designed to help every level of education. Please share your thoughts, feelings, and questions in the comments below!

Suggested Articles:

Subscribers get notified by publishing new articles. Registration is easy and free.

Author: Sar Maroof Education: Bachelor Science and Applied Science in Physics. Professional Java webdeveloper as well as several certificates in different branches |

Subscribe To LoaSite RSS Feeds! (Your Browser) Mail This Page To A Friend! Bookmark This Page! Subscribe To LoaSite Website! |