# Quick Answer: Can We Go Back In Time?

## Why is travel back in time impossible?

The law of causality follows from the fact that nothing can be faster than the speed of light.

The law states that the effect of an action can only occur after the cause, which would make time travel into the past impossible..

## How fast do you have to go to go back in time?

General relativity also provides scenarios that could allow travelers to go back in time, according to NASA. The equations, however, might be difficult to physically achieve. One possibility could be to go faster than light, which travels at 186,282 miles per second (299,792 kilometers per second) in a vacuum.

## How much is a time machine?

A: The average cost of a completed Delorean Time Machine replica costs about \$100K – \$125,000 or more when you factor in the cost of the Delorean car, the conversion to a “Time Machine”, basic repairs and upgrades and shipping.

## How long will the universe last?

Assuming that dark energy continues to make the universe expand at an accelerating rate, in about 150 billion years all galaxies outside the Local Supercluster will pass behind the cosmological horizon.

## Where does space end?

No, they don’t believe there’s an end to space. However, we can only see a certain volume of all that’s out there. Since the universe is 13.8 billion years old, light from a galaxy more than 13.8 billion light-years away hasn’t had time to reach us yet, so we have no way of knowing such a galaxy exists.

## How do I travel to the past?

1. Speed. This is the easiest and most practical way to get to the far future – go really fast. According to Einstein’s theory of special relativity, when you travel at speeds approaching the speed of light, time slows down for you relative to the outside world.

## Is it possible for humans to travel at light speed?

So will it ever be possible for us to travel at light speed? Based on our current understanding of physics and the limits of the natural world, the answer, sadly, is no. … So, light-speed travel and faster-than-light travel are physical impossibilities, especially for anything with mass, such as spacecraft and humans.

## Can a time machine be invented?

Recent investigations into this question have provided some evidence that the answer is no, but it has not yet been proven to be impossible.” Even the slight possibility of time travel exerts such fascination that many physicists continue to study not only whether it may be possible but also how one might do it.

## Does the universe end?

As the energy density, scale factor and expansion rate become infinite the universe ends as what is effectively a singularity.

## Who invented time machine Majnu?

Ali RazeghiAli Razeghi, a Tehran scientist has registered “The Aryayek Time Traveling Machine” with the state-run Centre for Strategic Inventions.

## Who created the universe?

In his 1988 book, A Brief History of Time, Hawking had seemed to accept the role of God in the creation of the universe. But in the new text, co-written with American physicist Leonard Mlodinow, he said new theories showed a creator is “not necessary”.

## Is it possible to travel faster than light?

Nothing can move faster than the speed of light. When Einstein set forth his theory of relativity, this was his inviolable postulate: that there was an ultimate cosmic speed limit, and that only massless particles could ever attain it.

## Why Is Time an Illusion?

According to theoretical physicist Carlo Rovelli, time is an illusion: our naive perception of its flow doesn’t correspond to physical reality. … He posits that reality is just a complex network of events onto which we project sequences of past, present and future.

## Can you travel faster than time?

He called it relativity. This theory says that time and space are linked together. Einstein also said our universe has a speed limit: nothing can travel faster than the speed of light (186,000 miles per second). … So, the clock on the airplane was traveling slightly slower in time than 1 second per second.