Time travel

there is no known way to travel through time in a practical and controlled manner. While time travel is a popular subject in science fiction, the reality of time travel as depicted in those stories is not supported by our current understanding of physics.

However, there are some hypothetical concepts in physics that suggest that time travel might be possible in theory. For example, some interpretations of Einstein's theory of general relativity suggest that it may be possible to travel forward in time by traveling at extremely high speeds or experiencing the effects of gravity on time dilation.

In addition, some physicists have proposed ideas such as wormholes, which are hypothetical tunnels through space-time that could potentially allow for time travel. However, none of these concepts have been proven experimentally, and they remain purely theoretical at this point.

So, while time travel remains a fascinating subject of speculation and imagination, it is not currently within our reach using any known technology or scientific understanding.

Time travel is a topic of much speculation and fascination, but currently, there is no scientific evidence to suggest that time travel is possible. The concept of time travel involves traveling to the past or the future, but as far as we know, time is a one-way arrow, and it only moves forward.

While it is possible to travel to other places in space, we are limited by the speed of light and other physical constraints, making it challenging to travel to distant locations in the universe, let alone traveling through time.

There are theories in physics, such as Einstein's theory of relativity, that suggest time is relative and can be affected by gravity and other factors. Some researchers have explored the idea of using black holes or wormholes to create a time-traveling "shortcut," but such theories are purely speculative and have yet to be tested or proven.

In summary, while time travel remains a popular topic in science fiction, there is no scientific evidence to suggest that it is currently possible.

How do we know that time travel is possible?

More than 100 years ago, a famous scientist named Albert Einstein came up with an idea about how time works. 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).

Animation of two train pieces coming together. One says space and the other says time.

Einstein's theory of relativity says that space and time are linked together. Credit: NASA/JPL-Caltech

What does this mean for time travel? Well, according to this theory, the faster you travel, the slower you experience time. Scientists have done some experiments to show that this is true.

For example, there was an experiment that used two clocks set to the exact same time. One clock stayed on Earth, while the other flew in an airplane (going in the same direction Earth rotates).

After the airplane flew around the world, scientists compared the two clocks. The clock on the fast-moving airplane was slightly behind the clock on the ground. So, the clock on the airplane was traveling slightly slower in time than 1 second per second.

Can we use time travel in everyday life?

We can't use a time machine to travel hundreds of years into the past or future. That kind of time travel only happens in books and movies. But the math of time travel does affect the things we use every day.

For example, we use GPS satellites to help us figure out how to get to new places. (Check out our video about how GPS satellites work.) NASA scientists also use a high-accuracy version of GPS to keep track of where satellites are in space. But did you know that GPS relies on time-travel calculations to help you get around town?

GPS satellites orbit around Earth very quickly at about 8,700 miles (14,000 kilometers) per hour. This slows down GPS satellite clocks by a small fraction of a second (similar to the airplane example above).