Travelling in time might sound like a flight of fancy, but some physicists think it might really be possible. BBC Horizon looked at some of the most promising ideas for turning this staple of science fiction into reality.
Is it possible to travel back in time?
General relativity. Time travel to the past is
theoretically possible
in certain general relativity spacetime geometries that permit traveling faster than the speed of light, such as cosmic strings, traversable wormholes, and Alcubierre drives.
Is it possible to go back in time and change the past?
Time travel is possible based on
the laws of physics, according to new calculations from researchers at the University of Queensland. But time-travelers wouldn’t be able to alter the past in a measurable way, they say — the future would stay the same.
How do you make a real time machine for kids?
- Cut a large opening for a door in your box using a box cutter.
- Label the box “Time Machine” using paint or markers and let your child begin decorating the box! …
- Create a time travel dial out of construction paper. …
- Using construction paper, create buttons for the time machine.
Is it possible to make a time machine?
To create a time machine would
require negative energy
, and quantum mechanics appears to allow only extremely small regions of negative energy. And the forces needed to create an ordinary-sized region with time loops appear to be extremely large.
Is it possible to travel the speed of light?
We can never reach the speed of light
. Or, more accurately, we can never reach the speed of light in a vacuum. That is, the ultimate cosmic speed limit, of 299,792,458 m/s is unattainable for massive particles, and simultaneously is the speed that all massless particles must travel at.
Can we go back in time if we travel faster than light?
So, simply
going faster than light does not inherently lead to backwards time travel
. Very specific conditions must be met—and, of course, the speed of light remains the maximum speed of anything with mass.
Do wormholes exist?
Physicists believe
wormholes may have formed in the early universe
from a foam of quantum particles popping in and out of existence. Some of these “primordial wormholes” may still be around today. … They may even help us understand some of the deepest cosmic mysteries, such as whether our universe is the only one.
What is the formula for time travel?
In fact, according to Albert Einstein’s famous equation,
E = mc2
, time travel is possible, at least in one direction.
Does past still exist?
In short, space-time would contain the entire history of reality, with each past, present or future event occupying a clearly determined place in it, from the very beginning and for ever.
The past would therefore still exist
, just as the future already exists, but somewhere other than where we are now present.
Can the present change the past?
Surprisingly,
yes
. At the level of quantum particles (we are talking individual photons, elementary particles or individual atoms), there is something called Wheeler’s delayed-choice experiments that show that actions in the present can influence the past.
What would happen if a time paradox occurred?
The consistency paradox or grandfather paradox occurs
when the past is changed in any way
, thus creating a contradiction. If a time traveler were ever to go back in time and kill their grandfather in his childhood, it would result in one of the time traveler’s parents, and ergo the time traveler, not being born.
Is time machine an Apple product?
Time Machine is
the backup mechanism of macOS
, the desktop operating system developed by Apple. The software is designed to work with both local storage devices and network-attached disks, and is most commonly used with external disk drives connected using either USB or Thunderbolt.
Who is Ali razeghi?
Iranian scientist
Ali Razeghi has registered a time machine with the country’s Center for Strategic Inventions. Razeghi, 27, cites algorithms as the source of the device’s ability to “predict five to eight years of the future life of any individual with 98 percent accuracy.”
Does anything travel faster than light?
Albert Einstein’s special theory of relativity famously dictates that
no known object can travel faster than the speed of light in vacuum
, which is 299,792 km/s. … Unlike objects within space–time, space–time itself can bend, expand or warp at any speed.
