What Did Einstein Mean By Time is an Illusion?

One of the most influential physicists to have ever lived, Albert Einstein, shared this view, writing, “People like us who believe in physics know that the distinction between past, present, and future is only a stubbornly persistent illusion.” In other words, time is an illusion.

When you think about it, it makes sense that time is an arbitrary construct — it’s our way of making sense of growing up and growing old while the world changes around us. It’s not all that hokey. So let’s look at how our perception of time changes in different locations. 

The logic behind gravitational time dilation is fairly simple: Objects with a lot of mass create a strong gravitational field. This gravitational field noticeably warps the fabric of spacetime around these objects, producing what we know as gravity. When a stream of light particles passes by an object with sufficient gravity, the stream of photons traveling at the speed of light appears to bend. 

What’s even more interesting is that mass can warp the fabric of time itself, causing it to move slower or faster depending on how massive the object is and how strong the object’s gravitational pull is, which is where time dilation becomes wonky to us.

It should be noted, however, that an observer in the strong gravity experiences time as running normally. It is only in relation to a reference frame with weaker gravity that time runs slowly. 

Time appears to pass normally to a person in strong gravity, while a clock in weak gravity runs fast. While to the person in weak gravity, the clock appears to run normally, and the clock in strong gravity runs slowly. Of course, there is nothing wrong with the clocks. Time is slowing down and speeding up because of the relativistic way mass warps space and time.

The faster one moves, the slower time passes in relation to a static observer’s perception. Matter traveling at the speed of light does not really experience time or distance, at least relative to a static point. Just watching a spaceship drift off into deep space, the people on Earth view the ship as moving much more slowly through space and time than the people on the ship perceive it to be moving. Crew members would also age slower the faster they move.

Astronauts on the ISS experience a much less dramatic form of time dilation, given that the International Space Station is not traveling near relativistic speeds. Two twin astronauts were part of an experiment conducted by NASA; they calculated that the twin who spent the most time in space, aged 5 milliseconds more than his Earth-bound twin.

From the outside, the observer at the event horizon would begin to redshift, which means the wavelength of light they emit would move toward the red portion of the electromagnetic spectrum until the light becomes dimmer and dimmer. Inevitably, time would appear to stop altogether before the observer plunges into the event horizon. In theory, we would never actually see this occur, as the object would appear to freeze and never actually disappear into the black hole.  

Black holes can be formed when a massive star reaches the end of its life; its core begins to collapse in on itself, spitting out large quantities of gas and dust in a supernova event. The star must be at least three times as massive as our Sun for this process to occur. It is thought that supermassive black holes, which range from 100,000 to tens of billions of times the mass of the Sun, may be formed by a sort of chain reaction, and this is where extreme time dilation comes in.