What do you need to know to understand Interstellar？

What is wormhole？

Multi-dimensional universe theory is used in this film， and the wormhole， connected the two space-time points in our universe， is a "shortcut" generated through high dimensional space-time. Based on the analogy demonstrated by Dr. Doyle in Interstellar， the actual distance of the interstellar travel is greatly shortened just like puncturing a piece of paper with a pencil so that the dream of interstellar traversing can be realized.

Why does the spaceship rotate？

The spaceship setting out to find colonies in space keeps rotating unceasingly， which is to use the centrifugal force to simulate gravity， so ?the health of the astronauts will not be affected in the environment of long-term weightlessness during the long journey. The maximum influence of the long-term weightlessness to human body is muscle atrophy and loss of calcium in the bone， in addition， the cardiac function will be weakened， the consequences caused by these changes are similar to senescence， but the "senescence" is very fast. When astronauts in the space station return to Earth， they need to be supported by others even when walking， and can recover only after a long rest.

1 hour here and 7 years there？

Mr. Cooper in the movie gives her daughter a watch to tell her that the time in the interstellar travel will be slower than the time on Earth， and the ages of them will be almost the same when he comes back. This is "time dilatation" in special theory of relativity. Because the spaceship has experienced acceleration and deceleration when it departs and returns to Earth， while The Earth is always approximately in inertial motion， it is the time of the astronauts that will be slow. And when arriving to research the planet near the black hole， the astronauts have mentioned that one hour on the planet surface passed is equal to seven years on Earth passed， which is the "gravitational time dilation" in general theory of relativity. However， the expression of "one hour and seven years" is actually based on the perspective of an observer on Earth （that is us， the audience）， the possibility to compare time only exists between two points where information can be communicated to each other.