Question

If black hole cannot be seen, how come interstellar

Answer 1

:GOOD QUESTION!!!

it has been designed by taking exact measurements and longitudinal theories by 250 computer engineers.........

Answer 2

Interstellar is an entertaining movie but when it comes to scientific accuracy it does lag a lot.

Any thing that crosses the event horizon of a black hole cannot survive. It gets disintegrated on an atomic level. And people often use a term called as Spaghettification to describe what happens when things get too close to a black hole. Because of its Enormous gravity things get stretched like a spaghetti. So reaching the center is out of question.

There are certain aspects in the film which are regarded as accurate by our current perception of the universe.

Interstellar is primarily based on String Theory. And when it comes to String theory you feel as if you enter the realm of sci-fi. The movie claims that somewhere in the near future humanity was capable of breaking inter-dimensional barrier. According to M-theory a derivative String Theory Gravitons are responsible for gravity and they are the only particles capable of moving through dimensions. And hence humans from the future communicate with us using gravity. This part is considered to be as valid by many string theorists.

And other important aspect which is fairly accurate was that Black holes weren't really black. Taking Hawking radiation into account Black holes emit particles that can be seen so they are not totally invisible.