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ELI5 Yahaaa

The edge is not a wall

What If You Fell Into a Black Hole?

You would cross the point of no return without noticing anything at all.

What you would feel Ordinary falling. Nobump, no barrier.What a friend would see You slowing,reddening, andstopping forever
Both of these are true at the same time.

  1. Step 1 of 5

    Falling in feels exactly like falling.

    Falling freely Nothing to feeluntil very close

    There is no wind, no wall and no sensation of speed. Falling freely feels like weightlessness — the same feeling as being in orbit, or the top of a rollercoaster drop, and it does not change as you go.

  2. Step 2 of 5

    You would not notice crossing the edge.

    The horizon, seenfrom outside?Crossing it: nomarker, no bump, nowarning

    The event horizon is not a surface; it is a boundary in the rules. For a big enough black hole there is no sign at all as you pass it. From that instant every direction that used to be forward is now inward — but nothing about the moment tells you so.

  3. Step 3 of 5

    Your feet get pulled harder than your head.

    You, falling feet firstFeet: pulled very hardHead: pulled slightly less
    Small difference, enormous consequence.

    Gravity weakens with distance, so whichever end of you is nearer is pulled more. Close enough in and that difference wins against whatever holds you together, and you are stretched out into a thin stream.

  4. Step 4 of 5

    To someone watching, you never arrive.

    1 You: youfall in2 They: youredden3 They: youslow4They: youfade andstay

    Light from you takes longer and longer to climb out, so they see you slow down, dim, and redden. You appear to freeze just above the edge and fade out — while from your own point of view you fell straight in, quite quickly.

  5. Step 5 of 5

    Bigger black holes are gentler.

    A star-sized black hole Stretched apartoutside the edgeA supermassive one Cross intact — andcannot return

    A small black hole would stretch you apart long before you reached the edge. A supermassive one is so spread out that you could cross the horizon perfectly intact — and only then discover there is no way back.

    What a black hole actually is, and why light cannot climb out, is its own page.

The short version

Falling into a big black hole feels like nothing until it is far too late — and to anyone watching, you never quite get there.

Try it yourself

Drop your phone onto a cushion while filming. For the falling phone there is no sensation of speed at all — only the landing.

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