Friday, November 14, 2008

Immortality and Black Holes?

Time dilation occurs in the presence of gravity. Near a black hole, time dilation approaches infinity. If you were fall backwards into such a black hole, you would see the cosmic movie seem to speed up faster and faster until the infinity of time passed before your eyes in a fraction of a second. To an outside observer, it would simply seem that it was taking you an infinite amount of time to reach the event horizon.

Meanwhile, tidal forces between the top and bottom parts of your body relative to the black hole wil normally tear you apart. However, in a large enough black hole, the forces difference between your head and your feet is less, meaning that you survive for a longer period of time.


Now to the questions:

1. What is the minimum required mass of a black hole to allow you to reach the black hole without tidal forces tearing you apart? For simplicity of calculation, assume the maximum force your body can sustain is your weight (a.k.a. your mass and earth's gravitation acceleration of 9.801 m/s^2)

2. If you were to fall into a black hole of at least the size calculated in question 1, and the universe flashed before you, does that not mean that the black hole will have ceased to exist as well? If so, how can you fall into something which has ceased to exist? Have you outlived the universe and are you an infinite amount of time in the future? Does this count as immortality?

3. If the black hole vaporizes along with the universe, it must first get smaller, which will increase tidal forces. What are the required parameters of minimum black hole mass and initial velocity into the black hole to cause the following situation: time dilation is great enough so that the time (from your perspective) during which the tidal forces exist that are strong enough to kill you is short enough to prevent the atoms in your body from separating to dangerous distances?

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