It is often said that passing the event horizon for a large black hole is basically a non event as the size of the tidal acceleration at the event horizon depends on the mass of the black hole.(adsbygoogle = window.adsbygoogle || []).push({});

But let's consider something else; what happens to the starsin frontof a free falling observer falling radially at escape velocity into a black hole. Can we devise a formula that expresses the red or blue shift as seen by the observer?

We have the redshift formula for starsbehind us, which is:

[tex] \sqrt { \left| \left( 1-\sqrt {{\frac {r_{{s}}}{r}}} \right) \left(

1+\sqrt {{\frac {r_{{s}}}{r}}} \right) ^{-1} \right| }{\frac {1}{

\sqrt { \left| 1-{\frac {r_{{s}}}{r}} \right| }}}[/tex]

Which graphically looks like:

http://img442.imageshack.us/img442/4100/redshift.png [Broken]

But what do we measure about the starsaheadof us?

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# Passing the event horizon

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