Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Sophie Seifert-Gram on 04/12/2009 13:30:03

Title: Could you make a mobile phone call in a Black Hole?
Post by: Sophie Seifert-Gram on 04/12/2009 13:30:03

Sophie Seifert-Gram  asked the Naked Scientists:
   
Hi
 
I know that in a black hole the gravity is so great that light waves are changed, but would it also affect radio waves? What would happen if you tried to make a mobile phone call in a black hole?
 
thanks!
 
Sophie Seifert-Gram
Chicago, Illinois
U.S.A.

What do you think?

Title: Could you make a mobile phone call in a Black Hole?
Post by: Mr. Scientist on 04/12/2009 14:58:06

If you lived inside of it in a space where the metric acts like the spacetime we experience. If you just passed the boundary you couldn't.

Title: Could you make a mobile phone call in a Black Hole?
Post by: graham.d on 04/12/2009 16:06:55

Mobile phone systems depend on a whole network system of cell sites and these are all relatively short range. I suppose what you mean is can you communicate with someone outside a black hole if you were inside and you both had two way radios. The short answer is "no". No information can go from inside the Event Horizon to outside the Event Horizon - at least not radio waves. If both of you were within the event horizon then, in theory, you could though you may have some problems depending on many factors.

Title: Could you make a mobile phone call in a Black Hole?
Post by: LeeE on 04/12/2009 16:40:31

Radio waves are light waves.  They just have a longer wavelength/lower frequency.