2 ms·

I know what a light year is. I just did the conversion to time given that we are receiving a EM wave.

• xenophonf 11y ago
  It doesn't work like that. Yes, a photon travels at 299792458 m/s, but photons emitted 13 billion years ago (a redshift of about z=8.6) travel much further than (1310^9 years 3.1510^7 seconds/year 299792458 m/s) due to the metric expansion of space. The correct calculation involves an integral, an example of which you can see here: http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=453fadbd8a1a3af50a9df4df899537b5&title=Comoving%20distance%20%28Mpc%29%20from%20redshift%20%28flat%20LCDM%29&theme=red&i0=70.&i1=0.25&i2=8.6&podSelect=&includepodid=Result http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=45...