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Another week, another batch of questions. If ice disappears in your freezer, how can it last in space? How can the Universe be expanding faster than the speed of light? And what is the risk from a coronal mass ejection in an airplane? All this and even more questions. If you’ve got a question for the Astronomy Cast team, please email it in to [email protected] and we’ll try to tackle it for a future show. Please include your location and a way to pronounce your name.
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Ice in Space, Expansion of the Universe, and Death from the Skies – Transcript and show notes.
The universal expansion and red-shift speed suggestion is intriguing. If expansion and red-shift interpretation is correct, then I suspect mankind is literally at the center of all we can see in any direction out to the visual ‘edge.’ This would also be the case for any intelligence at, on or beyond the their visual ‘edge.’ The same goes for mankind. We easliy could be at, on or beyond the visual edge of another intelligent observer in an infinitely large universe. Visual ‘sphere’ diameter would. of course, be governed by the speed limit of light and the rate of expansion. An infinite universe could simply be awash with alien overlapping ‘spheres.’ Who knows! It’s a fun thought.
Opp! The second sentence in the above is messed up. Should read ‘This would be the case with respect to their visual ‘edge.’
What if redshift and expansion are wrong?
What then?
I’m no whiz when it comes to science but my spidey senses say that just about anything could be causing the illusion of expansion. Just as gravitational lensing bends light one way something else could be bending light another way or just where we are in the cosmos could make a big difference in what we see. There just too many “what ifs” to just follow a big bang theory something else needs to be looked into. What? I dont know.
To LLDIAZ, We know or at least we think we know what gravitational lensing is about. This lensing thing begs the question, why don’t we see obvious lensing everywhere we look in the cosmos? There isn’t any question about galaxies behind galixies and so on ad infinitum. So, why isn’t the sky totally filled with lensed galaxies?