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| Thread ID: 112359 | 2010-09-02 09:22:00 | Hello, is there anybody out there? | KarameaDave (15222) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 1134058 | 2010-09-06 03:28:00 | Red shift because red has a higher frequency than blue so therefore travel faster... | SoniKalien (792) | ||
| 1134059 | 2010-09-06 04:27:00 | Red shift because red has a higher frequency than blue so therefore travel faster... Hmmm, got our education off the back of a cornflake packet did we? The frequency of red light is lower than that of blue, though we generally measure them in terms of wavelength not frequencies. However, all light travels at the same speed regardless of frequency. Light itself is just another sector of the electromagnetic spectrum, which starts at ELF (extra low frequency, and goes through ELF, SLF, ULF, VLF LF, MF, HF, VHF, UHF, SHF, EHF before it disappears into the exotic world of FIR, MIR, NUV, EUV, SX, HX, & Y. They all travel at the same speed, which is of course the speed of light, none slower, none faster. Cheers Billy 8-{) |
Billy T (70) | ||
| 1134060 | 2010-09-06 04:35:00 | Do you feel the burn, SoniKalien? :D Must be that red light.... :pf1mobmini: |
johcar (6283) | ||
| 1134061 | 2010-09-06 05:00:00 | I have a theory that the red shift is caused by gravity not things moving away. Our sun is supposed to be red shifted??? Red shift is caused by the same phenomenon as that which causes a train whistle to sound higher as it approaches you then lower as it moves away. The same effect occurs when standing next to a motorway or listening to F1 cars flash past on a racetrack and you can hear it clearly on TV programs. The frequency of the sound does not change but you get that aural impression of an increase as it approaches, apparently compressing the wavelength, then as it departs the frequency appears to drop as the delay in arrival at your ears appears to extend the wavelength. Because the universe is expanding, red shift lets astronomers determine the rate if expansion my measuring the wavelength of the light reaching us. i.e Red Shift. I wasn't aware of any suggestion that our sun is red shifted but unless our orbit is precisely circular about the sun, at times it will be. Cheers Billy 8-{) |
Billy T (70) | ||
| 1134062 | 2010-09-06 05:50:00 | There seem to be 3 types of Redshift: Doppler, Cosmological and Gravitational www.astro.virginia.edu |
Agent_24 (57) | ||
| 1134063 | 2010-09-06 06:01:00 | Hmmm, got our education off the back of a cornflake packet did we? Nah, by reading Batman comics... :annoyed: |
SoniKalien (792) | ||
| 1134064 | 2010-09-06 06:13:00 | There seem to be 3 types of Redshift: Doppler, Cosmological and Gravitational www.astro.virginia.edu though, they are all manifestations of the same observational effect. i.e. they cause an apparent shift in frequency. Mmmm...I would have thought that Doppler covered the basic principle and that cosmological would fit that nicely. Not being a physicist, I have problems with gravitational though, because "shift in the frequency of a photon to lower energy as it climbs out of a gravitational field" sounds like it slows down (or appears to slow down as measured by red-shift), which is again Doppler effect. Doppler is fundamentally a change in the apparent frequency of a wave-based phenomenon (typically electromagnetic, light or sound) when its position is changing in relation to the observer. I'm afraid my aging brain is too small and too slow to dice and slice that into digestible lumps...:waughh: Cheers Billy 8-{) Um.. Yes, I know light is electromagnetic! |
Billy T (70) | ||
| 1134065 | 2010-09-06 09:56:00 | A well is a hole in the ground with either oil, gas or water at the bottom unless of course it is a dried well in which case it will have just dirt or maybe rocks at the bottom. Then again it could have the entire universe at the bottom of the well Sorry, I thought a cave dweller would have noticed the universe is at the side of the well. Alternate universes are on the other side(s). Under the universe at the bottom of the well theory, multiple universes would necessitate multiple bottoms; the paperwork for that would be endless. |
R2x1 (4628) | ||
| 1134066 | 2010-09-06 10:20:00 | I was offering gravity as an alternative cause of the red shift , thus challenging the idea that the universe is expanding. I certainly don't get this curved space time ,, or that the rate of expansion is accelerating , most of this is still theory . I get the feeling some of these theories will be replaced with reality. |
Godfree (15970) | ||
| 1134067 | 2010-09-06 10:20:00 | Not if it made use of a finite unknown number of paperless functions. Paper is so last year. To gain the most use from your well don't use paper to soak up whatever, use a paperless vacuum, sucking thing. I hear that since there are no more street corners in Chch that wells have become much sought after real estate | gary67 (56) | ||
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