Observations takne at the speed of light

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Discussion Overview

The discussion revolves around the concept of an observer traveling at or near the speed of light and the implications for visibility and perception of light. Participants explore theoretical scenarios regarding light wavelengths and the effects of relativistic speeds on visibility, including blueshift and redshift phenomena.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question whether an observer traveling at the speed of light could see anything at all, considering the wavelengths of light might fall outside the visible spectrum.
  • Others assert that it is impossible for objects with mass to travel at the speed of light, emphasizing the theoretical nature of the discussion.
  • One participant suggests that if an observer could travel at light speed, only light directly in front would reach their eyes, while another elaborates on the effects of approaching relativistic speeds, noting that light would become increasingly blueshifted into higher frequencies.
  • Some participants discuss the implications of traveling very quickly away from a light source, raising the question of whether the light would redshift beyond the visible spectrum.
  • There is mention that while light may redshift or blueshift, other forms of radiation (like UV, X-rays, and gamma rays) would still be present and could be detected, albeit in altered forms.

Areas of Agreement / Disagreement

Participants generally agree that objects with mass cannot reach the speed of light, but there are multiple competing views on the visibility of light at relativistic speeds and the implications of redshift and blueshift. The discussion remains unresolved regarding the specifics of visibility at these speeds.

Contextual Notes

Participants express uncertainty about the specifics of light perception at relativistic speeds, including the effects of redshift and blueshift, and the detection of non-visible wavelengths. The discussion includes assumptions about the nature of light and the capabilities of observers at high velocities.

BuddyPal
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I've heard the concept of an observer traveling at the speed of light, but when i placed myself in that observer's shoes i came to wonder; If someone was actually traveling at the speed of light, would/could they SEE anything at all? wouldn't the wavelength of the light be outside of the spectrum of visible light?
 
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It is not possible for any object with mass to travel at the speed of light.
 
Yeah, as DaleSpam said, an object with mass cannot travel at the speed of light. However, if one were able to travel at c, then the only light that would reach the observer's eyes would be the light directly in front of his or her eyes.
 
Last edited:
Lambda3 said:
Yeah, and the only light that will reach the observers eyes is the light directly in front of his or her eyes.
No. There is no 'and'. Dalespam's post has a full stop at the end.
 
BuddyPal said:
I've heard the concept of an observer traveling at the speed of light, but when i placed myself in that observer's shoes i came to wonder; If someone was actually traveling at the speed of light, would/could they SEE anything at all? wouldn't the wavelength of the light be outside of the spectrum of visible light?
While one cannot travel at the speed of light, can can get arbitrarily close to it.

As you approach relativistic velocities, the light coming at you from the front will get be more and more blueshifted. Indeed, visible light will be blueshifted way up the spectrum, into UV, X-ray and gamma ray frequencies. This is one of the big showstoppers for relativistic travel - it will bring with it lethal levels of very hard radiation.

Note BTW that, as far as what the observer can see: infra-visible light will be blue-shifted into the visible spectrum. So what was originally infra-red, microwaves and radio waves will now become visible.
 
DaveC426913 said:
No. There is no 'and'. Dalespam's post has a full stop at the end.

Excuse me. I've been texting too much with people who don't care much for things like that. As a result, I've gotten into some bad habits. :/ Thank you for pointing that out to me. I will be more careful in the future. I will fix it immediately.
 
the question I asked wasn't very specific, what i am really wondering about is when we travel very very quickly, not at the speed of light, but very fast away from a light source, wouldn't the wavelength of the light coming from the light source become so long that it is outside of the spectrum of visible light?
 
BuddyPal said:
the question I asked wasn't very specific, what i am really wondering about is when we travel very very quickly, not at the speed of light, but very fast away from a light source, wouldn't the wavelength of the light coming from the light source become so long that it is outside of the spectrum of visible light?

There's nothing special about "visible light". That's why we have radio astronomy, IR detection, etc. Just because it is outside of the visible light spectrum, it doesn't mean we can't detect it. We've been doing that already for a very long time.

Zz.
 
BuddyPal said:
the question I asked wasn't very specific, what i am really wondering about is when we travel very very quickly, not at the speed of light, but very fast away from a light source, wouldn't the wavelength of the light coming from the light source become so long that it is outside of the spectrum of visible light?
Yes. If you looked out the rear of your spacecraft , the light would appear more and more redshifted, down through microwave and radio frequencies.

Note though, that there is always UV light, X-rays and gamma rays impinging on you, which will be progressively redshifted down into the visible spectrum as you go faster.

So, you will still be able to "see", just things will look more and more weird.
 

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