Always in the last place you look.......
Missing Matter in Universe Found
11–20 of 26 posts
Re: Missing Matter in Universe Found
#12Always in the last place you look.......
gods I've always hated that saying.
Re: Missing Matter in Universe Found
#13Does this remove the need for WIMPs and other exotic explanations for dark matter?
This study accounts for missing ordinary matter, not dark matter. The linked article makes this clear in the first paragraph. Sometimes I wonder if the first commenters (and often top commenters) on HN read the article at all or just respond based on the headline, because these comments often seem barely related to the actual article content.
> Sometimes I wonder if the first commenters (and often top commenters) on HN read the article at all ...
From the HN guidelines:
"Please don't comment on whether someone read an article."
Re: Missing Matter in Universe Found
#14> The vast majority of matter in the universe is dark—it is entirely invisible and detected only through its gravitational effects They state like dark matter is a fact. Isn't it a hypothesis? > The FRBs shine through the fog of the intergalactic medium, and by precisely measuring how the light slows down, we can weigh that fog, even when it's too faint to see Light slows down??
1. It is a phenomenon not a hypothesis. Dark matter is a collection of observational facts that indicate an unknown source of gravity. 2. Yes, in any medium lights slows down. This is what refractive index measures.
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Re: Missing Matter in Universe Found
#15Re: Missing Matter in Universe Found
#16Re: Missing Matter in Universe Found
#17> The vast majority of matter in the universe is dark—it is entirely invisible and detected only through its gravitational effects They state like dark matter is a fact. Isn't it a hypothesis? > The FRBs shine through the fog of the intergalactic medium, and by precisely measuring how the light slows down, we can weigh that fog, even when it's too faint to see Light slows down??
Light is always light and has always the same speed but its path in a gas is less straightforward than in a vacuum because of the interactions with atoms. It takes longer to get through. Its speed as we can measure it is c divided by the refractive index of the gas, if I'm not wrong. Same thing for light in a liquid or in a solid. Example: speeds of radio waves in networking cables https://en.wikipedia.org/wiki/Veloc…
Yep. And then journalists wonder why people don't like them. How much harder would it be to write "measuring how much longer would it take for the light to get to us" without making people feel gaslit next time they are told speed of light is obviously always the same
Re: Missing Matter in Universe Found
#18Always in the last place you look.......
Well, duh...
Re: Missing Matter in Universe Found
#19Earlier quoted context omitted.
Light is always light and has always the same speed but its path in a gas is less straightforward than in a vacuum because of the interactions with atoms. It takes longer to get through. Its speed as we can measure it is c divided by the refractive index of the gas, if I'm not wrong. Same thing for light in a liquid or in a solid. Example: speeds of radio waves in networking cables https://en.wikipedia.org/wiki/Veloc…
Yep. And then journalists wonder why people don't like them. How much harder would it be to write "measuring how much longer would it take for the light to get to us" without making people feel gaslit next time they are told speed of light is obviously always the same
This was written on a college website and probably assumes an audience that is familiar with basic physics, since refraction is something we learn in grade school.
Also, who doesn't like journalists? I appreciate journalists a lot, even when they make mistakes. They provide a valuable service.
Re: Missing Matter in Universe Found
#20Does this remove the need for WIMPs and other exotic explanations for dark matter?
This study accounts for missing ordinary matter, not dark matter. The linked article makes this clear in the first paragraph. Sometimes I wonder if the first commenters (and often top commenters) on HN read the article at all or just respond based on the headline, because these comments often seem barely related to the actual article content.
I had read the entire article, and it was not clear.