Astroboffins spot high-power 8b year old radio burst from pre-Earth event An international team of scientists have discovered a fast radio burst (FRB) so distant that it blows the previous record away, but is still one of the brightest they've ever seen. It took the signal from FRB 20220610A around eight billion years to reach Earth in June of last year, making it around 50 percent older than the …
Okay so, given that we're finding that rogue planetrs are a dime a dozen, does that have any impact on that evaluation ?
I mean, let's be clear : more than half of what we can detect is missing, that doesn't mean that it isn't there. Detecting a rogue planet must be even more difficult than detecting a black hole because at least a black hole influences stellar orbits around it. There is no such thing as a rogue planet that can influence a star it does not orbit.
So maybe this dark matter thing should be revisited ?
> more than half of what we can detect is missing
Nah, that would be grand larceny... Actually it's more like we somehow can't detect a huge part of what we calculate must be out there. So far nobody has a satisfactory explanation as to why that is, so in the meantime we nicknamed that apparently missing mass "dark matter" (but it could be anything).
"Actually it's more like we somehow can't detect a huge part of what we calculate must be out there."
So is the universe really missing a shit-ton of matter, or has someone perhaps forgotten to carry a 2 somewhere and the calculations are wrong? Seems a simpler answer to half a universe's worth of missing matter. Or perhaps our instrumentation is wrong, or is not yet able to detect this missing matter? We really need to develop FTL ships so we can get out there and look for ourselves.
Well, yes and no -- it's called "dark matter" because whilst indeed it could be anything, it isn't being seen (dark), and it seems to be have properties consistent with matter. In this it might either be hot or cold dark matter (with different implications), and very much differs from dark energy (doesn't seem to behave like matter).
So it's not "we have no clue" -- there are *some* constraints on it's properties.
"Okay so, given that we're finding that rogue planetrs are a dime a dozen, does that have any impact on that evaluation ?"
If you're suggesting that rogue planets might constitute a significant proportion of the missing mass, that's a reasonable question. But for the answer to be yes, it would take an awful lot of rogue planets. If our solar system is typical, that is pretty unlikely.
The sun constitutes about 99.9% of the total mass of the solar system. Even Jupiter (the most massive planet in the solar system, it has more mass than all the other planets and the asteroid belt combined) is only about 0.1% of the mass of the sun. So for rogue planets to be a significant portion of the missing mass, you would need something approaching 1000 Jupiter sized rogue planets for every star. If it's earth like planets we want to consider, you would need about a million for every star (I'm rounding to the nearest power of 10 because the numbers are so huge). It seems very unlikely that each star would form that many planets (the gravitational forces that drive stellar formation just don't work that way) and then for each star to lose nearly all of them as they go rogue.
.... do your research to find the bounds already observed by modern science that your idea needs to be working within.
Starts with a Bang is a damn good place to start. You get modern science explained in a way that those of us that are not experts in the fields concerned have a chance of understanding.
Why dark matter must exist from 2018 explaining how our observations of the Universe mean that we need something with the characteristics of Dark Matter to explain them.
And 5 Truth About Dark Matter which takes some things that people argue as alternatives and link them to the observations that mean those ideas are going to have a difficult time.
I believe the bottom line is that any of the alternatives (e.g. MOND) have to be tweaked to fit the current observations to the point that they are indistinguishable from Dark Matter. So why bother to create a Dark Matter clone just because you don't like Dark Matter?
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Well as I understand it the point where it when "bang" to arriving "here - now" is about 8 billion light years apart.
Of course it is not at the point where it went "bang" any more as it will have moved since... just we were not at "here - then" went it went "bang" as we have also moved in the meantime
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