LIGO has it down to 2.6x - however I suppose that is not far removed from 3x!
As the last paragraph of your information picked up from the web says, "...we have NOT found black holes tinier than 3-5 solar masses (stellar black holes)".
That does not necessarily mean they don't exist, it may simply be that they are difficult to find. Gaia may find them as its detection method becomes more sensitive.
Wiki suggests that there may be many such low-mass black holes that are not currently consuming any material and are hence undetectable via the usual x-ray signature (see "Lower mass gap" section): https://en.wikipedia.org/wiki/Stellar_black_hole
Here, Dr. Becky talks about the 5 types of black holes:
Then we are back to what I said earlier.
There are no known stellar processes that can produce black holes with mass less than a few times the mass of the Sun. If black holes that small exist, they are most likely primordial black holes. (This time I've taken the wording from the above Wiki link.)
;-)
Is there a scientist in this thread;-?!
https://principia-scientific.com/open-letter-to-the-nobel-committee-for-physics-2016/
Is there a scientist in this thread;-?!
https://principia-scientific.com/open-letter-to-the-nobel-committee-for-physics-2016/
;-) I nearly rose to the bait with our esteemed Plasma Physicist @cumbb! ;-)
W.W. Engelhardt turns out to be a Plasma Physicist too, of vague qualifications, as is common with the "Natural Philosopher" cabal.
He seems to attract people of the Maxwell/Faraday/Lorentz/Einstein/Hawkins (sic) was WRONG ilk! AND THE WORST THING is they have to tell us all about it!
There was even a strong belief in the Luminiferous Ether in his gang, and his debunking of LIGO discoveries to the Nobel Prize committee must have been music to their ears.
10-18m sounds a lot. Surely femtometers, fm, the size of a proton, are closer to LIGO's accuracy? But, hey what do I know?
Best, Steve.
W.W. Engelhardt turns out to be a Plasma Physicist too, of vague qualifications, as is common with the "Natural Philosopher" cabal.
He seems to attract people of the Maxwell/Faraday/Lorentz/Einstein/Hawkins (sic) was WRONG ilk! AND THE WORST THING is they have to tell us all about it!
There was even a strong belief in the Luminiferous Ether in his gang, and his debunking of LIGO discoveries to the Nobel Prize committee must have been music to their ears.
10-18m sounds a lot. Surely femtometers, fm, the size of a proton, are closer to LIGO's accuracy? But, hey what do I know?
Best, Steve.
Last edited:
Oh my - now I recall circa 2000 when the LIGO design and construction was first ramping up, there was a guy who had a webpage, I forget if it was Geocities or Angelfire, who had "proof" that LIGO wouldn't work and that it was a total waste of all the money being spent on it. I regret not saving it and I haven't been able to find it in online archives, but I thought it was hilarious.
A couple years later there was someone else complaining about the USA change to Digital TV and turning off the "pure" analog signal - as I recall, his main complaint (or the only one he could find to glom onto) was the stairstep of digitized audio, with an image he had surely copied from somewhere else on the Internet.
Where would we be without kooks? Probably discussing gravity in orbit somewhere.
A couple years later there was someone else complaining about the USA change to Digital TV and turning off the "pure" analog signal - as I recall, his main complaint (or the only one he could find to glom onto) was the stairstep of digitized audio, with an image he had surely copied from somewhere else on the Internet.
Where would we be without kooks? Probably discussing gravity in orbit somewhere.
But, hey what do I know?
I have seen a sensitivity of 10^-18 m quoted elsewhere, Steve.
This link says that, at its most sensitive, LIGO will detect a change 1/10,000th the width of a proton! https://www.ligo.caltech.edu/page/facts
Apparently, LIGO has improved its sensitivity with a little "quantum squeezing": https://news.mit.edu/2023/ligo-surpasses-quantum-limit-1023
Quantum squeezing will reduce the background hiss of quantum noise caused by particles that randomly pop in and out of empty space and so reduce the level of uncertainty in LIGO's measurements.
So 10-18 m might be a typo!
Remember the SIX P's! Prior Practice Prevents Pis Pauvre Performance!
I have got my new Nikon D60 DSLR camera doing the business, despite awful street lighting.
f3.8, 30 seconds on 2s time release, 20mm on short tripod.
Happy with that. Now ready for the Nova around 2nd magnitude sometime this summer. Bootes and Corona Borealis here.
The Nova will be HERE, marked by a T as in T Corona Borealis:
Can't wait. This is real science. I picked up a very faint meteor trail in this snap, but the forum compression to jpeg seems to have obscured it. Seemed to come from Lyra which is the Lyrid shower peaking around now in the early dawn for best viewing.
Remember the SIX P's! Prior Practice Prevents Pis Pauvre Performance!
I have got my new Nikon D60 DSLR camera doing the business, despite awful street lighting.
f3.8, 30 seconds on 2s time release, 20mm on short tripod.
Happy with that. Now ready for the Nova around 2nd magnitude sometime this summer. Bootes and Corona Borealis here.
The Nova will be HERE, marked by a T as in T Corona Borealis:
Can't wait. This is real science. I picked up a very faint meteor trail in this snap, but the forum compression to jpeg seems to have obscured it. Seemed to come from Lyra which is the Lyrid shower peaking around now in the early dawn for best viewing.
Last edited:
There was a fantastic paper on LIGO (very technical) instrumentation and how the mirrors were set up, low noise requirements etc. I've tried to find it on the web, but to no avail. Maybe someone has better search skills than me? IIRC one of the lead authors was a guy called 'Abbott', but there were a lot of contributors to the paper.
You would have thought that if the LIGO guys said 'Hey, we just detected a GW at xyz in the sky' and astronomers quickly pointed their equipment at said location and saw the event the LIGO people were claiming it would be proof enough. So how do the naysayers account for that? Serendipity?
It's depressing when people start with 'Einstein was wrong', ditto the people claiming QM is wrong. When you start with 'they are correct' and work on taking their science further, you make progress.
These people are quacks at best.
You would have thought that if the LIGO guys said 'Hey, we just detected a GW at xyz in the sky' and astronomers quickly pointed their equipment at said location and saw the event the LIGO people were claiming it would be proof enough. So how do the naysayers account for that? Serendipity?
It's depressing when people start with 'Einstein was wrong', ditto the people claiming QM is wrong. When you start with 'they are correct' and work on taking their science further, you make progress.
These people are quacks at best.
This is where the Pentax cameras have a real advantage. Most anti-shake systems do it by moving the lens elements (Nikon, Cannon), but Pentax moves the sensor. If you get a GPS unit for a Pentax (about £180 last time I looked), you can use it for astrophotography because it moves/tilts the sensor to track the Earth's rotation (special set-up mode in the camera). They use the sensor movement BTW to increase the resolution as well by moving it 1/2-1 pixel and then interpolating the data - all fancy DSP stuff of course.Can't wait for LISA to get going. 10 Years!
I too have been following this BH3 business:
View attachment 1300713
My understanding is most Supernovae leave a Black Hole after exploding. And there must have been a lot of them down history. IDK whether they attract dark matter to complicate things. You would think they do.
I am currently experimenting with astrophotography, despite some murky skies lately and a cold NE wind at night. Hoping to see this Corona Borealis Nova. I bought a Nikon D60 DSLR with an 18-55mm f3.5-f5.6 lens.
Camera shake is proving problematic but I am picking up faint stars, but it is possible to use a 30 second manual timer delay mode, a shortened tripod and a piece of Black Card as a very manual and clever shutter control to avoid trails.
https://www.space.com/astrophotography-for-beginners-guide
These settings can be set in the menus, so I am optimistic.
I also want to get hold of my nephew's 35mm and 50mm f1.8 lenses which seem more suitable. F1.8 is four times the light of f3.5, which is a magnitude or more, magnitude being a x2.5 factor to be combined with longer shutter speed.
The Higgs Boson continues to baffle me, but am making some progress:
https://theconversation.com/peter-h...ut-the-building-blocks-of-the-universe-227638
The key seems to be that the Higgs field, which is scalar and uniquely spin-0, breaks the expected symmetry as a Mexican Hat or Wine Bottle potential. Symmetries conserve properties like energy and momentum, but the Higgs Field bypasses some of the problems in the Goldstone theories.
Uniquely, Peter Higgs predicted the Boson which bears his name. Around a massive 125 GeV along with the heavy W and Z bosons of the weak force and the Top Quark.
The 1964 Higgs paper was beyond me, though the equations in it are no worse than in General Relativity. and the 1966 one only available on subscription. Yukawa potentials and the Goldstone Theorem are of course, highly technical things.
Onwards and upwards!
http://c758710.r10.cf2.rackcdn.com/...7548737_All_Bodies_Shake_Reduction_012208.pdf
https://www.ricoh-imaging.co.jp/english/explore/astro/
Pentax used to be the premium Japanese camera brand in the 1950's - 1970's but sadly lost their way. Pity, because they still make fantastic cameras.
Last edited:
I'm glad I remembered the strain figures I mentioned earlier! When I read the paper, they were etched into my brain. LIGO is a serious piece of engineering physics!
The paper you linked to is nice, but not the one I am looking for. That was quite a long paper with a lot of technical details. I'm wondering if it was removed for security reasons i.e. the tech was so bleeding edge the US government blocked it. Maybe I'm being conspiratorial - I dunno
The paper you linked to is nice, but not the one I am looking for. That was quite a long paper with a lot of technical details. I'm wondering if it was removed for security reasons i.e. the tech was so bleeding edge the US government blocked it. Maybe I'm being conspiratorial - I dunno
Here's a 2009 paper by Abbott that I originally posted but edited out: https://iopscience.iop.org/article/10.1088/0034-4885/72/7/076901
Unfortunately, one has to pay to access this article.
Speaking of geeky LIGO stuff, bout 20 years ago I was looking up info on LVDTs (Linear Variable Differential Transformer) as a position sensor - almost all designs use three fixed coils and a magnetic slug that moves inside them. I stumbled across the LIGO design that uses coils only. The middle coil is on the moving part and is driven with an AC signal and the other two are fixed and each has a variable signal level depending on the position of the driven coil. There's another paper from about the same time on a sigma-delta ADC deign used for the LVDT, it'll take more searching to find it.
https://www.researchgate.net/public...al_wave_interferometer_low-frequency_controls
https://www.researchgate.net/public...al_wave_interferometer_low-frequency_controls
