An email from Cosmoquest led me to find
Physicists Narrow Range of Potential Masses for Dark Matter Candidate
articles. Technical details at Theoretical bounds on dark matter masses
and on the Arxiv. The mass range is 10−3eV≲mφ≲107eV. Thus
we have a range from neutrino masses (still very uncertain, but nonzero) up to about 1/10
the mass of a muon. This appears to exclude WIMPs, which were
in trouble. This also suggests that finding dark matter is not a justification for building a more powerful particle accelerator than the LHC; 107eV is well
within the range of the LHC and other current devices.
We still do not have a complete theory of quantum gravity, but apparently enough is understood to make such calculations possible. I am looking forward to
seeing what other theoretical physicists say about this.
Approach to Scanning Historic Glass Plates Yields an Astronomical Surprise. Technical details at
Precise Photometric Measurements from a 1903 Photographic Plate Using a Commercial Scanner.
Professional astrophotography used to be done on emulsion-coasted glass places. That was how astromical discoveries were made for nearly a
More than an estimated 2.4 million glass plates are out there in collections in North America alone. These were taken starting in
the 1890s right up until the 1970s, when CCD (Charged Couple Device) detectors started to come online for astronomy. Of these, only an
estimated 400,000 plates have been digitized to research quality
The team in this article has found a much cheaper way to proceed with this process, using
Vector and Matrix Algebra is a short
tutorial from Complexity Explorer. It is really quite elementary. I took
a formal course in Linear Algebra long ago, and have reviewed the basics a couple times since then. I wanted to see if I
still understand those basics. The answer is that I do: I had no trouble at all with the material.
User Explains Why Elves’ Eyes In Lord Of The Rings Shouldn’t Look The Way They Do, but in fact
there is no problem.
In The Two Towers Legolas claims to clearly see the horsemen of Rohan at a distance of 5 leagues.
How is this possible when you consider the curvature of the Earth? You can come up with some bizarre
ideas about Elven anatomy which are not suggested in the books or seen in the movies. However, there is a
an elegant answer based on the nature of Arda, Tolkien’s world. It was flat, not round, until the end of the
second age. At that time the Valar made it round so that mortals could not access Valinor. But Elves
could still go there. For them the Earth was still flat and they could sail the straight path to Valinor.
Hence for Legolas the curvature of the Earth and the horizon
did not exist and hence he could accurately see the horsemen 5 leagues away.
Confession: I got through a 41 year career in IT, mostly in banking and government, without ever compiling
or running a COBOL program. I recently saw
A very short introduction to COBOL, which describes how to install COBOL
on a Mac and how to compile and run a very simple COBOL program. So I tried this on Ubuntu Linux 20.04.
Exploring the People of Middle-earth: Lobelia Sackville-Baggins, an Unexpected Hero.
… Lobelia is one of only a few Hobbit women who are given more than a momentary glance in Middle-earth, and a compelling character in her own right. And what’s more, her narrative arc illustrates beautifully some of the more important lessons The Lord of the Rings has to teach, as she becomes an unlikely hero to those who had consistently refused to give her a chance.
This will only make sense if you have read the books. Peter Jackson did not include the
Scouring of the Shire in the film version of The Return of the King.
I went (via Zoom) to a great lecture last night. Serafina Nance spoke to the
The Calgary Centre of the Royal Astronomical Society of Canada on
Tracing the Lives, Deaths, and
Explosions of Massive Stars.
Supernovae are cosmic events of gigantic power. Their explosions can shine as bright as a galaxy, a pinprick of extraordinarily bright light in the night sky. What is less well-understood, however, is which stars reach the point of explosion and how they evolve to their deaths. Interestingly, their explosions provide astronomers with key tools to uncover fundamental aspects of our Universe. While we know that the Universe is expanding at an accelerated rate due to dark energy, the rate of the expansion of the Universe is not well-constrained. Supernovae provide us with independent ways to measure this expansion and work to resolve one of the most pivotal questions in astronomy: How fast is the Universe really expanding?
The Book of Kings: The book that defines Iranians.
An epic poem written in the 11th Century helped save the Persian language
Mithra-ndir: Gandalf and the Roman cult of Mithras.
J.R.R. Tolkien described The Lord of the Rings as a fundamentally Catholic work. But a close reading of the epic novel reveals many more influences, including a connection between Mithras and the wizard Gandalf, whose Elvish name is Mithrandir.