The finite-differencing time-domain method [1] (sometimes also called leap-frog [2]) is easy to implement and robust for scalar and electromagnetic waves. This other book by LeVeque [3] is a great introduction on finite-differencing methods for linear equations.
Matter in neutron stars is compressed together by the enormous gravity. Once set free on your floor, this material would no longer be held together and will start expanding at close to the speed of light. The resulting explosion will probably obliterate the entire continent. A crude way to estimate it is to take into account the fact that the gravitational binding energy of matter at the surface of a neutron star is about 10% of the rest mass energy of the material, so once that material is removed it will liberate as much energy (If I got the numbers right, you get an explosion energy of 0.1 m c^2 ~ 10^13 megatons).
I think this is, at least in part, specific to the US/Western tradition. US physics curriculum is built to get people up to speed with quantum physics ASAP, because this is the core of most physics research in US physics departments. If you look at Landau-Lifshitz's Theoretical Physics curriculum, you will find plenty of classical physics: from fluid dynamics, to elasticity, and plasma physics. For example, Landau-Lifshitz Vol. 6 is an excellent introduction to Navier-Stokes equations and their applications.
RAS used to have all articles available to everyone for free after 1 year (immediately if one wanted to pay for open access). I thought this was a reasonable compromise. The new policy will damage early career researchers and groups at less established institutions that will not be able to publish their own research. I have published a number of papers on MNRAS, but now I will move to other journals. In principle, I can charge the publication costs to my NSF grant, in practice that means I would not be able to send my students to conferences, because research support funding is very stretched (no more than few thousand dollars per year per student). This would damage their career prospects. Theory grants are already very small and adding several thousand dollars extra to the budget can make the difference between the grant being awarded or rejected (it should not be, but this is how it works). Moreover, even at R1 institutions, a lot of theory research is actually not funded by federal grants.
Journals were created to support the scientific community and provide a platform for scientists to discuss. Charging exorbitant publication fees damages the very mission of these journals.
This is interesting, but all of the links I tried were broken or led to broken pages. Unfortunately, with the widespread use of LMSs a lot of useful material is now behind University firewalls.
Coincidentally, Alcubierre recently posted a review article on warp drives: https://arxiv.org/pdf/2103.05610.pdf. It looks like a good introduction to this topic.
I would also recommend "The Large Scale Structure of Space-Time" by Hawking and Ellis. It uses some advanced mathematics and some prior knowledge of GR, at least at the level of Schutz or Carroll, is needed, but it is a wonderful book to learn about the global structure of spacetimes with black holes, singularity theorems and so on.
Single academics will likely not bother with Office365/Google, but University administrators are the ones buying enterprise software. In the past few years the trend has been for the central administration to push departments to give up their self-hosted mail servers and switch to Office365 (I have witnessed this at three different Universities). My guess is that something like SwiftLatex could sweeten the deal and convince the faculty to support some of these changes.
Exactly. The data is about the backgrounds of data scientists, but is incorrectly interpreted as the probability of becoming a data scientist given a certain background. Obviously the two are related (Bayes' theorem), but to draw any conclusion one would need to know the number of PhDs, Masters, etc. that are applying to become data scientists. For example, the fact that a small fraction of data scientists has a MOOC degree does not imply that the probability of becoming a data scientist if having "only" a MOOC degree is low. For all that we know the few people in the market having this kind of non-traditional preparation could have 100% success rate in getting those jobs.
I am just thinking that, if future archeologists discover these warnings / language in frequent association with art, then they will probably not think twice about excavating an actual nuclear disposal site that exhibits them. They will probably think that the warnings were placed there to scare away thieves.
Fully agree. Academic career is already demanding enough without having to force each scientist to run his/her own PR operation. Outreach is important, but it is better done at the group or institutional level.
I got my PhD in 2013 (computational astrophysics / general relativity), I did almost 6 years as postdoc at two different institutions, and I am about to start a tenure track job. I write code for and run fairly large-scale HPC simulations of gravitational wave sources for LIGO, such as colliding neutron stars and black holes, and core-collapse supernovae.
I work on gravitational wave related science. I am not part of LIGO, so I speak only for myself. I think that most people in the scientific community have no doubts on the interpretation of the LIGO data for which they were awarded the Nobel prize. There is only one group who claim to have found problems with the data, but their analysis is problematic in several ways... The controversy has been largely exaggerated by the media.
Creating a blind injection without many people knowing about it and without leaving a trace in the detector diagnostics is also extremely unlikely.
I have studied in Europe (Italy and Germany) and now I am in the academia in the USA. Having student evaluate professors has been the standard practice for many years in Europe. I also do not think that American students have a worse attitude towards their professors than their EU counterpart. In my limited experience, I have actually found the opposite to be true: I found American students to be more actively involved in their education and less passive than Italian students (on average).
Large and close is respect to the light-crossing time and the accuracy with which you want to timestamp an event. If you care about years, 1 light year is already a large distance.
I agree that you can make such a construction in theory. However, in practice there is no way we can synchronize our clocks with an observer at the location of that binary star system. There is also no reason to do it: the precise time of the star merger does not have any physical meaning, it is just a label. Saying that some astronomical event took place on the date we observe it, is equally valid and free from ambiguities.
Please see my other reply below. Reference frames are local constructs. There is no such a thing as a (unique) reference frame of the entire galaxy that can be used to define simultaneity. In fact there are infinitely many of them.
Reference frames are local constructs, they cannot be used to (uniquely) define simultaneity over large distances. The time of any single event is just a "tag" in relativity. In fact there are infinitely many surfaces of simultaneity that contain the merger of those two stars and meet the Earth at a particular time "t" in the range ~[-2000, +5] from now, so that it is equally valid to state that the merger happened ~2000 years ago or ~20 years ago, or that it has not happened yet.
For this reason, to avoid confusion, it is much better and customary to "tag" astronomical events by the time we observe them. That is to say that they happen when we observe them.
According to OP these are "12 equations in 18 variables, where the variables were restricted to integers in the range [1, 26]". Can you solve them using the elimination theorem?