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Short observations from a scientist’s working notebook.
One of the most interesting aspects of the coronavirus is the time dependence of its infection rate. It determines how effective measures like quarantining can be. Spoiler: quite ineffective!
The next interesting question to ask when studying the coronavirus, is what is the effect of a mixed population which has different infection rates. That is, that some individuals are more infectious than others (e.g., a cashier in the supermarket vs. a farmer). Spoiler: it turns out that unless there are super-spreaders then all you care about is the arithmetic average of the transmission coefficient.
Armed with the data on the coronavirus such as the serial interval, incubation period, and the base growth rate, we are now in a position to start modeling the pandemic. Note that as the title suggests, these are simple models. Any conclusions drawn from this specific page should…
This is the first in a series of posts in which I study the COVID-19 (coronavirus) pandemic. My original goal was to understand the behavior of the pandemic. As a scientists my curiosity forces me to not to leave such problems untouched. I wanted to know what are the possible…
The I recently wrote an OpEd for the Epoch Times which tries to succinctly capture my main grievances with the global warming scare. Here is brought again with a few comments (and references) added at its end.
This paper made some waves in the Media recently. It is based on highly biased data selection, and therefore flawed to its bone. It shouldn't have passed refereeing.
An article interviewing me was removed yesterday from forbes. Instead, they published an article by Meteorologist Prof. Marshall Shepherd that claims that the sun has no effect on climate. That article, however, falls to the same pitfalls that pointed out on my blog yesterday.…
A few days ago I was interviewed by Doron Levin, for an article to appear online on forbes.com. After having seen a draft (to make sure that I am quoted correctly), I told him good luck with getting it published, as I doubted it will. Why? Because a year ago I was interviewed by…
Just over a week ago I gave a 20 minute talk (which lasted almost 22 min) about the role that the sun plays in global warming in the Heartland institute's climate conference in DC. Here it is brought again for posterity.
Last week I had the opportunity to talk in front of the Environment committee of the German Bundestag. It was quite an interesting experience, and frankly, something I would have considered unlikely before receiving the invitation. It was in fact the first time a climate…
Two months ago I wrote about the Cambridge Union Debate I participated in. The Cambridge Union has meanwhile posted the debate online. Here is my part of it. (It starts at 32m31s.) [VIDEO::https://www.youtube.com/watch?feature=youtu.be&v=PL2gRaXMMkA&t=32m31s] I should add that…
Last week I participated in an interesting debate that was held at the Cambridge Union, the oldest debating club in the world (dating back to 1815. The invite was to be on the side opposing the proposition “This house would rather cool the planet than warm the economy”. Although…
Just over a week ago I received an interesting call from a science magazine reporter. He asked me what do I think about the recent discovery of the Quantum Electrodynamic (QED) produced vacuum birefringence around neutron stars. It was an interesting surprise as my colleague…
Willis Eschenbach had a post on wattsupwiththat.com attacking my post on this blog , which explains why the new sunspot reconstruction may be irrelevant to the solar climate link and also discusses the recent paper I have co-written. I am not writing it as comments on…
After being asked by 5 independent people about the new sunspot number reconstruction and that it doesn’t show that the sun should have contributed any warming to the 20 th century, I decided to write about it here. I have one word to describe it – irrelevant. It is also a good…
Two weeks ago a science magazine paper appeared claiming that once various systematic errors in the sea surface temperature are corrected for, the global warming “hiatus” is gone. Yep, vanished as if it was never there. According to the study, temperatures over the past 18 years…
Bill "the science guy" Nye says that I am a denier. I recently stumbled on a transcript of Bill “the science guy” Nye’s interview on CNN last week. In it, he said that climate skeptics (i.e., people like myself), are at least as bad as people who deny that smoking causes cancer.…
Last month I visited the U of Washington to give a talk in which I discussed the effects of cosmic rays on climate. At the end of it, not one, but two people independently asked me about Overholt et al. , which supposedly ruled out the idea that passages through the galactic…
The recent bashing of Willie Soon from the Harvard Smithsonian Center for Astrophysics in the NY Times exemplifies, I think, how the climate debate has long left the realm of science, and it also demonstrates how scientific research is most often funded, quite the opposite of…
Since I began teaching "Order of Magnitude" physics a few years ago, I collected many examples of physics estimates from daily life (and the daily life of physicists... which I admit does not necessarily reflect the population as a whole). Here are several examples. More should…
I just found out that a dear friend had passed away. Nigel Calder was the voice of rationality within a sea of extreme, something which is very much missing in the global warming debate. He didn't accept things for granted, but on the other hand didn't make extreme claims in the…
My name is Nir Shaviv. I am a full professor at the Racah Institute of Physics in the Hebrew University of Jerusalem. My main research interests revolve around the following topics: - The behaviour of very luminous astrophysical objects, so luminous that their radiation pressure…
The IPCC summary for policy makers is out, and as I started writing these lines so was the last draft of the main report. Of course, it will take a while to digest the 2200 pages of the full report (it has a lot of starch!). Until I do, here are my first impressions from having…
Spring weather here in Israel was rather strange. Although winter with most of its precipitation should have been over, we had a few very rainy days. We're now in the midst of a heat wave with temperatures as much as 20°C higher than just a week before. In between there was a…
A very interesting paper recently appeared in nature . It describes the detection of a precursor eruption of a supernova progenitor more than a month before the supernova explosion itself. It is particularly interesting because this detection was not serendipitous—it was based on…
Last month I participated in EIKE's (Europäisches Institut für Klima und Energie) conference on Climate Change. They video record the lectures, which means that mine is now online. I thought I'd share it with you. Have fun.
After being busy with the submission of two research proposal and trying to stay afloat with the pretty heavy teaching load I have this semester, I decided I should take a short break and post something on my blog. I actually have quite a few things I have been wanting to write…
Estimate the future value of a retirement fund, including payment and yearly fund commissions.
Estimate a retirement fund and the extra money lost to payment and yearly fund commissions.
Dear Rep. Adam Schiff (representing California's 29th district). Although I presently live outside the US, I am a registered voter in the 29th district which you represent. I kindly ask that you will drop your support of SOPA. The continuing infringement of intellectual property…
Out of curiosity, I opened a few weeks ago a poll asking the visitors of this site, what do they think is the primary cause of global warming. 429 people answered the poll (thanks to all of you!). The results can be summarized as follows. First, the visitors of this site have the…
A few days ago I had a very pleasant meeting with Andrew Bolt . He was visiting Israel and we met for an hour in my office. During the discussion, I mentioned that the writers of the recent IPCC reports are not very scientific in their conduct and realized that I should write…
Archived results of the original ScienceBits expertise and climate-change-cause poll.
A few weeks ago, the hacker/whistleblower has done it again. A new release of a large amount of e-mails from the same source (University of East Anglia) has surfaced in Russia. It is most likely from the same original batch because the last of the new e-mails is from 2009. Here…
Three weeks ago I visited the underground laboratory of Gran Sasso near l'Aquila. Little did I know that it would make headline news so soon, for "discovering" particles moving faster than the speed of light. Since a few people asked me what did I think of it, I decided to write…
Masada, the Dead Sea, the Messinian Salinity Crisis and Augustus Ceasar, all in one post.
After a long lull in activity, I decided it's about time I write an update about my thoughts on global warming. Here it is.
Cosmic Rays and Climate
This is the second of the three part article on the climatic role of the sun.
With the exception of those who have been living in a dark cave, it is well known that Earth has warmed over the 20 th century. Anyone who reads papers or watches TV knows that it is humans who are those responsible for this warming. According to most media sources, and…
I recently stumbled upon one of the most meaningless papers I have ever seen. The paper "proves" that the scientists advocating an anthropogenic greenhouse warming (AGW) are statistically more credible than the "unconvinced". Their main goal is to convince people that they should…
Last May I had a conference in the island of Vulcano. During the conference I had a half day excursion to the Island of Stromboli, where I climbed the mountain and got to see one of the most impressive geological phenomena one can see... Here are my impressions, photos and even a…
After being asked once too many about the climategate scandal, I decided it would save me some time if I simply wrote down my opinion about it.
There are 12, but that's not the main point of this blog entry...
(On the hebrew translation of the "Chilling Stars") לאור העובדה שלא מעט מקוראי האתר בעברית מתענינים בנושא של השפעת השמש על האקלים, מצאתי לנכון "לפרסם" תרגום לעברית של הספר "chilling stars" של הנריק סוונסמרק ונייג`ל קולדר, שהם ידידי. הספר "הכוכבים המקררים" יצא לאור זה עתה בהוצאת…
A week ago was Earth day, and just like the trend elsewhere, Israel joined with an hour long blackout. In principle, I am very much in favor of environmental awareness, and if it brings some, so be it. But if you ask me, overall, this event is a rather pointless gimmick. Why?
Please do not re-post whole content without permission. Would you like me to copy your site? You can re-post up to half an article, and make sure you add a link to the original page If you take images of which I am the originator, please save the file locally on your server and…
I few months ago, I had a paper accepted in the Journal of Geophysical Research. Since its repercussions are particularly interesting for the general public, I decided to write about it. It's called, using the "Oceans as a Calorimeter to quantify the solar radiative forcing".
I recently returned from Lijiang (in Yunnan, China). One of my legs was a flight from Chengdu to Beijing, and it is certainly a flight I will never forget.
A random and subjective walk in science and physics in particular.
Realclimate.org continues with its same line of attack. Wishfulclimate.org writers try again and again to concoct what appears to be deep critiques against skeptic arguments, but end up doing a very shallow job. All in the name of saving the world. How gallant of them. This time…
By: Nir J. Shaviv & Ján Veizer Background Counter to claims by anthopogenic global warming enthusiasts, there is ample evidence to support the idea that cosmic rays do indeed affect climate (evidence will soon be summarized on this site). Thus, it is no surprise that we find in…
Jerusalem was under siege, again. Last time it was Bush. This time, it was snow because of which we had two snow days. So, I didn't have to teach and instead could build a snowman with my kids. I could also look at the rain radar, which appeared to exhibit a few interesting…
A few words about the longest strike ever in the Israeli Universities, a strike which ended last week. No science in this post. Sorry.
On my personal views of President Bush's visit to my humble town of Jerusalem. A few thoughts about quantum mechanics and the speed of sound.
I recently stumbled upon a nice black hole merger simulation . Since it is not in my habit of just regurgitating stuff I see on the internet, here is my added value. How can one estimate the quadrupole gravitational radiation of a binary? How close does the binary have to be for…
The panel. From left to right: Prof. Colin Price, Prof. Nathan Paldor, Prof. Dan Yakir, and myself. On Sunday last week, a global warming debate was held at the Hebrew University, in front of a large public audience. The speakers included myself, and Prof. Nathan Paldor from the…
התחממות גלובלית, מי יודע מדוע וכמה? A short "open letter" in hebrew about global warming. To all my english readers, sorry. This is a one time quirk.
On of the interesting manmade climate phenomenon is that of Ship Tracks , whereby a ship, with all the exhaust particles it releases, can change the characteristics of clouds in its wake. Last week, I saw first hand how a boat can pollute so much.
A few astro photographs, including one of Saturn under horrible seeing!
A few weeks ago, while debating the issue of global warming with an alarmist, my colleague pointed out two facts which appear to be consistent with the "standard" anthropogenic scenario, but not the one I advocate, that the natural climate drivers are large and that Earth's…
One of the "scientific" highlights in Al Gore's movie is the discussion about the clear correlation between CO 2 and temperature, as is obtained in ice cores. He leads his audience to beleive that this correlation implies a clear CO 2 →ΔT link, but does it really?
The recent discovery of a terrestrial like planet (i.e., one which is stony and not gaseous like Jupiter) gave rise to a minor media hype, with statements like "We may be witnessing the start of a cosmic real estate boom" being commonplace. However, is Gliese 581C really a place…
A few weeks ago, a few students saw a nice phenomenon in the sky. Knowing I liked this kind of stuff (and that I may be able to explain it), they called me out of the office to look at the sky. Above us was a nice and almost complete parhelic circle . Unlike the usual 22° halo…
Yesterday I was surprised to find out that the IPCC didn't really come out with the Fourth Assessment Report (4AR). I was also surprised to find an article with something which appeared to look like an interview of me. Since I am not senile (getting there, but not just yet) I…
Some time ago, I pondered about the effects that mass hysteria could have on a flu epidemic. In particular, on how a fright about flu vaccination (which happened in Israel a few months ago) would cause less people to be vaccinated , and thus be responsible for a larger flu…
Alleged paranormal phenomena tend to pop-up from time to time. The best example is probably that of Uri Geller. He became famous in the 70's with his "abilities" to bend spoons, read thoughts, etc. Unfortunately, Uri Geller decided to return back to his native Israel, and worse…
Some time ago, I noticed an interesting bias in the TAR scientific report (the third assessment report of the IPCC - the intergovernmental panel for climate change) regarding the climate sensitivity, that is by how much the average global temperature will increase if we double…
What is climate sensitivity? The equilibrium climate sensitivity refers to the equilibrium change in average global surface air temperature following a unit change in the radiative forcing. This sensitivity (often denoted as λ) therefore has units of °C/(W/m 2 ). Often, instead &…
Most people, when let alone, are not dumb. They can make reasonable decisions if given the right information. However, when people are part of large groups, somehow it seems, the IQ of an average individual, and even the effective IQ of the group as a whole, appears to decrease.…
After finding out that Earth is not a planet (it didn't clear out its orbit...), I now learned that Earth's doesn't have life on it. Sounds strange? Well, Navarro-González et la., in a recent paper that appeared in PNAS, showed that the same tests used on the Viking program and…
As is the case in recent years, the Nobel prize announcements last week made me proud of my home institute yet again. This year, Chemistry recipient is Prof. Roger Kornberg, who has been a regular visiting professor at the Hebrew University for already 20 years.
While buying diapers on the weekend from my muslim neighbors, I learned that the holy month of Ramadan has just recently started. The hot weather made me realize that Ramadan fast cyclicly varies from an easy obligation to one which is very hard. Fasting in summer implies…
The other day I found out to my dismay that the balcony underneath my air conditioner at home leaks water into the living room below it. Instead of sealing the balcony (as I should...) I temporarily solved the problem by placing a baby bath tub underneath. After "recycling" the…
Last week, a report by Jeff Kanipe appeared in nature . In it, Kanipe explains the solar → cosmic-ray → climate connection, and the planned CLOUD experiment in CERN, expected to finally resolve the issue. Given that my work is mentioned in the review, I through I should mention a…
Technical details about super-Eddington atmospheres. Proceed at your own risk.
I just recently read Motl's post on a particularly prolific crackpot, who solved all of the known problems in physics, and then some more. That reminded me of an old story, a true one, which teaches us that you can be a crackpot in many orthogonal ways (that is, in mutually…
Over the past two weeks, Kaytushas have been falling over Northern Israel causing casualties and damages. Here are some thoughts about the situation and how bad it is.
Everyone in Israel has heard of the Galsgow scale. Why? Because our former prime minister Ariel Sharon was and still is in a coma. The Glasgow scale, of course, measures the level of consciousness (or lack of). Ariel Sharon, for example, scored 6 out of 15. 8 or less is defined…
A conversation I had with a friend made me realize something interesting. Modern medical technology is responsible for the constant degradation of the human gene pool. How? Simple, we allow bad genes to propagate. Take me for example...
Archived results of the original ScienceBits poll about naming silent earthquakes.
Archived results of the original ScienceBits poll about naming silent earthquakes.
Links to the static pages and an archive of the blog entries.
A quick review of the cosmic ray / climate link.
My almost 3 year old daredevil son broke his hand in his last escapade. I found the x-ray rather cute, and interesting... you can see how his bones are forming. He learned not to jump from high places, and I learned all about bone age...
Water Rockets are simple homemade invensions that model their chemically fueled cousins. Unlike the latter, water rockets operate using water propulsion and hand-pump generated air pressure. Here we describe the equations of the problem. They are also solved numerically in the…
This article succinctly describes the theory of porous atmospheres, which naturally gives rise to super-Eddington systems. We quickly review the meaning of the Eddington luminosity and how nature can circumvent it.
Is 20th century global warming due to anthropogenic sources (i.e., greenhouse gasses) or natural variability? Find out here.
A summary of the debate prompted by the "infamous" paper written by Ján Veizer and myself. All the attacks and their rebuttals. Have fun.
The demise of Shinui party in the last Israeli parliamentary elections (March 2006), made me realize that Shas and Shinui should probably follow the Lotka-Volterra equation. As I explain below, the problems are not totally equivalent for several reasons. Nonetheless, many of the…
After quite a long while, during which I planned developing such a site, sciencebits.com has gone online. The "raison d'être" behind this site consists of several motives...
On long time scales, it appears that our journey through the Milky Way is responsible for large climate variations. Each time we pass through spiral arms of the galaxy, we witness a higher flux of cosmic rays, which in turn reduce the global temperature. Read more about the…
About my personal research.
Useful and interesting financial calculations and related entries.
Reynolds number is a dimensionless number which determines whether a given flow will be laminar or turbulent. It is basically the ratio between the inertial forces $v $ and the viscous forces $ L$. It is given by: $$ R -1pt e= { v L } = {v L }, $$ where $ $ is the density of the…
Physical Constants, in c.g.s.: Speed of Light: $ c = 3 10^{10}~ {cm/s} $
Sports is fun, but more so if you understand the physics behind it! Balls and Magnus force Skiing and snowboarding --> Rowers on a boat
ScienceBits is Nir Shaviv’s independent, random and subjective walk through physics, astrophysics, climate, computation, and scientific curiosities.
Physics and Mathematical Formulae, by topic: Vector Analysis Classical Mechanics Special Relativity
