Good example of how scientists need to step away from 'the textbooks' & group-think every so often

 In theoretical physics for the past 50 or so years, thousands of the world's best physics minds have dedicated themselves to looking for the quantum theory of gravity. Since Einstein, the dream has been to unify gravity with the other three forces of nature into a single theory - no one has done it, despite the HUGE effort given to this problem for decades. And on the experimental side, nothing has been found that suggests gravity comes in 'bundles' just like something like light comes in bundles of energy we call a photon.                  

Despite the lack of any substantial breakthrough, everyone keeps plugging away, assuming gravity MUST be quantized since the other forces are. In science, putting blinders on while looking to answer the unknown is dangerous. Part of the process of science is to be skeptical, even of things we do know! Check out this article and video about physicist Jonathan Oppenheim from University College of London, who has made the assumption that maybe gravity is not quantized as we all have been thinking - what if it is how Einstein describes it in General Relativity, where it is not a true force but rather just the consequence of curved space-time? 

Prof. Oppenheim and his students are developing a theory, as well as suggestions for experiments, that could test whether gravity is simply different and is a 'classical' force rather than a quantum force. When I teach gravity and Einstein's model, and we get into the modern thinking about quantum gravity, we have over the years asked the question if gravity might not be quantized, and that's why it is so different from the other three forces of nature and why no one has found the unified theory. It is good to see this possibility getting some attention and those isolated few who question the textbooks and group think that can happen in science...scientists are still humans, and fall into the same patterns and traps as everyone else! 

I look forward to seeing where this work goes, as all that matters is we make progress in understanding the true nature of Nature, regardless of whether it fits into our assumptions and expectations or not! 

Quasar clocks - another test of Einstein's GR

 Over 100 years later, and we continuously seem to be testing Einstein's ideas about space, time and gravity over and over, in numerous different contexts. The latest is a test of how the passage of time has changed as the universe has expanded! 

In Einstein's general theory of relativity (GR), he predicts the 'strength' of what we call gravity, which is really the consequence of the warping of space AND time, can change how quickly time passes. For someone living near a black hole, time would be passing very slowly compared to those of us living on earth, simply due to the gravity being MUCH stronger near a black hole compared to earth's gravity. 

Well, when the universe began the mass-energy density (which was really entirely energy until the universe expanded and cooled a bit so that matter could form) was large, and we might expect that time passed more slowly then when compared to the passage of time now, after the universe has expanded for 13.7 billion years and the densities have decreased tremendously. Because quasars are very far away, they 'lived' 12, 13 billion or more years ago, when the universe was young and time should have been running more slowly. By observing and measuring the light emitted from quasars so long ago, scientists have analysis techniques where they can compute how much that light was affected by the early universe compared to now, and the result is time had been running 5 times slower than time today!! These measurements once again are in line with Einstein's predictions from his GR field equations. Remarkable!!

Scientists detect collision of two supermassive black holes

 Astrophysicists and astronomers have detected the strange vibrations in space-time itself, caused by the collision of two supermassive black holes! These are the black holes at the centers of galaxies, with large masses from millions to billions of times more than the Sun. Gravitational wave detectors like LIGO have been sensing these since 2015, but now new techniques were used for the latest discovery. By looking at minute changes in the timing of a sample of pulsars, which are fast-spinning neutron stars that emit periodic, clock-like bursts of radio waves, the distortions of those precise bursts are measured by radio wave detectors, and are consistent with what Einstein's theory of general relativity predict. Amazing, and this constant 'churning' of the space-time sea is now being studied for all sorts of different events and signals! 

Quantum Computing - Want to learn about it? Here's a book and course anyone can take

 Quantum computing is already here in prototype form, and is rapidly evolving into a next generation computing technology, the consequences of which we do not fully understand. But let's also recognize that many companies, universities, national labs, the military, finance and business sectors, medical research and most other fields you can think of, will be in great need of workers who know what this is and how to use it. And the day is also coming where quantum computing and AI become mixed. 

If you are curious about this field and technology, here is an online textbook that is setup as a course in quantum computing. Use it and go at your own pace. Have fun! 

Countries and Institutions with most top Physics personnel

 The productivity and 'success' of scientists can be measured several ways, and perhaps the most popular is looking at the number of publications and citations a scientist has. This makes sense because to be  published in peer reviewed journals shows the work is considered strong, and people cite it when they find it useful, valuable, and well done. Citations mean the work is affecting the field. There is a measure called the D-index based on these criteria.

So you can find the countries and institutions with the most physics personnel with high D-index values. By far, the United States leads for countries, followed by Great Britain. For institutions, Caltech leads the way, and the only non-US institutions in the top ten are the Max Planck Institute and University of Cambridge.

Everyday physics important in real research - Example, don't use magnets to hunt for meteorites!

 What happens when a magnet gets close to an object that may have a weak magnetic field? 

Hopefully any senior who has gone through E&M should be able to answer that the weaker magnet can be affected and changed by a stronger magnet. 

A common way of searching for meteorites is to use magnets, since rocks from space are likely to have some iron in them. But this also means that using a magnet can change any magnetic field the meteorite may have, thus erasing valuable scientific information about the magnetism in our solar system that that rock had carried for perhaps billions of years before finally crashing into the earth. This is a problem for scientists who need meteorites to study and collect information about the ancient solar system! And this is a problem since so many meteorites are found by amateur 'hunters'. 

So basic physics we learn in high school make a difference in real life research efforts! 

                             

April 18, 1955 - the day Einstein died

 April 18, 1955, was the day the world lost one of the greatest minds, certainly scientific, in human history, when Albert Einstein died at the age of 76. 

For an interesting summary of what that day was like, check out this Life article. The below photo is from biography.com. 

How does ChatGPT work?

 ChatGPT and other AI platforms are causing a great deal of excitement, concern, ethical questions to be asked, and lots of interesting applications and concerns. But how does it actually work? 

A decent introductory article about how it works is here, from Stephen Wolfram.

"Where we go to College" Visualizations - Way cool!

 One of the pages I maintain on this blog is Where We Go To College - my former students go all over the place to top colleges and universities, and I want to honor their choices and commitment to learning, growing, and figuring out what they want to do in life. 

There are now some visualizations of that list, thanks to Dr. Liz Durango-Cohen. 

Here's a site for selecting a college and seeing, by graduation year, who has gone there. 

Here's a site with a national map showing how many have gone to each state, and to which colleges in each state. 

Earth's inner core more complex than once thought

 New seismic wave analysis by geophysicists suggest the earth's inner core has multiple layers/shells. The structure and composition of the core is really important for the behavior of the earth's magnetic field, which is vital in protecting us from harmful cosmic radiation. Check out this article for more information if interested.