General Relativity Einstein/Essen Anniversary Test
Posted on June 25, 2009 2 Comments
Project GREAT: General Relativity Einstein/Essen Anniversary Test is not your average home experiment but it is another great example of experiments people run at home.
By keeping the clocks at altitude for a weekend we were able to detect and measure the effects of relativistic time dilation compared to atomic clocks we left at home. The amazing thing is that the experiment worked! The predicted and measured effect was just over 20 nanoseconds.
But the time dilation was somewhere in the 20 to 30 ns range. The number we expected was 23 ns so I’m very pleased with the result.
Scientific Inquiry Process Finds More Evidence Supporting Einstein’s Theory
Posted on May 29, 2012 No Comments
As scientists have been able to see farther and deeper into the universe, the laws that govern its expansion have been revealed to be under the influence of an unexplained force.
In a paper on the arXiv, Astrophysical Tests of Modified Gravity: Constraints from Distance Indicators in the Nearby Universe, are a vindication of Einstein’s theory of gravity. Having survived several decades of tests in the solar system, it has passed this new test in galaxies beyond our own as well.
In 1998, astrophysicists made an observation that turned gravity on its ear: the universe’s rate of expansion is speeding up. If gravity acts the same everywhere, stars and galaxies propelled outward by the Big Bang should continuously slow down, like objects thrown from an explosion do here on Earth.
This observation used distant supernovae to show that the expansion of the universe was speeding up rather than slowing down. This indicated that something was missing from physicists’ understanding of how the universe responds to gravity, which is described by Einstein’s theory of general relativity. Two branches of theories have sprung up, each trying to fill its gaps in a different way.
One branch — dark energy — suggests that the vacuum of space has an energy associated with it and that energy causes the observed acceleration. The other falls under the umbrella of “scalar-tensor” gravity theories, which effectively posits a fifth force (beyond gravity, electromagnetism and the strong and weak nuclear forces) that alters gravity on cosmologically large scales.
“These two possibilities are both radical in their own way,” University of Pennsylvania astrophysicist Bhuvnesh Jain said. “One is saying that general relativity is correct, but we have this strange new form of energy. The other is saying we don’t have a new form of energy, but gravity is not described by general relativity everywhere.”
Jain’s research is focused on the latter possibility; he is attempting to characterize the properties of this fifth force that disrupts the predictions general relativity makes outside our own galaxy, on cosmic length scales. Jain’s recent breakthrough came about when he and his colleagues realized they could use the troves of data on a special property of a common type of star as an exquisite test of gravity.
A Possible Explanation for the Faster Than Light Result Anomaly
Posted on October 14, 2011 2 Comments
So from the point of view of a clock on board a GPS satellite, the positions of the neutrino source and detector are changing. “From the perspective of the clock, the detector is moving towards the source and consequently the distance travelled by the particles as observed from the clock is shorter,” says van Elburg.
By this he means shorter than the distance measured in the reference frame on the ground.
The OPERA team overlooks this because it thinks of the clocks as on the ground not in orbit.
How big is this effect? Van Elburg calculates that it should cause the neutrinos to arrive 32 nanoseconds early. But this must be doubled because the same error occurs at each end of the experiment. So the total correction is 64 nanoseconds, almost exactly what the OPERA team observes.
It is great to see the scientific process at work. Those is support of the scientific method support open access science and this explanation is available via arxiv: Times Of Flight Between A Source And A Detector Observed From A GPS Satellite.
Faster Than Light Speed Anomaly Reported by CERN
Posted on September 23, 2011 1 Comment
The OPERA result is based on the observation of over 15000 neutrino events measured at Gran Sasso, and appears to indicate that the neutrinos travel at a velocity 20 parts per million above the speed of light, nature’s cosmic speed limit. Given the potential far-reaching consequences of such a result, independent measurements are needed before the effect can either be refuted or firmly established. This is why the OPERA collaboration has decided to open the result to broader scrutiny. The collaboration’s result is available on the preprint server arxiv.org.
The OPERA measurement is at odds with well-established laws of nature, though science frequently progresses by overthrowing the established paradigms. For this reason, many searches have been made for deviations from Einstein’s theory of relativity, so far not finding any such evidence. The strong constraints arising from these observations makes an interpretation of the OPERA measurement in terms of modification of Einstein’s theory unlikely, and give further strong reason to seek new independent measurements.
“This result comes as a complete surprise,” said OPERA spokesperson, Antonio Ereditato of the University of Bern. “After many months of studies and cross checks we have not found any instrumental effect that could explain the result of the measurement. While OPERA researchers will continue their studies, we are also looking forward to independent measurements to fully assess the nature of this observation.”
“When an experiment finds an apparently unbelievable result and can find no artefact of the measurement to account for it, it’s normal procedure to invite broader scrutiny, and this is exactly what the OPERA collaboration is doing, it’s good scientific practice,” said CERN Research Director Sergio Bertolucci. “If this measurement is confirmed, it might change our view of physics, but we need to be sure that there are no other, more mundane, explanations. That will require independent measurements.” This is a great reminder of the proper application of the scientific inquiry process. Our understanding moves forward based on evidence and incredible results require a high burden of proof before we accept them.
In order to perform this study, the OPERA Collaboration teamed up with experts in metrology from CERN and other institutions to perform a series of high precision measurements of the distance between the source and the detector, and of the neutrinos’ time of flight. The distance between the origin of the neutrino beam and OPERA was measured with an uncertainty of 20 cm over the 730 km travel path. The neutrinos’ time of flight was determined with an accuracy of less than 10 nanoseconds by using sophisticated instruments including advanced GPS systems and atomic clocks. The time response of all elements of the CNGS beam line and of the OPERA detector has also been measured with great precision.
“We have established synchronization between CERN and Gran Sasso that gives us nanosecond accuracy, and we’ve measured the distance between the two sites to 20 centimetres,” said Dario Autiero, the CNRS researcher who will give this afternoon’s seminar. “Although our measurements have low systematic uncertainty and high statistical accuracy, and we place great confidence in our results, we’re looking forward to comparing them with those from other experiments.”
“The potential impact on science is too large to draw immediate conclusions or attempt physics interpretations. My first reaction is that the neutrino is still surprising us with its mysteries.” said Ereditato. “Today’s seminar is intended to invite scrutiny from the broader particle physics community.”
The OPERA experiment was inaugurated in 2006, with the main goal of studying the rare transformation (oscillation) of muon neutrinos into tau neutrinos. One first such event was observed in 2010, proving the unique ability of the experiment in the detection of the elusive signal of tau neutrinos.
This is great stuff, wether it turns out to be an amazing result that changes our understanding of physics or even if it doesn’t (if it turns out the apparent result is not what it seems). It is great to see us attempt to learn. My guess is that we find some explanation for the anomaly that does avoids something traveling faster than the speed of light.
Brian Cox on the BBC 6: “This is the way science works, we go away and do it again and check, and then do it again and check. If it is confirmed then it will be the most significant discovery in physics in the last, at least, 100 years.”
Related: full press release – The Sun is a Miasma of Incandescent Plasma – Gravity and the Scientific Method – More Mysterious Space Phenomenon – Neutrino particle traveling faster than light? Two ways it could rewrite physics
Quantum Information Theory Postulated As Source of Emergent Theory of Gravity
Posted on August 15, 2011 No Comments
I love the advances we have made using our understanding of science and engineering, like the internet, air conditioning and antibiotics. I also love the discussion of research where we really have only educated guesses about what the scientific inquiry process is telling us about the way things are. This research from the University of York is very interesting.
Dr Patra adds: “We cannot claim to have proven that escape from a black hole is truly possible, but that is the most straight-forward interpretation of our results. Indeed, our results suggest that quantum information theory will play a key role in a future theory combining quantum mechanics and gravity.”
It is too bad the University of York supports closed science and allows work to be withheld from the public to support outdated publishers business models. Luckily scientists often support open science and publish material openly – I have provided a link for those interested in science instead of the link the University of York gives to a publishers closed system.
Ten Things Everyone Should Know About Science
Posted on March 20, 2011 3 Comments
As the writer of this blog (which is located at engineering.curiouscatblog.net) I am a strong believer in the importance of scientific literacy. Neil Degrasse Tyson stated the importance very well, as I mentioned in a previous post, the scientifically literate see a different world
The Financial Times has complied a list of the 10 things everyone should know about science
- Evolution – previous posts: Evolution is Fundamental to Science – posts tagged: evolution
- Genes and DNA – tags: genes – genetics – DNA – RNA
- Big bang – tags: physics, posts mentioning big bang
- Relativity – General Relativity Einstein/Essen Anniversary Test – posts mentioning relativity
- Quantum mechanics – Quantum Mechanics Made Relatively Simple Podcasts, Quantum mechanics
- Atoms and nuclear reactions
- Molecules and chemical reactions – posts on chemistry
- Digital data – I must admit, even reading their comments, I don’t understand what they are thinking here. There certainly is a great deal of digital data and the future certainly going to involve a great deal more, but this just doesn’t fit, in my opinion.
- Statistical significance – Seeing Patterns Where None Exists, Statistics Insights for Scientists and Engineers, Correlation is Not Causation post on statistics – experimentation
It is a challenge to create such a list. I agree with most of what they have. I would like to look at changing the last 2 and radiation, though. I would probably include something about the scientific method rather than statistical significance. Another area I would consider is something about bacteria and/or viruses. You can maybe include them under genes, but viruses and bacteria are amazing in the very strange things they do with genes and I think that is worthy of its own item. Another possibility is thinking of separating out a second spot for things related to the scientific method – causation, randomized testing, multivariate experiments… I would also consider one, or more of the following or something related to them biology – chlorophyll, the the life of bacteria in our bodies, something related to human health (how drugs work, medical studies…), etc..
An important feature of Darwinian evolution is that it operates at the level of the individual. There is no mechanism for natural selection to change the species as a whole, other than through the accumulation of changes that lead to the survival of the fittest individuals.
The rate of evolution varies enormously between different types of organism and different environmental circumstances. It can proceed very quickly when the pressure is great, as, for example, with bacteria exposed to antibiotics, when drug-resistant mutations may arise and spread through the bacterial population within months.
Why does it matter? Evolution is coming under renewed assault, particularly in the US, from fundamentalist Christians who want creationism to be taught in schools. Although evolution has had virtually unanimous support from professional scientists for at least a century, polls show that American public opinion still favours creationism.
Big Bangless and Endless Universe
Posted on July 29, 2010 1 Comment
A new the theory does away with the big bang and dark energy by having space, time and energy and no beginning and no ending.
Shu’s idea is that time and space are not independent entities but can be converted back and forth between each other. In his formulation of the geometry of spacetime, the speed of light is simply the conversion factor between the two. Similarly, mass and length are interchangeable in a relationship in which the conversion factor depends on both the gravitational constant G and the speed of light, neither of which need be constant.
So as the Universe expands, mass and time are converted to length and space and vice versa as it contracts. This universe has no beginning or end, just alternating periods of expansion and contraction. In fact, Shu shows that singularities cannot exist in this cosmos.
It’s easy to dismiss this idea as just another amusing and unrealistic model dreamed up by those whacky comsologists.
That is until you look at the predictions it makes. During a period of expansion, an observer in this universe would see an odd kind of change in the red-shift of bright objects such as Type-I supernovas, as they accelerate away. It turns out, says Shu, that his data exactly matches the observations that astronomers have made on Earth.
That’s not to say Shu’s theory is perfect. Far from it. One of the biggest problems he faces is explaining the existence and structure of the cosmic microwave background, something that many astrophysicists believe to be the the strongest evidence that the Big Bang really did happen. The CMB, they say, is the echo of the Big bang.
How it might arise in Shu’s cosmology isn’t yet clear but I imagine he’s working on it.
Science is useful in letting us understand the world better. But it also is an evolving understanding as we learn more and search for answers to more questions. Many attempts to put forth new ideas and have them gain acceptance are made. Most fail to gain traction. But even many of the ideas that are not accepted are interesting.
Read Cosmological Models with No Big Bang by Wun-Yi Shu (on the wonderful open access arXiv).
Gravity Emerges from Quantum Information, Say Physicists
Posted on April 1, 2010 1 Comment
perhaps the most powerful idea to emerge from Verlinde’s approach is that gravity is essentially a phenomenon of information.
Over recent years many results in quantum mechanics have pointed to the increasingly important role that information appears to play in the Universe. Some physicists are convinced that the properties of information do not come from the behaviour of information carriers such as photons and electrons but the other way round. They think that information itself is the ghostly bedrock on which our universe is built.
Gravity has always been a fly in this ointment. But the growing realisation that information plays a fundamental role here too, could open the way to the kind of unification between the quantum mechanics and relativity that physicists have dreamed of.
This speculative physics is fascinating. Open access paper: Gravity from Quantum Information.
Experimenting Social Network
Posted on August 29, 2009 No Comments
Social media is definitely a fad filled with lots of ways to waste time. It also does have real value, ways to connect to things people care about and wish to focus on. Reddit is a good site for finding interesting resources online. Sub-reddits are topical areas within Reddit (I have set up management and investing sub-reddits). A new experiment subreddit looks very interesting:
Don’t research ways other people have experimentally determined these things. Submit original ideas to the experimental design thread. Try to come up with a novel way to discover things, but don’t be completely limited by this suggestion. This is chiefly about rediscovery, not repeating someone else’s experiment, but sometimes there’s fun and merit in that as well.
I have joined. You can go to Reddit and join this subreddit to see experiences with experimenting to learn about the world around us.
Related: posts about experimenting – General Relativity Einstein/Essen Anniversary Test – Curious Cat StumbleUpon – Home Experiment: Deriving the Gravitational Constant – Dell, Reddit and Customer Focus – Joel Spolsky Webcast on Creating Social Web Resources – Encyclopedia of Life, social science – John Hunter Online
Home Experiment: Tape Makes Frosted Glass Clear
Posted on July 22, 2009 No Comments
Interesting result. A comment on Reddit seems plausible to me:
Additional experimenting could include, what the view is like from the other side of the glass. What the view is like if you also put tape on the other side of the glass.
Before the Big Bang
Posted on December 16, 2008 1 Comment
LQC is in fact the first tangible application of another theory called loop quantum gravity, which cunningly combines Einstein’s theory of gravity with quantum mechanics. We need theories like this to work out what happens when microscopic volumes experience an extreme gravitational force, as happened near the big bang, for example.
If LQC turns out to be right, our universe emerged from a pre-existing universe that had been expanding before contracting due to gravity. As all the matter squeezed into a microscopic volume, this universe approached the so-called Planck density, 5.1 × 1096 kilograms per cubic metre. At this stage, it stopped contracting and rebounded, giving us our universe.
In classical cosmology, a phenomenon called inflation caused the universe to expand at incredible speed in the first fractions of a second after the big bang. This inflationary phase is needed to explain why the temperature of faraway regions of the universe is almost identical, even though heat should not have had time to spread that far – the so-called horizon problem. It also explains why the universe is so finely balanced between expanding forever and contracting eventually under gravity – the flatness problem. Cosmologists invoke a particle called the inflaton to make inflation happen, but precious little is known about it.