No Arabic abstract
A century after observing the deflection of light emitted by distant stars during the solar eclipse of 1919, it is interesting to know the concepts emerged from the experiment and the theoretical and observational consequences for modern cosmology and astrophysics. In addition to confirming Einsteins gravitational theory, its greatest legacy was the construction of a new research area to cosmos science dubbed gravitational lensing. The formation and magnification of multiple images (mirages) by the gravitational field of a compact or extended lens are among the most striking phenomena of nature. This article presents a pedagogical view of the first genuine gravitational lens effect, the double quasar QSO 0957 + 561. We also describe the formation of rings, giant arcs, arclets and multiple Supernova images. It is also surprising that the Hubble constant and the amount of dark matter in the Universe can be measured by the same technique. Finally, the lensing of gravitational waves, a possible but still not yet detected effect, is also briefly discussed.
Our proposed experiment aimed to test the validity of the Lorentz factor with two methods: The time of flight (TOF) of various particles at different momenta and the decay rate of pions at different momenta. Due to the high sensitivity required for the second method the results were inconclusive, therefore we report only on the results of the first method.
In this paper, we use a science fiction theme (i.e. the iconic lightsaber from the Star Wars universe) as a pedagogical tool to introduce aspects of nonlinear electrodynamics due to the quantum vacuum to an audience with an undergraduate physics background. In particular, we focus on one major problem with lightsabers that is commonly invoked as an argument to dismiss them as unrealistic: light blades are not solid and thus cannot be used in a duel as normal swords would. Using techniques coming from ultra intense laser science, we show that for high enough laser intensities, two lightsaber blades can `feel solid to each other. We argue that this aspect of lightsabers is not impossible due to limitations of the laws of physics, but is very implausible due to the high intensities and energy needed for their operation.
Newly discovered descriptions about the great aurora observed in March 1582 are presented in this work. These records were made by Portuguese observers from Lisbon. Both records described the aurora like a great fire in the northern part of the sky. It was observed during three consecutive nights, according to one of the sources. Thus, we present a discussion of these auroral records in order to complement other works that studied the aurora sighted in March 1582.
Pyramids are the greatest architectural achievement of ancient civilization, so people all over the world are curious as to the purpose of such huge constructions. No other structure has been studied as thoroughly, nor have so many books and articles been written about it. We created a computer model of the pyramid. To validate the model, we compare our calculations with the experimental data of Luis W. Alvarez. The fact that the Egyptians set up 2.5 million stone blocks without any purpose seems to be unimaginable. Therefore, we attempt to examine the internal structure of the pyramid using muon tomography. With our measurements we performed and verified a calibration of the attenuation of muons for primary beam momenta of 2.5 GeV/c and 3 GeV/c at the T9 experimental area of CERN.
The great conjunction of 21 December 2020 saw Jupiter and Saturn appear together in the sky, separated by just a tenth of a degree (equivalent to a distance five times smaller than the diameter of the full Moon). This provided a potential once-in-a-lifetime opportunity to view the solar systems two biggest planets - and up to five of their moons - through a telescope eyepiece at the same time. Moreover, this was the first such opportunity, ever; previous observable conjunctions at similarly close separations took place before the development of the telescope in the early 1600s. Our team of scientists from the University of Exeters Astrophysics Group and Exeter Science Centre worked with local social enterprises to develop a series of promotional and concurrent events to tie in with our live telescope broadcast of Jupiter and Saturn, to celebrate this spectacular celestial event. We hoped not only to inform and educate the public about great conjunctions, and the solar system more generally, but also to bring some light relief in what had been a rather difficult year.