The effects predicted by Einstein’s general relativity on the motion of a star passing through the extreme gravitational field have been validated near the supermassive black hole in the center of the Milky Way.
Obscured by thick clouds of absorbing dust, the closest supermassive black hole to the Earth lies 26 000 light-years away at the centre of the Milky Way. This gravitational monster, which has a mass four million times that of the Sun, is surrounded by a small group of stars orbiting around it at high speed. This extreme environment — the strongest gravitational field in our galaxy — makes it the perfect place to explore gravitational physics, and particularly to test Einstein’s general theory of relativity.
[Eleni Petrakou, Ph.D., is a physicist and an independent researcher, besides being a longtime follower of this blog. She now has a newsletter of her own; it is high S/N stuff - check it out here. After a past collaboration with the CMS experiment, she has recently become intrigued with the dynamics of the Sun, and she developed a model to try and predict the solar cycle, a 11-year variation of the activity of sunspots and solar flares whose origin is still debated. I asked her to describe the matter for this blog, and the text below is the result - TD]
DESCRIBING THE SOLAR CYCLE
Everyone knows that water is a molecule in which a single oxygen atom is linked to two hydrogen atoms - H20.
But the story of water gets a lot more scientifically interesting the deeper you go. Water actually exists in two different forms, called isomers, at the molecular level.
They have almost identical physical properties, you can't tell the difference, but chemists can tell them apart by the relative orientation of the nuclear spins of the two hydrogen atoms. They are called ortho-
depending on whether the spins are aligned in the same or opposite direction.
If you want to know how to do time travel, ask a mathematician. If you want to show how math is not science, but is instead the language of science, hand those equations to a physicist.
What is spectroscopy ?
(A) the observation of ghosts by infrared visors or other optical devices
(B) the study of excited states of matter through observation of energy emissions
If you answered (A), you are probably using a lousy internet search engine; and btw, you are rather dumb. Ghosts do not exist.
Otherwise you are welcome to read on. We are, in fact, about to discuss a cutting-edge spectroscopy measurement
, performed by the CMS experiment using lots of proton-proton collisions by the CERN Large Hadron Collider (LHC).
The ICHEP conference opened today in Seoul. This is the most well-attended conference in particle physics around, with usually over 1000 participants.
The week-long event dictates the deadline of particle physics and astrophysics experiments around, as every collaboration wants to show updated results of their searches and measurements in that venue, to have a share of the spotlights. This means that you can bet the month of June was a hectic one for ATLAS and CMS collaborators alike (but also those of LHCb and ALICE, just to mention the main four CERN endeavours).
Happy Birthday Higgs boson! The discovery of the last fundamental particle of the Standard Model was announced exactly 6 years ago at CERN (well, plus one day, since I decided to postpone to July 5 the publication of this post...).
In the Standard Model, the theory of fundamental interactions among elementary particles which enshrines our current understanding of the subnuclear world, particles that constitute matter are fermionic: they have a haif-integer value of a quantity we call spin; and particles that mediate interactions between those fermions, keeping them together and governing their behaviour, are bosonic: they have an integer value of spin.
1. Imitation or enactment
2. The act or process of pretending; feigning.
3. An assumption or imitation of a particular appearance or form; counterfeit; sham.
Well, high-energy physics is all about simulations.
We have a theoretical model that predicts the outcome of the very energetic particle collisions we create in the core of our giant detectors, but we only have approximate descriptions of the inputs to the theoretical model, so we need simulations.
Neutrinos, the most mysterious and fascinating of all elementary particles, continue to puzzle physicists. 20 years after the experimental verification of a long-debated effect whereby the three neutrino species can "oscillate", changing their nature by turning one into the other as they propagate in vacuum and in matter, the jury is still out to decide what really is the matter with them. And a new result
by the MiniBoone collaboration is stirring waters once more.
Living in Padova has its merits. I moved here since January 1st and am enjoying every bit of it. I used to live in Venice, my home town, and commute with Padova during weekdays, but a number of factors led me to decide on this move (not last the fact that I could afford to buy a spacious place close to my office in Padova, while in Venice I was confined to a rented apartment).