Republican Sen. Ted Cruz of Texas accused TikTok of “pushing pro-Hamas propaganda” Wednesday as the House of Representatives considers legislation that could force the social media app’s Chinese…

By Jake SmithDaily Caller News Foundation The U.S. is sending anti-terrorism forces to Haiti as the nation continues to delve into violence and chaos. Haitian Prime Minister Ariel Henry agreed to resign…

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Gamma-ray telescopes observing neutron star collisions might be the key to identifying the composition of dark matter. One leading theory explaining dark matter it that is mostly made from hypothetical particles called axions. If an axion is created within the intensely energetic environment of two neutron stars merging‚ it should then decay into gamma-ray photons which we could see using space telescopes like Fermi-LAT. About 130 million years ago‚ a pair of neutron stars collided violently. The powerful gravitational waves from the impact radiated outwards at the speed of light‚ followed shortly after by a tremendous flash of radiation. On 17 August 2017‚ the gravitational waves reached Earth‚ and were detected by both detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States‚ and the Virgo interferometer in Italy. This event was named GW170817. Mere seconds later‚ the Fermi-LAT gamma ray telescope recorded a burst of gamma rays in the same region of sky. Over the next few days‚ other telescopes saw and recorded the event in visible light and other wavelengths. This marked the first ever multi-messenger observation of two neutron stars merging. What is an axion? One of the leading theories around the composition of dark matter is that it is mostly made from a hypothetical particle called an axion. If enough axions were created in the big bang‚ and if their masses fall within a specific range‚ then they could account for much of the dark matter shaping the universe today. Unfortunately‚ axions have never been observed‚ and nobody has yet confirmed whether they even exist. But according to Dr Bhupal Dev of Washington State University‚ axions and axion-like particles (ALPs) could be created within the extreme conditions of a neutron star collision‚ and we might be able to see their signature from Earth. An artist’s depiction showing how an ALP (dashed line)‚ after being produced in the NS merger‚ escapes and decays outside the merger environment into photons‚ which can be detected by the Fermi satellite (or future MeV gamma-ray telescopes. Physicists have spent decades trying to solve the mystery of dark matter. It seems likely that it could be made mostly from axions and axion-like particles‚ but these particles are still only hypothetical. The axion was first proposed in 1977‚ as a solution to the Strong CP Problem‚ but has yet to be confirmed. Theory predicts‚ however‚ that axions can be briefly created by passing high-energy photons through a powerful magnetic field. These axions last for a short while‚ then decay back into a pair of gamma-ray photons. A number of experiments are being conducted around the world‚ using this phenomenon to try and create axions‚ and watching for the gamma radiation of their decay. Others‚ like the Axion Dark Matter eXperiment (ADMX) are looking for naturally existing axions by using a similar process to convert them into microwave photons. But there are lots of places in the Universe where axions can be created in this manner‚ including the cores of stars‚ around magnetars‚ and anywhere else with strong magnetic fields. One possible location is the site of a neutron star collision. When such massively dense objects collide‚ they release a tremendous amount of energy‚ some of it in the form of hard electromagnetic radiation and powerful magnetic fields: perfect conditions to create axions! By modelling the energies involved‚ researchers can predict the masses of axions that will be produced. From there they can deduce the specific frequency of gamma ray photons that would be produced when they decay. If we can detect another such merger‚ and spot that specific spectrum of gamma radiation coming from the collision‚ that would confirm that axions are real‚ and provide evidence supporting a major theory about dark matter. Natural particle accelerators One of the H.E.S.S. telescopes in Namabia. Credit: H.E.S.S. An experiment like this would not be the first time scientists have tried to use natural events in place of a particle accelerator. Our own upper atmosphere is one such place where high energy particle collisions happen all the time. Unlike gamma radiation‚ cosmic rays are subatomic particles hurtling through space at relativistic speeds‚ and they from catastrophic events like supernova explosions. When they encounter our atmosphere‚ they smash into air molecules with greater violence than we are able to create in our largest particle accelerators. Telescopes like the High Energy Stereoscopic System (HESS) in Namibia are built to detect these collisions‚ high up in the sky. HESS is a pair of telescopes which focus on the upper atmosphere‚ looking for the characteristic bursts of cherenkov radiation that reveal the cascades of particles generated whenever a cosmic ray smashes into the atmosphere. The observations from GW170817 have already been used by Dr Dev: careful analysis of the gamma rays observed by Fermi-LAT have already helped to narrow the constraints on the properties of axions and axion-like particles. Observations like this‚ combined with the work of earth-bound experiments like ADMX‚ are critical to finding out whether axions exist. And although they haven’t found it yet‚ we still learn something each time an experiment fails to find anything. Each test is tuned for a specific mass‚ so those negative results all work together to narrow the range of possibilities. Hopefully it won’t be long before we have a definitive answer. To learn more‚ visit https://source.wustl.edu/2024/03/finding-new-physics-in-debris-from-colliding-neutron-stars/ The post Colliding Neutron Stars are the Ultimate Particle Accelerators appeared first on Universe Today.

I often drag out the amazing fact that the Andromeda Galaxy‚ that faint fuzzy blob just off the corner of the Square of Pegasus‚ is heading straight for us! Of course I continue to tell people it won’t happen for a few billion years yet but a recent study suggests that we are already seeing hypervelocity stars that have been ejected from Andromeda already. It is just possible that the two galaxies have already started to exchange stars long before they are expected to merge.  We tend to think of stars as stationery objects in the sky‚ except for their slow westward drift across the sky as the Earth rotates. The reality is different though‚ stars do move but due to the vast distances in interstellar space‚ that motion is largely not noticeable. There are exceptions such as Barnard’s star in the constellation Ophiuchus. This inconspicuous red dwarf star moves 10.39 seconds of arc each year (by comparison‚ the full Moon is 1‚900 seconds or arc in diameter.) Another type of star can be observed‚ hypervelocity stars (HVSs)‚ and these are among the fastest objects in the Galaxy. They are defined as stars that have a velocity which is of the order 1‚000 km per second and by comparison‚ the Earth travels through space at a velocity of around 30 km per second! The first was discovered in 2005 but since then a number of HVSs have been found‚ and some of them have the potential to escape from the Milky Way.  Typically the motion of stars is the result of their motion around the centre of a galaxy. Our own star the Sun‚ takes 220 million years to complete one orbit of the centre of the Milky Way. The origin of the HVSs high velocity is believed to stem from gravitational interactions between binary stars and black holes. The idea was proposed by Jack Gilbert Hills is a stellar dynamicist‚ born on 15 May 1943. In this process‚ a black hole (stellar or the supermassive black hole at Galactic centre) captures one of a binary star system while the other gets ejected at high velocity. Other theories include ejection of one of a binary star system when the other goes supernova or from galactic interactions. To understand the interactions between the Milky Way and the Andromeda Galaxy the team (led by Lukas Gülzow from the Institute for Astrophysics in Germany) had to go through painstaking analyses. First they had to understand the relative motion fo the two galaxies‚ they then had to model the gravitational potential of the entire system – this is the total acceleration acting upon an object at any position in either of the galaxies at any time. Finally the team could generate simulations of stellar motion to model the HVSs trajectories.  The study calculated the trajectories of 18 million HVSs for two different scenarios taking into account the two galaxies having equal mass and the other with the Milky Way having about half the mass of the Andromeda Galaxy. The starting positions of the HVSs in the simulation were randomly generated around the centre of Andromeda. The ejection directions were random and the results showed that 0.013 and 0.011 percent of HSVs are now within a radius of 50kpc around the Milky Way centre.  The explored the velocity of HVSs on arrival with both galaxy mass simulations and found that many approximately retain their initial velocity. Interestingly due to the time taken for the journey‚ a significant proportion may well evolve off the main sequence during their journey. Some of the HVSs slow down sufficiently to be captured by the Milky Way. Artist impression of ESA’s Gaia satellite observing the Milky Way (Credit : ESA/ATG medialab; Milky Way: ESA/Gaia/DPAC) The team mapped the simulated position of stars against the sky and ran the data against high velocity star positions from Gaia data (Release 3) and found the simulated position distribution consistent with the Gaia data. The study concludes that it is highly likely that HVSs from Andromeda could indeed migrate to the Milky Way. Whilst they are not expected in their thousands‚ they are expected to distribute equally around the Milky Way centre. It might even be possible to detect them based on stellar velocity and trajectories but further studies are now required to take that next step.  Source : On Stellar Migration from Andromeda to the Milky Way The post Are Andromeda and the Milky Way Already Exchanging Stars? appeared first on Universe Today.

If you‚ like me‚ have dabbled with telescope making you will know what a fickle friend light can be. On one hand you want to capture as much as you can (but only from the object‚ not from nearby lights) and want to reflect or refract it to the point of observation or study.  What you most certainly don’t want is stray light to be bounced around inside the telescope so components (except the mirror!) are sprayed as black as possible. Unfortunately black paints tend to be quite susceptible to damage and struggle to cope with the harsh conditions and cold temperatures telescopes are subjected to. A team has recently developed a new atomic-layer deposition method which absorbs 99.3% of light and is durable too.  A team of scientists from the University of Shanghai for Science and Technology and the Chinese Academy of Sciences have recently published a paper in the Journal of Vacuum Science and Technology. The paper announces that they have engineered an ultrablack thin-film coating which boasts the remarkable light absorption rate of 99.3%. The technique is tailored for coating aerospace grade magnesium alloys (not a lot of help for my telescope but there is hope) and the result is a coating that is durable and capable of withstanding harsh environmental conditions.  Of course‚ this is designed for telescopes operating in the harsh environment of space rather than the cold winter nights of Norfolk in the UK but it will certainly help with professional observatories atop mountains too. Current coatings like vertically aligned carbon nanotubes or black silicon tend to be easily damaged needing repair and leaving contamination that has to be carefully managed.  Another problem is the often difficult and intricate shapes and curves that the black coatings are to be deposited upon. To overcome these problems‚ the team explored atomic layer deposition (ALD). Items to be coated are paced in a vacuum chamber and exposed to different gasses in sequence which will adhere to the object’s surface in thin layers. It’s a technique not too dissimilar to aluminising a telescope mirror that is placed inside a vacuum chamber before allowing the aluminium to be deposited on the mirror surface.  The vacuum coating method is far easier to apply to intricate shapes than previous techniques. To build up the layers‚ the process uses alternating layers of aluminium mixed with titanium carbide and silicon nitride. The two materials work well together to stop nearly all light from reflecting off the coated surface.  During the test phase‚ the team tested wavelengths of light from violet light at 400 nanometers to near infrared at 1‚000 nanometers and found average absorption levels over 99% across all wavelengths. The coating seems to withstand heat‚ friction‚ damp and extreme changes in temperature well so it is most certainly suited to space instrumentation. The team haven’t given up yet though‚ they are now working to improve the performance of the material.  Source : Ultrablack coating could make next-gen telescopes even better The post Ultrablack Coating Could Be Ideal for Telescopes appeared first on Universe Today.

'I a hundred percent am gonna listen to the people back home who I represent in this house,' says rising GOP rep.

Voters in the 2020 battleground state of North Carolina lean toward former Presiden Trump in 2024 by a 5.4 point margin over incumbent President Biden‚ a new poll conducted after Super Tuesday shows. The statewide poll conducted by Cygnal from March 6-7 and published by the Carolina Journal on Tuesday found that 45.2% of likely voters said they are planning to vote for Trump‚ while 39.8% said they plan to vote for Biden. A substantial amount – 9.4% – of likely voters indicated that they plan to...