July 2022 was the month when the iconic James Webb Space Telescope unveiled its first set of magnificent science images, the LHC discovered a set of three exotic hadrons, and researchers found a possible new theory for Earth’s formation. Here is a list of the top five discoveries in the arena of Physics and Astronomy in the previous month.
Webb revealed its first set of scientific images
On July 12, NASA released the first five scientific images captured by James Webb Space Telescope, which have exceeded expectations. The first image released was that of the galaxy cluster SMACS 0723. Showing bright stars in the foreground, a plethora of never seen examples of gravitational lensing, and revealing galaxies as they looked around 4.6 billion years ago, it is so far the deepest and sharpest infrared image of the distant universe ever taken by a telescope.
After the condensed deep field image, NASA revealed a transmission spectrum of an extremely hot gas giant, WASP-96 b, an exoplanet lying almost 1000 light years away. The spectrum containing 141 data points indicated the presence of water vapors in the planet’s atmosphere and also hinted that the planet has an atmospheric temperature of about 725°C.
The next image on the floor was a view of a dying star: the Southern Ring Nebula. And Webb didn’t reveal one but two images of this cosmic beauty, one taken with Near Infrared Camera (NIRCam) and the other with Mid-Infrared Instrument (MIRI). Like all other images taken with Webb, this one also overflew with details as it captured the hidden binary partner at the center of the nebula and highlighted a faraway galaxy seen edge-on in the background.
This was followed by the fourth image representing an enormous mosaic of Stephan’s Quintet, a visual collection of five galaxies captured by NIRCam and MIRI. Although this group is referred to as a quintet, only four galaxies can be seen close together, with the fifth, NGC 7320, lying in the foreground compared with the other four. This image contains over 150 million pixels and is constructed from almost 1,000 separate image files, covering about one-fifth of the Moon’s diameter. This makes it the largest astronomical image captured to date.
And last but not least, the fifth image was Webb’s version of a star-forming region in the Carina nebula. This spectacular image revealing previously invisible areas of stellar nurseries was taken with the joint forces of Webb’s Near-Infrared Camera and Mid Infrared instrument. Carina Nebula is a nearby star-forming region lying in the Milky Way at a distance of 7600 light years from us. This is the sharpest image of the majestic nebula.
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A new theory explains how the Earth formed
For a long time, it has been believed that Earth formed from chondritic asteroids, considered the most primitive meteorites in the solar system. However, Earth’s composition is quite different from the composition of chondrites. The planet has a poor composition of light and volatile elements compared to chondrites. And so far, no mixture of chondrites has been known to explain the exact composition of the Earth.
Although various hypotheses have been put forward to explain this discrepancy over the years, none has been able to explain it to a full extent. But now, simulations have found a new theory behind Earth’s formation, which doesn’t include chondrites but planetesimals. Like chondrites, planetesimals are also small bodies of rock and metal. But, they have a differentiated metallic core and a rocky mantle. Moreover, planetesimals forming in distinct areas around the young Sun or at different times have different chemical compositions.
To check if a random combination of different planetesimals can match the Earth’s composition, researchers ran different simulations where numerous planetesimals collided with one another in the early solar system. The models were designed to correspond to the formation of Mercury, Venus, Earth, and Mars. And as a result, Earth’s composition emerged as the most likely outcome of the simulations, explaining the formation of the Earth in a better manner than chondrites.
The study highlights the importance of dynamics and chemistry in understanding the planetary formation and is expected to provide links to explain the formation of other rocky planets in a better way.
LHC discovers new exotic particles
Adding to the growing list of hadrons, LHCb has discovered three never-seen-before exotic particles. These include a new kind of pentaquark and the first-ever pair of tetraquarks, which further comprises a new type of tetraquark.
The pentaquark in the list was observed while analyzing the decay of negatively charged B mesons. This pentaquark is made up of a charm quark, a charm antiquark, an up, a down, and a strange quark, thereby becoming the first pentaquark found to contain a strange quark. The second kind of particle, the tetraquark, is a doubly electrically charged particle. Carrying a charm quark, a strange antiquark, an up quark and a down antiquark, it is an open-charm tetraquark and was spotted together with its neutral counterpart during a joint analysis of decays of positively charged and neutral B mesons.
While the pentaquark was found with a whopping statistical significance of 15 standard deviations, the doubly charged and the neutral one were found with a statistical significance of 6.5 and 8, all being above the standard five sigma limit required to claim the observation of a particle in particle physics. Finding such particles will help theorists to develop a unified model of exotic hadrons, the exact nature of which is not known yet.
A fast radio burst (FRB) beating like a heart
In another breakthrough in astronomy, researchers detected a mysterious signal from space beating like a heart. The signal involves radio flashes that are 3 seconds long, with high-intensity radiation bursts occurring every 0.2 seconds. Fast radio bursts or FRBs are one of the most exciting puzzles in astronomy. Although they last only for a fraction of seconds, they can release energy equivalent to around 500 million Suns within that short duration.
The first FRB within the Milky Way was discovered in 2020 and was traced back to a magnetar, a highly magnetized neutron star. The newly detected FRB has features in common with magnetar and pulsar emissions. However, the outbursts are millions of times stronger than those obtained from these objects in the Milky Way. And so far, no object in our galaxy has been known to emit radio bursts of this intensity.
Looking at these properties, this signal appears to be coming from some other galaxy, but the exact source is not confirmed yet. Researchers are now hoping to narrow down the source of this never-seen-before FRB, and it is expected to provide some deep insights into how neutron stars and pulsars work.
Fastest moving S star around Sgr A*
Researchers have found the fastest S star known around the Milky Way’s black hole, Sagittarius A*. This star, named S4716, comes as close as 100 AU to the black hole and reaches speeds of around 8,000 kilometers per second, thereby completing its orbit around the black hole in just around four years.
S4716 is part of a dense and tightly packed group of fast-moving stars called the S cluster orbiting close to the galactic center and Sagittarius A*. So far, S2, a star having an orbital period of 16 years around Sgr A*, has been the most famous star of the group. However, S2 behaves like a large person sitting in front of you in a movie theatre , thus blocking the view of things lying behind it. Due to this, it took the team 20 years to refine the analytical techniques and combine them with 20 years of observations to finally confirm the orbital period of S4716.
The discovery is a joint result of data collected by five facilities: the Keck observatory instruments NIR2 and OSIRIS and the Very Large Telescope instruments SINFONI, NACO, and GRAVITY, and it is expected to provide great insights into understanding the evolution of our galaxy, especially its fast-moving central stars.
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