A rocket carrying satellites explodes from China's commercial aerospace zone
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The small quantum satellite created a secure link between China and South African terrestrial stations, sharing quantum encrypted data over a record distance of 12,900 kilometers. Similar microsatellites could become part of the quantum internet of things in the future.
The record-breaking feat that took place in October 2024 was also notable for the use of satellites with small, light payloads. The miniaturized equipment on the Jinan-1 microsatellite weighed only 23 kilograms, about 10 times the payload of previous experiments.
Petite quantum satellites like Jinan-1 say “like what SpareX does with StarLink for the Internet, it could launch many satellites in one shot with the same space launcher.” Laurent de Forge de Panney at Thales Alenia Space, a space technology company headquartered in France.
In this experiment, the researchers used the quantum state of photons to generate a secret key for encrypting and decrypting the data. This key was used to encode photographs of the Great Wall in China and Stellenbosch University in South Africa, and was then transmitted between the Zinan-1 satellite and various ground stations using lasers and telescopes. Research team led by Jianwei Pan The University of Science and Technology in China has performed this quantum key distribution process 20 times, including a test of 12,900 km set record.
There are limits to this showcase of quantum technology. Jinan-1 satellites “apparently optimized for quantum key distributions and do not perform common quantum communication tasks such as teleportation or entanglement distributions.” Alexander Lynn At the National University of Singapore. Nevertheless, Lynn, who praises the demonstration, says it could become part of the actual communications network within the next decade.
Quantum Key Distribution can be “are considered the first practical quantum communication use case,” and “the first step into a quantum information network,” says De Forges de Parny. “China's activities will definitely help develop a second-generation small satellite for the quantum internet,” he says.
The Jinan-1 was originally launched in 2022, and PAN says China will send two or three more quantum satellites in 2025. Other countries are expecting to release their own quantum satellites by 2026. projectfunded by the European Space Agency. Boeing, a US aerospace company, is working on it Another.
New observations by NASA/ESA/CSA’s James Webb Space Telescope confirm previous measurements by the NASA/ESA Hubble Space Telescope of the distances between nearby stars and galaxies, and confirm measurements of the universe’s mysterious expansion. Provide critical cross-checking to address discrepancies. This contradiction, known as the Hubble tension, remains unexplained by even the best cosmological models.
This artist’s impression shows the evolution of the universe, starting with the Big Bang on the left and continuing with the emergence of the Cosmic Microwave Background. The formation of the first stars ends the Dark Ages of the universe, followed by the formation of galaxies. Image credit: M. Weiss / Harvard-Smithsonian Center for Astrophysics.
“The discrepancy between the observed rate of expansion of the universe and the predictions of the Standard Model suggests that our understanding of the universe may be incomplete,” said Nobel laureate and Johns Hopkins University professor Adam Riess. “There is,” he said.
“Now that NASA’s two flagship telescopes are confirming each other’s discoveries, we must take this issue very seriously. It’s a challenge, but it’s a It’s also a great opportunity to learn more.”
The new research builds on Professor Rees’ Nobel Prize-winning discovery that the expansion of the universe is being accelerated by a mysterious dark energy that permeates the vast expanses of space between stars and galaxies.
The authors used the largest sample of Webb data collected during the first two years of the universe to test the Hubble telescope’s measure of the rate of expansion of the universe, a number known as the Hubble constant.
They used three different methods to measure the distance to the galaxy where the supernova occurred, using a method previously measured by the Hubble telescope and known to provide the most accurate “local” measurement of this number. We focused on the distance that is being
Observations from both telescopes were in close agreement, revealing that Hubble’s measurements were accurate and eliminating inaccuracies large enough to attribute the tension to Hubble’s errors.
Still, the Hubble constant remains a mystery. This is because measurements based on current telescopic observations of the universe produce higher values compared to projections made using the standard model of cosmology. The Standard Model is a widely accepted framework for how the universe works, calibrated with cosmic microwave background data. Weak radiation left over from the Big Bang.
The Standard Model Hubble constant is approximately 67-68 km/sec per megaparsec, but measurements based on telescope observations typically yield higher values of 70-76, with an average of 73 km/sec/megaparsec.
This discrepancy has puzzled cosmologists for more than a decade. A difference of 5 to 6 kilometers per second per megaparsec is too large to be explained solely by deficiencies in measurement and observation technology.
Webb’s new data eliminates significant bias in Hubble’s measurements, so the Hubble tension could be due to unknown factors or gaps in cosmologists’ understanding of physics that have yet to be discovered.
“Webb’s data represent the first high-definition view of the universe, greatly improving the signal-to-noise ratio of the measurements,” said Xiang Li, a graduate student at Johns Hopkins University. .
This image, taken with the Nicholas U. Mayall 4-meter telescope, shows the spiral galaxy Messier 106. Two dwarf galaxies (NGC 4248 in the lower right and UGC 7356 in the lower left) also appear in the image. Image credits: KPNO / NOIRLab / NSF / AURA / New Mexico State University MT Patterson / University of Alaska Anchorage TA Chancellor / M. Zamani & D. de Martin.
The astronomers used the known distance to the spiral galaxy Messier 106 (also known as M106 or NGC 4258) as a reference point to cover roughly one-third of Hubble’s total galaxy sample.
Despite the small dataset, they achieved impressive accuracy, showing less than 2% difference between measurements. This is much smaller than the approximately 8-9% size of the Hubble tension mismatch.
In addition to analyzing pulsating stars called Cepheid variable stars, the gold standard for measuring distances in the universe, they cross-checked measurements based on the brightest red giant stars in the same galaxy as carbon-rich stars. .
All galaxies observed by Webb with supernovae yielded a Hubble constant of 72.6 km per second per megaparsec. This is about the same as the 72.8 km per second per megaparsec that Hubble found for the very same galaxy.
“One possible explanation for the Hubble tension is that something was missing in our understanding of the early universe, such as a new component of matter that unexpectedly bombarded the universe after the Big Bang, nascent dark energy. I guess so,” Johns said. Mark Kamionkowski, a cosmologist at Hopkins University, was not involved in the study.
“And there are other ideas that might do the trick, like interesting dark matter properties, exotic particles, changing electron masses, or primordial magnetic fields. Theorists have a right to be pretty creative. It is.”
A fast radio burst phenomenon called FRB 20220610A flashed in an unlikely location: a collection of at least seven galaxies that existed when the universe was only 5 billion years old. Most fast radio bursts to date have been found in isolated galaxies.
This Hubble image shows the host galaxy of the extremely powerful fast radio burst FRB 20220610A. Image credit: NASA/ESA/STScI/Alexa Gordon, Northwestern University.
FRB 20220610A was first detected by the Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope in Western Australia on June 10, 2022.
ESO's Very Large Telescope confirmed that the FRB came from a distant place. The Fed was four times more energetic than its closer counterpart.
“We needed Hubble's acuity and sensitivity to pinpoint the source of the FRB,” said Northwestern University astronomer Alexa Gordon.
“Without Hubble's images, it will remain a mystery whether this arose from a monolithic galaxy or some kind of interacting system.”
“It's these kinds of environments, these strange environments, that are driving us to a deeper understanding of the Fed's mysteries.”
Hubble's sharp images suggest that FRB 20220610A arose in an environment where up to seven galaxies could be on a potential path to a merger, which is also very significant.
“We're ultimately trying to answer the question: What causes this? What are their ancestry and their origin?” said Wen-Fai Fung, an astronomer at Northwestern University. Ta.
“Hubble observations provide an incredible view of the surprising types of environments that give rise to these mysterious events.”
Although hundreds of FRBs have been detected, their ancestry is unknown. One of the leading candidates is magnetars.
They have magnetic fields so strong that if a magnetar were to be located halfway between the Earth and the Moon, it would erase the magnetic stripes on everyone's credit cards around the world.
Even worse, if the astronaut traveled within a few hundred miles of the magnetar, they would effectively be dissolved, as every atom in their body would be destroyed.
Possible mechanisms include some kind of shocking starquake, or an explosion triggered when the magnetar's twisted magnetic field lines break and recombine.
A similar phenomenon occurs on the Sun, causing solar flares, but the magnetar's magnetic field is a trillion times more powerful than the Sun's magnetosphere.
This snap can cause a flash of the FRB or create a shock wave that incinerates the surrounding dust and heats the gas to create a plasma.
There can be several types of magnetars. In some cases, it could be an explosive object orbiting a black hole surrounded by a disk of matter.
Another option is a pair of orbiting neutron stars whose magnetospheres interact periodically to create cavities in which eruptions can occur.
Magnetars are estimated to be active for about 10,000 years before becoming permanent, and are expected to be discovered in areas where violent storms of star formation occur. However, this does not seem to be the case for all magnetars.
In the near future, the sensitivity of FRB experiments will improve and FRBs will be detected at unprecedented rates at these distances.
“We need to continue to find more of these FRBs in different types of environments, both near and far,” Dr. Gordon said.
Astronomers announced that findings in AAS243243rd Meeting of the American Astronomical Society, New Orleans, Louisiana, USA.
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alexa gordon other. 2024. Revealing the environment of the most distant FRB with the Hubble Space Telescope. AAS243summary #3679
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