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Hubble Snaps a Galactic Jellyfish
Mar 24, 2023
The galaxy JW100 (lower right) features prominently in this image from the NASA/ESA Hubble Space Telescope. The streams of star-forming gas dripping from the disk of the galaxy like streaks of fresh paint are formed by a process called ram pressure stripping. Their resemblance to dangling tentacles led astronomers to refer to JW100 as a ‘jellyfish’ galaxy. JW100 is over 800 million light-years away, in the constellation Pegasus.
Ram pressure stripping occurs when galaxies encounter the diffuse gas that pervades galaxy clusters. As galaxies plow through this tenuous gas, it acts like a headwind, stripping gas and dust from the galaxy and creating the trailing streamers that prominently adorn JW100. The bright elliptical patches in the image are other galaxies in the cluster that hosts JW100.
Toward the top of this image are two bright blotches surrounded by a remarkably bright area of diffuse light. This is the core of IC 5338, the brightest galaxy in the galaxy cluster. IC 5338 is an elliptical galaxy with an extended halo, a type of galaxy called a cD galaxy. These galaxies likely grow by consuming smaller galaxies, so it’s not unusual for them to have multiple nuclei since it can take a long time for their cores to be absorbed. The bright points of light studding the galaxy’s outer fringes are a rich population of globular star clusters.
This observation took advantage of Hubble’s Wide Field Camera 3 and its capabilities. The data is part of a sequence of observations designed to explore star formation in the tendrils of jellyfish galaxies. These tendrils represent star formation under extreme conditions and could help astronomers better understand the process of star formation elsewhere in the universe.
https://www.nasa.gov/image-feature/goddard/2023/hubble-snaps-a-galactic-jellyfish
Harvard physicist plans expedition to find ‘alien artefact’ that fell from space
Mar 24 2023
A prominent Harvard physicist is planning a Pacific expedition to find what he thinks might be an alien artefact that smashed into the ocean.
Avi Loeb announced that he is organizing a $1.5m ocean expedition to Papua New Guinea to look for fragments of an object that crashed off the coast of its Manus Island in 2014.
Loeb noticed the object in 2019 and identified it as the first interstellar meteor ever discovered – meaning it originated outside our solar system. According to Loeb, the meteor’s interstellar origin was confirmed to Nasa in April 2022 by the department of defense’s space command.
Loeb and his team also concluded that the meteor was tougher than all other 272 meteors in Nasa’s Center for Near Earth Object Studies catalog.
“Intrigued by this conclusion, I established a team that designed a two-week expedition to search for the meteor fragments at a depth of 1.7km on the ocean floor. Analyzing the composition of the fragments could allow us to determine whether the object is natural or artificial in origin,” Loeb wote in a post on Medium.
“We have a boat. We have a dream team, including some of the most experienced and qualified professionals in ocean expeditions. We have complete design and manufacturing plans for the required sled, magnets, collection nets and mass spectrometer,” he added.
According to Loeb, it is possible that the meteor is tough “because they are artificial in origin … launched a billion years ago from a distant technological civilization.”
The ocean expedition is expected to use a ship with a magnetic sled deployed using a long line winch. The team will consist of seven sled operations, as well as a scientific team.
“We will tow a sled mounted with magnets, cameras and lights on the ocean floor inside of a 10km × 10km search box. A number of sources have been used to narrow the search site to this relatively small search box,” Loeb and his team wrote.
The size of the fragments to be potentially found by Loeb’s team will depend on the composition of the meteor. For an iron meteorite, the physicist predicts about a thousand fragments larger than a millimeter. If the meteor is of stainless-steel composition, Loeb’s team expects to find larger sizes with tens of fragments larger than a centimeter.
Loeb said that in case his team recovers a “sizable technological relic” from the expedition, he promised Paola Antonelli, the curator of the Museum of Modern Art, that he will bring it to New York for display.
The expedition is expected to launch this summer, the Daily Beast reports.
“There is a chance it will fail,” Loeb, who is co-founder of the $1.755m Galileo Project that is tasked with searching for extraterrestrial signs, told the outlet. Nevertheless, he remains adamant about the mission.
“Extraordinary claims require extraordinary evidence,” he said.
https://www.theguardian.com/world/2023/mar/24/harvard-physicist-pacific-expedition-first-interstellar-meteor
https://avi-loeb.medium.com/we-are-going-to-visit-the-first-interstellar-meteor-8cf498d4d6fc