Astronomers Observe Blobs of Dark Matter Down to a Scale of 30,000 Light-Years Across
Dark matter remains mysterious and… well… dark. While we don’t yet have a definite idea of what this cosmic “stuff” is made of, astronomers are learning more about its distribution throughout the Universe. Since we can’t see it directly, observers need to use indirect methods to detect it. One way is through gravitational lensing. Another is by looking for emissions from hydrogen gas associated with small-scale dark matter structures in the Universe.
A group of astronomers led by Kaiki Taro Inoue of Kindai University in Japan used the Atacama Large Millimeter Array in Chile to study a distant gravitational lens system called MG J0414+534. A massive foreground galaxy is bending and distorting the light from a distant quasar that lies some 11 billion light-years away. The result is four images of the quasar. When they looked at the data, the team found some strange anomalies in the images. They are actually variations in the distribution of dark matter along the line of sight between us and the quasar. The gravitational lens magnified the fluctuations and analysis of the data allowed them to map the fluctuations down to a scale of 30,000 light-years.
A conceptual diagram of the gravitational lens system MG J0414+0534. Dark matter associated with the lensing galaxy shows in pale blue and white. Dark matter in intergalactic space shows in orange. Solid lines show the actual paths of the radio waves which are bent by gravity. Dotted lines show the apparent observed positions of the lensed images. (Credit: NAOJ, K. T. Inoue)
What The Blobs of Dark Matter Mean
Throughout the universe, dark matter is associated with massive galaxies and galaxy clusters. However, small-scale clumps and distributions aren’t as well understood. So, astronomers want to find ways to map the smaller concentrations of it. Gravitational lensing provides one way to do that. In the case of MG J0414+0534, the positions and shapes of the lensed quasar images look a little strange. They don’t fit the model of gravitational lensing predicted when you plug in the numbers for the galaxy and its associated dark matter component.
The fluctuations indicate that there’s a gravitational lensing effect from the smaller concentrations, in addition to that of the galaxy and its dark matter shell. In this case, there are spatial fluctuations in the density of dark matter down to a size of about 30,000 light-years. That’s way smaller than what the scientists term the “cosmological scale” for larger concentrations (several tens of billions of light-years).
Interestingly, the team’s work shows that such smaller concentrations work with predictions made about cold dark matter (CDM). Essentially, it says that dark matter clumps exist within galaxies, but also can populate intergalactic space. The gravitational lensing effects due to the clumps of dark matter found in this study are so small that it is extremely difficult to detect them alone. That’s why the team used ALMA to detect the fluctuations. It can provide very high-resolution radio observations of fluctuations caused by the smaller concentrations of dark matter.
Starless Dark Matter Halo in the Local Universe?
Astronomers used a giant radio telescope, the Five-Hundred-Aperture Spherical Radio Telescope (FAST) in China to look at another interesting dark matter-related object that lies near the galaxy M94. The system, which they call “Cloud-9, is a source of 21-centimeter radio emissions from cold neutral interstellar hydrogen. Interestingly, Cloud-9 appears to be relatively starless. So, astronomers using FAST wondered if this 21-cm emission from the cloud could function as a tracer of dark matter. In a preprint paper, they describe Cloud-9 as being very similar to something called a
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Iran Sent a Capsule Capable of Holding Animals into Orbit.
Despite popular opinion, the first animals in space were not dogs or chimps, they were fruit flies launched by the United States in February 1947. The Soviet Union launched Laika, the first dog into space in November 1957 and now, it seems Iran is getting in on the act. A 500kg capsule known as the “indigenous bio-capsule” with life support capability was recently launched atop the Iranian “Salman” rocket. It has been reported by some agencies that there were animals on board but no official statement has been released.
The Iranian Space Agency (ISA) are gearing up to getting humans into space before 2029 but is testing its launch capability with animal passengers. The capsule was launched on December 6 2023 and attained an orbital altitude of 130 kilometres. According to their Telecommunications Minister Isa Zarepour, it is aimed at sending Iranian astronauts to space by 2029.
The “Salaman” solid-fuelled rocket was designed by the aerospace division of the Ministry of Science, Research and Technology and built and launched by the Ministry of Defence and Armed Forces Logistics. It has already been used to launch a data collecting satellite and in 2013 successfully sent and returned monkeys into space.
Ham, a chimpanzee, became the first great ape in space during his January 31, 1961, suborbital flight aboard Mercury-Redstone 2 (Credit : NASA)
To date, only three counties have human spaceflight capability; USA, Russia and China. India are attempting to become the fourth as they work on their Gaganyaan program. Will Iran become the fifth!? Iran plans further tests with further launches bearing animal occupants before attempting to send humans up.
According to the Iranian Space Agency, its satellite program is purely for scientific research and other civilian applications. There is however, international suspicion because there are suspicions that the Salamn rockets could very easily be converted to long range missiles.
Source : Iran says it sent a capsule capable of carrying animals into orbit as it prepares for human missions
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What Could a Next Generation Event Horizon Telescope Do?
Telescopes have come a long way in a little over four hundred years! It was 1608 that Dutch spectacle maker Hans Lippershey who was said to be working with a case of myopia and, in working with lenses discovered the magnifying powers if arranged in certain configurations. Now, centuries on and we have many different telescope designs and even telescopes in orbit but none are more incredible than the Event Horizon Telescope (EHT). Images las year revealed the supermassive black hole at the centre of our Galaxy and around M87 but now a team of astronomers have explored the potential of an even more powerful system the Next Generation EHT (ngEHT).
There is no doubt that our understanding of the processes within our Universe have come on leaps and bounds since the invention of the telescope. The resolution of these space piercing instruments is dictated by the telescope’s aperture. The technique known as interferometry hooks individual telescopes together and combines their signal so they act as one BIG telescope, boosting the resolution.
Telescopes like the EHT have been using interferometry to great advantage to study black holes. These enigmatic and mysterious stellar corpses defy our probing; we do not fully understand their origins and processes and indeed our laws of physics break down if you get too close to the point source in the centre, the singularity. Due to their interaction with space and time, understanding the full nature of black holes will – hopefully – unlock our understanding of the Universe.
Previously, observations have only revealed the movement of stars around galactic centre suggesting an object was lurking there weighing in at around 4 million times the mass of the Sun. Data from the EHT collected during 2022, finally revealed an image of the object at the centre – SgrA* – a super massive black hole and the matter in the immediate vicinity of the event horizon. Whilst this image did not reveal the black hole itself – another article required to explain that – it certainly revealed the telltale signs.
Sag A* compared to M87* and the orbit of Mercury. Credit: EHT collaboration
A recently published paper explores the possibilities of the ngEHT and how they might be able to unpick some of the physics around black holes. The ngEHT will increase the geographical footprint of EHT by 10 further instruments that span across the Earth. Making use of the significant improvement in resolution, the ngEHT will also improve image dynamics range, provide a multi-wavelength capability and facilitate long term monitoring.
The team conclude that future enhancements in measurement sensitivity and data analysis techniques in ngEHT will substantially advance our understanding of black holes and the immediate environments surrounding them with particular focus on the photon ring, mass and spin analysis, binary supermassive black holes and more besides.
Source : Fundamental Physics Opportunities with the Next-Generation Event Horizon Telescope
The post What Could a Next Generation Event Horizon Telescope Do? appeared first on Universe Today.
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Déjà vu All Over Again: Backpacking in Glacier National Park
By Michael Lanza
In the second week of September, the cool air in the shade of the forest nips at our cheeks as we leave our first night’s camp beside Glenns Lake in the backcountry of Glacier National Park, starting at a reasonably early hour for a day where we will walk nearly 16 miles and 6,000 feet of combined uphill and downhill. I’m hiking in a fleece hoodie, pants, and gloves and my friends Pam Solon and Jeff Wilhelm are similarly layered up. Once the sun reaches us within an hour, we’ll strip down to shorts and T-shirts.
Where the trail crosses a meadow, the expansive view west across a calm and insistently blue Cosley Lake reveals what looks like a long wall of overlapping stone shields jammed into the earth, each 2,000 or more feet tall and tilting at different angles. At the lake’s outlet—now in warm sunshine—we ford the Belly River, ankle- to calf-deep here with just a few tiny riffles and not very cold. More hiking through quiet forest brings us to the refrigerated, cliff-shaded alcove below Dawn Mist Falls, which spills thunderously over a sheer drop and crashes onto fallen boulders at its base, its force releasing a perpetual mist. Moss wallpapers the alcove’s short cliffs.
A backpacker hiking the Ptarmigan Tunnel Trail in Glacier National Park.
” data-image-caption=”Pam Solon backpacking the Ptarmigan Tunnel Trail in Glacier National Park.
” data-medium-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/12/Gla7-35-Pam-Solon-backpacking-the-Ptarmigan-Tunnel-Trail-in-Glacier-National-Park.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/12/Gla7-35-Pam-Solon-backpacking-the-Ptarmigan-Tunnel-Trail-in-Glacier-National-Park.jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/12/Gla7-35-Pam-Solon-backpacking-the-Ptarmigan-Tunnel-Trail-in-Glacier-National-Park.jpg?resize=900%2C600&ssl=1″ alt=”A backpacker hiking the Ptarmigan Tunnel Trail in Glacier National Park.” class=”wp-image-61144″ srcset=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/12/Gla7-35-Pam-Solon-backpacking-the-Ptarmigan-Tunnel-Trail-in-Glacier-National-Park.jpg?resize=1024%2C683&ssl=1 1024w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/12/Gla7-35-Pam-Solon-backpacking-the-Ptarmigan-Tunnel-Trail-in-Glacier-National-Park.jpg?resize=300%2C200&ssl=1 300w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/12/Gla7-35-Pam-Solon-backpacking-the-Ptarmigan-Tunnel-Trail-in-Glacier-National-Park.jpg?resize=768%2C512&ssl=1 768w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/12/Gla7-35-Pam-Solon-backpacking-the-Ptarmigan-Tunnel-Trail-in-Glacier-National-Park.jpg?resize=150%2C100&ssl=1 150w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2022/12/Gla7-35-Pam-Solon-backpacking-the-Ptarmigan-Tunnel-Trail-in-Glacier-National-Park.jpg?w=1200&ssl=1 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />Pam Solon backpacking the Ptarmigan Tunnel Trail in Glacier National Park.
After a thoroughly relaxing lunch break on the pebbly beach at Elizabeth Lake—where the perfect combination of solar warmth and soft breeze probably converts in direct value to about a thousand hours of counseling—we start the long climb to the Ptarmigan Tunnel. Reaching the open alpine terrain, I repeatedly stop to spin 180 degrees and take big bites of our view of the valley of Helen and Elizabeth lakes and the peaks on the other side, which shelter what remains of a couple of glaciers in the shade of north-facing cliffs just below the mountaintops.
I’ve backpacked this trail before; this isn’t new to me. But time slowly renders a bit fuzzier the memory of how constantly breathtaking it is—which is, in a funny way, a gift to us: We get to experience that awe anew each time.
Everyone laughed when the legendary Yogi Berra said, “It’s like déjà vu all over again,” but I think I knew what he meant.
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