May 7, 2025 05:23 PM
(This post was last modified: May 8, 2025 02:39 PM by C C.)
Statistically speaking, we should have heard from space aliens by now
https://www.universetoday.com/articles/s...ens-by-now
EXCERPTS: The Drake equation suggests there should be many civilisations out there yet searches like SETI have not detected any signals. This raises questions about whether SETI is a valuable scientific effort.
[...] The paper presents a model to explore the Fermi Paradox and assess the value of SETI in the search for intelligent life. Despite its limitations, the model suggests that the absence of detected electromagnetic signals from alien civilizations can place limits on how many such civilizations exist. Under certain assumptions, the model predicts a 99% chance of detecting at least one signal if the estimated number of civilizations (based on the Drake equation) is around 1. Although this is a basic model, it shows that even a lack of results from SETI can help rule out certain combinations of the number and lifespan of civilizations, potentially aiding in solving the Fermi paradox.
[...] As SETI efforts continue and models improve, we may increasingly be able to use non-detections not as dead ends, but as data points that refine our understanding of the cosmos and our place within it. Ultimately, the search for extraterrestrial intelligence is not just about finding others—it’s also a way to better understand ourselves and the conditions that make intelligent life possible... (MORE - missing details)
The freckled universe
https://www.symmetrymagazine.org/article...y=undhttps
INTRO: Astronomers knew the James Webb Space Telescope would reveal new things about the cosmos. The most powerful space telescope ever built, JWST can look deeper into the universe—and thus farther back in time—than humans had ever seen.
JWST launched in December 2021 and started science operations about six months later. And it wasn’t long before the telescope delivered on its promise.
When data started coming in as part of the Cosmic Evolution Early Release Science Survey, CEERS, astronomers noticed something unusual: The early universe is freckled with small, red galaxies that they’d never seen before.
These came to be known as “little red dots.” Their properties were so strange that they were deemed an entirely new class of cosmic object.
And the more we learn about them, the more befuddling they seem. “Every time we think we understand something [about LRDs], they surprise us again by not having the properties we expect,” says Jenny Greene, a professor of astrophysical sciences at Princeton University.
Evidence so far points to two possible explanations: Little red dots are likely either galaxies that host surprisingly large or luminous supermassive black holes, or they are compact galaxies with inexplicably huge numbers of old stars.
“The interpretations are kind of uncomfortable either way,” says Hollis Akins, a PhD student at the University of Texas at Austin who is studying LRDs. Whatever they are, the nature of little red dots will have profound implications for our understanding of black holes, galaxy formation and cosmic evolution.
“It feels like a once-in-a-career moment of discovery,” says Greene... (MORE - details, no obtrusive ads)
https://www.universetoday.com/articles/s...ens-by-now
EXCERPTS: The Drake equation suggests there should be many civilisations out there yet searches like SETI have not detected any signals. This raises questions about whether SETI is a valuable scientific effort.
[...] The paper presents a model to explore the Fermi Paradox and assess the value of SETI in the search for intelligent life. Despite its limitations, the model suggests that the absence of detected electromagnetic signals from alien civilizations can place limits on how many such civilizations exist. Under certain assumptions, the model predicts a 99% chance of detecting at least one signal if the estimated number of civilizations (based on the Drake equation) is around 1. Although this is a basic model, it shows that even a lack of results from SETI can help rule out certain combinations of the number and lifespan of civilizations, potentially aiding in solving the Fermi paradox.
[...] As SETI efforts continue and models improve, we may increasingly be able to use non-detections not as dead ends, but as data points that refine our understanding of the cosmos and our place within it. Ultimately, the search for extraterrestrial intelligence is not just about finding others—it’s also a way to better understand ourselves and the conditions that make intelligent life possible... (MORE - missing details)
The freckled universe
https://www.symmetrymagazine.org/article...y=undhttps
INTRO: Astronomers knew the James Webb Space Telescope would reveal new things about the cosmos. The most powerful space telescope ever built, JWST can look deeper into the universe—and thus farther back in time—than humans had ever seen.
JWST launched in December 2021 and started science operations about six months later. And it wasn’t long before the telescope delivered on its promise.
When data started coming in as part of the Cosmic Evolution Early Release Science Survey, CEERS, astronomers noticed something unusual: The early universe is freckled with small, red galaxies that they’d never seen before.
These came to be known as “little red dots.” Their properties were so strange that they were deemed an entirely new class of cosmic object.
And the more we learn about them, the more befuddling they seem. “Every time we think we understand something [about LRDs], they surprise us again by not having the properties we expect,” says Jenny Greene, a professor of astrophysical sciences at Princeton University.
Evidence so far points to two possible explanations: Little red dots are likely either galaxies that host surprisingly large or luminous supermassive black holes, or they are compact galaxies with inexplicably huge numbers of old stars.
“The interpretations are kind of uncomfortable either way,” says Hollis Akins, a PhD student at the University of Texas at Austin who is studying LRDs. Whatever they are, the nature of little red dots will have profound implications for our understanding of black holes, galaxy formation and cosmic evolution.
“It feels like a once-in-a-career moment of discovery,” says Greene... (MORE - details, no obtrusive ads)
