Some of the universe's stars have gone missing. But where did they go?
https://www.livescience.com/hunt-for-uni...stars.html
EXCERPTS: . . . But what if some stars suddenly just wink out of visibility? According to everything we know about stars, that should be impossible, but over the past few years, a group of astronomers has set out to see whether such impossible things do happen, comparing data across decades of observations.
VASCO is the Vanishing and Appearing Sources during a Century of Observations project," said Beatriz Villarroel of the Nordic Institute for Theoretical Physics, Sweden. "We're actually interested in all kinds of vanishing objects, but ideally I'd like to find a star that's been steady and has been there in the sky for as long as we can remember and as long as we have data for, and one day it just vanishes. And you can point the biggest telescopes in the world at it and still see nothing there."
[...] So far, the survey has delivered more than 800 apparently 'missing' stars, many of which still need to be processed and studied in depth. And while there's no perfect match for Villarroel's ideal object — a vanishing act by a long-lived, stable star —many of the candidates that have been spotted are still intriguing in their own right.
[...] At the moment it's hard to imagine other natural processes that might result in a star simply disappearing — and until a candidate emerges with features that can be studied, there's little point in speculating on possible new physics that might be involved in this cosmic vanishing act. However, that raises one other possibility that's inspired VASCO from the outset: The idea that apparently impossible astronomical events might give away the existence of advanced alien civilizations... (MORE - details)
Five unproven claims that alien life exists
https://theconversation.com/mushrooms-on...sts-161366
EXCERPTS: Mushrooms on Mars? A recent study claims to have found evidence for mushroom-like life forms on the surface of Mars. As it happens, these particular features are well known and were discovered by cameras aboard Nasa’s Mars Exploration Rover Opportunity, shortly after it landed in 2004. They are not, in fact, living organisms at all, but “haematite concretions” – small sphere-shaped pieces of the mineral haematite, and their exact origin is still debated by scientists...
[..] Fossilised worms. ... On August 7, 1996, the then US president Bill Clinton stood on the White House lawn and announced the possibility that scientists had discovered the ancient, fossilised remains of micro-organisms in a meteorite that had been recovered from Antarctica in 1984. ... The tiny structures discovered within, using powerful microscopes, resemble microscopic worm-like organisms and are likely to be billions of years old. ... many scientists have pointed out that well known inorganic processes are quite capable of producing structures which resemble living organisms...
Mystery gases. In the 1970s Nasa’s Viking robotic landers carried a series of experiments designed to test the Martian soil for the presence of microorganisms. [...] Intriguingly, this particular experiment did show a steady increase in carbon-14 over time which was indeed terminated after heating to above the boiling point of water. Several inorganic chemical reactions have been proposed as an explanation. These results therefore remain inconclusive and are still debated today... [Why waste money on experiments whose positive results can or will be predictably explained by other factors?]
[...] Wow! In 1977, the Big Ear radio telescope in the US detected an unusual radio signal while scanning the sky. ...factors make it quite difficult to envisage a natural cause ... The exact signal has not been detected again since ... The signal was so remarkable at the time that the astronomer on duty, Jerry Ehman, circled the print out of the signal with red pen and wrote “Wow!” next to it. Various explanations have been proposed over the years ... The exact origin of the Wow! signal is still not fully agreed upon today, and remains an intriguing mystery.
[...] Tabby’s Star. ... In 2015, professional astronomers working with citizen scientists from the Planet Hunters project announced the discovery of a nearby star displaying unusually strong and consistent dimming over time. ... This highly unusual behaviour prompted numerous theories to explain the observations ... Some also speculated that these were signatures of an advanced alien species building a structure around the star. But further observations have found no corroborating evidence to support this possibility...
[...] As exciting as they are, it is important to treat claims of alien life with a healthy dose of scepticism, and this is indeed what scientists do... (MORE - missing details)
https://www.livescience.com/hunt-for-uni...stars.html
EXCERPTS: . . . But what if some stars suddenly just wink out of visibility? According to everything we know about stars, that should be impossible, but over the past few years, a group of astronomers has set out to see whether such impossible things do happen, comparing data across decades of observations.
VASCO is the Vanishing and Appearing Sources during a Century of Observations project," said Beatriz Villarroel of the Nordic Institute for Theoretical Physics, Sweden. "We're actually interested in all kinds of vanishing objects, but ideally I'd like to find a star that's been steady and has been there in the sky for as long as we can remember and as long as we have data for, and one day it just vanishes. And you can point the biggest telescopes in the world at it and still see nothing there."
[...] So far, the survey has delivered more than 800 apparently 'missing' stars, many of which still need to be processed and studied in depth. And while there's no perfect match for Villarroel's ideal object — a vanishing act by a long-lived, stable star —many of the candidates that have been spotted are still intriguing in their own right.
[...] At the moment it's hard to imagine other natural processes that might result in a star simply disappearing — and until a candidate emerges with features that can be studied, there's little point in speculating on possible new physics that might be involved in this cosmic vanishing act. However, that raises one other possibility that's inspired VASCO from the outset: The idea that apparently impossible astronomical events might give away the existence of advanced alien civilizations... (MORE - details)
Five unproven claims that alien life exists
https://theconversation.com/mushrooms-on...sts-161366
EXCERPTS: Mushrooms on Mars? A recent study claims to have found evidence for mushroom-like life forms on the surface of Mars. As it happens, these particular features are well known and were discovered by cameras aboard Nasa’s Mars Exploration Rover Opportunity, shortly after it landed in 2004. They are not, in fact, living organisms at all, but “haematite concretions” – small sphere-shaped pieces of the mineral haematite, and their exact origin is still debated by scientists...
[..] Fossilised worms. ... On August 7, 1996, the then US president Bill Clinton stood on the White House lawn and announced the possibility that scientists had discovered the ancient, fossilised remains of micro-organisms in a meteorite that had been recovered from Antarctica in 1984. ... The tiny structures discovered within, using powerful microscopes, resemble microscopic worm-like organisms and are likely to be billions of years old. ... many scientists have pointed out that well known inorganic processes are quite capable of producing structures which resemble living organisms...
Mystery gases. In the 1970s Nasa’s Viking robotic landers carried a series of experiments designed to test the Martian soil for the presence of microorganisms. [...] Intriguingly, this particular experiment did show a steady increase in carbon-14 over time which was indeed terminated after heating to above the boiling point of water. Several inorganic chemical reactions have been proposed as an explanation. These results therefore remain inconclusive and are still debated today... [Why waste money on experiments whose positive results can or will be predictably explained by other factors?]
[...] Wow! In 1977, the Big Ear radio telescope in the US detected an unusual radio signal while scanning the sky. ...factors make it quite difficult to envisage a natural cause ... The exact signal has not been detected again since ... The signal was so remarkable at the time that the astronomer on duty, Jerry Ehman, circled the print out of the signal with red pen and wrote “Wow!” next to it. Various explanations have been proposed over the years ... The exact origin of the Wow! signal is still not fully agreed upon today, and remains an intriguing mystery.
[...] Tabby’s Star. ... In 2015, professional astronomers working with citizen scientists from the Planet Hunters project announced the discovery of a nearby star displaying unusually strong and consistent dimming over time. ... This highly unusual behaviour prompted numerous theories to explain the observations ... Some also speculated that these were signatures of an advanced alien species building a structure around the star. But further observations have found no corroborating evidence to support this possibility...
[...] As exciting as they are, it is important to treat claims of alien life with a healthy dose of scepticism, and this is indeed what scientists do... (MORE - missing details)