Planets that can potentially support life... - Page 42

Scientists at a prominent SETI group say they’ve identified a signal coming from Proxima Centauri, the closest star to our Sun, that could possibly be from an alien civilization.

The news first broke yesterday in a story by The Guardian. The signal was discovered by Breakthrough Listen, a project founded to listen for signs of extraterrestrial life affiliated with the late physicist Stephen Hawking.

“It is the first serious candidate since the ‘Wow! signal’,” a researcher familiar with the finding, who requested anonymity to discuss the work, told the newspaper. The “Wow! signal,” recorded in 1977, is widely considered to be the most promising finding in the history of SETI — though, like the most recent finding, its implications have been hotly debated.

According to the Guardian‘s sources, the signal was picked up by the Parkes telescope in Australia last year, where it appeared to be originating from the Proxima Centauri system.

It caught the interest of researchers for several reasons. One is that it’s around 980MHz, a band in which there shouldn’t be any human spacecraft transmitting. Another is that its frequency is shifting in a way that scientists say indicates that it could be coming from the surface of an orbiting exoplanet — and Proxima Centauri is known to have an exoplanet in the “habitable zone.” The researchers are now working on a paper about the finding, according to the Guardian.

Still, the scientific community remains skeptical.

“The chances against this being an artificial signal from Proxima Centauri seem staggering,” University of Westminster astrobiologist Lewis Dartnell told the Guardian. “We’ve been looking for alien life for so long now and the idea that it could turn out to be on our front doorstep, in the very next star system, is piling improbabilities upon improbabilities.”

Dartnell also told the paper that Proxima Centauri’s most habitable-looking planet doesn’t seem, at first bluff, like a particularly strong candidate for life.

“But I’d love to be proved wrong,” he added.

The Guardian‘s reporting was corroborated later the same day by Scientific American, which locked down better access to the researchers behind the project and reported that they are urging skepticism — but, strikingly, are leaving open the possibility that it could be an alien technosignature.

“The most likely thing is that it’s some human cause,” Pete Worden, the executive director of Breakthrough’s parent organization. “And when I say most likely, it’s like 99.9 [percent].”

Insiders familiar with the finding also clarified to Scientific American that the signal does not appear to contain any information. In other words, it’s basically just a tone — and likely coming from a spacecraft launched from Earth.

“If you see such a signal and it’s not coming from the surface of Earth, you know you have detected extraterrestrial technology,” Jason Wright, a SETI researcher at Penn State University in Pennsylvania, told Scientific American. “Unfortunately, humans have launched a lot of extraterrestrial technology.”

Wright also had an intriguing exchange with the Scientific American writer later on in the story, when he was asked about the truism “it’s never aliens.”

“I hate that phrase, because if you say that then why even look,” he told the magazine. “What we mean by that is that it’s never been aliens before.”

That’s the spirit of possibility, of course, that motivates all SETI projects. To wit, the Guardian pointed out that when Breakthrough Listen kicked off, back in 2015, the famed physicist Stephen Hawking made remarks to the same effect.

“Mankind has a deep need to explore, to learn, to know,” he said, according to the paper. “We also happen to be sociable creatures. It is important for us to know if we are alone in the dark.”

Researchers from the United States and India working with NASA have now discovered four strains of bacteria living in different places in the ISS – three of which were, until now, completely unknown to science.

Three of the four strains were isolated back in 2015 and 2016 – one was found on an overhead panel of the ISS research stations, the second was found in the Cupola, the third was found on the surface of the dining table; the fourth was found in an old HEPA filter returned to Earth in 2011.

All four of the strains belong to a family of bacteria found in soil and freshwater; they are involved in nitrogen fixation, plant growth, and can help stop plant pathogens. Basically, good bacteria to have around if you're growing things.

You might wonder what such soil bacteria were doing all the way up on the ISS, but the astronauts living on the space station have been growing small amounts of food for years, so it's unsurprising that we've found plant-related microbes aboard.

One of the strains – the HEPA-filter find – was identified as a known species called Methylorubrum rhodesianum. The other three were sequenced and found to all belong to the same, previously unidentified species, and the strains were named IF7SW-B2T, IIF1SW-B5, and IIF4SW-B5.

The team, lead by University of Southern California geneticist Swati Bijlani, has proposed calling the new species Methylobacterium ajmalii after Ajmal Khan, a renowned Indian biodiversity scientist. This new find is also closely related to an already known species called M. indicum.

"To grow plants in extreme places where resources are minimal, isolation of novel microbes that help to promote plant growth under stressful conditions is essential," two of the team, Kasthuri Venkateswaran and Nitin Kumar Singh from NASA's JPL, explained in a press statement.

Astronomers using the NASA James Webb Space Telescope detected the super-hot water vapour in an inner ring of gas and dust around a distant star known as PDS 70 which shares a remarkable amount of similarities with the sun.

PDS 70 is roughly three-quarters the mass of the sun, and at 5.4 million years old is relatively close in age to the sun, which is roughly 4.6 billion years old.

The water vapor, detected using the James Webb Space Telescope’s mid-infrared instrument, was also found at a distance from the star similar to the Earth’s distance from the sun (93 million miles), signaling the area could be conducive to life.

Giulia Perotti, an astronomer at Germany’s Max Planck Institute for Astronomy who led the study told Space.com that knowledge about PDS 70 provides crucial information about how planets in the sun’s solar system likely formed, and confirms that water is present in a region where “planets similar to Earth may be assembling.”

A new investigation with NASA’s James Webb Space Telescope into K2-18 b, an exoplanet 8.6 times as massive as Earth, has revealed the presence of carbon-bearing molecules including methane and carbon dioxide. Webb’s discovery adds to recent studies suggesting that K2-18 b could be a Hycean exoplanet, one which has the potential to possess a hydrogen-rich atmosphere and a water ocean-covered surface.

The first insight into the atmospheric properties of this habitable-zone exoplanet came from observations with NASA’s Hubble Space Telescope, which prompted further studies that have since changed our understanding of the system.

K2-18 b orbits the cool dwarf star K2-18 in the habitable zone and lies 120 light-years from Earth in the constellation Leo. Exoplanets such as K2-18 b, which have sizes between those of Earth and Neptune, are unlike anything in our solar system. This lack of equivalent nearby planets means that these ‘sub-Neptunes’ are poorly understood, and the nature of their atmospheres is a matter of active debate among astronomers.

The suggestion that the sub-Neptune K2-18 b could be a Hycean exoplanet is intriguing, as some astronomers believe that these worlds are promising environments to search for evidence for life on exoplanets.

"Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere," explained Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper announcing these results. "Traditionally, the search for life on exoplanets has focused primarily on smaller rocky planets, but the larger Hycean worlds are significantly more conducive to atmospheric observations."

The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b. These initial Webb observations also provided a possible detection of a molecule called dimethyl sulfide (DMS). On Earth, this is only produced by life. The bulk of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments.



The inference of DMS is less robust and requires further validation. “Upcoming Webb observations should be able to confirm if DMS is indeed present in the atmosphere of K2-18 b at significant levels,” explained Madhusudhan.

While K2-18 b lies in the habitable zone, and is now known to harbor carbon-bearing molecules, this does not necessarily mean that the planet can support life. The planet's large size — with a radius 2.6 times the radius of Earth — means that the planet’s interior likely contains a large mantle of high-pressure ice, like Neptune, but with a thinner hydrogen-rich atmosphere and an ocean surface. Hycean worlds are predicted to have oceans of water. However, it is also possible that the ocean is too hot to be habitable or be liquid.

"Although this kind of planet does not exist in our solar system, sub-Neptunes are the most common type of planet known so far in the galaxy," explained team member Subhajit Sarkar of Cardiff University. “We have obtained the most detailed spectrum of a habitable-zone sub-Neptune to date, and this allowed us to work out the molecules that exist in its atmosphere.”

Characterizing the atmospheres of exoplanets like K2-18 b — meaning identifying their gases and physical conditions — is a very active area in astronomy. However, these planets are outshone — literally — by the glare of their much larger parent stars, which makes exploring exoplanet atmospheres particularly challenging.

The team sidestepped this challenge by analyzing light from K2-18 b's parent star as it passed through the exoplanet's atmosphere. K2-18 b is a transiting exoplanet, meaning that we can detect a drop in brightness as it passes across the face of its host star. This is how the exoplanet was first discovered in 2015 with NASA’s K2 mission. This means that during transits a tiny fraction of starlight will pass through the exoplanet's atmosphere before reaching telescopes like Webb. The starlight's passage through the exoplanet atmosphere leaves traces that astronomers can piece together to determine the gases of the exoplanet's atmosphere.

"This result was only possible because of the extended wavelength range and unprecedented sensitivity of Webb, which enabled robust detection of spectral features with just two transits," said Madhusudhan. "For comparison, one transit observation with Webb provided comparable precision to eight observations with Hubble conducted over a few years and in a relatively narrow wavelength range."

"These results are the product of just two observations of K2-18 b, with many more on the way,” explained team member Savvas Constantinou of the University of Cambridge. “This means our work here is but an early demonstration of what Webb can observe in habitable-zone exoplanets.”

The team’s results were accepted for publication in The Astrophysical Journal Letters.

The team now intends to conduct follow-up research with the telescope's MIRI (Mid-Infrared Instrument) spectrograph that they hope will further validate their findings and provide new insights into the environmental conditions on K2-18 b.

"Our ultimate goal is the identification of life on a habitable exoplanet, which would transform our understanding of our place in the universe," concluded Madhusudhan. "Our findings are a promising step towards a deeper understanding of Hycean worlds in this quest."

On September 12 2023 11:23 KwarK wrote:
Surely a big heavy planet implies small life, not big life. You don't get bigger to deal with high gravity, you get smaller.

Miller and Urey injected ammonia, methane and water vapor into an enclosed glass container to simulate what were then believed to be the conditions of Earth’s early atmosphere. Then they passed electrical sparks through the container to simulate lightning. Amino acids, the building blocks of proteins, soon formed. Miller and Urey realized that this process could have paved the way for the molecules needed to produce life.

Scientists now believe that Earth’s early atmosphere had a different chemical makeup from Miller and Urey’s recipe. Even so, the experiment gave rise to a new scientific field called prebiotic or abiotic chemistry, the chemistry that preceded the origin of life. This is the opposite of biogenesis, the idea that only a living organism can beget another living organism.

Some scientists think that some of the molecules important to life may be produced outside the Earth. Instead, they suggest that these ingredients came from meteorites or comets.

On September 12 2023 22:29 Harris1st wrote:


As soon as the energy problem is solved, I expect huge leaps in all kinds of technology.
Imagine rockets/ starships with a fusionreactor on board. Then we only need to convert that energy into forward momentum in space somehow and it would open the possibilty of insane travelling speed

On September 12 2023 22:29 Harris1st wrote:


As soon as the energy problem is solved, I expect huge leaps in all kinds of technology.
Imagine rockets/ starships with a fusionreactor on board. Then we only need to convert that energy into forward momentum in space somehow and it would open the possibilty of insane travelling speed

On September 18 2023 18:36 Harris1st wrote:


A. When you have no gravity and no weight, does that even matter? Did not know that about 0 G. Can this solved by having a pressured space suit? Keeping your eyes where they belong ^^'

B. Most definitely does a long range space ship need some kind of protection against radiation. Very good point

C. I do kinda expect a long range spaceship to be gigantic with a crew 100+ people just for the people on board not becoming insane because of isolation issues. If this can be constructed on earth or in some kind of space port needs to be seen.

D. Absolutely. Don't have anything to add to that right now.

On September 21 2023 18:04 Silvanel wrote:
The first step would be making a colony on Luna or Mars, then probably on one of the moons of Jupiter/Saturn/Neptun. Once we do that, we will know a lot more about survival in space and long travels and we can start thinking about interstellar jurney..

On September 21 2023 18:04 Silvanel wrote:
The first step would be making a colony on Luna or Mars, then probably on one of the moons of Jupiter/Saturn/Neptun. Once we do that, we will know a lot more about survival in space and long travels and we can start thinking about interstellar jurney..