Latest news with #astrobiology
CBC
16 hours ago
- Health
- CBC
What does space smell like? This perfume-making astrobiologist is trying to find out
After a long career of creating designer perfumes, Marina Barcenilla decided to turn her nose to the cosmos. The fragrance designer enrolled in university in 2015 to study planetary science. She was taking classes in astrochemistry — the chemical makeup of outer space — when she realized she could marry her two passions. "Whenever I see something new, the first question is: I wonder what that smells like," she told As It Happens host Nil Köksal. "One day I thought: Actually, this molecule that I'm studying? I have it in my perfume lab. And this smell that I am imagining? I could actually create it." Barcenilla is now an astrobiology doctoral researcher at the University of Westminster in London, England. When she's not exploring the feasibility of life on Mars, she's recreating the smells of space, from the sulfuric stench of Jupiter's deepest clouds, to the pungent alcohol-like punch at the centre of the Milky Way. Four of those stellar scents are now available for public sniffing at the London Natural History Museum, as part of the ongoing exhibit: Space: Could life exist beyond Earth? 'Antiseptic,' but also like gunpowder? So what does space smell like? "I don't think it smells very good in general," said Barcenilla. Those in the know can attest. Canadian astronaut Julie Payette, upon returning from the International Space Station, told CBC News in 2009 that space smells "cold" and "antiseptic." "I opened the hatch six hours after the space walk. This entire airlock area had been exposed to the vacuum of space for all those hours. So when I opened the door, I smelled what was kind of an antiseptic smell," she said. "It was not detergent but it was definitely like a hospital-smell type and I thought, 'Wow, that's the smell of space.' The more I thought about it, I thought: 'Wow, this is what nothing smells like, because there's probably nothing left in there, not a single microbe or anything.'" Canadian astronaut Chris Hatfield, meanwhile, described it differently, noting in 2013 that he and many others aboard the station reported a "burnt steak and gunpowder" smell in the airlock. "Not exactly a spring garden," he said in a Canadian Space Agency video. Barcenilla says that when it comes to the smells of space, it really depends on what, specifically, you mean. "Most of space is quite empty and … it isn't really going to smell," she said. "But it's when you get to specific planets or moons, or when you go to a molecular cloud where we find high concentrations of different gases and microscopic dust, that we can then find molecules and chemical compounds that have a smell." Barcenilla says she's created 25 smells since she began doing this work in 2017. For the museum exhibit, she whipped up the scent of Mars, which is her scientific specialty; Titan, a large moon orbiting the planet Saturn; Bennu, an asteroid; and Earth as it was some 3.5-4 billion years ago, when life was just beginning. "The early Earth is a bit smelly. It's a combination of a little bit of kind of earthy wet smell, like what you get when it rains, but also with the smell that you get from various microbial strains," she said. "One of the smells that you get is a kind of sulphury cabbagey smell that goes in there as well. So that's a bit stinky." She admits that none of her creations can be fact-checked, per se. "In space, you can't smell so it's always going to be impossible. We don't have air that we can breathe, so that's completely out of the question," she said. "But what I'm trying to do is recreate the chemistry that we find in various places in space." 'The more it stinks, the more people like to smell it' Barcenilla has brought her space smells to schools to teach children, and she's also had a chance to watch people interact with them at the museum. "I always thought people are going to be a bit scared about the smelly stuff, but no, those are the best ones," she said. "The more it stinks, the more people like to smell it and the more they laugh and the more questions they ask about it." Triggering that curiosity, she says, is the whole point. "It's about bringing space closer to Earth, and it's for people to open their minds and understand that everything that we have out there in space has also ended up here on Earth," she said. As foreign as the final frontier may seem, Barcenilla says there's nothing out there that's truly unfamiliar, at least from an olfactory perspective. Jupiter's inner clouds? Barcenilla tells BBC News they're full of ammonia and sulphur, something you might find in fertilizer, and which smells like rotten eggs. The very centre of our galaxy? There you'll find Ethyl formate, a compound commonly found in fruit, and which probably smells, at best, like rum, and at worst, like nail polish remover.
The Independent
6 days ago
- General
- The Independent
The truth is out there? Why the scientific community struggles to accept ‘proof' of alien life
The search for extraterrestrial life has long gone back and forth between scientific curiosity, public fascination and outright scepticism. Recently, scientists claimed the 'strongest evidence' of life on a distant exoplanet – a world outside our solar system. Grandiose headlines often promise proof that we are not alone, but scientists remain cautious. Is this caution unique to the field of astrobiology? In truth, major scientific breakthroughs are rarely accepted quickly. Newton's laws of motion and gravity, Wegener's theory of plate tectonics, and human-made climate change all faced prolonged scrutiny before achieving consensus. But does the nature of the search for extraterrestrial life mean that extraordinary claims require even more extraordinary evidence? We've seen groundbreaking evidence in this search beforehand, from claims of biosignatures (potential signs of life) in Venus's atmosphere to Nasa rovers finding 'leopard spots' – a potential sign of past microbial activity – in a Martian rock. Both stories generated a public buzz around the idea that we might be one step closer to finding alien life. But on further inspection, abiotic (non-biological) processes or false detection became more likely explanations. In the case of the exoplanet, K2-18 b, scientists working with data from the James Webb Space Telescope (JWST) announced the detection of gases in the planet's atmosphere – methane, carbon dioxide, and more importantly, two compounds called dimethyl sulphide (DMS) and dimethyl disulphide (DMDS). As far as we know, on Earth, DMS/DMDS are produced exclusively by living organisms. Their presence, if accurately confirmed in abundance, would suggest microbial life. The researchers even suggest there's a 99.4% probability that the detection of these compounds wasn't a fluke – a figure that, with repeat observations, could reach the gold standard for statistical certainty in the sciences. This is a figure known as five sigma, which equates to about a one in a million chance that the findings are a fluke. So why hasn't the scientific community declared this the discovery of alien life? The answer lies in the difference between detection and attribution, and in the nature of evidence itself. JWST doesn't directly 'see' molecules. Instead, it measures the way that light passes through or bounces off a planet's atmosphere. Different molecules absorb light in different ways, and by analysing these absorption patterns – called spectra – scientists infer what chemicals are likely to be present. This is an impressive and sophisticated method – but also an imperfect one. It relies on complex models that assume we understand the biological reactions and atmospheric conditions of a planet 120 light years away. The spectra suggesting the existence of DMS/DMDS may be detected because you cannot explain the spectrum without the molecule you've predicted, but it could also result from an undiscovered or misunderstood molecule instead. Climate comparison Given how momentous the conclusive discovery of extraterrestrial life would be, these assumptions mean that many scientists err on the side of caution. But is this the same for other kinds of science? Let's compare with another scientific breakthrough: the detection and attribution of human-made climate change. The relationship between temperature and increases in CO₂ was first observed by the Swedish scientist Svante Arrhenius in 1927. It was only taken seriously once we began to routinely measure temperature increases. But our atmosphere has many processes that feed CO₂ in and out, many of which are natural. So the relationship between atmospheric CO₂ and temperature may have been validated, but the attribution still needed to follow. Carbon has three so-called flavours, known as isotopes. One of these isotopes, carbon-14, is radioactive and decays slowly. When scientists observed an increase in atmospheric carbon dioxide but a low volume of carbon-14, they could deduce that the carbon was very old – too old to have any carbon-14. Fossil fuels – coal, oil and natural gas – are composed of ancient carbon and thus are devoid of carbon-14. So the attribution of anthropogenic climate change was proven beyond reasonable doubt, with 97% acceptance among scientists. In the search for extraterrestrial life, much like climate change, there is a detection and attribution phase, which requires the robust testing of hypotheses and also rigorous scrutiny. In the case of climate change, we had in situ observations from many sources. This means roughly that we could observe these sources close up. The search for extraterrestrial life relies on repeated observations from the same sensors that are far away. In such situations, systematic errors are more costly. Further to this, both the chemistry of atmospheric climate change and fossil fuel emissions were validated with atmospheric tests under lab conditions from 1927 onwards. Much of the data we see touted as evidence for extraterrestrial life comes from light years away, via one instrument, and without any in situ samples. The search for extraterrestrial life is not held to a higher standard of scientific rigour, but it is constrained by an inability to independently detect and attribute multiple lines of evidence. For now, the claims about K2-18 b remain compelling but inconclusive. That doesn't mean we aren't making progress. Each new observation adds to a growing body of knowledge about the universe and our place in it. The search continues – not because we're too cautious, but because we are rightly so. Oliver Swainston is a Research Assistant at RAND Europe. Chris Carter is an Analyst on the Science and Emerging Technology Team at RAND Europe.
RNZ News
18-05-2025
- Science
- RNZ News
Claims of alien life 'fatally flawed'
Caroline Freissinet. Photo: Supplied / Caroline Freissinet Headlines last month captured global excitement after astronomers claimed they detected the "strongest evidence to date" of life on another planet, but a world-leading astrobiologist says the science behind the claim is "fatally flawed". However, one of the scientists behind the claims is standing behind their work. In April, a team from Cambridge claimed to have recorded a possible biosignature, or signs of past or present life linked to biological activity, on an exoplanet named K2-18b. Using the James Webb Space Telescope, the team detected chemical fingerprints that suggest the presence of dimethyl sulphide (DMS) and dimethyl disulphide (DMDS), molecules that on Earth are only produced by microbial life. Carolyn Freissinet is a leading astrobiologist at the French National Center for Scientific Research. She told RNZ's Saturday Morning she believed the claims made by the Cambridge researchers were premature - and potentially misleading. Freissinet, who collaborates with NASA and leads studies of Martian samples collected by the Curiosity rover, said the science behind the announcement simply did not stack up. "This finding is super controversial," she said. "It's not based on a very serious scientific study. It has fatal flaws in the method that has been used." According to Freissinet, just a week after the initial announcement, another team reviewed the same spectral data and found no trace of DMS at all. "So first, there's a problem with the measurement itself." Even if DMS was detected, she said, we shouldn't jump to the conclusion that it's a biosignature. "We understand very poorly the sulphur chemistry of exoplanet atmospheres. There is this famous quote by Carl Sagan. He said that extraordinary claims, such as finding life, require extraordinary evidence." One of the study's authors however said Freissinet's understanding of the findings was "clearly incorrect". Nikku Madhusudhan, professor of astrophysics and exoplanetary science at the Institute of Astronomy, University of Cambridge, told RNZ their study was "the most advanced analysis conducted for an exoplanet with this [James Webb Space Telescope] instrument, and reported the first mid-infrared atmospheric spectrum of a potentially habitable planet outside the solar system ever". "This is a major advancement in the field." He said claims no other teams had detected molecules suggesting evidence of biological processes were also incorrect. "None of them claim that the gases we reported cannot be found. The first study they mentioned, that came a week after ours, was a preliminary analysis which didn't even look for the gases so no conclusive statement can be drawn from it regarding our findings. "The second and third papers which used more realistic models confirmed our calculations and suggested additional gases that could provide alternate explanations to at least some of the data. Our original suggestion of the gas DMS is still the most favoured at this point, considering all available data." Freissinet did not dismiss the search for extraterrestrial life - it was the core of her work. But she argued that the search must be methodical, rigorous, and grounded in evidence. "Right now, we're accumulating hints... pieces of a puzzle." Some of those puzzle pieces are found on Mars. In 2013, Freissinet and her team also made headlines with the discovery of long-chain hydrocarbons in 3.7-billion-year-old Martian rocks at a site called Cumberland. These molecules, made up of ten or more carbon atoms, are incredibly fragile, especially on Mars, where conditions are harsh and preservation is rare. "What we can say now is that if life ever existed on Mars... we could find those traces of life." But she's careful not to overstate the findings. "It's definitely not hints of life," she clarified. "We cannot tell if the origin of the molecules if they are biological or if they are pure chemical reactions." So what would "life" look like? Freissinet emphasised just how difficult it was to identify alien life, especially when we only have one known example - Earth. "We try to identify life as we don't know it," she said. "It's really hard." One method scientists use is to look for chemical imbalances that suggest biological processes. For example, amino acids, the building blocks of proteins, exist in two mirror-image forms. On Earth, life uses only one of these forms. A similar imbalance found elsewhere could be a clue. Still, even these signs require cautious interpretation. Natural processes can sometimes mimic the patterns life creates. At the Cumberland site, Freissinet's team also found traces of nitrates and lighter isotopes of carbon and sulphur elements, which, on Earth, were often associated with biological activity. But even these, she said, had potential non-biological explanations. Madhusudhan said there was "usually a lot of debate" around the subject, but urged people "not to confuse debate with misinformation". Freissinet's perspective was not one of scepticism, but of scientific integrity. She said discovering evidence of life beyond Earth would likely be a long, slow process and should not take the form of rushed conclusions or overhyped discoveries. "For now, we're we are very far from biosignature detection. We are accumulating hints everywhere in the solar system and elsewhere in the universe, looking at exoplanets to make a story. "We're accumulating pieces of a puzzle. And one day, hopefully, this puzzle will assemble." 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