Science News Oct 26

Welcome everyone to this week’s Science News. Today we’ll talk about how life on Mars might have caused its own extinction, how to find life on Earth, a new paper about the Hubble tension, stranded whales, researchers who bioengineered a more deadly COVID strain, or maybe didn’t, how surviving the middle age might have contributed to auto-immune disorders, the world’s largest digital camera, the health benefits of sleeping, and whether smiling really makes you happy.

Scientists believe that ancient Mars may have been teeming with microbial life. This isn’t news, but according to a new paper just published in Nature Astronomy those microbes might have caused their own extinction.

The authors of the study did a computer simulation of early Mars. They populated the simulated planet with a type of microbial life that also existed on earth. Those microbes breathe in molecular hydrogen and carbon dioxide and breathe out methane. On Earth, methane is a greenhouse gas, but the same was not true for the young Mars. Instead, the warming effect on Mars came from the very combination of hydrogen and carbon dioxide that the microbes were breathing.

So the microbes were consuming the greenhouse gases and the temperature dropped. To escape the cold, the microbes moved deeper into the crust of Mars while the surface froze over with what little water there was. Eventually they cut themselves off from hydrogen supply and game over.

The study is a reminder that not all forms of life come into equilibrium with their environment. It’s possible that they create a runaway effect and cause their own extinction. The computer simulation also reveals which places on Mars are the most likely ones to have traces of those microbes, if they existed, and future missions might go look for them.

Hi Elon.

No, I still don’t want to move to Mars with you.

Come on, we’ve talked about this. It’d take three minutes to reply to someone on twitter. By that time, they might have resigned.

Sure, see you later.

We’ve seen lots of headlines about exoplanets and how physicists try to find out whether they might be hospitable to life. But here’s a new question. What if aliens are observing *our planet and try to figure out whether *Earth is hospitable to life?

According to a recent study by Tilman Spohn and Dennis Höning, Earth may be somewhat of a rarity among the habitable exoplanets. They used a computer model to study how continents and water distribute on Earth-like planets and found there’s an 80 percent probability that the planets are mostly covered by land. They’re pale, *yellow dots rather than the familiar blue-white of our home planet. Another 19 percent of the planets in their simulation are almost entirely covered by water. Less than one percent had a share of earth and water like we have on our planet.

But of course water alone doesn’t signal the presence of life. Scientists try to find signs of at least basic life on other planets by scanning the atmosphere. They look for resonances of molecules that are indicative of biological processes for life as we know it. Such molecules are for example methane, ozone, and carbon dioxide.

In a pre-print that just appeared last week a group from Switzerland and the USA tried to extract this information from data of our own planet. They found that how well they could infer the presence of those molecules depended strongly both on the season and on the part of Earth that was probed by the measurements. So if aliens are looking at us, they might have a hard time figuring out if this planet is even populated. I hope that astrophysicists will soon find intelligent life on earth because we could really need some.

Engineers and scientists at SLAC in California are about to complete the world’s largest digital camera. Its lens is one point five seven meters across, that’s a little more than 5 feet. It weighs more than 3 tons and has a resolution of 3 point 2 billion pixel.

According to SLAC that’s good enough to see a golf ball from 15 miles away, though it’s probably easier to buy a new one. The camera isn’t quite finished yet. It’s currently undergoing some final checks in a clean room at SLAC, but it’s still missing the cooling system and filters.

This camera will become part of the telescope at the Vera Rubin Observatory in Chile where it will be used for the Legacy Survey of Space and Time, LSST, for short. If all goes well, the camera will be shipped to Chile next year in May.

The LSST is a ten-year mission to collect data from the southern sky, most importantly about weak and strong gravitational lensing, supernovae, and the distribution of galaxies in the universe. Scientists hope that the improved data will tell them more about dark matter, dark energy, and the formation of structures in the universe.

And another news item about the universe. A new analysis of supernovae data confirms a cosmological anomaly known as the Hubble tension. For several years now, evidence has built up that different measurements of a cosmological parameter known as the Hubble constant don’t fit together. The Hubble constant measures how fast the universe expands at the current moment. But depending on what data astrophysicists analyse, they get a somewhat different result for the Hubble constant. This shouldn’t happen.

In a paper that was just published last week, a team of astrophysicists used the biggest available data set of supernovae together with two other data sets. They tried to fit those sets with several different cosmological models, but, to make a long story short, none of the models properly fits. In this table you see the problem. It’s that the best fitting numbers from those two methods don’t agree with each other. Their analysis also shows that systematic uncertainties in the supernovae measurements can’t explain the discrepancy. That’s interesting because that was one of the possible explanations that astrophysicists previously considered.

The Hubble constant is one of the key parameters in the current standard model of cosmology, that’s the model with dark energy and dark matter. That there’s no single value of this constant which fits to all the observations might mean that there’s something wrong with the model. One of the most suspicious assumptions in this model is the Cosmological Principle, that’s the idea that matter in the universe is on the average evenly distributed. I talked about this in an earlier video. Whatever is going on, the solution of this riddle is bound to be interesting, what do you think Albert?

Over two hundred pilot whales have stranded on New Zealand’s remote Chatham Islands, just a month after a mass stranding on the island of Tasmania in Australia. Local authorities have decided not to attempt to refloat the whales because of the high number of sharks in the water. The whales are likely to die or will have to be euthanized.

Scientists remain baffled at why these mass strandings occur. One theory is that the whales encounter some kind of navigation problem. Another theory is that once one whale is floated, others follow it, leading to mass stranding, which is also how YouTube trends work.

The middle ages are still haunting us, and no, I’m not talking about flat earthers. New research has shown that the bubonic plague might have selected a DNA variant that benefits certain auto-immune disorders.

The bubonic plague of the 14th century was caused by a bacterial infection that at the time could not be treated. It had a fatality rate of more than 50 percent. Estimates say it killed a total of 25 million people, about a third of the European population.

According to a paper that was just published in Nature, a particular genetic variant helped the immune system fight off the infection. The researchers studied the remains of more than 500 people in London and Denmark and found that this particular gene improved the odds of survival by as much as 40 percent. But the same gene is known to be linked to Chron’s disease, an auto-immune disorder that causes chronic inflammation of the gastrointestinal tract.

Since we’re talking about diseases already, researchers at Boston University have created a new COVID strain. According to a recent preprint, the purpose of their study was to investigate the role of the spike protein in the function of the COVID virus. Their new strain is a version of the Omicron BA 1 strain. It has a similar immune escape as the omicron strain but it has a higher fatality rate in mice, though the fatality rate is still lower than that of the first COVID strain.

This research has widely been reported as the creation of an especially deadly strain of COVID because the fatality rate in the particular breed of mice that the researchers used is much higher than in humans. These poor little mice die from the original COVID virus. The new version of Omicron which the researchers created kills “only” eighty percent of the mice.

The internet has been all over this allegedly so deadly COVID strain. The researchers tried to clarify what they did but everyone is very upset. There’s now a controversy around the question whether or not this study should have been declared as “gain of function” research. The researchers argue “no”, because the new strain is less dangerous than the first COVID strain. Other researchers say “yes” because it’s more dangerous than the strain they began with. I don’t have an opinion on that but I think you don’t need to worry about it, unless you’re a mouse in which case please let us know what you think in the comments.

Hi Liz,

No, we’re not hiring, sorry.

I’d say go back and start with the basics.

Spinach, Mushrooms, Tomatoes. You can do it.

Good luck.

Lack of sleep is correlated with chronic disease, according to a paper that appeared last week. It’s a new analysis of data from a study that followed about 10 thousand people in the UK from 1985 to 2016.

About 8000 of those records had information on both chronic illness and sleep duration. The new analysis found that those who slept five hours or less at age 50 were 30 percent more likely to have multiple chronic diseases. At age 60, it was 32 percent, and at age 70, 40 percent.

However, the study has some limitations. For one, the sleep durations were self-reported and might not be very reliable. Also, correlation is not causation. Quite possibly chronic illness makes it difficult to sleep, or indeed the causation could go both ways. Finally, most of the study participants were white men and civil servants in the UK, so the results might not carry over to other demographic groups.

Our final news item for today is that smiling indeed makes you happy, at least according to a paper that was just published in Nature Human Behavior. Psychologists have debated this question since the 1980s when a study seemed to show that holding a pen in your mouth without letting your lips touch it makes you feel better. But this finding was later not reproduced in other studies. A meta-analysis in 2019 came out inconclusive. For psychologists this is no laughing matter, which is probably why the new paper was stuck in peer review for two and a half years.

But it did finally get published, so here’s what they found. They recruited almost 4,000 participants from 19 countries and split then into three different groups. One group mimicked photos of smiling actors, one group was asked to force a smile by placing a pen in their mouth like in the original study, and one group forced a smile without the pen.

The participants then rated their happiness. Turned out that those who smiled indeed reported being happier though it wasn’t a large effect. The exception was the group with the pen. So, pens don’t make you happy, but smiling does. Guess I’ll have to work on that.