In his book Auguste Comte in Course of Positive Philosophy, published in 1835, the French philosopher argued that the stars will always remain “mechanical objects” for us. We will be able to determine their position in the sky, measure the distance to them, and learn the patterns of their movement. But what this or that bright speck in the sky is, what it is made of, what its temperature is, will remain a mystery to us forever. The philosopher lived only a couple of years before the publication of articles by Gustav Kirchhoff and Robert Bunsen, who proposed to determine the elemental composition of a radiating body by the characteristic lines in its spectrum. Since then, spectral analysis has been virtually the only tool that allows astronomers to analyze distant objects. No wonder scientists want to use it to search for life on other planets.

Of course, spectral analysis has some limitations. First, it is best suited for detecting substances in a gaseous state. That is, for example, the presence of liquid water can be detected only by the “spectral signatures” of water vapor. Secondly, habitable planets usually orbit quite close to their stars, and it is extremely difficult to separate them when observing them from Earth. In the future, this problem will probably be solved by improving astronomical instruments and imaging technologies, but for now, it has to be circumvented by other means, which are not always effective.

One way or another, the spectra of some exoplanets – or rather, their atmospheres – have already been recorded. None of the bodies studied by spectroscopy orbits in the habitable zone, where the surface temperature allows liquid water to exist; however, spectral data will be obtained for such objects sooner or later. What do scientists looking for signs of life hope to see in them?

In the image and likeness

It should be noted that modern science is aware of only one type of living organism, the one we encounter on Earth all the time. It is based on carbon chains and biochemical reactions in aqueous solutions. There are many explanations for why this combination seems to be the best for life. A separate article could be devoted to them, but one of them must be mentioned. Water is one of the most widespread chemical compounds in the universe, and it is also one of the most efficient solvents, remaining in a liquid state over a wide temperature range. This means that water provides the optimal conditions for the chemical transformations necessary to build the molecular structures of living organisms and supply them with energy.

Of course, no one can completely rule out the existence of exotic life forms based on ammonia or even rarer fluorine. Similarly, carbon does not necessarily have to be the main component of biological molecules. But the manifestations of such life are likely to be so different from what scientists are used to seeing around them that they will simply be impossible to recognize as inanimate nature. Therefore, astrobiologists are now focusing on the search for water as the most likely habitable environment. Hence, the concept of the habitable zone. This term sounds quite promising, but in fact, it only means a favorable temperature regime on the exoplanet’s surface and does not imply any “population”.

What will we see in the spectrum of an exoplanet potentially habitable for Earth-type life? First of all, of course, scientists will look for water vapor lines. However, there should not be much of it in the atmosphere: on Earth, even in the wettest jungles, its concentration reaches a maximum of a couple of percent. But our air has a lot of oxygen – more than 20%. It would seem that this is a sign of life! At least, the one we are most familiar with.

For a long time, experts have been carefully compiling a list of biomarkers, which are simple molecules that living organisms need to sustain their vital functions or are released during them. Oxygen is considered one of them, with many caveats. First, it became an essential component of the Earth’s biosphere about 2 billion years ago. Earlier, life on our planet managed quite well without it, and even now, there are many bacteria and fungi (the most famous example is yeast) that do not need it at all and even harm it. And secondly, this gas can occur, in particular, during the decomposition of water molecules under the influence of high-energy radiation. This is the so-called abiogenic oxygen, which is quite capable of confusing astronomers.

Heavier and more complex molecules, such as ethyl and methyl alcohol, formic and acetic acid, are considered more reliable signs of life. However, not everything is so simple with them. As it turned out, they can also be synthesized without any participation of living organisms, and not even on planets, but in interstellar gas and dust clouds, if there is a star nearby that can warm them up a bit. Nowadays, compounds such as amino acids, which are essential for life, are also found in these clouds. This has led to the assumption that they did not appear on Earth as a result of the vital activity of primitive cells, but were brought here from space.

On the other hand, a substance that we are used to considering a terrible poison – hydrogen cyanide, or hydrocyanic acid (HCN) – may well be associated with life. Its danger is not least determined by its high reactivity, but it is thanks to this that this substance is quite easily converted into organic molecules (the same amino acids). Hydrocyanic acid and its derivative cyanide are also quite common outside the Earth – they are almost an essential component of cometary nuclei and have been repeatedly detected in the gases that evaporate from them.

Perhaps it is easier to say which molecules are practically incompatible with Earth-type life, and thus their presence would mean that it is not worth looking for it on this particular planet. These are primarily the highly reactive halogens fluorine and chlorine, as well as some of their compounds with silicon, sulfur, and phosphorus. They quickly enter into chemical reactions with biological molecules that are familiar to us and turn them into something completely unfit for life.

So, we already know a lot of potential biomarkers. But none of them, if discovered in the spectrum of a celestial body, is unequivocal proof of the existence of life there. So how can we prove its presence using spectral methods?

Unnatural combinations

After analyzing all possible data in detail, a team of scientists led by University of Washington professor Victoria Meadows concluded that in search of life signs, it is not necessary to focus on any one universal molecule. It is much more effective to track combinations of substances that are not usually found together. The best example is oxygen and methane. Both gases are present in the Earth’s atmosphere, but in the absence of living organisms, this would be impossible: they would have reacted with each other long ago, and only the one that was initially present in excess would remain. The reaction products would be water and carbon dioxide, substances that are not directly related to life. In other words, for the planet’s gas membrane to contain oxygen along with methane, there must be a constant source of replenishment of both. The likelihood that this source is of a biological nature is not so small.

Other examples of such “incompatible pairs” are oxygen and ammonia, or oxygen and hydrogen sulfide. The latter, however, is difficult to detect spectroscopically, but with improved observational techniques, this will not be a big problem. By the way, this is also the reason why scientists were so inspired by the recent discovery of phosphine (a compound of hydrogen and phosphorus) in the Venusian atmosphere: while on Jupiter and Saturn, where it was also observed, this gas is formed as a result of abiogenic processes and can exist for a relatively long time, on Venus it would have to disappear very quickly. However, further research has shown that phosphine is present in concentrations that can also be explained by natural causes.

The development of infrared astronomy has opened up new perspectives for astronomers, allowing them to search for quite exotic molecules, such as chlorofluorocarbons (CFCs). In their case, the most interesting thing is that they are not formed in the course of any natural processes, but are exclusively the product of artificial chemical synthesis. Also, these molecules or their closest derivatives are quite resistant to decomposition and can stay in the atmosphere for a long time. If we encounter such “exotics” in the spectrum of an extrasolar planet, it is likely to mean that there is not just life, but an advanced technological civilization.

However, to find CFCs in the atmospheres of even the closest exoplanets using the available astronomical instruments, their concentration there must be ten times higher than what we currently have on Earth. It is clear that the observational technique is not standing still – perhaps in a few years, this obstacle will be overcome. The prospect of detecting brothers in mind by the spectral characteristics of only one type of molecule at once is very attractive. Therefore, it is time for scientists to expand the list of biomarkers by adding “technomarkers” or “technosignatures” – volatile substances that can only be produced and released into the air artificially. And here, not only astronomers and biologists, but also ecologists and chemists should have a say.

• This article was published in Universe Space Tech magazine #1 (189) 2023. You can buy this issue in the electronic version in our store.

Microgravity conditions dictate their own rules. Fragile products are prohibited — their small particles pose a threat to equipment. Liquids pose a particular hazard: stray drops can damage electronics. How do astronauts solve the seemingly simple hygiene task of washing their hair while spending months in space? 

NASA astronaut Nichole Ayers, who arrived at the ISS in March 2025, recently demonstrated this process. “It’s similar to the process on Earth, but without gravity pulling the water down,” she explains.

To wet long, thick hair, Ayers uses a special water bag equipped with a one-way valve. This allows for precise control of the fluid flow. To prevent water droplets from flying into the air, she presses the tube firmly against her scalp before releasing the water, directing it first onto the ends of her hair.

Despite all efforts, the hair only gets wet on the surface. But this is enough to apply shampoo in the form of a solid bar and start washing. When rinsing, Ayers focuses on the scalp. After quickly drying her hair with a towel, the astronaut adds a little conditioner, combs her hair, and lets it dry naturally.

Where does the water go after washing? “It evaporates, enters the air, and humidifies it. Then we will return it by condensation. Perhaps tomorrow this water will become someone’s coffee,” Ayers remarks humorously, alluding to the closed water recycling system on the ISS.

Earlier, we reported on how a NASA astronaut invented a funny way to put on pants on the ISS.

• According to Digital Trends

A leak of vital air continues at the International Space Station (ISS). Despite the crew’s hopes that the latest crack in the Russian Zvezda module has finally been repaired, prolonged observations confirm that the station is still losing precious air supplies. 

Roscosmos notes that after repairing the hull, the team believed the problem had been solved, but further data dispelled these hopes. The repairs only slowed down the air leak, but did not stop it completely.

The history of the hole

The air leak from the ISS was first detected in September 2019. Its source is located in the airlock connecting the docking node with the main body of the Zvezda module. Over the past six years, the situation has deteriorated significantly: the rate of air loss has roughly doubled, from around 0.45 kg to almost 0.9 kg per day. This growth caused NASA to raise the risk level to maximum.

An important obstacle to resolving the problem remains the dispute between NASA and Roscosmos regarding the root cause of the leak and the best way to fix it. Even the encouraging sign in June — a change in pressure that could have indicated the leak had stopped after certain manipulations — turned out to be false. 

Possible solutions to fix the problem

As a radical solution, space agencies are considering permanently closing the hatch leading to the Zvezda module. If this happens, the ISS will be able to continue operating as normal, and the air leak will indeed stop, but one docking port for cargo or manned spacecraft will be lost, which will be a significant operational limitation.

For now, the crew and ground services continue to search for the elusive “wound” on the space station, trying to maintain the airtightness of the key segment of the ISS in the face of an unpredictable challenge.

We previously reported that astronauts on the ISS complained about the terrible smell coming from the Russian Poisk module.

• According to Gizmodo

NASA specialists have found a way to enable the Curiosity rover to perform several tasks simultaneously. This will allow for maximum efficiency in using its energy source and extend its service life.

Curiosity’s energy budget

Curiosity recently reached a region filled with cell-like formations. These hardened ridges are believed to have been created by underground waters billions of years ago. Spanning many kilometers in this part of Mount Sharp, these formations may shed light on whether hypothetical microbial life could have survived in the depths of Mars billions of years ago, extending the planet’s habitability until it began to dry out. 

Performing this detective work requires a great deal of energy. In addition to moving and extending its robotic arm to study rocks and boulders, Curiosity is equipped with a variety of scientific instruments and heaters that require power.

Other NASA missions, such as the Spirit and Opportunity rovers and the InSight lander, relied on solar panels to recharge their batteries. However, this technology always carries the risk of insufficient sunlight. Therefore, engineers equipped Curiosity with a radioisotope generator (RITEG). Thanks to this, the rover is not affected by changes in lighting conditions. The downside is that because plutonium decays over time, charging Curiosity’s batteries takes longer each year, leaving less energy for scientific research.

More effective science

NASA engineers generally send Curiosity a list of tasks to complete one by one before the rover ends its day and takes a break to recharge. In 2021, the team began investigating whether it would be safe to combine two or three of the rover’s tasks, thereby reducing its active time.

For example, the Curiosity radio regularly sends data and images to a passing orbital spacecraft, which transmits them to Earth. Can the Mars rover communicate with the orbital spacecraft while moving, shifting its robotic manipulator, or taking images? Combining tasks can shorten each day’s plan, requiring less time with heaters and equipment turned on and ready for use, which reduces energy consumption. Testing has shown that Curiosity is capable of doing all this safely.

Another technique is to allow Curiosity to decide when it needs to rest if it finishes its tasks early. Engineers always overestimate the duration of daily activities in case of unforeseen circumstances. Now, if Curiosity completes these actions ahead of schedule, it will go to sleep earlier.

By allowing the rover to manage its own rest time, it is possible to reduce the charging time before the next day’s schedule. Even actions that reduce the time required to complete a single task by just 10 or 20 minutes can have a significant long-term effect, maximizing the service life of the RITEG for further scientific research and exploration. 

A lot remains to be done

Engineers are implementing new features in Curiosity based on their experience operating it. Several mechanical issues required a redesign of the sample collection method using a drill bit mounted on a robotic arm, and movement capabilities were improved through software updates. When the color filter stopped rotating on one of the two cameras mounted on Mastcam, Curiosity’s rotating “head,” the team devised a workaround that allowed them to capture the same beautiful panoramas. 

NASA has also developed an algorithm to reduce damage to Curiosity’s wheels, which are worn down from hitting rocks. Although engineers are closely monitoring any new damage, they are not concerned. After 35 kilometers of driving and extensive research, it became clear that, despite wear and tear, the wheels are capable of serving for many more years. In combination, these measures allow Curiosity to operate as actively as before.

• According to JPL

The Perseverance rover has discovered unusual formations that are almost perfectly spherical in shape. According to scientists, they were formed as a result of the cooling of molten material.

Spherical particles are not what you would expect to find in Martian soil. However, two decades ago, the Opportunity rover discovered spherical hematite formations (unofficially nicknamed “blueberries”) near its landing site on the Meridiani Plateau.

Now, the Perseverance rover has also managed to detect spherical particles. The discovery was made in an area unofficially named Witch Hazel Hill. Spherical formations are embedded in the bedrock and scattered throughout the area. Perseverance studied them by taking a series of images and measuring their elemental composition.

Despite their external similarity to “blueberries,” these spherical particles have a completely different composition and, probably, origin. The fragments found by Opportunity consisted of hematite minerals, and they’re thought to have formed in groundwater-rich sediments way back in Mars’ past.

For comparison, these spherical particles are composed of basalt and were probably formed as a result of a meteorite impact or volcanic eruption. When a meteorite hits the surface of Mars, it can melt rock and spray droplets of molten rock into the air. These droplets can cool quickly, solidify into spherical particles, and fall as rain onto the surrounding area. Alternatively, spherical particles could have formed from molten lava during the eruption.

The Perseverance team intends to continue searching for answers to the question of the origin of these spherical particles. If they were formed as a result of an ancient impact, they can tell us about the composition of the impactor and shed light on the formation of craters in the early history of Mars. If they were caused by a volcanic eruption, they may preserve traces of past volcanic activity in the area around Jezero crater. In any case, these spherical particles are a reminder of a dynamic period in the distant past of the Red Planet.

Earlier, we reported on how Perseverance encountered a stubborn rock during its “battle.”

• According to NASA

Abduction of humans by aliens

Imagine that you have arrived in another star system, discovered an Earth-like planet, and that it has not only life, but also an advanced alien civilization. What would you do in this case? How about abducting a few dozen aliens and doing something strange with them on board your ship?

At least, according to popular beliefs, this is what aliens who come to our planet do to people. Dozens of movies have been made about this, and many people claim to have experienced something similar.

Of course, there is no scientific evidence that anything like this is happening. The proof of the existence of UFOs was extremely dubious 50 years ago, and it remains so. But let’s imagine that the aliens are us, that we have arrived in the Solar System and seen cities inhabited by some intelligent beings. Does it make sense for us to resort to crime?

Biochemistry and Biology

The first and foremost reason given for alien abductions is biological research. At first glance, this seems logical, but not from the point of view of an evolutionary biologist and ecologist.

Because any intelligent life on the planet is part of the biosphere, and the biosphere is the result of biological evolution. Its source is biochemical processes. Therefore, the basis for studying the biology of intelligent beings is the study of the physical parameters and chemical composition of the atmosphere and hydrosphere. This data is already sufficient in principle to understand the basis of life on the new world.

Further, microorganisms can be obtained from air and water samples, the study of which will already provide more information about the intelligent population of the planet than primitive vivisection. Since the synthesis of proteins based on DNA and RNA in living organisms is essentially the same, the process is not significantly different.

In addition, we should not forget about passive surveillance. Flying drones into a forest, coral reef, or savannah and getting information from them about how people move, who eats whom, and how they reproduce is much easier than abducting some drunken native and then having to deal with him when he starts telling you what you did to him.

Then we can take representatives of non-sapient species from nature and study them. This will already provide enough information about the general anatomy of living beings on this planet, and as a result, about the approximate anatomy of representatives of the local civilization. This is called the method of deduction, which is the derivation of individual statements from general ones.

Based on the study of the anatomy of species close to them and simple observations, it is already possible to find out 99 percent of all the information that can be obtained by directly studying the abducted intelligent being.

Books and the Internet

All of the above makes sense only if the alien ship is dealing with a civilization that is at a pre-industrial stage of development. To study the biology of natives with a more advanced civilization, you can use their help.

After all, any advanced civilization must have medicine. And stealing an anatomy textbook and a medical encyclopedia will be much easier and more invisible than stealing a person. After all, who knows their biology better than the locals?

Of course, the language will have to be deciphered, but if you have the time and desire to remain undetected, this is a much more justified practice than abducting people. The library should be one of the first targets for aliens, because it is ready-made knowledge, not only about biology but also about everything that is happening or has happened on the planet. Of course, there may be mistakes in interpreting what is written, but stealing books for aliens is still much more effective than abducting people.

What can we say about the Internet? You can simply connect to it, decrypt it, and you do not need any hijacking at all.

Culture, politics, and volunteers

By the way, if the aliens, which we are, want to interact with the natives in the future in some way other than turning around and flying away, then information about the culture and political realities of the latter will be more important to them than biology. After all, even if it is in your interest to simply destroy your competitors, provoking a world war would be the most effective way to weaken them.

Suppose your plans are more peaceful, for example. In that case, you simply want to turn the planet into your colony, then information about how local culture and politics work becomes vital to you. And again, it is easiest to get this information from publicly available information sources, if they have already appeared on the planet.

And forcibly abducting someone to find out all the clear points is probably the worst way to keep up with all the events. It is much more effective to look for voluntary helpers. After all, if the civilization on the planet has already “grown up” to the idea of the existence of other worlds and life on them, there will be enthusiasts for contact among the population.

And these are the natives who do not need to be abducted. They will voluntarily provide their bodies for the study of everything that is still in question in the field of biology and tell us everything they know about the world around them.

After all, unlike abduction victims, they will not tell you that something strange has happened to them. And finally, assistants can then run errands for you on the planet, search for information, or prepare the ground for contact.

Exotic causes

The abduction of humans by aliens for study for further peaceful contact, conquest, or extermination does not make sense if they have sufficient time and resources for detailed research. It does make sense if the contact is certain to be non-peaceful and very quick.

For example, if some nomadic horde of aliens is planning to pass through the Solar System in the coming decades, and they are going to just eat everything here and fly on, abduction, interrogation, and anatomization may be a strategy. But then there will be no aborigines who return to their people and tell them that they were abducted.

The situation is similar with such exotic possibilities as abducting people for alien zoos, hunting us for food or for ritual purposes, and all that. In these cases, there would simply be no witnesses. At the same time, the scenarios themselves seem somewhat far-fetched.

Finally, if we are to consider all versions, we should not forget about the idea of abduction for mating and hybridizing aliens and natives, no matter how strange it may sound. And this is where abduction is a completely unnecessary thing. This particular task is much easier to accomplish with the help of volunteers.

So in fact, even if aliens are exploring the Earth right now, they are not likely to abduct someone by force and then return them. But they will get collaborators, but the latter will not talk about any violence on their part.

But they will almost certainly tell you how good it is to meet aliens. By the way, there are plenty of such stories, although they are less common than abduction stories. In ge }neral, we cannot rule out the possibility that other civilizations have been observing us for centuries, and their methods of obtaining information are so integrated into our society that we simply do not distinguish them from our own culture.

As every conspiracy theorist knows, governments around the world and especially the United States hide from us the truth about unidentified flying objects that are UFOs. However, while everyone is looking for classified materials, we have prepared for you a number of completely unclassified facts about these phenomena, about which you might not have known anything until now.

1. Who coined this term?

The term “UFOs” means “unidentified flying objects”. This term means absolutely everything that flies, but at the same time it is not possible to understand what this is right away. Then such an object may turn out to be a secret plane, a bird, an enemy probe, a plastic package, a cloud, or something completely mysterious. But the term does not mean any mystical or extra-planetary origin of the object.

The term “UFO” was first used in 1951 by Edward James Ruppelt. He was an engineer and an officer of the American Air Force and, among other things, participated in the Blue Book program, the purpose of which was to figure out what it was flying in the American sky.

2. When did people first observe UFOs?

However, people saw strange objects in the sky long before Ruppelt first used the term “UFO”. Reports about them can be found even in medieval chronicles. However, until the 20th century, these were isolated cases that no one paid much attention to. They became massive during the Second World War. 

But even then the attention to them was limited. The real hysteria began only in 1947, when the pilot of a private plane, Kenneth Arnold, reported that he saw 9 objects similar in shape to sickles, which made strange movements in flight, like saucers that were thrown along the surface of the water. So they were bouncing.

However, the journalists misunderstood Arnold and thought that the objects were shaped like saucers. So the term “flying saucer” got into the media, and since then most UFOs that people see have this shape.

3. Do UFOs have any explanation?

Every year people see hundreds and thousands of unidentified flying objects in the sky. However, over time, quite earthly explanations are found for the absolute majority of them. Astronomical and atmospheric phenomena account for a large share. Quite a few UFOs also turn out to be airplanes, helicopters, balloons and drones.

Usually 5-10 percent of the total number of observations remains, for which there is no explanation. However, this does not always mean that something unnatural happened in these cases. Often, there is simply not enough data about what exactly happened to identify an object.

4. What is Area 51?

In the state of Nevada there is an object that is officially called Homey Airport, but most people know it by the name “Area 51”. Allegedly, this is how it is named in one of the documents from the Vietnam War.

From 1955 to the present day, Homey Airport has been a top secret facility of the American Air Force. And, according to popular conspiracy theories, it is here that the wreckage of shot-down UFOs, or even the bodies of aliens, are stored. 

However, there is a completely earthly reason for the secrecy of this place. It was here that the high-altitude reconnaissance aircraft U-2 and SR-71 and the F-117 stealth aircraft were tested

5. Why did UFOs disappear from American secret documents?

It is impossible to find the term “UFO” in modern documents of the American military. But this does not mean that they have lost interest in them or completely classify everything. On the contrary, right now these studies have the most global character in recent decades and are as open as the situation allows.

The Pentagon has officially created an entire AARO department, which collects information about all the incomprehensible things that happen in the sky, studies them and even issues reports that are partially open. Why they cannot be fully discovered became clear in 2023, when part of the “unidentified aerial phenomena”, as UFOs are now called, turned out to be Chinese unmanned balloons that were studying something in the United States with the help of “scientific” equipment.

August 5, 2025, will be one of the shortest days in history. Meanwhile, scientists are at a loss as to the reasons for the mysterious acceleration of the Earth.

The period of the Earth’s rotation around its axis (one full rotation of 360 degrees relative to the stars) lasts 23 hours, 56 minutes, and 4.1 seconds. This is known as a sidereal day. It explains why stars and planets rise in the east about four minutes earlier each day, and why the night sky changes depending on the season. After all, the Earth moves in its orbit around the Sun while simultaneously rotating around its axis.

But the fact is that we live according to the solar day, not the sidereal day. It is measured from noon to noon and lasts exactly 24 hours (86,400 seconds). Since official records began in 1973, the length of daylight has steadily increased, mainly due to the Moon. As it moves around the Earth, it creates friction, causing its orbit to shift further away from our planet. At the same time, the Earth’s rotational energy is transferred to the Moon, which leads to a slowdown in the Earth’s rotation and, consequently, to an increase in the length of days.

However, this situation has changed in recent years. After decades of slowing down, our planet’s rotation has accelerated — and researchers cannot provide a clear explanation for why. In 2025, they predicted three dates when the solar day on Earth would be shorter than 24 hours: July 9 (1.23 milliseconds shorter than 24 hours), July 22 (1.36 milliseconds shorter), and August 5 (1.25 milliseconds shorter). The title of the shortest day in history is currently held by July 5, 2024. On that day, the day was 1.66 milliseconds shorter than 24 hours.

A difference of just 1.25 milliseconds from the 86,400-second mark may seem insignificant, but it is indicative of global processes that we are not yet able to understand. According to one theory, global warming is to blame. On the other hand, the acceleration is caused by the slowing down of the liquid part of the Earth’s core, as a result of which the rest of the planet rotates faster.

Regardless of the reasons for the acceleration, according to scientists, if the current trend continues until 2029, then, for the first time in history, a so-called negative leap second may be added to compensate for the deviation.

• According to Space.com