Astrophotographer Satoru Murata has published a photograph of interstellar comet 3I/ATLAS. It shows its tail and anti-tail.

The 3I/ATLAS image was taken on the morning of November 16 in New Mexico. To capture the image, Murat used a Celestron EdgeHD800 telescope and a Touptek ATR2600C camera. The image he published is composed of 24 frames taken with a 60-second exposure.

The photograph shows the complex structure of the tails of 3I/ATLAS. They consist of volatile substances that have sublimated from its surface. Observations have shown that 3I/ATLAS is unusually rich in carbon dioxide. Astronomers have also detected substances such as water ice, carbon monoxide, carbonyl sulfide, and cyanide. It is the molecules of the latter that are responsible for the characteristic blue-green color of the interstellar comet. Earlier it was reported that 3I/ATLAS changed color as it passed through perihelion, but as it turned out later, this was incorrect.

In addition to its main tail, the ATLAS comet also has an anti-tail. In the image, it looks like a small spike. The anti-tail consists of larger dust particles that are less affected by the Sun’s radiation pressure and tend to remain roughly in the plane of the comet’s orbit, eventually forming a disk along its orbit. When Earth passes through the plane of the comet’s orbit, this disk is visible from the side and looks like a distinctive spike.

In addition to the comet, the photo also captured the galaxy NGC 4691. It is located 70 million light-years from Earth in the direction of the constellation Virgo.

Earlier, we reported on how the Mars mission helped to pinpoint the location of comet 3I/ATLAS.

Participats in the LRO mission have published an image showing a young crater on the Moon. It formed after the spacecraft began operating.

Throughout its history, the Moon has been regularly bombarded by comets and asteroids. This bombardment was particularly intense during the first billion years after the formation of the Solar System. It was then that the Moon acquired its largest “scars.”

Although the frequency of collisions has decreased since then, they have not stopped completely. And since the Moon has no atmosphere, even small objects that would not be able to reach the Earth’s surface can reach the Moon’s surface unhindered.

It was precisely such an object, several meters in size, that formed the crater found by LRO. It is located north of the 44-kilometer-wide Römer crater. The 22-meter funnel formed between December 2009 and December 2012, when the spacecraft photographed this area again.

The crater discovered by LRO is surrounded by bright rays consisting of lighter subsurface material ejected during the impact. They extend tens of meters from the crater. Over time, under the influence of space weathering, the rays will darken to match the color of the surrounding regolith.

The discovery of new craters using LROC is important for understanding the frequency of impacts and the rate of crater destruction over time. Planetary scientists use this data to estimate the age of surface features on celestial bodies. This data is also important for future manned missions to the Moon.

The Moon is not the only object in the Solar System that is subject to cosmic bombardment. Earlier, we talked about known cases of asteroids and comets falling on other planets.

• According to LROC

The von Neumann probe is one of the most daring concepts related to space exploration. It is a hypothetical unmanned spacecraft that can travel between stars and create copies of itself. And this idea is even crazier than it might seem.

Self-replicating machines

The arrival of interstellar comet 3I/ATLAS in the Solar System has prompted many people to recall the concept of a von Neumann probe. This is not surprising, given that any object approaching us from outer space that we have not yet been able to identify properly could potentially be one of these.

This has nothing to do with 3I/ATLAS specifically. Over the past few months, this comet has been studied many times with all possible telescopes, and we know for sure that it consists only of ice and rocks. However, it is still necessary to know what exactly to be afraid of.

The von Neumann probe is a hypothetical spacecraft designed to explore the Galaxy. It must be capable of exploring a star system, have a complete set of equipment for extracting resources in space, converting them into parts and mechanisms, and an engine capable of interstellar flight.

Source: phys.org

The flights themselves take place at pre-light speed, meaning they take at least decades. But once it reaches a star system, the machine finds resources and begins to build copies of itself, which fly off to surrounding star systems and repeat the cycle there until they have explored the entire Milky Way.

From the title, one might think that the author of this idea is someone named von Neumann. But in fact, the Hungarian mathematician János Lajos Neumann, or John von Neumann, as he was known in the United States, never wrote anything about automatic spaceships.

He is indeed one of the authors of the very concept of computing and automation, and all our computers are built based on a scheme called “von Neumann architecture.” It was precisely this research into how complex a machine’s response to different input conditions could be that led him in 1949 to the concept of self-replicating machines.

The idea may seem revolutionary even now, but its fundamentals are quite simple. In industrial construction, machines are capable of manufacturing individual parts and assembling them, creating systems of any complexity without human involvement, provided that all processes are well thought out.

So why not create a copy of the assembly line that can make its own copies? Von Neumann’s early work focused solely on the assembly process. However, by the 1950s, it became clear that the process could be expanded to include the extraction of raw materials. In theory, copies of all this could be built according to a predetermined program.

Von Neumann probe and Fermi paradox

Von Neumann himself called such machines simply self-replicating, but as these ideas gained popularity after he died in 1957, they became known as “von Neumann machines.” It is not known for certain who first attempted to put one of them on board a spacecraft and called it a “von Neumann probe.”

The only thing that can be said with certainty is that this term was already well known among English-speaking fans of science fiction and futurology when, in 1981, American physicist Michael Hart applied this concept in his work on the Fermi paradox and the related Drake equation.

The Fermi paradox can be formulated as follows: if Earth is a typical planet in the universe and it gave rise to humans, then why don’t we see aliens who should have emerged on some other planet in the Milky Way? There are many approaches to solving this problem, but they all ultimately rely on unverified assumptions, so any of them could be right or wrong.

The Drake equation is a mathematical embodiment of the Fermi paradox, which, in theory, should tell us how many intelligent civilizations we should encounter while exploring the Milky Way, but in practice, it contains too many variables that are unknown to us.

However, the known data, such as the rate of star formation and the total number of stars in the Galaxy, was enough for Hart to calculate that von Neumann’s wave of probes would have to travel the Milky Way from end to end in just 640,000 light-years, meaning that if there were at least one advanced civilization other than ours, we would have already encountered its probes right here in the Solar System.

And since we see nothing of the sort, the Fermi paradox is relatively easy to solve: we do not know the reason, but there are no intelligent species in the Galaxy other than us. This conclusion immediately drew criticism from renowned scientist and science popularizer Carl Sagan.

He stated that Hart was correct, but underestimated the power of self-repairing machines. If they functioned as he believed, they would have long ago not only reached the Solar System, but also dismantled Earth, us, and even their own creators and their home world for raw materials for their copies. Therefore, no truly intelligent civilization would create such machines. Consequently, the absence of von Neumann probes is not a sign of the absence of life in the Galaxy.

Since then, science and science fiction enthusiasts have repeatedly revisited Hart and Sagan’s arguments, inventing various restrictions on the replication of probes, but ultimately, it all boiled down to yet another set of theories about the Fermi paradox.

Development of the idea

The main reason why von Neumann probes are so popular is that this method of conquering the Galaxy seems to be the simplest and cheapest. Traveling faster than light is still the stuff of science fiction. To avoid a journey lasting thousands of years, the ship must be accelerated to a tenth of the speed of light. This requires an incredible amount of energy, so it is better to make it as light as possible. The payload should not exceed tens of tons.

At the same time, the von Neumann probe itself does not necessarily have to have full-fledged artificial intelligence. However, beyond the task of “flying and copying,” other functions can be assigned to it. For example, it can simultaneously be a so-called Bracewell probe. This is another concept of an interstellar drone, whose main task is to establish contact with other civilizations.

But there could be a much worse scenario. In 1967, American science fiction writer Fred Saberhagen described a berserker – a variant of the von Neumann probe, which is armed and designed to destroy any intelligent life it encounters. It is a radical way to get rid of competitors once and for all.

There is also a concept that is radically opposed to the berserker – the seeder ship. In this case, the von Neumann probe carries biological material from its home planet or the embryos of the creatures that created it. When it reaches a world that has no biosphere or civilization, it uses its reserves to create intelligent or non-intelligent life, and only then sends out copies of itself. In this way, the Galaxy could be completely populated in a couple of million years.

There is also a lighter version of von Neumann’s probe. It is called an astro-chicken. Its author is the famous physicist Freeman Dyson, the same one who invented giant spheres. The idea is to use a very small device to explore the solar system, whose main payload will be a system for extracting resources and manufacturing parts from them. Just as a chick moves around the yard and, pecking at seeds, grows into a hen, so this device must “grow” its own equipment for movement and exploration of the planets.

Is the von Neumann probe a form of life?

Behind all this lies a much more interesting question. We are now accustomed to thinking that if a machine is capable of performing some complex task, it must have some kind of highly intelligent control system. That is, when we think of the von Neumann probe flying to another star system, we most often imagine it with full-fledged AI.

However, Don von Neumann himself, working on the theory of self-replicating machines, thought in the opposite direction. How simple do they have to be to still retain the ability to create their own kind?

This is indeed a significant question. We are already seeing machines that have very little intelligence but are capable of effectively adapting to an extremely wide range of conditions. We are talking about biological life: RNA (including viruses), bacteria, and multicellular organisms. Human machines still cannot match them in terms of the efficiency of converting matter, in terms of the effort spent on decision-making.

A truly effective von Neumann probe is not a supercomputer in a jar, but a virus. Something like the protomolecule from James Corey’s Expanse series of novels. On the other hand, even a very cumbersome system in which a single ship cannot reproduce itself but can be rebuilt into a stationary factory already has a set of characteristics in terms of resource and energy consumption, behavior, reproduction, and information inheritance, with the possibility of changes according to the given conditions.

Altogether, this is the definition of life. It is the best we have, because even on Earth, it demonstrates an incredible variety of forms and mechanisms that are difficult to describe in more narrow terms. So, is it possible to draw a line between a self-reproducing mechanism and an organism? Especially if the former is made not of metal but of polymers.

And if von Neumann probes are equipped with artificial intelligence, will they be able to build their own civilization? Will it be a mind alien to us, or a continuation of our own? What will happen if machines created by two completely different biological species meet somewhere? Will they find more in common than their creators would have found?

There are no answers to all these questions. But searching for them is extremely interesting.

Comet C/2025 K1 ATLAS has broken up. Its nucleus has split into several fragments, as shown in recent images taken on November 13.

Not that comet ATLAS

C/2025 K1 ATLAS should not be confused with the much more famous interstellar comet 3I/ATLAS, which is currently the focus of global attention. Both were discovered in 2025 by the ATLAS system, a network of robotic telescopes designed to search for small near-Earth objects and warn of possible collisions with Earth. This is why the word ATLAS appears in the designation of both comets.

As for the alphanumeric designations, they are deciphered as follows. In the case of C/2025 K1/ATLAS, the letter “C” means that the comet is long-period (its orbital period around the Sun exceeds 200 years), 2025 is the year of its discovery, the letter “K” is the half-month of discovery (the second half of May), and the number 1 indicates that it is the first comet discovered during that half-month.

In turn, in the case of comet 3I/ATLAS, the letter “I” means that it is an interstellar object, and the number 3 means that it is the third such object found. In the future, as the number of interstellar objects found increases, changes may be made to their designation system.

Golden Comet

Although C/2025 K1 ATLAS is not an interstellar visitor, it is still a rather curious object. The comet arrived from the Oort Cloud, a cluster of icy bodies located at the far reaches of the Solar System. This means that its material has never been exposed to solar radiation.

On October 8, C/2025 K1 ATLAS passed the perihelion of its orbit at a distance of 0.33 AU (50 million km) from the Sun. The comet surprised scientists by acquiring a very rare golden color. Subsequent studies revealed that C/2025 K1 ATLAS contained very few carbon-containing molecules, such as dicarbon, carbon monoxide, and cyanide. In the absence of these compounds, light is reflected differently, creating a golden glow effect. This peculiarity in the chemical composition is probably due to the fact that the comet originated in the Oort cloud.

Initially, astronomers believed that due to its fragility and small size, C/2025 K1 ATLAS would not survive perihelion. However, to the surprise of many, the comet passed through it intact. Nevertheless, the encounter with the Sun did not remain without consequences. Images taken on November 10 showed that the comet’s nucleus had begun to fragment. Three days later, astronomers confirmed the fragmentation of C/2025 K1 ATLAS. Its nucleus broke up into at least three fragments.

Before its demise, comet C/2025 K1 ATLAS was moving along a hyperbolic trajectory. This means that if any of its fragments manage to survive, they will be ejected from the Solar System forever, after which they will continue their journey through interstellar space.

The European Space Agency has published images taken by the Mars Express spacecraft. They show traces of the Martian ice age.

Over the past 2.5 billion years, our planet has experienced several ice ages. These were part of an ancient geological cycle caused mainly by changes in the Earth’s orbit around the Sun and fluctuations in its axis of rotation. The last glaciation peaked about 20,000 years ago, lowering the planet’s average temperature to 7–10 °C (8 °C lower than today).

But Earth is not the only planet to have experienced glaciation. Ice ages also occurred on Mars, as clearly demonstrated by images taken by the Mars Express spacecraft. They show an area known as Coloe Fossae.

Coloe Fossae is crisscrossed by long parallel lines resembling scratches. These are the remains of glaciers that repeatedly advanced and retreated, gradually carving out deep depressions and trenches. Like other parts of Mars, this region is covered with numerous craters of varying degrees of erosion. At their bottom, you can see another sign of the glacial period: spiral patterns.

These patterns provide insight into the climate of the Red Planet in the past. They were formed when ice flows covered with a thick layer of rock material slowly flowed across the surface of Mars (something similar happened on Earth).

The area photographed by Mars Express is located at 39° north latitude, which is very far from the north pole and raises the obvious question of how ice could have reached such low latitudes. The answer lies in the pulsation of advancing and retreating glaciers. Although Mars is currently dry, throughout its history it has experienced alternating periods of warming and cooling, freezing and thawing, caused by changes in the tilt of its axis.

During cold periods, ice spread from the poles of Mars to the mid-latitudes, and when it got warmer, it receded, leaving behind characteristic traces. Spacecraft have discovered valleys and craters filled with glacial deposits across this entire latitudinal band, evidence of global climate change on the planet. This area may have been covered in ice as recently as half a million years ago, when the last ice age ended on Mars.

Earlier, we reported on how Mars Express photographed a potential landing site for a manned expedition.

• According to ESA

The X5.1-class eruption from sunspot AR4274 is the most powerful flare of the year, accompanied by a coronal mass ejection. Our planet is in its path.

X5.1-class solar flare

On the morning of November 11, the Sun exploded in spectacular fashion, releasing a powerful X5.1-class solar flare, the strongest since 2025 and the most intense since October 2024.

The explosion peaked at 5 a.m. Eastern Standard Time (10:00 GMT) from sunspot AR4274, which has been very active in recent days. The flare caused severe (R3-level) radio interference in Africa and Europe, disrupting high-frequency radio communications on the sunlit side of the Earth.

Danger of geomagnetic storms

This flare is the latest in a series of intense flares from AR4274, which also caused an X1.7 flare on November 9 and an X1.2 flare on November 10. These flares were accompanied by coronal mass ejections (CMEs) that could combine and affect Earth tonight, possibly causing strong (G3) geomagnetic storms and widespread auroras, according to the NOAA Space Weather Prediction Center. Today’s coronal mass ejection may also join them, as it is moving toward Earth at a speed of 4.4 million miles per hour. NOAA predicts that the CME could affect Earth around noon on November 12. With this third CME, we may experience strong (G4) geomagnetic storms.

Solar flares are classified by strength into five classes: A, B, C, M, and X, with each step corresponding to a tenfold increase in energy output. X-class solar flares are powerful, and the number after X describes the intensity of the flare. With an intensity of X5.1, this latest flare is at the top of the scale.

Peak solar activity

The eruption resulted in a stream of X-rays and extreme ultraviolet radiation toward Earth, ionizing the upper layers of the atmosphere and causing a significant deterioration in radio signal quality. Severe (R3) radio interference was recorded over Africa and Europe.

This active region has become one of the most prolific sources of solar flares in the 25th solar cycle, marking the peak of activity in what has already been an extraordinary week for solar activity.

According to forecasts, the coronal mass ejection that occurred this morning during the X5.1 solar flare will reach Earth on November 12. According to NOAA, the coronal mass ejection could cause a strong (G4) geomagnetic storm on November 12.

• According to www.space.com

Chinese scientists have announced the discovery of a previously unknown crater named Jinlin. It was formed after the end of the last ice age.

The Jinlin crater is located in Zhaoqing, Guangdong Province. The impact structure is located on a hillside, preserved under a thick granite weathering crust. Its diameter is 900 meters.

According to scientists’ estimates, the crater is very young. It was formed in the early to mid-Holocene epoch, our current geological era, which began after the end of the last ice age about 11,700 years ago. This makes Jinlin the largest impact crater in modern human history. In terms of size, it significantly exceeds the Macha crater, which was formed in the Holocene and has a diameter of only 300 meters.

One of the most remarkable features of the Jinlin crater is its good preservation, considering the climatic conditions. The region where it is located is characterized by monsoons, heavy rains, and high humidity. In the granite layers that helped protect and preserve its structure, researchers found many pieces of quartz with unique features that prove its impact origin.

According to scientists, the crater was formed by the impact of a small asteroid. However, the research team has not yet determined whether it was made of iron or stone.

At present, there are about 200 confirmed impact craters on Earth. In reality, there were many more, but due to erosion and plate tectonics, many of them have completely disappeared without leaving any traces. This makes the discovery of the Jinlin crater particularly significant. It shows that the scale of impacts of small extraterrestrial objects on Earth during the Holocene was much greater than previously thought.

Earlier, we reported on another crater recently discovered in China, which was photographed by a NASA satellite.

• According to Eurekalert.org

A team of Chinese scientists has announced the discovery of a new type of cave on Mars, created by water flows. They could have been home to life.

If there is or ever was life on Mars, it most likely existed in caves, protected from severe dust storms, extreme temperature fluctuations, and high levels of radiation on the planet’s surface. However, until recently, most of the Martian caves found were lava tubes (cavities in solidified lava flows), which could hardly claim to be an oasis of life.

However, it appears that there are other types of caves on Mars. In an article published in The Astrophysical Journal Letters, a team of Chinese scientists presented the first evidence of karstic caves on the Red Planet.

On Earth, karstic caves usually form when water dissolves rocks such as limestone or gypsum, creating and enlarging underground cracks and fissures that become large enough to become caves. Scientists believe that similar processes occurred on ancient Mars, where water dissolved carbonate- and sulfate-rich rocks.

The caves we are talking about are located in a region called Hebrus Valles. It is a system of ancient valleys and drainage channels in the Northern Hemisphere of Mars. After studying images from spacecraft, scientists discovered eight pits. These are deep and mostly circular depressions, rather than impact craters, which usually have raised edges and debris scattered around them.

Data collected by the Mars Global Surveyor’s thermal emission spectrometer indicate that the rocks around the pits are rich in carbonates and sulfates. These are types of rocks that water can easily dissolve. The team also used high-resolution images to create three-dimensional structural models, which showed that the shapes of the pits correspond to collapse caused by water, rather than volcanic or tectonic activity.

According to the authors of the discovery, eight potential karstic caves should be priority targets for future Mars missions. Even if there is no life there, they could serve as natural shelters for astronauts and a place to set up their base.

We previously reported on the existence of a habitable ocean on Enceladus.

• According to Phys.org