On July 5, 2025, astronomers recorded a flash caused by an object falling onto Saturn. Of course, scientists already knew that the sixth planet in the Solar System was regularly bombarded by various small bodies. However, until then, they had never seen anything fall on Saturn with their own eyes.

In this article, you will learn about other well-known cases of cosmic bombardment of bodies in the Solar System, from Jupiter to our Moon.

Heroic Jupiter

Jupiter is the most massive planet. Its mass is more than twice that of all the other planets combined. Because of this, its gravity has a huge impact on the Solar System, including asteroids and comets. Some scientists even believe that Jupiter should be called the protector of Earth – after all, its powerful gravity protects our planet by deflecting bodies that would otherwise fall on it.

The flip side of the coin is that Jupiter is regularly bombarded by comets and asteroids. The most famous such event occurred in July 1994, when debris from the Shoemaker-Levy 9 comet fell on the gas giant.

The consequences of the Shoemaker-Levy 9 debris falling far exceeded all astronomers’ expectations. Telescopes recorded giant fireballs that appeared in the planet’s atmosphere at the moment the debris entered it. Their temperature exceeded 30,000 degrees. The impacts created giant plumes of material from the lower layers of Jupiter’s atmosphere, which rose three thousand kilometers above the cloud tops into the stratosphere. They were spotted by Hubble and ground-based observatories.

But that was not the end of it. After the bombardment, Jupiter was left with numerous “scars” – huge dark spots marking the places where the debris had fallen. The largest of these was as wide as Earth itself – it was more visible through telescopes than the famous Great Red Spot. It took several months for the spots to finally dissipate.

Since then, astronomers have recorded 12 more instances of objects large enough to produce a flash visible from Earth falling on Jupiter. The most powerful such incident occurred on July 19, 2009. It led to the formation of a black spot in the planet’s atmosphere, comparable in size to the Pacific Ocean. The diameter of the impactor is believed to have been between 200 and 500 meters. According to NASA estimates, collisions between Earth and objects of this size occur approximately once every 100,000 years. Jupiter, on the other hand, experiences them regularly.

Secretive Mars

Since Mars’ orbit passes close to the main asteroid belt, the Red Planet is more frequently hit by asteroids than Earth. In addition, the Martian atmosphere is much thinner than Earth’s. This means that a body that is unable to pass through our planet’s atmosphere is very likely to reach the Martian surface.

Over the past quarter-century, spacecraft have discovered over a hundred fresh Martian craters. On average, they range from 10 to 30 meters in diameter and were created by impacts from objects several meters in size.

Recent research suggests that Mars is bombarded by meteorites even more frequently than previously thought. Analysis of seismic data collected by the InSight mission has shown that many Marsquakes are caused not by geological activity, but by impacts from space. For example, in 2021, the device recorded two powerful Marsquakes with a magnitude of 4. Researchers were later able to determine the areas where the objects that caused the underground vibrations fell. It turned out that they left behind craters with diameters of 130 and 150 meters.

All Martian impact events have one thing in common: the craters were found after the fact. To date, astronomers have never witnessed the process of objects falling on Mars. However, if humanity seriously sets out to conquer the Red Planet, this situation is likely to change. Data on the frequency of meteorite impacts on Mars will clearly be useful when planning manned missions and deciding where best to locate future settlements.

Defenseless Moon

Unlike Mars, the Moon does not even have a thin atmosphere. Therefore, any space object can reach its surface without any problems. Astronomers regularly record flashes caused by various meteoroids falling on it. On average, they last a fraction of a second and are usually observed on the unlit side of the Moon.

As with Mars, these collisions leave new scars on the surface of the Moon. In just the first seven years of its operation, the LRO identified over two hundred fresh craters ranging in diameter from several meters to 43 meters. In reality, there must be many more. Scientists estimate that several hundred impact events occur on the Moon each year, which, under the right conditions, can be detected from Earth.

In addition to craters of natural origin, man-made craters can also be found on the Moon. Some of them date back to the space race and the Apollo program. These include the landing sites of the first Soviet and American probes, as well as craters from the third stages of Saturn V rockets. They were deliberately sent to the Moon as part of seismic experiments.

In recent years, several more man-made craters have appeared on the Moon as a result of unsuccessful landings and accidents involving the Beresheet, Vikram, Hakuto-R, Resilience, and Luna-25 spacecraft.

In conclusion, we can also mention an incident that occurred in 1178. At that time, five monks from Canterbury reported to the abbey chronicler that shortly after sunset, they saw the upper horn of the Moon “split” in two. In the 20th century, a hypothesis emerged that the monks had observed the aftermath of an impact that formed the 22-kilometer Bruno crater on the far side of the Moon.

However, most scientists still believe that these events are unrelated. It is most likely that the crater is about a million years old. The monks may have seen a meteor superimposed on the lunar disk.

As interstellar visitor Comet 3I/ATLAS hurtles through the Solar System, scientists from around the world are taking advantage of this rare opportunity to actively study this visitor from distant worlds. The results of two new studies shed light on its remarkable properties, which challenge conventional wisdom about comet behavior.

The spectrum obtained by the 4.1-meter SOAR telescope on July 3, 2025, when the comet was far from the Sun, revealed a red tint in the reflected light. However, no signs of radiation from typical cometary gases (CN, C3, C2, CO+) or atomic oxygen were detected. This creates a paradox: the comet became active early, but without the usual sublimation of ice. Scientists suggest that dust release may occur through a different, unusual mechanism characteristic of ancient interstellar “travelers.”

A second study conducted by David Jewitt’s team based on images from the Hubble Space Telescope between July 4 and 5 made it possible to estimate the size of the comet’s nucleus. It turned out to be very compact – only 0.32 to 5.6 kilometers in diameter. This is consistent with preliminary predictions based on the limited availability of durable material in the interstellar medium. However, this tiny nucleus is surrounded by an impressively large cloud of dust, which makes up the bulk of the visible object.

Amazing glow in an unusual place

The most unexpected discovery made by Hubble was the structure of the coma of 3I/ATLAS. Instead of the classic tail extending from the Sun, the telescope detected a diffuse glow ahead of the comet’s movement toward our star. This contradicts the usual picture for comets.

An explanation for this phenomenon was proposed back in early August: the comet’s nucleus rotates very slowly. The sun heats only one side of it. The dust evaporation occurs precisely there. If the nucleus does not rotate fast enough, this hot daytime side does not have time to cool down significantly. Consequently, dust continues to be actively released from the “illuminated” part, creating a glowing effect in front. This hypothesis has been confirmed.

Remaining mystery

The latest ground-based observations complete the picture: the rotation period of 3I/ATLAS is 16.16 hours (±0.01 hours). This means that “night” and “day” on its surface last about 8 hours each. During these 8 hours, dust particles released from the day side are carried away from the nucleus to a distance of up to 10,000 km. In Hubble images, this corresponds to 0.35 arcseconds — the scale at which the elongated forward glow is observed.

The key point is that the surface of the nucleus has to cool down quickly after it goes into shadow, meaning in less than 8 hours. Otherwise, the release of dust would become more uniform and would not produce a clear frontal effect.

The main mystery that remains is the combination of intense dust release, visible by its glow, with the complete absence of any traces of gases that usually “carry” this dust in comets.

As it approaches the Sun, 3I/ATLAS will become brighter. The greatest hopes for unraveling its mystery are pinned on the James Webb Space Telescope. Its infrared vision will help analyze the comet’s thermal radiation and dust composition in greater detail, possibly finally answering questions about its true nature and the mechanism behind its unusual activity.

Earlier, we reported on how Juno, instead of dying, got a new chance at life by hunting 3I/ATLAS.

• According to medium.com

The European Space Agency has published a series of new images obtained by the Mars Express spacecraft. They show a region whose geological history holds memories of the Red Planet’s turbulent past. 

Modern Mars is a cold and desert world where, at first glance, no significant geological processes are taking place. But this was not always the case. Over billions of years of its existence, the Red Planet has gone through periods of water bodies, eruptions of giant supervolcanoes, and numerous glaciation cycles. All of them left distinctive marks on its surface.

One of the most striking examples demonstrating the tumultuous past of Mars is the Acheron Fossae region. It is located 1,200 km from Olympus Mons, the largest volcano in the Solar System, whose formation directly influenced the appearance of this area. Acheron Fossae is a surprisingly diverse mix of rugged and smooth terrain, covered with ancient faults, craters, and solidified lava. In April, Mars Express already photographed its eastern part. Now the vehicle returned to it to show the western edge, where the landscape is equally diverse: deep cracks, valleys, and winding channels carved out and filled by slowly moving streams of ice and rocks.

According to scientists, this structure emerged more than 3.7 billion years ago, when Mars was most geologically active, as a result of hot material rising beneath the Martian crust associated with the formation of supervolcanoes. This rise in molten rock stretched and tore the surface, creating cracks and valleys kilometers deep, some of which are hundreds of kilometers long.

After their formation, these valleys continued to transform. Now their bottom is relatively flat, with soft, winding lines reminiscent of a flowing river. It is believed that these valleys were once filled with a slow, viscous flow of ice-rich rock, very similar to the rock glaciers found on Earth. 

Rock glaciers are very sensitive to climate change and are therefore good indicators of how the planet’s climate has changed over time. Here, they point out that this region of Mars experienced alternating periods of cooling and warming, freezing and thawing. 

These temperature fluctuations are caused by the tilt of Mars’ axis of rotation. Unlike Earth, whose axis maintains a relatively stable and moderate tilt thanks to the stabilizing influence of the Moon, Mars’ tilt varies significantly over time. This leads to alternating warm periods and ice ages, resulting in ice periodically advancing toward the planet’s equator and then retreating back to the poles.

Although our Earth also experiences similar fluctuations, they are much stronger on Mars. Over the past 10 million years, Mars’ tilt has fluctuated between 15 and 45 degrees, while Earth’s tilt has varied between 22 and 24.5 degrees. These regular shifts, known as Milankovitch cycles, play an important role in our planet’s climate, but their influence is more subtle than on Mars. 

• According to ESA

Dark matter — an invisible substance that holds galaxies together like glue — remains the main cosmological mystery. Efforts to find it using traditional methods have reached an impasse. Against the backdrop of this crisis, physicist Stefano Profumo of the University of California, Santa Cruz, proposed two revolutionary, albeit speculative, scenarios for the origin of this mysterious matter.

Scientists discovered dark matter only because of its gravitational influence: galaxies rotate faster than they should, considering only visible matter. The difficulty lies in the fact that this mysterious substance does not emit or absorb light at all, making direct detection impossible. Decades of searching have been fruitless. Hypothetical particles that dark matter is supposed to consist of, such as WIMPs, have never been found. This deadlock forces scientists to seek radical alternatives, which may even be fantastical.

Mirror Universe

In his first article, Profumo addresses quantum chromodynamics, the theory of the strong nuclear force. He suggests the existence of a parallel “mirror” universe, where similar but invisible forces and particles — analogues of protons and neutrons — act. In the early Universe, the concentration of these dark particles could have been extremely high. This resulted in the formation of compact objects – dark matter black holes. They interact with our world exclusively through gravity, explaining the observed effects.

Birth on the edge

Profumo’s second article offers an even more exotic idea. He considers the cosmic horizon — the boundary of the observable Universe, similar to the event horizon of a black hole, but on a global scale. During the period of extremely rapid expansion of the Universe (inflation) after the Big Bang, quantum fluctuations at this cosmic horizon could spontaneously generate dark matter particles with a wide range of masses. These particles, born at the very edge of our existence, could also be a source of invisible mass.

Verification methods

“Both mechanisms are highly speculative,” Profumo notes, “but they offer self-sufficient and calculable scenarios that are independent of problematic traditional models.”

Although the theories are based on modern physics, they require significant refinement and verification in future experiments and observations. Despite this, Profumo’s work opens up new, bold avenues for unraveling one of the deepest mysteries of the cosmos — the nature of dark matter, which shapes our universe.

• According to Science Alert

The European spacecraft Hera, located in the asteroid belt, managed to obtain images of several of its objects. These observations served as both a successful test of the instruments and a demonstration of capabilities that could be useful for protecting our planet. 

The Hera spacecraft was launched to study the double asteroid Didymos. In 2022, NASA’s DART probe deliberately crashed into its companion, Dimorphos. The aim of the experiment was to study the possibility of deflecting dangerous celestial bodies away from Earth.

This spring, Hera flew past Mars and used its gravity to accelerate and change its trajectory. Shortly thereafter, the spacecraft entered the Main Asteroid Belt. Hera’s flight path does not suggest that it will encounter any asteroids along the way. Nevertheless, the mission specialists decided to take advantage of this opportunity to test the instrument. They chose the asteroid Otero, located 3 million km from Hera.

On May 11, 2025, Hera took pictures of Otero with its AFC camera. This navigation and science instrument will be used to guide the spacecraft as it gets closer to Didymos. According to experts, Otero’s imaging was conducted under conditions similar to the ones that would occur next year – when Hera reaches its destination and needs to keep the asteroid in the center of the camera’s field of view. 

Hera accomplished the task. The device successfully tracked Otero for three hours, taking one photo every six minutes. On July 19, Hera conducted a new photo shoot. This time, the camera was aimed at the asteroid Kellyday. Despite being approximately 40 times dimmer than Otero, the device managed to get an image of it.

Although science was not the primary goal of these observations, they demonstrate how a spacecraft in space can quickly perform accurate observations of a new object. This ability can be very useful for protecting our planet.

One example is asteroid 2024 YR4. Earlier this year, astronomers around the world pointed their telescopes at it because they were worried it might hit Earth in 2032. If a spacecraft similar to Hera were in the right place, it could conduct impromptu observations of the asteroid. Additional information about its size and orbit would help astronomers better assess the danger it poses to Earth.

Similarly, a spacecraft located at a suitable point could be used to observe interstellar objects passing through the Solar System, such as the recently discovered comet 3I/ATLAS. At the end of this year, it will fly past Mars, and right now the scientific community is assessing whether any of the spacecraft orbiting the Red Planet will be able to observe it.

• According to ESA