The discovery of 3I/ATLAS, a mystery interstellar object, has sent shockwaves through the scientific community. This ancient visitor is likely to be the oldest comet ever seen, possibly predating our solar system by more than three billion years. According to University of Oxford astronomer Matthew Hopkins, 3I/ATLAS could be more than seven billion years old and may be the most remarkable interstellar visitor yet.

Unlike previous objects that entered our solar system from elsewhere in the cosmos, 3I/ATLAS appears to be traveling on a steep path through the galaxy. Its trajectory suggests it originated from the Milky Way’s ‘thick disk’ – a population of ancient stars orbiting above and below the thin plane where the Sun and most stars reside.

Hopkins explained that all non-interstellar comets, such as Halley’s comet, formed with our solar system and are up to 4.5 billion years old. However, interstellar visitors have the potential to be far older, and 3I/ATLAS is likely to be the oldest comet ever seen.

The object was first spotted on July 1, 2025, by the ATLAS survey telescope in Chile, when it was about 670 million kilometers from the Sun. As 3I/ATLAS approaches the Sun, sunlight will heat its surface and trigger cometary activity, or the outgassing of vapor and dust that creates a glowing coma and tail.

Early observations already suggest the comet is active, and possibly larger than either of its interstellar predecessors, 1I/’Oumuamua (spotted in 2017) and 2I/Borisov (2019). If confirmed, this could have implications for how many similar objects future telescopes, such as the new Vera C. Rubin Observatory, are likely to detect.

The discovery of 3I/ATLAS has sparked excitement among astronomers, who believe it may provide clues about the role that ancient interstellar comets play in seeding star and planet formation across the galaxy. As the comet continues on its journey towards the Sun, scientists will be closely monitoring its activity and behavior.

The Red Planet’s Hidden Past Revealed: Scientists Discover 15,000 Kilometers of Lost Rivers on Mars

A groundbreaking study has shed new light on Mars’ history, suggesting that the planet was once much wetter than previously thought. Led by PhD student Adam Losekoot and funded by the UK Space Agency, researchers have identified over 15,000 kilometers of ancient riverbeds in the Noachis Terra region of Mars’ southern highlands.

The discovery was made possible by analyzing fluvial sinuous ridges, also known as inverted channels, which are believed to have formed when sediment deposited by rivers hardened and was later exposed as the surrounding material eroded. These features have been found across various terrains on Mars, indicating that flowing water was once widespread in this region.

The new research focuses on fluvial sinuous ridges as an alternate form of evidence for ancient surface water, rather than relying on valley networks, which are branching erosional features that have traditionally been used to infer historical rainfall and runoff. The study’s findings indicate that surface water may have been stable in Noachis Terra during the Noachian-Hesperian transition, a period of geologic and climatic change around 3.7 billion years ago.

“This is an exciting discovery because it shows that Mars was once a much more complex and active planet than we thought,” said Losekoot. “Studying Mars, particularly an underexplored region like Noachis Terra, is really exciting because it’s an environment which has been largely unchanged for billions of years. It’s a time capsule that records fundamental geological processes in a way that just isn’t possible here on Earth.”

The researchers used data from three orbital instruments: the Context Camera (CTX), the Mars Orbiter Laser Altimeter (MOLA) and the High Resolution Imaging Science Experiment (HiRISE). These datasets allowed the team to map the locations, lengths, and morphologies of ridge systems across a wide area.

Many of the features appear as isolated ridge segments, while others form extensive interconnected systems. The spatial distribution and extent of these ridges suggest that they likely formed over a geologically significant period under relatively stable surface conditions.

“Our work is a new piece of evidence that suggests that Mars was once a much more complex and active planet than it is now,” said Losekoot. “The fact that the ridges form extensive interconnected systems suggests that the watery conditions must have been relatively long-lived, meaning Noachis Terra experienced warm and wet conditions for a geologically relevant period.”

These findings challenge existing theories that Mars was generally cold and dry, with a few valleys formed by ice-sheet meltwater in sporadic, short periods of warming. The discovery of ancient riverbeds on Mars provides new insights into the planet’s history and suggests that it may have been more similar to Earth than previously thought.

The cosmic explosion that marks the end of a star’s life has long been a topic of fascination for astronomers. For the first time, scientists have captured visual evidence of a star meeting its end by detonating twice. The remains of supernova SNR 0509-67.5, studied with the European Southern Observatory’s Very Large Telescope (ESO’s VLT), show patterns that confirm its star suffered a pair of explosive blasts.

The explosions of white dwarfs play a crucial role in astronomy. Much of our knowledge of how the Universe expands rests on Type Ia supernovae, and they are also the primary source of iron on our planet, including the iron in our blood. However, despite their importance, the exact mechanism triggering these explosions remains unsolved.

All models that explain Type Ia supernovae begin with a white dwarf in a pair of stars. If it orbits close enough to the other star in this pair, the dwarf can steal material from its partner. In the most established theory behind Type Ia supernovae, the white dwarf accumulates matter from its companion until it reaches a critical mass, at which point it undergoes a single explosion.

However, recent studies have hinted that at least some Type Ia supernovae could be better explained by a double explosion triggered before the star reached this critical mass. This alternative model suggests that the white dwarf forms a blanket of stolen helium around itself, which can become unstable and ignite. This first explosion generates a shockwave that travels around the white dwarf and inwards, triggering a second detonation in the core of the star — ultimately creating the supernova.

Until now, there had been no clear, visual evidence of a white dwarf undergoing a double detonation. Recently, astronomers have predicted that this process would create a distinctive pattern or fingerprint in the supernova’s still-glowing remains, visible long after the initial explosion. Research suggests that remnants of such a supernova would contain two separate shells of calcium.

Astronomers have now found this fingerprint in a supernova’s remains. Ivo Seitenzahl, who led the observations and was at Germany’s Heidelberg Institute for Theoretical Studies when the study was conducted, says these results show “a clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the ‘double-detonation’ mechanism does indeed occur in nature.”

The team were able to detect these calcium layers (in blue in the image) in the supernova remnant SNR 0509-67.5 by observing it with the Multi Unit Spectroscopic Explorer (MUSE) on ESO’s VLT. This provides strong evidence that a Type Ia supernova can occur before its parent white dwarf reaches a critical mass.

Type Ia supernovae are key to our understanding of the Universe. They behave in very consistent ways, and their brightness allows them to be seen from vast distances. By studying these cosmic events, scientists gain insights into the life cycles of stars and the evolution of the cosmos itself.

The discovery of a double-detonation mechanism in Type Ia supernovae has significant implications for our understanding of the Universe. It suggests that these explosions can occur at different stages of a star’s life, potentially leading to new observations and a deeper understanding of the cosmic web.

As scientists continue to study the remnants of supernova SNR 0509-67.5, they may uncover more secrets about the double-detonation mechanism and its role in shaping the Universe. The findings of this research have far-reaching implications for our understanding of the cosmos and the life cycles of stars.