Apologies, but interstellar visitor 3I/ATLAS is truly a comet, not an extraterrestrial.

Interstellar comet 3I/ATLAS captured by the Gemini South Telescope in Chile

International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist; J. Miller & M. Rodriguez (International Gemini Observatory/NSF NOIRLab), TA President (University of Alaska Anchorage/NSF NOIRLab), M. Zamani (NSF NOIRLab)

The interstellar object 3I/ATLAS is acting oddly once more. This foreign visitor from another star is now obscured by the sun’s shadow, leading some to speculate about its secretive nature. The only likely explanation, they whisper, is that it’s an alien spacecraft.

This notion, however, is utterly baseless. It simply doesn’t hold up that a spacecraft would choose to stay hidden for just a few days while previously visible and likely to be so again. If this were actually a stealthy spacecraft, then the aliens piloting it would either be incredibly foolish or believe us to be.

How can we assert this? As an astronomer recently explained to me, if 3I/ATLAS is indeed a spacecraft, it’s doing a remarkable job of masquerading as a comet. This is what fuels the sensational discussions surrounding 3I/ATLAS (named after the eagle’s eye). planetary defense equipment (I first noticed it in July), which was both amusingly frustrating and clearly ridiculous. The evidence overwhelmingly indicates that it is a comet.

Let’s explore why. It possesses a coma, a shell of vaporized ice. It exhibits a luminous tail. Its trajectory can best be described as that of an icy projectile entering our solar system from beyond. So, why is it “hiding” behind the sun? It just reached perihelion, the closest point to our solar star in its voyage through our cosmic neighborhood. Every celestial voyager, from comets to asteroids, experiences perihelion. 3I/ATLAS happens to be behind the Sun, yet closest to it from Earth’s viewpoint.

There are certainly some intriguing aspects of 3I/ATLAS that excite astronomers. For instance, it contains a higher concentration of carbon dioxide ice compared to water ice. Nevertheless, it remains a comet, not a space probe. Some materials are composed of – hold on, aren’t those metals? Spaceships are built from metal! So, could 3I/ATLAS actually be a spacecraft? Absolutely not; we routinely observe metals in the rocky, icy cores of comets. In truth, numerous comet types exist in our solar system, many of which are indeed peculiar.

It was also somewhat unusual that at one point 3I/ATLAS had its dusty tail oriented toward the Sun instead of the opposite direction. Some speculated it was not the tail but rather a spacecraft’s exhaust plume attempting to decelerate. However, the issue is that 3I/ATLAS’s orbit is consistent with that of an interstellar comet; it’s not as if someone applied brakes to an interstellar probe. The unique orientation of its tail resulted from the specific icy, powdery particles released from its surface. This transient object would typically be pushed away from the sun by solar radiation pressure, but some of this comet’s material was so dense that it couldn’t be redirected and consequently rolled toward the sun.

3I/ATLAS is only the third interstellar object ever documented, so investigating its small population is likely to uncover some remarkable characteristics. ‘Oumuamua, the first identified interstellar visitor, was significantly stranger. Its shape was likely cigar-like, rapidly accelerating as it left the solar system. Yet even this oddity can be perfectly rationalized: it was a flashy comet-like entity. The next two interstellar objects, 2I/Borisov and 3I/ATLAS, also showcase interesting features. But to propose they are spacecraft rather than comets is equivalent to calling ice in the freezer a pineapple. You can certainly say that, but if you aim to convince me, you must present more substantial proof.

Many among us, myself included, eagerly anticipate the day we learn we’re not alone in the universe. Thus, it’s no wonder that people jump to the unfounded conclusion that 3I/ATLAS might signal that this long-awaited day has finally come. However, in an age rife with misinformation, to suggest, against overwhelming evidence, that this comet could be alien is not just misguided; it’s profoundly irresponsible.

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Source: www.newscientist.com

Our Third Interstellar Visitor Might Be 8 Billion Years Old

Paths of interstellar comet 3I/Atlas through the solar system

NASA/JPL-Caltech

The interstellar entities currently traversing our solar system may include one of the oldest comets ever observed.

Comet 3I/Atlas was identified earlier this month near Jupiter’s orbit, moving at approximately 60 km per second and estimated to be about 20 km in size. It is the third recognized interstellar object in our solar system, having passed near Mars in October before entering the solar orbit.

Matthew Hopkins from Oxford University and his team utilized data from the ESA Gaia spacecraft, which cataloged billions of stars in our galaxy, to simulate the comet’s speed and trajectory, revealing its point of origin. It seems to have emerged from an area close to our galaxy, which is about 13 billion years old, specifically from what is referred to as a thick disk.

“Objects from the thicker disk tend to be quicker,” explains Hopkins, noting that the previous two identified interstellar objects (Oumuamua in 2017 and Comet Borisov in 2019) exhibited a decline in speed. “Their velocities aligned with expectations for thin disk objects.”

Modeling by the team indicates that 3I/Atlas may have originated from a star nearly 8 billion years old, potentially twice the age of our sun, hinting at it being one of the oldest comets ever witnessed. “This might be the oldest comet I’ve encountered,” Hopkins states. Interstellar objects are typically ejected early during a star’s lifecycle and are often propelled by interactions with massive planets.

Hopkins mentioned that ancient stars are likely to possess lower metallicity compared to our sun, implying that these comets might have a higher water content. If this hypothesis holds, we may witness significant water activity from the comet as it nears the sun in the upcoming months.

This could be our first interaction with another star, providing insights into pristine materials that have existed for billions of years, unaltered since before Earth’s formation. “I believe many interstellar objects we’ve encountered are our first meetings with stars, even those that are 8 billion years old,” Hopkins asserts. “They have likely traversed vast distances through empty space before approaching us.”

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Source: www.newscientist.com