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Astronomers discover 3I/ATLAS – Third interstellar object to visit Solar System

Original Article

Hacker News Discussion

This Hacker News discussion revolves around the discovery of a third interstellar object, with a significant portion of the conversation dedicated to understanding why we're suddenly finding so many and the implications of these discoveries. Here's a breakdown of the key themes:

Increased Detection Capabilities

A primary theme is the advancement in astronomical technology and observational techniques, which is directly leading to the discovery of more interstellar objects. Users emphasize that this is not necessarily an increase in the actual number of objects, but rather our ability to detect them.

  • "It's 1. A combination of better telescopes and GPU accelerated algorithms for picking out moving objects." - elchananHaas
  • "Vera Rubin just came online, will will start to do surveys of the entire sky every 3 nights, which makes spotting stuff like this easier." - polytely
  • "We're going to see a lot more of these in the next couple of years due to the new Vera Rubin observatory." - sgt101
  • "If this new 8m diameter telescope already provides us with so many new discoveries then I can't wait until the ELT with 39m diameter goes online." - jcfrei
  • "On the other hand, Vera Rubin was designed to be a survey telescope, repeatedly imaging the entire night sky to discover new objects." - sapiogram
  • "I am assuming with that the newly commissioned Vera Rubin telescope should start finding a lot more of these." - zeristor

This is contrasted with the initial discovery of 'Oumuamua.

  • "Judging by how humanity didn't see any of those for millennia and now three in just several years, I can propose two hypotheses: 1. Astronomers became good enough to notice them..." - ordu
  • "3. After we found the first one by chance we started looking for more objects outside the solar system's orbital plane" - haiku2077
  • "This object was found by ATLAS, the Asteroid Terrestrial-impact Last Alert System. The project goal is to identify near-earth asteroids, evaluate the risk they might impact the Earth, and alert others if impact is predicted. The project started in 2015, two years before ʻOumuamua. It was not made specifically to find interstellar objects transiting the solar system." - eesmith

The Nature and Origin of Interstellar Objects

There's considerable speculation about the composition and origin of these objects. While many assume they are "rocks," some users highlight that we don't definitively know their composition yet, and the possibility of them being more complex or artificial is raised.

  • "We don't know if they're all rocks or not yet." - TheBlight
  • "When ʻOumuamua flew past, we should have noticed it was a passive sensor drone. Now it is too late." - 9dev
  • "It's not 'the Universe'; it's an alien race that wants to destroy us before we become a threat to them." - shiroiuma
  • "The first two were used up, empty deceleration stages of a giant alien spaceship, discarded during interstellar cruise while the rest of the assembly kept burning for its years long deceleration from relativistic speeds. This is the main ship." - fouronnes3
  • "The more interstellar objects we find that resemble comets, the weirder Oumuamua is." - rjinman
  • "The Ramans do everything in threes." - LeoPanthera
  • "Maybe. I think it's more likely that an alien probe - assuming there are aliens and they fly probes - would be the size of a cubesat, and we wouldn't even notice it. Perhaps Oumuamua was the mothership and the solar system is now swarming with cubesats we're not noticing." - TheOtherHobbes

The relatively low speeds of these objects are also discussed, leading to the categorization of them as "extra solar."

  • "given the low relative speed of these objects so far, we can define them as extra solar, something exra galactic could be moveing at fractional light speed relative to us and be almost impossible to see and track unless it was realy big and close..." - metalman

Potential for Catastrophic Impact and Terraforming Speculation

A significant portion of the discussion delves into the potential impact of these objects, particularly the newly discovered one, on planets, including Mars. This leads to some elaborate speculative scenarios, ranging from destruction to terraforming.

  • "If it were to come right for us, what do we have today to stop it (if at all) ?" - artur_makly
  • "I know nothing about this type of data; what does it mean and how can it be interpreted as an object ?" - jerpint
  • "I would recommend staying on Earth..." - ddahlen (in response to a question about the impact on Mars)
  • "Assuming it’s at the upper range of the size estimate above, and of average rocky density, the kinetic energy of the impact would be something like a 10 billion megaton nuke." - jl6
  • "If we could steer it to hit one of Mars’s poles, it might do a bit of terraforming for us!" - jl6
  • "The kinetic energy of the impact would be something like a 10 billion megaton nuke." - jl6. (Followed by a lengthy discussion and correction of this calculation by multiple users, highlighting the importance of precise units and parameters).
  • "Would be wild if a sufficiently large object with a lot of water and organic molecules hit Mars, ejected a lot of material in to Mars’ orbit to then go on to form a sufficiently large moon that tidally massaged Mars’ core to cause a dynamo to generate a sufficiently strong magnetic field to… Terraform Mars!" - nandomrumber
  • "TVickery: I know it’s incredibly, vanishingly unlikely but what would happen if an object with these characteristics smacked into Earth?" "_joel: The end, unless you're a small proto-mammal ;). An object (depending on consistency) of about 100m is enough to wipe out a city and do enough damage to the environment. Something of 8-20km is in the same category as what wiped out the dinosaurs (10-15km)." "MaxikCZ: 8-22km at interstellar speeds? Probably total extinction level." "ra: With this much mass and velocity - it would smash the planet, rupturing the entire crust at the very least. No matter how infinitesimally small the probability - the universe is infinite, and so it probably will happen. i3 is much bigger than the Chicxulub asteroid that ended the Cretaceous period (and extinct all non-avian dinosaurs)."

Solar System Dynamics and Celestial Positioning

Users discuss the trajectory and positioning of the latest interstellar object relative to the solar system's orbital plane and planets. The fact that it's not highly inclined is noted as potentially significant or due to observational biases.

  • "This object is near the solar system's orbital plane - far closer than Halley's comet, for example." - eesmith
  • "un-nervingly near the orbital plane, as the depiction shows the object passing just above, on approach, and juct below, on departure, of the orbital plane of mars" - metalman
  • "Teever: > It is almost on the plane of the solar system, not very inclined. Is this also random chance or is there a reason why it's so close to the plane of the solar system?" "ddahlen: It is also a factor of where our surveys look on the sky. A lot of asteroid surveys have biases to look at the plane of our solar system (since this is where a lot of asteroids are). It is probably random chance, however there may be some biases from where they come from on the sky (I know people who work on that, but I don't know much about it). N=3 does not provide very robust statistics yet, give us another decade or two."
  • "defrost: Good question, especially given the plane of our solar system is almost orthogonal to the greater plane of the Milky Way galaxy that contains us."
  • "rbanffy: I would expect most visitors would come from the galactic plane."
  • "ddahlen: The closest it will come is Mars, but when I say close these are quite literally astronomical distances, about 0.2 au from Mars. This is about 75x further than the moon is from the Earth."

Existential Threats and Galactic Context

The discovery of these objects, particularly in conjunction with discussions about extinction events, sparks speculation about humanity's place in the cosmos and potential existential threats, both from external sources and self-inflicted.

  • "These rocks are first in an incoming flood of such objects, the Universe decided to destroy humanity." - ordu
  • "Get ready for the, uh, Latter Day Late Heavy Bombardment!" - tigerlily
  • "Maybe. The solar system was in this galactic position about 250 million years ago (one galactic year) and there was a major extinction event around that time" - kirykl
  • "Benevolent aliens are planting incompetent people in positions of power so that we are perpetually on the verge of self-annihilation. But this is all to save us from the malevolent aliens who would obliterate us if they thought we had any chance of survival." - dguest
  • "We are a much bigger threat to ourselves." - belter
  • "Yep, the best thing for a race that is (rightfully) worried about our aggressiveness is to wait it out." - phatskat
  • "The great filter: light years of travel needed by detection probes." - carlsborg
  • "They’re always coming through. The solar system is an interstellar highway." - andrewstuart

The Vastness of Space and Data Interpretation

Several users reflect on the immense scale of the universe and the challenges of interpreting astronomical data, often referencing popular science fiction for analogies. There's also appreciation for the technical details and sourcing provided by users with relevant expertise.

  • "Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is.” ~Douglas Adams" - TMEHpodcast
  • "Instead, go out to the ocean on a clear day, and observe how absurdly vast the ocean is. Just ocean, as far as you can see. Look around and realize you’ve gained absolutely nothing in terms of comprehending the vastness of space, to which the difference between your room and the most sweeping views on Earth are just totally insignificant." - bee_rider
  • "The single best depiction of the Solar System to help grok size and distance is Josh Worth's 'If the Moon were only 1 pixel':" - GolfPopper
  • "Source: Working on my PhD in orbital dynamics and formerly wrote the asteroid simulation code used on several NASA missions:" - ddahlen (This comment is frequently cited as an example of the high quality of information on the forum).
  • "This is one of the big reasons I love HN" - RcouF1uZ4gsC
  • "I agree and I’m old enough to remember when Reddit was like this" - TMEHpodcast