[HN Gopher] Interstellar Object 3I/Atlas Passed Mars Last Night
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Interstellar Object 3I/Atlas Passed Mars Last Night
Author : jandrewrogers
Score : 55 points
Date : 2025-10-03 20:40 UTC (2 hours ago)
(HTM) web link (earthsky.org)
(TXT) w3m dump (earthsky.org)
| pelagicAustral wrote:
| Was it glowing green?
| ares623 wrote:
| Ulaaaaa!
| suprnurd wrote:
| Looking forward to seeing what images they received, especially
| after Avi Loeb's comments on it.
| ares623 wrote:
| Avi's the new "it's Aliens" meme guy
| zikzak wrote:
| No, he's the new "we should consider what this would look
| like if it were an artifact of an alien civilization" guy.
| You know, open minded.
|
| He's also a well respected and very accomplished person who
| has acknowledged this is a comet.
|
| If it happens to slow down and change trajectory after it
| passes behind the sun, he might change his tune but he's
| pretty focused on the science at this point.
| ceejayoz wrote:
| He _was_ well respected. As the saying goes, open your mind
| too far and it falls out of the cranium.
| efavdb wrote:
| Here's an interview of his on this
|
| https://www.youtube.com/watch?v=nf0xB3EtQX0
| dostick wrote:
| > 3I/ATLAS is thought to have been drifting through interstellar
| space for many billions of years before encountering our solar
| system.
|
| It is hard to believe, but it means it's been a fiery comet for
| billions of years, how is that possible that it havent burned
| up...
| blacksmith_tb wrote:
| Well nothing much in hard vacuum is "fiery" - comets in our
| solar system do get ablated by the solar wind as they orbit the
| sun more closely; I assume in this case the majority of those
| billions of years were in deep space where there wasn't much
| pushing/pulling mass off.
| motoboi wrote:
| Yeah but then it wouldn't be drifting would it?
|
| Joke explanation: a drifting vehicle is burning tires and
| leaving a cloud of smoke behind, like a comet.
| grues-dinner wrote:
| Whether it's drifting through space or hammering through at
| dozens of kilometres a second is rather a matter of
| perspective. Perhaps as far as it's concerned, its sedate
| drift has been interrupted by a very ill-mannered solar
| system making a reckless close pass.
| 8fingerlouie wrote:
| Because what makes it glow is actually solar wind from our sun
| as it passes through the solar system.
|
| For possibly billions of years, it has simply been an inert
| lump of ice passing through the universe.
| TheOtherHobbes wrote:
| It could be extra-galactic. It's going at a fair clip, and
| (if I haven't dropped a zero or ten) it would only take
| around 800 million years to get here from one of the
| Magellanic Clouds.
|
| Just as an indicator of the speed and possible distances.
| BirAdam wrote:
| If it were traveling through interstellar space, it would have
| been highly irradiated but it would also have been far from any
| source of heat. From what we know of it so far, it has some
| strange chemistry going on, but that's somewhat expected given
| its estimated age. We'd also need to assume that a few billion
| years of interstellar radiation would do strange things we
| haven't really seen before hence pointing every instrument
| possible at it.
| ceejayoz wrote:
| Comets don't do anything much until they get close to a star.
| TMWNN wrote:
| I was surprised to recently learn that NASA has aimed pretty much
| everything it has at 3I/Atlas, even the Perseverance Mars rover!
| <https://science.nasa.gov/solar-system/comets/3i-atlas/>
| Marsk wrote:
| https://science.nasa.gov/solar-system/comets/3i-atlas/
| interesting blurb at the top of the site... "Due to the lapse in
| federal government funding, NASA is not updating this website."
| preisschild wrote:
| at least it's not saying "thanks to the radical left democrats"
| like other govt websites
| CamperBob2 wrote:
| Looks like you were downvoted by someone who either thought
| you were kidding, thought you were posting false partisan
| flamebait, or thinks that the language used by the Trump
| administration is just peachy keen. Regardless, they were
| wrong.
|
| https://abc7.com/post/government-websites-displaying-
| message...
| reaperducer wrote:
| Some departments have even added similar language to
| employees' e-mail out-of-office messages.
| mystraline wrote:
| Thats correct. Some groups have. More groups refuse to
| break the Hatch Act and take partisan sides.
|
| Theres a LOT of people who work for the government that
| want to do a good job, and faithfully keep doing what
| they're paid to do. Administrations dont matter. The
| mission does. And that mission goes year by year.
|
| Well, until now.
| downrightmike wrote:
| So far left, they are actually far right
| dnw wrote:
| Have we gotten better at detecting these objects in the past 5
| years or is the solar system going through a bumpy area of Milky
| Way lately? We have observed (or I have heard about) many
| interstellar objects in the past five years than any previous
| times.
| bravoetch wrote:
| From wikipedia: "As of 2025, three interstellar objects have
| been discovered traveling through the Solar System:
| 1I/`Oumuamua in 2017, 2I/Borisov in 2019, and 3I/ATLAS in 2025"
|
| I would guess that observation improves over time. The
| wikipedia article is fascinating, estimating 10,000 such
| objects passing within Neptune's orbit in our solar system each
| day. I think that includes dust and sand sized objects.
| eugenekay wrote:
| Computing Power has increased tremendously, along with the
| higher resolution of digital imaging technology compared to
| analog film plates. Sky Survey projects like the Vera C. Rubin
| Observatory have become active in recent years, which generate
| Terabytes of spectrographic data each night which can be
| rapidly examined for differences from previous captures. In the
| past each exposure had to be hand-aligned on a Light table and
| "flipped" between to spot differences.
| throwup238 wrote:
| There has been a significant increase in NEO observation
| projects in the last eight years and there's one coming online
| soon that should increase the detection capabilities even more.
|
| Pan-STARRS (discovered 1I/`Oumuamua), Zwicky Transient Facility
| (2I/Borisov), and ATLAS (3I/ATLAS) are the major existing
| projects and the Rubin Observatory/LSST will be a huge upgrade.
| We're going to detect a lot more if these objects, especially
| since a lot of the work of the projects are looking at
| historical data.
| baggy_trough wrote:
| How likely is it that a random object from outside the solar
| system would pass so closely by Mars and Jupiter?
| grues-dinner wrote:
| How likely is it that a random alien object does a wellness
| check on a barren planet in the same decade the humans happen
| to turn on the big survey telescope array?
| baggy_trough wrote:
| Pretty likely if there are a lot of them!
| grues-dinner wrote:
| Then I guess we'll see another one soon (unless we freak
| them out by noticing them and broadcasting about it!).
|
| Once more survey telescopes like Nancy Grace Roman and
| Xuntian come online we'll increasingly find out how many
| there really are and I suppose if they seem to like buzzing
| the proverbial tower.
| ceejayoz wrote:
| Shuffle a deck of cards, and statistically no one has ever
| shuffled the same sequence in all of human history.
|
| It is extraordinarily unlikely you will shuffle one
| particular order of cards. It is 100% likely you will result
| in _a_ sequence of cards.
|
| Space is full of trillions and trillions and trillions of
| these. Given the rate of detection, we'll probably see them
| come through regularly.
| grues-dinner wrote:
| That's my point. If you turn on several telescopes
| particularly good at seeing these things and see three
| objects in fairly quick succession, the implication is
| probably (not certainly) that there are lots of
| interstellar objects hammering in all the time, not that
| the first ones you see are particularly special, even if
| one of them seems to be making a statistically unlikely
| near approach to Mars.
| ceejayoz wrote:
| Yeah, like exoplanets. When I was in middle school there
| were none. Now there's 6,000 confirmed ones.
| downrightmike wrote:
| I wonder if we are going through a debris cloud and these are
| just the first small objects.
| rkomorn wrote:
| I find this to be an interesting thought.
| codr7 wrote:
| This one is anything but small.
| simonh wrote:
| We have only recently been able to detect them at scale, so
| we should not confuse first ones detected with first ones to
| arrive in the solar system. It's just as likely they are the
| tail end of a debris cloud, but our detection tech wasn't up
| to spotting all the previous ones.
| pedalpete wrote:
| I may be super naive here, but are we really defining "close"
| or is it that the object is close enough that it makes sense to
| point our objects that are close to Jupiter at the new object?
|
| It is passing between two point in our night sky. I believe
| from a plane view, if you look at our universe from the
| perspective of it laying flat, it is my understanding the spin
| of our universe means that everything ends up within a flat
| plane, so in a 3 dimensional space, we have a limited Y axis.
| The other planets are spaced out across the X and Y axis, this
| is passing between or across two points.
|
| Am I thinking of this right? I know very little about
| astronomy.
| giardini wrote:
| "Oh, my God! That's the intergalactic mail van from Xenorph 44!
| We won't get any more supplies for another century!888----<(((
| Gaaah! Nothing to eat but Earthlings...."
|
| - overheard on Avi Loeb's radio telescope, but fortunately mis-
| translated.
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